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Co-RICH Fe-Mn CRUSTS FROM THE MARSHALL ISLANDS (LEG 1) AND HYDROTHERMAL AND HYDROGENETIC Fe- Mn DEPOSITS FROM MICRONESIA (LEG 2), KODOS 98-3 CRUISE, WEST PACIFIC

By

James R. Hein 1 , Jai-Woon Moon2, Kyeong-Yong Lee2, Jennifer S. Bowling 1 , Ki- Hyune Kirn2, Malia Burrows 1 , Sung Hyun Park2, Youn-ji Choi2, Anthony A. Schuetze1 , Hoi Soo Jung2, Hyun-Sub Kim2, Gun Chang Lee2, Cheong-Kee Park2, Seung Kyu Son2, and Chan Young Park2

Open-File Report 99-412

1999

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government

!U.S. Geological Survey, 345 Middlefield Rd., MS 999, Menlo Park, CA, 94025, USA2Korea Ocean Research and Development Institute, P.O. Box 29, Ansan, 425-6000, Seoul, Korea

INTRODUCTION

The KODOS 98-3 cruise took place 13-28 August 1998 aboard the R.V. Onnuri and was divided into two legs. Leg 1 operations included mapping and sampling Litakpooki Ridge and mapping Lomilik Seamount, both within the Exclusive Economic Zone (EEZ) of the Republic of the Marshall Islands (RMI) (Figs. 1-3). Leg 2 operations included mapping and sampling a corridor of the Yap convergent margin (YCM) extending from the southwestern margin of the West Caroline Ridge west to the Yap back-arc region in the EEZ of the Federated States of Micronesia (FSM) (Figs. 4, 5). Members of the KODOS 98-3 cruise (Table 1) participated in this second cruise of a renewed effort by the Korea Ocean Research and Development Institute (KORDI) and the U.S. Geological Survey (USGS) to study seamount mineral deposits. Earlier efforts included three USGS-KORDI cooperative cruises aboard the R.V. Farnella, one each in the years 1989-1991, and more recently cruise KODOS 97-4 in 1997.

The first set of objectives of the KODOS 98-3 cruise was to map the distribution of thick ferromanganese oxyhydroxide crusts (Fe-Mn crusts) on Lomilik Seamount and Litakpooki Ridge and to determine the geologic and oceanographic conditions that promoted growth of thick Fe-Mn crusts. Reconnaissance sampling and mapping of Lomilik Seamount were completed in 1989 during the first cooperative USGS-KORDI cruise aboard the R.V. Farnella (F10-89-CP; Hein, Kang, et al., 1990) and both Lomilik and Litakpooki were studied during the KODOS 97-4 cruise (Hein, Moon, et al., 1998). Lomilik was chosen for detailed work because during the 1989 cruise, the thickest (180 mm) shallow-water Fe-Mn crust ever recovered from the ocean basins was collected from its summit; thick Fe-Mn crusts (up to 130 mm) were also collected in 1997. Thick Fe-Mn crusts up to 154 mm thick were collected on Litakpooki Ridge during cruise KODOS 98-3, which are described here.

The second set of objectives of the KODOS 98-3 cruise was sampling and mapping of the YCM. Reconnaissance sampling and mapping of that region was completed in 1990 and 1991 during the second and third cooperative USGS-KORDI cruises (F11-90-CP and F7-91-WP) aboard the R.V. Farnella (Hein, Ahn, et al., 1992). During the 1990 cruise, hydrothermal stratabound Mn-oxide deposits were recovered from the crest of Yap arc, along with hydrothermally altered rocks, serpentinite, blue-serpentinite muds, and abundant vein quartz. Additional hydrothermal deposits were collected during leg 2 of KODOS 98-3.

Representative Fe-Mn crust samples, hydrothermal stratabound Mn oxides, and substrate rock samples from the dredge hauls taken from those areas during KODOS 98-3 were analyzed for this study, which extends our previous work on Fe-Mn crusts collected in and around RMI and FSM (Hein et al., 1988; Hein, Kang, et al., 1990; Hein, Ahn, et al., 1992; Hein et al., 1997a; Hein, Moon, et al., 1998). This report presents data for all dredge hauls, including sample descriptions, detailed chemical (major, minor, platinum group, and rare earth elements) and mineralogical analyses of bulk Fe-Mn crusts, individual crust layers, hydrothermal Mn, and substrate rocks collected during KODOS 98-3. Correlation coefficients and Q-mode factor analysis are used to determine relationships between and among elements and associations of elements with mineralogical phases.

Shipboard Operations

Shipboard operations on Litakpooki Ridge included four dredge hauls, two piston cores, two CTD casts, and 534 km of SeaBeam bathymetric lines including 152 km of 12-channel airgun lines (Tables 2-5; Figs. 1-3). Operations on Lomilik Seamount included 279 km of SeaBeam bathymetric lines. Operations on the YCM included five dredge hauls, two piston cores, two box cores, two multiple cores, nine CTD casts, one deep-sea camera-video survey, and 737 km of SeaBeam bathymetric lines and 12-channel airgun lines (Tables 2-5; Figs. 4-5). Of the nine dredge hauls attempted, six provided usable samples, one contained mostly pumice, and two had no recovery (Tables 5, 6).

Bathymetry and Seafloor Descriptions

Litakpooki Ridge is located at the southwestern margin of the RMIEEZ (Fig. 1). The bathymetry of the central part of the ridge shows a relatively flat top at 2000-2800 m water depth dotted with small hills that rise as shallow as about 1600 m depth (Fig. 2). The ridge summit narrows and extends to the northeast to the edge of the survey area. A rift zone is defined by a ridge that extends to the northwest from the summit. The base of the Litakpooki ridge is at about 5000 m water depth. Channels characterize the very steep northern slope. Slope angles on the summit are mostly less than 5°, whereas those on the flanks are up to 30°, with an average slope angle of about 11° (KODOS, 1999a).

Foraminiferal sediment fills some lows and forms a thin blanket over the central and northeast parts of the summit where dredges D3 and D4 encountered only sediments (Fig. 2). Seismic- reflection profiles (KODOS, 1999a) show that much of the summit is underlain by sedimentary rocks, with protruding volcanic hills composed of basalt. Dredges Dl and D2 and dredges D14 and D15 from KODOS 97-4 (Hein, Moon, et al., 1998) show that those sedimentary rocks consist of bioclastic and foraminiferal limestones, breccia composed of mostly volcanic and phosphorite clasts in a carbonate fluorapatite cement, phosphorite, and minor ironstone. Most thick crusts were collected from saddles between summit hills.

Lomilik Seamount is located among a large group of seamounts to the west of Anewetak Atoll in the western Marshall Islands. The bathymetry reveals a flat-topped edifice with a summit at about 1500 m water depth and small hills rising to about 1350 m (Fig. 3). A broad, gently sloping summit terrace occurs on the NE flank down to about 2400 m which steepens in slope on the SE flank, but does not exist on the north, west, and south flanks. The terrace is separated from the summit by a 200-250 m-high scarp. Many volcanic pinnacles occur on the east, southeast, and west flanks of the seamount (Fig. 3). Lomilik Seamount is connected to Lami Seamount (Fig. 1) by a ridge on its NW flank (Fig. 3). A large landslide likely created the notch in the south flank which begins where the summit narrows before changing trend to the northwest along the ridge that connects with Lami Seamount. The seamount base is at about 4600 m water depth. The summit region slopes at less than 5° and the flanks up to 20°, with an average slope of Lomilik of about 11° (KODOS, 1999a).

The terrace and summit support a thin blanket of foraminiferal ooze between outcrops of basalt, volcaniclastic rocks, and foraminiferal and bioclastic limestones (Hein, Moon, et al., 1998). Most thick crusts were collected from the terrace and the scarp that separates the terrace from the summit, whereas the thinnest crusts were collected from the middle and upper steep flanks of the seamount; the lowermost flanks were not sampled.

YCM bathymetry from east to west is characterized by a gently dipping summit of the southwestern margin of West Caroline Ridge at about 1500-2200 m water depth (Fig. 5). West from the summit, the outer trench slope is characterized by an upper steep wall; rough, central ridge and valley topography; and a lower steep, irregular slope showing block faulting that bottoms at about 8600 m. The trench axis deepens to the south. The inner trench wall is more uniform in topography than the outer trench wall and rises through a series of thrust faults to a summit ridge at about 1500 m. A summit seamount shallows to about 500 m water depth (Fig. 5). Most sampling was completed on the west side of the summit ridge in the back-arc area at water depths of 1750- 2800 m. Seismic-reflection profiles (KODOS, 1999b) show that most of the region supports thin sediment cover, with basement highs cropping out in the arc and back-arc regions.

CTD Data

Water temperatures measured in CTD-1 (Litakpooki Ridge; Fig. 2) and CTD-2 (open-ocean between Litakpooki Ridge and Lomilik Seamount; Fig. 1) profiles range from 2.2° to 29.2° C and salinities from 34.4 to 34.9 psu, defining high temperature and low salinity surface waters and a seasonal thermocline at about 100 m water depth (KODOS, 1999a). Dissolved oxygen contents range from 1.3 to 4.3 ml/1, with maximum values occurring at about 100 m water depth and minimum values at about 300 m (Table 4). The depth to the top of the oxygen-minimum zone

(OMZ) is about the same (280 and 275 m), although the depth to the lowest oxygen content is 36 m deeper at the more northerly site. The 5° and 10° isotherms are also deeper at the more northerly site (Table 4).

Nine CTD profiles were taken at the YCM, where the lowest oxygen content at each site is very uniform at 2.0Q±0.08 ml/1. These values show that primary productivity in surface waters is not as high in this region as in the western RMI, where minimum values are 1.3 ml/1, indicating greater amounts of oxygen consumption during degradation of organic matter. Indications of hydrothermal activity were not seen in water column properties at any of the sites.

METHODS

X-ray diffraction was completed on a Philips diffractometer using Cuka radiation and a curved-crystal carbon monochromator. Abundances of the 10 major oxides and Cr, Ba, Sr, Y, Zr, Nb, and Rb in substrate rocks were determined by X-ray fluorescence spectroscopy (XRF; Taggart et al., 1987); Fe(II) by colorimetric titration (Peck, 1964); CO2 by coulometric titration(Engleman et al., 1985); H2O+ by water evolved at 925°C as determined coulometrically by Karl- Fischer titration (Jackson et al., 1987); E^O by sample weight difference at 110°C for greater than one hour (Shapiro, 1975); F and Cl by specific ion electrode, S by combustion and infrared spectroscopy (Jackson et al., 1987), and C by induction furnace; Y, U, Th, and rare earth elements (REEs) by inductively coupled plasma-atomic emission spectrometry-mass spectrometry (ICP-MS; Aruscavage et al., 1989; Lichte et al., 1987a,b); and Au, As, Sb, and W by neutron activation analysis (NAA; McKown and Millard, 1987). Low totals for the phosphorite sample occurs because of typically high F, Cl, and S contents, which are not included in the total.

For Fe-Mn crusts and hydrothermal stratabound Mn, the concentrations of Mn, Fe, Si, Al, Mg, Ca, Na, K, Ti, P, Ba, Nb, Rb, Zr, and Y were determined by XRF; Be, B, Co, Cu, Ge, Li, Mo, Ni, Pb, Sc, Sr, V, Zn, and Ag were determined by ICP; Bi, Cd, Ga, In, Sn, Tl, Y, Au, REEs, and platinum group elements (PGEs) by ICP-MS; As, Au, Br, Cr, Cs, Hf, Sb, Se, Ta, Th, U, and W by NAA; Te by graphite furnace atomic-absorption spectroscopy; Hg by wet chemical techniques; S by combustion and infrared spectroscopy; and Cl by specific ion electrode. REEs in plots are normalized to both chondrites (Anders and Grevesse, 1989) and shale (PAAS, Post- Archean Australian Shale; McLennan, 1989).

The usual Pearson product moment correlation coefficient was used to calculate the correlation coefficient matrices. For Q-mode factor analysis, each variable percentage was scaled to the percent of the maximum value before the values were row normalized and the cosine theta coefficients calculated. The factors were derived from orthogonal rotations of the principal component eigenvectors using the Varimax method (Klovan and Imbrie, 1971). Communalities for all samples are >0.97.

Growth rates of non-phosphatized crusts were determined using the empirical equations of Puteanus and Halbach (1988): GR = 1.28/Co-0.24, with cobalt content in weight percent; and Manheim and Lane-Bostwick (1988): Co" = Co-0.0012%, GR = 0.68/(Con) 1>f7 .

LITAKPOOKI RIDGE SUBSTRATE ROCKS

Descriptions

Substrate rocks based on dredges Dl and D2 as well as dredges D14 and D15 from KODOS 97-4, in decreasing order of abundance include limestone, breccia, phosphorite, basalt, and ironstone (Tables 5, 6; Hein, Moon, et al., 1998). As seen in hand samples, most limestones from KODOS 98-3 Litakpooki dredges are either friable to well-lithified foraminiferal limestone or bioclastic limestone composed of shell hash and foraminifera. Limestones are pale-brown to off- white, yellow-brown, or brown. They are commonly peppered with Fe-Mn oxyhydroxide grains,

contain Mn dendrites, or have vugs lined with Fe-Mn oxyhydroxides. Some limestone samples are partly phosphatized, which grade into phosphorites. Phosphorites are massive, vuggy, or pebbly. Pebbly phosphorite contains sparse, brown basalt clasts commonly coated with Fe-Mn oxyhydroxides, and yellow-green altered hyaloclastite clasts. Vugs in vuggy phosphorites are lined with Mn oxides. Carbonate fluorapatite (CFA) veins and Mn-oxide dendrites are common in all three types. Most of the phosphorite is CFA-replaced limestone, more rarely CFA-replaced basalt.

Breccias most commonly consist of white to brown phosphorite, brown basalt, and brown ironstone clasts in cream to pinkish CFA cement, rarely Fe-Mn oxyhydroxide cement. CFA veins are common and Fe-Mn oxyhydroxide veins also occur. Volcanogenic clasts are commonly partly to completely replaced by smectite. Basalt is altered, brown to red-brown, and may be laced with CFA and Fe-Mn oxyhydroxides and contain large yellow-green amygdules. Sample D2-2E consists solely of smectite, yet maintains relict volcanic textures.

Ironstone samples are brown to dark brown, massive, and dense. Ironstone also occurs as clasts in breccia and pebbly limestone and formed by replacement of basalt. Ironstone most likely formed from hydrothermal processes related to formation of the volcanic edifice during the Cretaceous (Hein et al., 1994).

X-ray Diffraction Mineralogy

For the four samples for which minerals were identified by X-ray diffraction, primary volcanogenic and sedimentary minerals include plagioclase and calcite; and secondary minerals include CFA and smectite (Table 7). Secondary CFA is the most abundant mineral in these samples and occurs in three of the four samples as a major or moderate constituent, regardless of rock type (Table 7).

Fresh basalt was not recovered in dredges Dl and D2. Altered basalt consists of plagioclase and various amounts (up to 100%) of smectite and CFA. The most altered basalts lack all primary minerals, but maintain volcanic textures. CFA replaces basalt and fills vesicles and fractures.

Limestones are composed chiefly of calcite, with various amounts of CFA, showing all gradations from limestone (only calcite) to phosphorite (only CFA). Most phosphorites have relict limestone textures, especially that of foraminiferal sand.

Chemistry

The most P2Os rich CFA-replaced sedimentary rock has a CaO^Os ratio of 1.63 (Table 8), whereas theoretical compositions for CFA produce ratios that range from 1.5 to 1.6 (Manheim and Gulbrandsen, 1979). The very slight excess Ca over P in some KODOS 98-3 samples may be due to additional Ca associated with minor contamination by volcanogenic plagioclase, phillipsite cement (an alteration product of volcanic debris), or to relict calcite in the phosphatized limestone. However, Hein, Moon, et al. (1998) showed that, CaO^Os ratios between 1.60 and 1.66 characterize chemically very pure phosphorites, indicating that CaO/P2O5 ratios between 1.58 and 1.66 are characteristic of uncontaminated marine CFA. Ratios in that range have been found in many of our previous studies (e.g., Hein, Kang, et al., 1990; Hein, Ahn, et al., 1992; Hein et al., 1993). The CaO^Os ratio of 1.63 is very near the most cation- and anion-substituted francolite (1.62) end of the fluorapatite (1.32)-CFA range (Manheim and Gulbrandsen, 1979; McClellan and van Kauwenbergh, 1990). The Sr content for the phosphorite sample is 1260 ppm, near the middle of the range (900-1600 ppm) found for other central Pacific phosphorite samples (Hein et al., 1993). Normalized REE plots of phosphatic limestone (Table 9) show a seawater-type pattern with large negative Ce anomaly, small positive Gd anomaly, and heavy REE enrichment (Fig. 6). These identical patterns indicate that the CFA as well as the calcite were derived from seawater.

Smectite occurs in major to moderate amounts in two of the four samples analyzed, and is especially abundant in the strongly altered basalts. The pure smectite sample (D2-2E) has relatively

high Si, Al, Fe, and Zr contents and low Mg content, indicative of an iron-rich montmorillonite (Tables 7, 8).

Most samples of basalt and basalt clasts in breccia are altered to smectite and goethite and are rarely replaced by phosphorite and phillipsite. Alteration is best characterized by increases in Fe2O3 and water and decreases in FeO and K2O contents (Table 8). Volcaniclastic mudstone and hyaloclastite have compositions comparable to highly altered basalts.

SOUTHWEST CAROLINE RIDGE SUBSTRATE ROCKS

Dredge D7 was taken on southwest Caroline Ridge and consists of pillow basalt wedges, limestone, and breccia in that order of abundance (Table 6). The basalt is gray (relatively fresh) to brown (altered), massive, and variably vesicular with a red-brown alteration rind underlain by a black basaltic glass rind. Small vesicles occur in the basalt below the glass rind, which grades into massive basalt. The basalt is composed of primary plagioclase, pyroxene, magnetite, and secondary smectite and hematite.

Foraminiferal limestone is white, friable, massive, and one sample contains a gray volcanic ash layer. The limestone is composed solely of calcite.

Breccias are composed of basalt, basaltic glass, and limestone clasts in (1) calcite cement; (2) calcite-phillipsite cement, with fine-grained volcanogenic minerals; (3) calcite-smectite-phillipsite cement; (4) phillipsite cement, with fine-grained plagioclase and smectite. The limestone clasts consist of foraminiferal limestone and reef fossils such as coral, bryozoans, and benthic foraminifera.

YAP ARC SUBSTRATE ROCKS

Descriptions and Composition

Substrate rocks based on dredges D5, D6, D8, and D9, in decreasing order of abundance are limestone, andesite and basalt, breccia, sandstone, serpentinite, and hydrothermal stratabound Mn deposits (Tables 5, 6). Carbonates consist of white to brown foraminiferal ooze; pale-brown, friable, burrowed, sandy foraminiferal limestone; pale-brown, argillaceous, burrowed micritic limestone with Mn veinlets interbedded with sandy foraminiferal limestone. Sand grains are basalt. A small amount of reef limestone and sandy chalk were also recovered. Foraminiferal sediment also comprise the matrix of some breccia samples. The limestones are composed of calcite and various amounts of volcanogenic minerals, chiefly plagioclase, and their alteration products, chiefly smectite (Table 7).

Volcanic rocks consist mainly of andesite, dacite, and basalt (Tables 6, 7, 10; KODOS, 1999b). Basalts are brown, mottled greenish-pale brown, and gray-brown, altered, commonly plagioclase phyric, and show a brown, altered chill margin. Some samples are amygdaloidal, have calcite veins, or disseminated sulfides. Basalts consist chiefly of plagioclase and pyroxene, with minor amounts of magnetite, smectite, and hematite. Vesicles are lined with phillipsite or filled with smectite. A large hydrofracture vein in basalt sample D9-8D is composed of altered glassy basalt fragments in Mn oxide, smectite, and phillipsite cement with small grains of disseminated amphibole. Andesites are fresh to mildly altered (Table 10), gray, massive, vesicular, and plagioclase phyric; or black, plagioclase phyric, andesite glass with an altered, soft, gray rind. Andesite from dredge D5 is composed chiefly of plagioclase and pyroxene, with minor tridymite and quartz and the secondary minerals calcite and smectite. Andesite from dredge D7 is composed chiefly of tridymite, cristobalite, plagioclase, and pyroxene, with minor hematite and smectite. Phillipsite is abundant and magnetite occurs in moderate amounts in the alteration rind of andesite glass (Table 7, sample D9-6-2).

Breccia in dredge D5 is matrix supported and consists of clasts of volcaniclastic sandstone, andesite, breccia, and rarely hydrothermal(?) quartz in a fine-grained matrix of plagioclase, pyroxene, tridymite, smectite, and calcite (Table 6). Fe-Mn-oxide cement occurs near the contact with crusts. Two fragments of breccia consisting of serpentinite clasts in a quartz-calcite cement were also recovered. Breccia sample D5-2B is enriched in Au about 4 times over its earth's crust mean content of 4 ppb (Govett, 1983; Table 10). Breccia in dredge D8 is matrix supported and consist of altered brown basalt clasts in a pale-brown matrix of carbonate with blue serpentine grains, Mn oxides, and metamorphic rock fragments. Three types of breccia occur in dredge D9: 1. Andesite and altered basalt clasts in clast-supported fine-grained volcaniclastic matrix; 2. Black andesite glass, andesite, and altered basalt in brown to yellow-green smectite matrix; 3. Gray, aphyric to feldspar phyric basalt and andesite clasts in yellow-green smectite matrix, phillipsite cement and veinlets, and Mn veinlets and grains.

Reworked pyroclastic rocks were recovered in dredge D9 and consist predominantly of sandstone, siltstone, and mudstone, which are commonly interbedded. Primary grains and glass have been completely replaced by phillipsite and smectite (Table 7). Different beds are black, brown, and yellow-green, display soft-sediment deformation and burrowing, and are peppered with Mn-oxide grains that also form laminae and graded beds. Smectite veins are also present. Gold is enriched about 4 times over its earth's crust mean content in some beds (Table 10). Volcaniclastic sandstone and siltstone consist of black glassy andesite grains with Fe-oxide and minor Mn-oxide cements (Fe2O3 is 19.5%, MnO is 0.88%, Table 10). The sandstone is composed of plagioclase, smectite, and X-ray amorphous Fe-oxide. Volcaniclastic siltstone and mudstone are pale-brown, yellow-green, and greenish, with Fe-Mn veinlets, dendrites, and grains. Those rocks are completely altered to smectite. The sandstone is enriched in Au about 6.5 times over its earth's crust mean content (Table 10).

Serpentinite from dredge D5 is partly replaced gabbro that is mottled white, dark-gray, blue- gray, green, and yellow-brown, and is dense and heavy. The serpentinite is composed of serpentine (probably lizardite), pyroxene, plagioclase, and minor smectite, talc, tridymite, and magnetite as determined by XRD and also minor brucite, tremolite, chlorite, and hornblende as determined by thin-section petrography. The dominant replacement texture is bastite, indicating that pyroxene (less commonly amphibole) was the dominant mineral that was replaced (Wicks et al., 1977). Minor mesh texture also occurs, indicating replacement of minor olivine. Some replaced grains are laced with magnetite, which also forms veins, surrounds the margin of grains, and is disseminated. Serpentinite from dredge D8 is nearly completely replaced peridotite(?) that is brown with black patches and contains Mn dendrites, large lizardite plates, and extensive magnetite veins. Coarse-grained magnetite and lizardite indicate that the serpentinite is at a mature stage of development. The mineral composition is lizardite, magnetite, and chromite. The replacement texture is approximately 70% mesh and 30% bastite, indicating replacement predominantly of olivine and secondarily of pyroxene (Wicks and Whittaker, 1977; Wicks et al., 1977). Compared to other serpentinites (Faust and Fahey, 1962), serpentinites from dredges D5 and D8 have high Cr (to 3560 ppm) and Fe (to 10.3% Fe2O3) contents, reflecting their high contents of magnetite and chromite (Tables 7, 10).

LITAKPOOKI RIDGE FERROMANGANESE CRUSTS

Description

Fe-Mn crusts collected during KODOS 98-3 vary in thickness from a patina to 154 mm (Tables 5, 6). Dredge Dl had a maximum crust thickness of 120 mm and an average crust thickness of 80 mm. Dredge D2 has a maximum crust thickness of 154 mm and an average crust thickness of 48 mm. Thicker crusts are composed of two or more layers, five being the maximum and three and four layers being the most common. The typical bedding sequence is an uppermost massive black layer (layer 1); which is underlain by a black, porous to vuggy layer that is stained reddish (layer 2); which in turn is underlain by a dense, massive, black, phosphatized layer (layer 3). Layer 3

may contain CFA-filled veins and lenses in addition to being impregnated by CFA. Layer 3 can be sub-divided into as many as four layers based on content and form of CFA and degree and orientation of fractures. All crusts greater than 60 mm thick have a phosphatized older crust generation. CFA in the 32-mm-thick crust D2-6A results from contamination from the substrate phosphorite, which has a gradational contact with the crust.

The growth rates and ages of nonphosphatized, or very mildly phosphatized bulk crusts and crust layers were determined using the empirical equation of Puteanus and Halbach (1988), which is based on Co contents and assumes a constant flux of Co in space and time, and that of Manheim and Lane-Bostwick (1988) (Table 11). The Puteanus and Halbach (1988) equation produces growth rates that range from 2.7 to 9.3 mm/Ma (mean 5.8 mm/Ma) for bulk crusts and 1.5 to 7.5 mm/Ma (mean 4.0 mm/Ma) for crust layers. In contrast, growth rates determined by the Manheim and Lane-Bostwick (1988) equation are much slower, with a range for bulk crusts of 1.2 to 3.5 mm/Ma (mean 2.4 mm/Ma) and for crust layers a range of 0.6-3.0 mm/Ma (mean 1.7 mm/Ma). The latter growth rates are much more in line with those determined by U-series and Be isotopes, which range from <1-10 mm/Ma, but mostly fall within the range of 1-3 mm/Ma (Hein et al., 1999). Using the slower growth rates, the age range for the beginning of growth of bulk crusts is 16.0-30.3 Ma. The 30.3 Ma age for the 100-mm-thick crust D1-1A is probably much too young and that age needs to be confirmed with Be isotope dating. The ages for initiation of crust growth are much younger than the age of the volcanic edifices on which they grew. Marshall Islands seamounts range in age from about 76-138 Ma old, ages of 76-86 Ma being most common (Davis et al., 1989; Lincoln et al., 1993). The fast growth rates determined by the Puteanus and Halbach (1988) equation produce unreasonably young ages for initiation of crust growth, especially for the thick crusts. Analytical precision in the chemical composition of the crusts produces growth rates and resulting crust ages with relative differences that range from 6-13%.

X-Ray Diffraction Mineralogy

Great care was taken in sampling crusts for chemical and mineralogical analyses. Contamination from recent sediments was removed, which was especially critical in porous crust layers. Also, special attention was paid to obtaining a clean separation of the lowest crust layer from the substrate; however, that was not possible with crust D2-6A where the contact was gradational. Any minerals or elements determined to exist in the various crust layers were incorporated into those layers during deposition or diagenesis and are not due to sampling procedures or post-depositional infiltration of sediment. Finally, encrusting organisms and other debris were cleaned from the crust surfaces before subsampling. Bulk always refers to the entire crust thickness, whether composed of layers or not.

6-MnO2 (vernadite) contents of bulk crusts and crust layers range from 69% to 100% (Table 12). 6-MnO2 has only two X-ray reflections at about 2.42A and 1.41 A. X-ray amorphous Fe oxyhydroxide epitaxially intergrown with the 6-MnO2 is also a dominant phase in these crusts, but is not included with the crystalline phases listed in Table 12. Part of this X-ray amorphous iron phase crystallized to goethite in 56% of the layers analyzed. CFA occurs in 78% of the bulk crusts and 44% of the layers analyzed. Crust layer samples contain up to 26% CFA, always within the lowermost one or two layers of the crust. CFA is not found in the outer layers of thick crusts or in thin crusts. CFA is found in such a high percentage of the bulk crusts because most of the crusts analyzed are thick.

Quartz occurs in 24% of the samples analyzed; it was detected in 11% of the bulk crusts and 31% of the crust layers (Table 12). Quartz contents are less than or equal to about 1%. Plagioclase (<1 to 7%) was found in six samples and K-feldspar in one sample. The quartz and some of the plagioclase are of eolian origin, earned by the westerlies from Asia, as there is no local or regional source for quartz in the west-central Pacific. The Marshall Islands are south of the main westerly wind belt which is reflected in lower quartz contents compared to crusts from higher latitudes (Hein et al., 1985, 1987; Hein, Kang, et al., 1990). The remainder of the plagioclase, as well as the smectite, phillipsite, K-feldspar, and calcite were reworked from local outcrops and

incorporated into the crusts during precipitation of the Fe-Mn oxyhydroxides. Smectite occurs in about 24% of the samples.

Calcite occurs in two crust layers. The outermost layer of crust D2-1B contains calcite that probably resides in the outermost few millimeters of that layer. Calcite is replaced by Fe-Mn oxyhydroxides after burial by more than a couple of millimeters of crust. Calcite in the inner layer (25-55 mm) of crust Dl-2 is probably the result of contamination.

Chemistry

Twenty-five Fe-Mn crust samples (9 bulk crusts and 16 crust layers) were analyzed for chemical composition (Tables 13-18). Data are presented including hygroscopic water (Table 13)and on a hygroscopic water-free basis-that is normalized to 0% H2O" (Tables 14-17). Hygroscopic water varies from about 6% to 19% (to 30% in other samples from the region) and consequently can significantly affect the contents of all other elements. Sample compositionsnormalized to 0% H2O can be more meaningfully compared and also more closely represent the grade of the potential ore. The following discussion is confined to hygroscopic water-free compositional data.

Bulk Crusts: The mean Fe and Mn contents of the 9 bulk crusts are 20.1% and 25.2%, respectively (Tables 14, 16). The mean Fe/Mn ratio (0.8) is higher than the mean ratio for the entire central Pacific region (0.72; Hein et al., 1992), the ratio for the entire Marshall Islands EEZ (0.64; Hein et al., 1999), and the ratio for the area to the northwest of the Marshall Islands EEZ (0.76; Hein et al., 1997a). For the entire Marshall Islands EEZ, the mean Mn content is more (26.3%), while the Fe content is less (16.9%) compared to bulk crusts from this study. The mean contents of the economically important metals Co (0.48%), Ni (0.34%), and Pt (0.54 ppm) are less than the mean contents of 0.79%, 0.57%, and 0.63 ppm, respectively, for the entire Marshall Islands EEZ (Hein et al., 1999). The mean Co and Ni contents are less and Pt about the same compared to mean contents for crusts from the entire equatorial Pacific region. Phosphorus, a potential byproduct of mining crusts for Co and Ni, has a mean value of 2.2%, higher than the central Pacific mean of about 1%, and the mean content of 1.8% for crusts from the entire Marshall Islands EEZ. Analysis of a large number of thick crusts lowers the mean contents of many metals, and that is probably why this study shows mean concentrations below the regional and Marshall Islands means for Co, Ni, and other metals. Studies that include only analyses of thin crusts yield mean concentrations higher than those of regional means (for example, Pichocki and Hoffert, 1987; see Hein et al., 1992 for discussion). The Co+Ni+Cu mean content for all bulk crusts is 0.92% and the maximum mean percent is 1.40%. If Pb is added to that group of elements, the mean content is 1.07% and the maximum mean content is 1.57%. The mean content of Co+Ni+Cu decreases with increasing crust thickness, for example the mean is 1.22%; for crusts <60 mm thick, and 0.83% for crusts >60 mm thick. That decrease in metals is controlled by Co and Ni contents because Cu contents increase in thick crusts, 0.07% for <6() mm-thick crusts versus 0.11% for crusts >60 mm thick. Mean Pb contents are about the same in thin and thick crusts. The relationship of Co+Ni+Cu to Fe and Mn contents can be seen on a Bonatti et al. (1972) diagram (Fig. 7), on which the KODOS 98-3 data fall in the range typical for central Pacific Fe-Mn crusts (Halbach et al., 1982; De Carlo et al., 1987; Hein et al., 1992).

Other metals of potential economic interest that are concentrated in the Fe-Mn crusts include Zr (535 ppm), Tl (121 ppm), Te (95 ppm), Bi (mean 52 ppm), W (-36 ppm), and Pt (0.5 ppm). Only recently have crusts been analyzed for Tl, Te, and Bi. Te contents are remarkably high compared to its earth's crust mean content of about 1 ppb-95,000 times enrichment for the Fe-Mn crust mean of 95 ppm and 145,000 times enrichment for the maximum Te content of 145 ppm in bulk crusts. However, the mean Te content of the earth's crust is poorly known and some estimates have placed it as high at 10 ppb, which would lower those enrichments by a factor of 10. The interesting aspect is that the mean content of two of those elements, Bi and Te increase in thick crusts, while Tl, Zr, and W decrease in thick crusts, that is, they are 39, 80, 159, 569, and 44 ppm in <60 mm-thick crusts and 58, 102, 102, 519, and 32 ppm, respectively, in >6() mm-thick

crusts. Mean contents of Ca, P, S, As, Cr, Cu, Mo, Pb, Sr, Th, U, V, Y, and Pt increase in thick crusts, whereas the other elements decrease except for Be, Ga, Hf, Rb, Sb, Sc, Sn, Rh, and Os, which are about the same in both crust thickness groups. This means that the ore grade for some rare metals (Bi, Te, Pt) increases with tonnage (thickness), the reverse of the situation for Co in crusts, the chief metal of economic interest. This decrease in grade with increase in tonnage is typical for metals of interest in most types of ore deposits. The increases in Ca and P contents are the result of phosphatization of the older generation of thick crusts.

Crust Layers: Individual layers from five crusts were analyzed: Two crusts were split into four layers, two crusts into three layers, and one crust into two layers (Tables 14, 17). Crust D2-5 was divided into two layers and the change in element contents is controlled by the high content of detritus in the inner layer. Therefore, Si, Al, and other aluminosilicate-associated elements are higher in the inner layer and Fe and Mn oxide-associated elements are higher in the outer layer (Table 14). For the crusts divided into three layers, Dl-1 shows uniform increases toward the substrate for Ca, P, Ba, Cu, (CFA associated elements) and Te and uniform decreases in Mn, B, Cd, Co, Ga, Ni, Tl, Hg, Ru, mostly Mn oxyhydroxide-associated elements. Aluminosilicate- associated elements are highest in the middle layer and residual biogenic-associated elements are lowest in the middle layer. For crust D2-2, there are uniform increases toward the substrate for Ca, P, Ba, Be, and Sr (CFA-associated elements), similar to Dl-1, and uniform decreases in Fe and Mn oxyhydroxide-associated elements. Aluminosilicate-associated elements are lowest in the middle layer and residual biogenic-associated elements are highest in the middle layer. For the crusts divided into four layers, Dl-2 shows uniform decreases to the substrate of Mn, B, Co, Tl, and Hg and a uniform increase in Cu. Only the lowermost layer of the crust is phosphatized. All other elements have maximum values in one of the four layers, with variable distributions in the other layers. For crust D2-1, there are uniform decreases to the substrate only for Cd and uniform increases for Be, Bi, and Sr. The lower two layers are phosphatized with layer 3 having the highest P content; consequently, most other elements have their highest contents in layer 1, 2, or 4. Platinum typically increases with depth in thick crusts, although here it increased in one crust and decreased in another. In general, the trends indicate that there is a decrease of manganophile elements with depth in the crusts accompanied by increases in elements characteristic of the residual biogenic phase. Non-phosphatized crust layers generally have higher trace metal contents relative to Fe and Mn contents than do phosphatized crust layers.

Platinum Group Elements and Gold

Four bulk crusts and six crust layers were analyzed for PGEs, and nine bulk crusts and 12 crust layers for Au (Table 14). Mean palladium (mean 8 ppb), Os (2 ppb), and Au (~5 ppb) contents are roughly at their earth's crust mean content. One high Au outlier (54 ppb) raises the mean Au content to its earth's crust mean, otherwise it would be lower than its earth's crust mean. Two samples analyzed from the KODOS 97-4 cruise had high Au contents of 543 and 51 ppb, but overall crusts from that cruise had a mean Au content about at its earth's crust mean. The other PGEs are enriched over their earth's crust mean content by 7 times for Ir (Fe-Mn crust mean of 7 ppb), 20 times for Ru (mean 20 ppb), 30 times for Rh (mean 31 ppb), and 130 times for Pt with a mean content of 648 ppb. Crust layer D2-2B has an uncommonly high Pt content of 1930 ppb, the maximum measured content being 2650 ppb (Hein et al., 1997a). The high content in D2-2B is especially unusual in that it occurs in the outermost layer of the crust rather than the innermost phosphatized layer, which is more common. That same layer has the highest Mn, Ti, Te, Sn, As, Sb, Nb, Au, Ir, Rh, and Ru contents measured in this study, all of which decrease toward the substrate; Co has its second highest content. These element enrichments are likely associated with the high Mn content, that is with the S-MnO2 phase. There is also an uncommonly low Pt content of 151 ppb for the outermost layer of crust D1-1B. The mean Pt content of 648 ppb is comparable to the mean for the entire RMIEEZ (634 ppb; Hein et al., 1999) and lower than the mean content for a large area of the northwest Pacific, 777 ppb (Usui and Someya, 1997).

Enrichment of PGEs in the inner parts of crusts is common for central Pacific crusts. The highest Pd and Ru concentrations occur in crusts from the Yap and Mariana arcs, as do other

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elements indicative of clastic input. As shown in previous studies, Pt, Ir, and Rh are derived predominantly from seawater, whereas Pd and much of the Ru are derived from clastic debris, the remainder of the Ru being derived from seawater. The extraterrestrial component (meteorite debris) in the bulk crusts is small. However, meteorite debris may be concentrated locally in the crusts by formation of dissolution unconformities, or by proximity of the crust to meteorite fallout during formation of the layer. Localized extraterrestrial debris-rich horizons, however, do not alter the overall hydrogenetic signature of the PGEs. In addition, the PGE ratios are non-chondritic, with Fe-Mn crust compositions showing more than an order of magnitude more Pt relative to Ir and Rh relative to Ir. More likely, Pt is a redox sensitive element and its changing concentration reflects changing redox conditions, and diagenesis in the inner parts of the crusts (see Hein et al., 1997b).

Rare Earth Elements

For 7 bulk crusts and 6 crust layers, total REEs vary from about 0.15% to 0.27% (Table 18). For bulk crusts, total REE contents range from 0.15% to 0.24%, with a mean of 0.20%. The range and mean for individual crust layers are somewhat higher than for bulk crusts, 0.15%;- 0.27% and 0.21%, respectively. Mean total REE content differences between thick and thin crusts is 0.22% and 0.18%, respectively. The two samples for which layers were analyzed show different patterns of REE concentrations with depth in the crusts. The three layers of crust D1-1 generally show a decrease of light REEs (La to Gd) from the innermost layer 3 to the outer two layers, which have similar contents; the heavy REEs (Gd-Lu) have their highest content in the outermost layer, next highest in the innermost layer and lowest content in the middle layer. Total REEs and the Ce anomalies follow the pattern of the light REEs. The three layers of crusts D2-2 show the highest content of each element in the middle layer (except La), the next highest content in the lowermost layer, and lowest content in the uppermost layer. Total REEs follow the same pattern, but the Ce anomalies decrease from the surface to the substrate. These two trends are not related to degree of phosphatization of the crust layers. For crusts from the area northwest of the RMI, 11 of 13 crusts analyzed showed decreases in REE contents from the substrate to the crust surface (Hein et al., 1997a), as did total REEs for crust Dl-1 here.

Chondrite-normalized REE patterns show moderate to large positive Ce anomalies, small positive Gd anomalies, light REE enrichments, and slight decreases in heavy REEs with increasing atomic number, or flat heavy REE patterns (Figs. 8-10). PAAS shale-normalized REE patterns show nearly flat heavy REEs, light REE depletion, and positive Ce and Gd anomalies. A small positive Gd anomaly is typical of hydrogenetic Fe-Mn crusts and of seawater (Hein et al., 1988). In crust Dl-1, the Ce anomalies increase through the crust from the surface to the substrate, where as the opposite trend in seen in crust D2-2.

Element Associations

Correlation coefficients and Q-mode factor analysis coupled with X-ray diffraction mineralogy can be used to interpret which elements are associated with the mineral phases that make up Fe-Mn crusts. We analyzed correlation coefficient matrices and Q-mode factor analyses for three data sets including nine bulk crusts from Table 14 (Table 19; Fig. 11), four bulk crusts <62 mm (Table 20), and five bulk crusts >85 mm (Table 21; Fig. 12). We interpret the data for bulk crusts to indicate that the following elements are associated with the following phases. Detrital (aluminosilicate) phase: Si, Al, Fe, Ti, K, Na, Zr, B, Nb, Hf, Li, Y; Mn-oxyhydroxide phase: Mn, Tl, Co, Ni, Pb, Ga, Mo, Cd, Na, Bi; Fe-oxyhydroxide phase: Fe, As; CFA phase: Ca, P, S, Sr, As, Te, Bi, Ba, Be, Cu, Sn, Hf, Pb, Sc; residual-biogenic phase: Sr, Ba, Cu, W, Zn, As, V, Bi.

Only minor differences exist between the data sets of bulk crusts <62 mm thick and all bulk crusts, but significant differences exist for crusts >85 mm thick. It has been shown that element associations for very thick crusts do not follow those typical of Fe-Mn crusts because of extensive phosphatization and remobilization of elements (e.g. Hein, Kang, et al., 1990; Koschinsky et al., 1997; Hein and Morgan, 1999). The detrital phase shows minor differences but the other three

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phases are mixed (Table 21; Fig. 12): Mn-oxyhydroxide plus residual biogenic phase includes Mn, W, As, Sr, Bi, Cu, Zn, V, Ca, P, Ba, Pb, Ni; the CFA-diagenetic phase includes Te, Sn, P, Tl, Ca, Co, Nb, Pb, Ti, Bi. This latter phase contains those elements that are known to be, or thought to be, incorporated into Fe-Mn crusts through an oxidation reaction (Co, Pb, Te, Tl, Bi, Ti, Sn).

Element associations indicate that the rare metals (Te, Tl, W, Bi, Hf, Zr, Nb, Sn) are associated with several phases. Tl is clearly associated solely with the Mn-oxyhydroxide phase. Te may be associated primarily with the CFA phase, secondarily with the residual biogenic phase, and possible also with the Mn phase. Hf, Zr, and Nb are predominantly part of the detrital phase, but Hf may also, in part, be associated with the CFA phase, Zr with the residual biogenic phase, and Nb with each of the other three phases. Bi appears to be associated predominantly with the CFA phase and secondarily with the residual biogenic and Mn phases. W may be associated with the residual biogenic phase and secondarily with the Mn oxyhydroxide phase. Sn may be predominantly associated with the CFA phase and, in part, with each of the other three phases. Tl, Hf, and Zr associations are very consistent among the various data sets analyzed here, but the other rare metals need to be analyzed in greater detail with a larger data set.

Correlation coefficients also show that the following elements increase with increasing crust thickness: Ba, S, Bi, Ca, P, Be, and Sr, whereas Si, Cd, B, Al, and K decrease with increasing crust thickness. These relationships indicate that the CFA and residual biogenic phases increase and the detrital phase decreases with increasing crust thickness. It has been noted many times that Co contents, the most important metal of economic interest, decreases with increasing crust thickness, but that correlation is not seen here at the 95% confidence level.

YAP CONVERGENT MARGIN FERROMANGANESE CRUSTS AND STRATABOUND MANGANESE DEPOSITS

Description

Fe-Mn crusts collected on the YCM during KODOS 98-3 are thin and vary in thickness from a patina to 15 mm for Yap Arc samples (D5, D6, D8-, D9) and a patina to 10 mm for dredge D7 from southwest Caroline Ridge (Tables 5,6). The Fe-Mn crusts are composed of one or two layers. Crust layers are black, massive, and porous and rarely dendritic or acicular. Crust surfaces are granular to smooth and rarely botryoidal. None of the crusts have been phosphatized.

Stratabound hydrothermal deposits consists of Mn oxyhydroxide-cemented volcaniclastic sandstone (D5) composed of medium sand-sized grains in gray to black cement; and a 15 mm- thick, submetallic, gray layer of Mn oxyhydroxide with adjacent layers of Mn-cemented volcaniclastic sandstone (D8). The submetallic luster and gray color is a hallmark of hydrothermal Mn deposits.

Growth rates of the Fe-Mn crusts based on the Manheim and Lane-Bostwick (1988) equation (3.1-6.1 mm/Ma) are typical of hydrogenetic precipitation. Based on those growth rates, the oldest crust began forming only 2.6 Ma ago. The growth rate of the Stratabound hydrothermal Mn layer is about 38 mm/Ma, which is slow compared to other hydrothermal Mn deposits (e.g. Hein, Ahn, et al., 1992). That relatively slow growth rate is the result of an anomalously high Co content for hydrothermal Mn. The ages for initiation of crust growth are much younger than the age of the volcanic edifices on which they grew, which is Oligocene for southwest Caroline Ridge and Oligocene and Miocene for Yap Arc (Hein, Ahn, et al., 1992).

X-Ray Diffraction Mineralogy

8-MnO2 (vernadite) contents of bulk crusts range from 91% to 95% (Table 12). X-ray amorphous Fe oxyhydroxide epitaxially intergrown with the S-MnO2 is also a dominant phase in these crusts, but is not included with the crystalline phases listed in Table 12. Quartz, plagioclase,

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and calcite occur as accessory minerals. Hydrothermal birnessite cements the volcaniclastic sandstone, which is composed of plagioclase, serpentine, pyroxene, amphibole, and quartz. The hydrothermal Mn layer is predominantly birnessite, with moderate smectite and quartz (Table 12). It is difficult to distinguish 8-MnO2 in the presence of birnessite because of overlapping peaks, so it is possible that 8-MnO2 occurs in addition to the birnessite.

Chemistry

Three bulk Fe-Mn crust samples, one Mn-cemented sandstone, and one stratabound Mn layer were analyzed for chemical composition (Tables 22-24).

Bulk Crusts: The mean Fe and Mn contents of the 3 bulk crusts are 22.2% and 22.6%, respectively (Tables 23, 24). The mean Fe/Mn ratio (1.0) is higher than the mean ratio for the entire central Pacific region (0.72; Hein et al, 1992), the Marshall Islands EEZ (0.64; Hein et al., 1999), the area to the northwest of the Marshall Islands EEZ (0.76; Hein et al., 1997a), and Fe-Mn crusts from Litakpooki Ridge from this study; but is about the same as the ratio for the FSM EEZ, 1.02 (Hein et al., 1999). Generally, island-arc Fe-Mn crusts form by both hydrogenetic and hydrothermal input and have Fe/Mn ratios greater than 1.0. However, only the bulk crust from southwest Caroline Ridge (D7) has more Fe than Mn. The Co contents, Fe/Mn ratios, and growth rates indicate that the YCM crusts are solely of hydrogenetic origin. The southwest Caroline Ridge crust is similar in composition to the Yap Arc crusts, but with somewhat higher Fe, Cl, Nb, Rb, and Zr contents and lower Al and Ba contents. The Caroline Ridge crust has an unusually high Si/Al ratio (>645) indicating a low detrital component and likely a high biogenic silica content.

Mean contents of the economically important metals Co (0.34%) and Ni (0.34%) are less than their mean contents (0.79% and 0.57%, respectively) for the RMI EEZ crusts (Hein et al., 1999). The Co+Ni+Cu mean content for bulk crusts is 0.75% and the maximum mean content is 0.86%. If Pb is added to that group of elements, the mean content is 0.86% and the maximum mean content is 0.98%. The relationship of Co+Ni+Cu to Fe and Mn (Fig. 7), show that the YCM samples have relatively less trace metals and more Fe compared to Litakpooki Ridge samples.

Other metals of potential economic interest that are concentrated in the YCM Fe-Mn crusts include Zr (554 ppm), Tl (98 ppm), Te (37 ppm), and Bi (mean 14 ppm). Zr is somewhat more, Tl somewhat less, and Bi and Te much lower that mean contents from Litakpooki Ridge crusts. The recovery of only thin crusts from the YCM limits their economic potential.

Stratabound deposits: The hydrothermal stratabound Mn-oxide layer (D8-1 A) has very high Mn (44%), Ba (1.18%), Ni (0.64%), and copper (0.2%) contents, as well as moderately high Zn (0.16%), Cd (16 ppm), and Li (179 ppm) contents, with an Fe/Mn ratio of 0.03 (Table 23). The high Mn and low Fe/Mn ratio are characteristic of hydrothermal Mn deposits. The high trace- metal contents are found in some hydrothermal Mn deposits (Hein et al., 1997b). Previously analyzed hydrothermal Mn samples (n=7) from Yap Arc also had high Mn (44%), Ni (0.45%), Ba (0.31%), Cu (0.26%), Zn (0.16%), Cd (44 ppm), and Cr (436 ppm) contents (Hein, Ahn, et al., 1992), although the sample from this study has much higher Ni and Ba contents. Yap Arc hydrothermal Mn deposits have higher trace metal contents than similar deposits from other regions (Hein et al., 1997b), which may be the result of intensive leaching of ultramafic rocks by the hydrothermal fluids and the lack of precipitation of sulfides at depth, or the leaching of sulfides that formed at depth in the hydrothermal system. A high serpentinite content (Table 12) in the Mn- cemented sandstone (D5-16A) attests to the ubiquitous occurrences of ultramafic and mafic rocks in the Yap Arc, which had previously been dredged from outcrops and collected as blue-green muds that formed from serpentinite diapers (Hein, Ahn, et al., 1992).

Rare Earth Elements

Total REE contents for the 3 bulk crusts vary from 0.14% to 0.16%, with a mean of 0.15%; whereas the total REE contents for the hydrothermal deposits are very low, 130 ppm for the Mn- cemented sandstone and 34 ppm for the stratabound Mn layer (Table 18).

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Chondrite-normalized REE patterns for the Fe-Mn crusts show small positive Ce and Gd anomalies, light REE enrichments, and decreases in heavy REEs with increasing atomic number (Fig. 13). These characteristics are typical of west Pacific hydrogenetic Fe-Mn crusts (Hein, Ahn, et al, 1992). PA AS shale-normalized REE patterns show nearly flat heavy REEs, light REE depletion, convex up middle REEs, and small positive Ce and Gd anomalies. The stratabound Mn layer shows a strong negative Ce anomaly, typical of hydrothermal Mn deposits, and a positive Eu anomaly, which reflects weathering of the basement rock and sediments by the mineralizing fluids (Fig. 14). The REE pattern for the Mn-cemented sandstone is very similar to those of the Fe-Mn crusts, but with an order of magnitude less enrichment relative to chondrites and shale. This indicates that there is a hydrogenetic component in the hydrothermal Mn-cemented sandstone. The negative Yb anomaly probably results from analytical error because of the very low contents of the heaviest REEs.

RESOURCE CONSIDERATIONS

The commonly cited cut-off grade for potential economic development is 0.8% Co and the cut­ off thickness is 40 mm. On a water-free basis, KODOS 98-3 samples have moderate mean Pt (0.54 ppm), Mn (25.2%), Co (0.48%), Ni (0.34%), and Cu (0.10%) contents, with a mean Co+Ni+Cu content of 0.92%. The mean crust thickness is >40 mm for dredge hauls from Litakpooki Ridge, with one being 80 mm; none of the dredge hauls from the YCM yielded thick crusts. It is not known whether ultimately grade or tonnage (thickness) will be the most important factor in choosing a potential mine site, but if it is tonnage, then both Litakpooki Ridge and Lomilik Seamount in the RMIEEZ are excellent sites for additional work.

It is important that several very rare metals, such as the PGEs, Te, and Bi increase in grade with increasing crust thickness in the RMI crusts. Te contents are especially interesting because its earth's crust abundance may be as much as 5 times less than that of Pt, but its concentration in Fe- Mn crusts is about 200 times greater than that of Pt. Te, Bi, Nb, Tl, W, and Zr need to be looked at in detail in terms of their resource potential in Fe-Mn crusts. Elevated gold contents in some of the dredged Yap Arc rocks indicate that epithermal gold deposits like those that occur on nearby Gagil-Tamil and Maap Islands may also occur offshore.

ACKNOWLEDGMENTS

We thank the captain, crew, and scientific staff of the R. V. Onnuri cruise KODOS 98-3 for excellent support while at sea. We thank Jane Reid, U.S. Geological Survey (USGS), for reviewing this report, and C. Degnan, D. Mosier, and F. Wong of the USGS for help with the maps.

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Hein, J.R., Koschinsky, A., Halbach, P., Manheim, F.T., Bau, M., Kang, J.-K., and Lubick,N., 1997b, Iron and manganese oxide mineralization in the Pacific: in Nicholson, K., Hein,J.R., Biihn, B., and Dasgupta, S. (eds.) Manganese Mineralization: Geochemistry andMineralogy of Terrestrial and Marine Deposits. The Geological Society Special PublicationNo. 119, London, p. 123-138.

Hein, J.R., Moon, J.-W., Lee, K.-Y., Kirn, K.-H., Roberts, L., Burrows, M., Park, S.H.,Dowling, J., Choi, Y.-J., Zielinski, S.E., Chi, S.-B., Benninger, L., Kim, H.-S., and Park,C.-K., 1998. Composition of Co-rich ferromanganese crusts and substrate rocks from theMarshall Islands, cruise KODOS 97-4. U.S. Geological Survey Open File Report 98-375, 71pp.

Hein, J.R., Koschinsky, A., Bau, M., Manheim, F.T., Kang, J.-K., and Roberts, L., 1999,Cobalt-rich ferromanganese crusts in the Pacific. In, CRC Handbook of Marine Minerals,Cronan, D.S. (Ed.), CRC Press, Boca Raton (in press).

Jackson, L.L., Brown, F.W., and Neil, S.T., 1987, Major and minor elements requiringindividual determination, classical whole rock analysis, and rapid rock analysis: in Baedecker,P.A. (ed.) Methods for Geochemical Analysis. U.S. Geological Survey Bulletin 1770, p. Gl-G23.

Klovan, J.E. and Imbrie, J., 1971, An algorithm and FORTRAN-IV program for large-scale Q-mode factor analysis and calculation of factor scores. Mathematical Geology, v. 3, p. 61-77.

KODOS, 1999a, Distribution and genesis of Co-rich crusts in the Marshall Islands, WesternPacific. Korea Ocean Research and Development Institute, Technical Report Number BSPE98729-00-1172-7, 205 pp (in Korean with English summary).

KODOS, 1999b, A geochemical study for the submarine hydrothermal mineralization. KoreaOcean Research and Development Institute, Technical Report Number BSPE 98712-00-1162-7, 271 pp (in Korean with English summary).

Koschinsky, A., Stascheit, A., Bau, M., and Halbach, P., 1997. Effects of phosphatization onthe geochemical and mineralogical composition of marine ferromanganese crusts. Geochimicaet Cosmochimica Acta, v. 61, p. 4079-4094.

Lichte, F.E., Golightly, D.W., and Lamothe, P.J., 1987a, Inductively coupled plasma-atomicemission spectrometry: in Baedecker, P.A. (ed.), Methods for Geochemical Analysis. U.S.Geological Survey Bulletin 1770, p. B1-B10.

Lichte, F.E., Meier, A.L., and Crock, J.G., 1987b, Determination of the rare earth elements ingeological materials by inductively coupled plasma-mass spectrometry. Analytical Chemistry,v. 59, p. 1150-1157.

Lincoln, J.M., Pringle, M.S., and Silva, I.P., 1993, Early and Late Cretaceous volcanism andreef-building in the Marshall Islands. In, The Mesozoic Pacific: Geology, Tectonics, andVolcanism, Pringle, M.S., Sager, W.W., Sliter, W.V., and Stein, S. (Eds.), AmericanGeophysical Union Geophysical Monograph 77, Washington, D.C., p. 279-305.

Manheim, F.T. and Gulbrandsen, R.A., 1979, Marine phosphorites, in Burns, R.G. (ed.),Marine Minerals. Mineralogical Society of America Short Course Notes, v. 6, p. 151-173.

16

Manheim, F.T. and Lane-Bostwick, C.M., 1988, Cobalt in ferromanganese crusts as a monitor ofhydrothermal discharge on the Pacific sea floor. Nature, v. 335, p. 59-62.

McClellan, G.H. and van Kauwenbergh, S.J., 1990, Mineralogy of sedimentary apatites. In,Phosphorite Research and Development, Notholt, AJ.G. and Jarvis, I. (Eds.), The GeologicalSociety, London, p. 23-31.

McKown, D.M. and Millard, H.T., Jr., 1987, Determination of uranium and thorium by delayedneutron counting, in Baedecker, P.A. (ed.), Methods for Geochemical Analysis. U.S.Geological Survey Bulletin 1770, p. 11-112.

McLennan, S.M., 1989, Rare earth elements in sedimentary rocks: Influence of provenance andsedimentary processes: in Lipin, B.R. and McKay, G.A. (eds.) Geochemistry and Mineralogyof Rare Earth Elements. Mineralogical Society of America's Reviews in Mineralogy, v. 21,Washington D.C.

Peck, L.C., 1964, Systematic analysis of silicates. U.S. Geological Survey Bulletin 1170, 89 p. Pichocki, C. and Hoffert, M., 1987, Characteristics of Co-rich ferromanganese nodules and crusts

sampled in French Polynesia. Marine Geology, v. 77, p. 109-119. Puteanus, D. and Halbach, P., 1988, Correlation of Co concentration and growth rate: A method

for age determination of ferromanganese crusts. Chemical Geology, v. 69, p. 73-85. Shapiro, L., 1975, Rapid analysis of silicate, carbonate, and phosphate rocks-revised edition.

U.S. Geological Survey Bulletin 1401, 76 p. Taggart, I.E., Lindsay, J.R., Scott, B.A., Vivit, D.V., Bartel, A.J., and Stewart, K.C., 1987,

Analysis of geologic materials by wavelength-dispersive X-ray fluorescence spectrometry: inBaedecker, P.A. (ed.), Methods for Geochemical Analysis. U.S. Geological Survey Bulletin1770, p. E1-E19.

Usui, A. and Someya, M., 1997, Distribution and composition of marine hydrogenetic andhydrothermal manganese deposits in the northwest Pacific, in Manganese Mineralization:Geochemistry and Mineralogy of Terrestrial and Marine Deposits, Nicholson, K., Hein, J. R.,Biihn, B., and Dasgupta, S. Eds., Geological Society Special Publication No. 119, London,p. 177-198, 1997.

Wicks, FJ. and Whittaker, E.J.W., 1977. Serpentine textures and serpentinization. CanadianMineralogist, v. 15, p. 459-488.

Wicks, F.J., Whittaker, E.J.W., and Zussman, J., 1977. An idealized model for serpentinetextures after olivine. Canadian Mineralogist, v. 15, p. 446-458.

17

Table 1. Scientific personnel on R.V. Onnuri cruise KODOS 98-3

Jai Woon MoonKyeong Young LeeJames R. HeinMalia BurrowsYoun-ji ChoiJennifer S. DowlingRaymond Freeman-LyndeYoung Geun JinHoi Soo JungHyun Sub KimDuk Kee LeeGun Chang LeeSang Heon NamChan Young ParkCheong Kee ParkSung Hyun ParkSeung Kyu SonIn Sung Yoo_______

Co-chief scientistCo-chief scientistGeochemistrySamplingCTD4SamplingSedimentologyAirgun SeismicSamplingSBP, PDRAirgun SeismicSampling DSCAirgun SeismicData ProcessingSeaBeam BathymetrySamplingCTDAirgun Seismic___

KORDI1KORDIUSGS2USGSKORDIUSGSUGA3KORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDIKORDI

1 Korea Ocean Research and Development Institute 2United States Geological Survey 3University of Georgia, Athens4 CTD = conductivity, temperature, density; SBP= sub-bottom profiler; PDR precision depth recorder; DSC = deep sea camera

18

Table 2. Station locations and operations for cruise KODOS 98-3

Station Operation1 Location

Marshall Islands Fe-Mn crust leg

SB 1 CTD1SB 2 PCISB 3 PC2SB 4 DlSB 5 D2SB 6 D3SB 7 D4SB 8 CTD2

FSM Hvdrothermal leg

Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge Litakpooki Ridge SW of Litakpooki

HIH2H3H4H5H6H7H8H9H10H 11H 12H13H14HISH 16H17H18H19H20

CTD3CTD4CTD5BC1, 2PC3MCID5D6DSC1CTD6CTD7CTD8CTD9MC2D7PC4CTD 10D8D9CTD11

Yap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap TrenchW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeYap TrenchYap ArcYap ArcYap ArcYap Arc

CTD = conductivity, temperature, density, and oxygen profile; PC piston core; D = dredge; BC = box core; MC = multiple core; DSC = deep-sea camera

19

Table 3. Twelve channel, two-150 in3 airgun lines (AG); 3.5kHz and 12 kHz bathymetry lines (3.5, 12); and SeaBeam lines (SB) (see Figures 2, 3, and 5)

LocationMarshall Islands Fe-Mn crustLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLitakpooki RidgeLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountLomilik SeamountSubtotal

FSM Hydrothermal legAcross Convergent MarginYap ArcAcross Convergent MarginW. Caroline RidgeAcross Convergent MarginYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcYap ArcW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeW. Caroline RidgeSubtotalTotal

Line NumberlepSB1SB 1-1SB 2SB 2-1SB 3SB 3-1SB 4SB 5SB 6SB 6-1SB 7SB 8SB 9SB 10SB 11SB 12SB 13SB 14SB 15SB 16SB 17SB 17-1SB 17-2SB 18SB 19SB 20SB 21SB 22SB 23-

HIH 1-1H2H2-1H3H3-1H4aH4bH4cH4dH4eH5H5-1H6aH6bH6cH6dH6eH6fH6gH7aH7bH7cH7dH7eH7fH7gH7h -

Operation

3.5, 12, SB3.5, 123.5, 12, SB3.5, 123.5, 12, SB3.5, 123.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 123.5, 12, SB3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB3.5, 12, SB

AG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SBAG, 3.5, 12, SB -

Nautical Miles

23.784.98

23.794.98

23.792.49

16.857.47

23.804.98

23.8025.7928.2123.2930.413.677.079.35

26.414.35

11.733.24

11.402.8

26.3214.4117.3826.23

6.65439.42

78.95.1

78.98.2

78.83.0

10.25.64.88.67.6

20.35.6

17.82.52.12.02.24.9

12.74.97.32.23.03.03.84.1

10.0397.8837.2

Kilometers

44.049.22

44.059.22

44.064.61

31.2113.8344.079.22

44.0847.7652.2543.1456.31

6.813.0917.3148.91

8.0621.726.00

21.115.18

48.7426.6832.1948.5712.31

813.74

146.19.4

146.115.2

1465.6

18.810.38.9

1614.137.610.333.04.63.93.74.09.0

23.59.0

13.54.05.65.57.07.5

18.5736.7

1550.4

20

Table 4. Prelim

inary oxygen and temperature data from

CT

D casts, cruise K

OD

OS 98-3 (see Figures 2 and 5)

Latitude(N

)L

ongitude Station

(E) N

umber

Julian D

ayG

reenwich

Low

est O2

Mean

Content

Tim

e1 (m

l/1)

Water D

epth at m

inimum

0

2(m

)

Water D

epth at T

op of O

MZ2 (m

)

Water D

epth at!0°C

Isotherm

(m)

Water D

epth at5°C

Isotherm

(m)

Marshall Islands Fe-M

n crust lee

Litakpooki R

idge C

TD

1

CTD

2

8°09.15'N

10°24.31'N

160°

161

32.02'E

°9.61'E

18

226

227

1327-1457

0827-1010

1.34

1.33

307

343

280

275

279

308

890

919

FSM H

ydrothermal leg

Yap A

rcC

TD

3

CT

D 4

CT

D 5

CT

D 6

CT

D 10

CT

D 11

Yap Trench

CT

D 7

8°58.21'N

8°55.25'N

8°54.64'N

8°57.03'N

8°57.58'N

8°57.39'N

8°46.23'N

137°

137°

137°

137°

137°

137°

138° 28.67'E

32.04'E

37.73'E

40.96'E

41.05'E

34.94'E

08.15'E

9101118252819

234

234

235

236

237

238

236

0942-1216

1310-1510

1354-1600

2145-2335

0958-1200

0202-0418

0208-0651

2.01

1.98

2.03

2.07

2.06

1.94

2.04

406

440

467

479

482

419

434

350

350

340

300

360

275

310

301

285

315

279

313

270

288

887

886

878

910

913

903

904

W. C

aroline Ridge

CT

D 8

CT

D 9

8°35.07'N

8°31.75'N

138°

138° 45.07'E

36.57'E

2021

236

237

1200-1325

1423-1618

2.08

1.92

450

421

300

275

287

285

948

953

'Local Tim

e equals GM

T plus eleven hours for CTD

1 and 2 and GM

T plus ten hours for CTD

3-11 2O

MZ

= oxygen m

inimum

zone

Table 5. Dredge sum

mary for cruise K

OD

OS 98-3 (see Figures 2 and 5)

to

to

Dredge

number

Location

Marshall Islands Fe-M

n

Dl

D2A

2D

2B2

D3

D4

Litakpooki LitakpookiLitakpookiLitakpooki Litakpooki

Water depth on-off

bottom (m

)

crust leg

2058-1893 1862-16801610-14682200-1850 2700-2388

Water depth

Recovery

corrected (kg)

(m)1

2040-1900 1840-17701600-1500

:

55 14575:

Max. crust

thickness (m

m)

120 1541

Mean crust

Dom

inant thickness

substrate (m

m)

80 B

reccia 4g3

Basalt, lim

estone<1

Foram lim

estone

:: ::

Com

ments

Ironstone, phosphorite M

egacrustsLarge bouldersN

o recovery N

o recovery

FSM H

ydrothermal leg

D5

D6

D7

D8

D9

Yap A

rc Y

ap Arc

W. C

arolineR

idge Y

ap Arc

Yap A

rc

2757-2250 2720-1779 2280-1778

2672-1778 2676-2223

2600-2350 2720-1779 2250-1950

2600-2350 2650-2450

3.2 1.3 122

150 81

11

10615

3 B

reccia <1

Pumice

1 B

asalt

< 1 Foram

limestone

3 M

icritic limestone

Serpentinite, hydrothermal M

n 1 breccia fragm

ent Foram

iniferal limestone

Serpentinite, hydrothermal M

n A

ndesite, sandstone

1 Depth interval from

which sam

ples were likely recovered

2Dredge repositioned because of ship's drift off station, clear change in rock types from

lower to upper dredged sam

ples3A

verage for basalt substrate is 95 mm

and for limestone substrate is 19 m

m

Tabl

e 6.

Loc

atio

n an

d de

scrip

tion

of d

redg

e ha

uls,

Mar

shal

l Isl

ands

Fe-

Mn

crus

t and

FSM

hyd

roth

erm

al le

gs, K

OD

OS

98-3

cru

ise

to Ui

Dre

dge

num

ber

Dl

D2

Latit

ude

(ON

)1

08°1

3.97

' 08

°13.

42'

08°1

1.79

'08

°10.

77'

Long

itude

(°E)

160°

35.9

7'

160°

35.4

6'

160°

34.4

8'16

0°34

.59'

Tota

lre

cove

ry(k

g) 55 220

Bro

ken

from

outc

rop

(%)

100

99

Talu

s(%

)

0 1

Fe-M

nen

crus

ted

rock

100

66

Des

crip

tion

offe

rrom

anga

nese

oxi

des

Bot

ryoi

dal s

urfa

ce, r

arel

y gr

anul

ar to

smoo

th,

gran

ular

on

side

s; T

hick

crus

ts w

ith 3

or 4

lay

ers:

1. m

assi

vebl

ack,

2. p

orou

s to

vug

gy,

3.m

assi

ve d

ense

bla

ck, 4

. whe

repr

esen

t, an

upp

erm

ost <

10 m

m

mas

sive

laye

r; l

ayer

3 m

ay b

e su

bdiv

ided

into

up

to 4

laye

rs b

ybe

ddin

g pa

ralle

l fra

ctur

es &

occu

rren

ce o

f CFA

vei

ns a

nd b

lebs

;th

inne

r cr

usts

are

mis

sing

laye

r 3;

2no

dule

s w

ith l

arge

nuc

lei;

som

ebr

ecci

a w

ith F

e-M

n ce

men

t;th

ickn

ess:

max

=120

mm

, av

=80m

mT

hick

cru

sts

on b

asal

t+ph

osph

orite

:Sm

all/m

ediu

m b

otry

oids

on

surf

ace,

gran

ular

on

side

s; 3

to

4 la

yers

: 1.

blac

k m

assi

ve,

2. p

orou

s to

vug

gy &

colu

mna

r, Fe

sta

ined

, 3.

mas

sive

,de

nse,

bla

ck, d

isse

min

ated

CFA

&ve

ins;

lay

er 3

may

be

divi

ded

into

an

uppe

r la

yer

with

out a

ppar

ent C

FAan

d a

low

er la

yer

with

muc

h C

FA&

/or

frac

ture

s; 4

. Whe

re p

rese

nt, a

nup

perm

ost <

10m

m m

assi

ve la

yer;

TT

iin c

rust

s on

lim

esto

ne &

phos

phor

ite: L

arge

to m

odif

ied

botr

yoid

s on

sur

face

, gra

nula

r on

thin

crus

ts;

1-3

laye

rs:

1. m

assi

ve b

lack

,2.

por

ous,

few

vug

s, 3

. por

ous

&vu

ggy,

im

preg

nate

d lim

esto

ne o

rph

osph

orite

; 1

com

plet

ely

encr

uste

dco

bble

with

3 l

ayer

s: 1

. aci

cula

rbl

ack,

2. b

lack

, mas

sive

, fra

ctur

ed,

3.m

assi

ve,

CFA

vei

ns a

nd v

ug f

ill;

spar

se g

ranu

lar

crus

ts o

n fr

iabl

efo

ram

lim

esto

ne;

thic

knes

s on

bas

alt:

max

= 15

4mm

, av

=95m

m;

onlim

esto

ne:

max

=35m

m,

av=1

9mm

;on

fri

able

lim

esto

ne:

av=

<lm

m

Des

crip

tion

ofsu

bstra

te r

ocks

70%

bre

ccia

with

whi

te to

bro

wn

phos

phor

ite, b

row

n ba

salt,

& b

row

nir

onst

one

clas

ts in

cre

am to

pin

kish

CFA

cem

ent l

aced

with

Mn

dend

rites

and

cut b

y C

FA v

eins

; mor

e ra

rely

Fe-M

n ox

ide

cem

ent;

20%

peb

bly

phos

phor

ite w

ith s

pars

e br

own

basa

lt (s

ome

coat

ed w

ith F

e-M

n cr

ust)

&ye

llow

-gre

en a

ltere

d hy

aloc

last

itepe

bble

s; C

FA v

eins

& M

n de

ndrit

es;

5% b

asal

t, br

own,

alte

red;

5%

iron

ston

e, b

row

n, o

oliti

c to

mas

sive

,re

plac

ed b

asal

t

Roc

ks a

re d

ivid

ed in

to tw

o gr

oups

D

2A, e

ncru

sted

& D

2B n

oten

crus

ted-

beca

use

ship

was

repo

sitio

ned

durin

g op

erat

ion

&sa

mpl

es w

ere

colle

cted

from

two

plac

es o

n a

smal

l hill

at t

he s

umm

itof

theg

uyot

. D

2A:

65%

lim

esto

ne&

diff

eren

tially

CFA

-rep

lace

d lim

esto

ne, y

ello

w-b

row

n to

bro

wn,

fora

min

ifera

l, ha

rd to

sof

t dep

endi

ngon

deg

ree

of p

hosp

hatiz

atio

n,m

assi

ve to

vug

gy, l

aced

with

Mn

dend

rite

s, b

lebs

, & v

ein

& v

ug f

ill.

35%

bas

alt,

brow

n to

red-

brow

n,al

tere

d, la

rge

yello

w-g

reen

amyg

dule

s, la

ced

with

CFA

and

Fe-

Mn

oxid

es.

D2B

: 10

0%fo

ram

inife

ral l

imes

tone

, fria

ble,

pal

ebr

own

to o

ff w

hite

, lar

ge v

ugs

lined

with

gra

nula

r Fe-

Mn

oxid

es

Tabl

e 6

cont

inue

d

D3

D4

D5

D6

08°1

9.12

'08

°19.

01'

08°2

2.10

'08

°23.

06'

08°5

6.67

'08

°54.

38'

08°5

3.53

'08

°51.

81'

W4

3.4

21

160°

42.5

5'16

0°49

.19'

160°

44.4

5'

137°

40.7

4'13

7°4U

7'

137°

37.0

2'13

7°41

.36'

0 0 3.2

1.3

- 80 <1

- 20 >99

- 50 <1

No

reco

very

No

Rec

over

y

Smoo

th, g

ranu

lar,

and

mic

robo

tryo

idal

sur

face

s; 1

or 2

laye

rs:

1. b

lack

ver

y po

rous

, 2.

blac

k, p

orou

s, d

endr

itic;

for

one

laye

r=bl

ack,

por

ous,

mas

sive

; 1

sam

ple

of s

ands

tone

cem

ente

d by

hydr

othe

rmal

Mn

oxid

e; th

ickn

ess:

max

=llm

m,

av=3

mm

Spar

se, p

atch

y, g

ranu

lar p

atin

a on

brec

cia

frag

men

t; no

ne o

n pu

mic

e

No

reco

very

No

Rec

over

y

60%

bre

ccia

: gra

y vo

lcan

icla

stic

sand

ston

e, v

olca

nic,

& b

recc

ia c

last

sin

gre

enis

h-br

own

volc

anic

last

icm

atrix

; mat

rix

supp

orte

d; F

e-M

nox

ide

cem

ent n

ear s

urfa

ce w

ith F

e-M

n cr

usts

; rar

ely

hydr

othe

rmal

(?)

quar

tz c

last

s an

d ce

men

t; 2

sam

ples

with

ser

pent

inite

cla

sts

in q

uartz

-ca

lcite

cem

ent;

21%

ser

pent

inite

,m

ottle

d w

hite

, dar

k-gr

ay, b

lue-

gray

,gr

een,

and

yel

low

-bro

wn,

den

se a

ndhe

avy;

8%

alte

red

basa

lt, m

ottle

dgr

eeni

sh ta

n to

gra

y, s

ome

with

sulfi

des,

cal

cite

vei

ns, c

hill

mar

gin,

&/o

r am

ygda

loid

al; 4

% g

ray

volc

anic

last

ic s

ands

tone

, cal

cite

&/o

rqu

artz

cem

ent,

quar

tz c

ryst

als

invu

gs;

1 sa

mpl

e ce

men

ted

by F

e-M

nox

ides

; 5%

ree

f lim

esto

ne &

san

dych

alk;

1%

cru

st fr

agm

ents

with

out

subs

trate

; pum

ice

pebb

le &

gol

den

cora

l98

% g

ray

pum

ice;

2%

bre

ccia

,br

own

volc

anic

cla

sts

alte

red

to c

lay

min

eral

s in

gra

y-gr

een

mat

rix o

f cla

ym

iner

als;

vei

ns o

f qua

rtz &

hydr

othe

rmal

(?) M

n ox

ides

Tabl

e 6

cont

inue

d

to

D7

D8

08°4

3.42

'08

°42.

69'

08°5

5.05

'08

°53.

71'

138°

44.8

6'13

8°45

.24'

137°

39.9

7'13

7°42

.54'

122

150

100

95

- 52

75 <1

Gra

nula

r to

smoo

th s

urfa

ces;

pat

chy

crus

t w

ith 1

lay

er, b

lack

, por

ous,

in

plac

es c

appe

d by

lim

esto

ne;

fora

min

ifera

l lim

esto

ne b

ould

ers

with

spar

se, p

atch

y, g

ranu

lar

crus

t; so

me

vesi

cles

in b

asal

t may

be

fille

d w

ithhy

drot

herm

al b

oxw

ork,

Mn

oxid

es;

thic

knes

s: m

ax=1

0mm

, av=

lmm

Gra

nula

r to

smoo

th s

urfa

ces

onm

ostly

pat

chy

patin

a or

thin

cru

st;

1la

yer,

mas

sive

, bla

ck, p

orou

s, r

arel

yac

icul

ar;

1 pi

ece

of h

ydro

ther

mal

Mn

oxid

e, s

trata

boun

d, s

ubm

etal

lic g

ray

to b

lack

, mas

sive

to p

orou

s; c

rust

thic

knes

s: m

ax=6

mm

, av=

<lm

m

68%

pill

ow b

asal

t wed

ges:

1. g

ray,

mas

sive

, var

iabl

y ve

sicu

lar,

1-2

mm

red-

brow

n al

tera

tion

rind

und

erla

in b

y10

-12

mm

bla

ck g

lass

rin

d va

riabl

yal

tere

d, u

nder

lain

by

10-1

3 m

m o

fsm

all v

esic

les

in th

e ba

salt;

aph

yric

to p

lagi

ocla

se &

/or

oliv

ine

phyr

ic;

2. s

ame

as #

1, b

ut b

asal

t is

alte

red

brow

n; 3

. mas

sive

, gr

ay b

asal

t; 4.

amyg

dalo

idal

bas

alt;

limes

tone

encl

oses

man

y ba

salt

frag

men

ts;

31%

whi

te, f

riabl

e, m

assi

vefo

ram

inife

ral l

imes

tone

, 1

sam

ple

with

a g

ray

calc

areo

us a

sh la

yer;

1%1.

brec

cia

with

bas

altic

gla

ss, b

asal

t,an

d lim

esto

ne, c

last

s in

cal

cite

cem

ent,

grai

n su

ppor

ted;

2. l

arge

tabu

lar b

asal

tic g

lass

cla

sts

inye

llow

-whi

te to

gre

enis

h ca

rbon

ate

+sm

ectit

e m

atrix

, mat

rix

supp

orte

d;3.

gra

y ba

salt

clas

ts in

gre

enis

h so

ftsm

ectit

e m

atrix

, mat

rix s

uppo

rted,

zeol

ite v

ug f

ill60

% f

oram

inife

ral o

oze,

whi

te to

brow

n; 3

2% f

oram

inife

ral l

imes

tone

,fr

iabl

e, e

xten

sive

ly b

urro

wed

, pal

ebr

own,

silt

- &

san

d-si

zed

grai

ns o

fba

salt;

4%

ser

pent

inite

, bro

wn,

alte

red,

mot

tled

blac

k w

ith M

nox

ides

& M

n de

ndrit

es, l

arge

serp

entin

e fla

kes,

sof

t; 2%

bre

ccia

,al

tere

d vo

lcan

ic ro

ck c

last

s in

pal

ebr

own

carb

onat

e m

atrix

with

blu

ese

rpen

tine

grai

ns, M

n ox

ides

, and

met

amor

phic

rock

frag

men

ts, m

atrix

supp

orte

d; 1

% g

ray,

pla

gioc

lase

-ph

yric

and

esite

; 1%

hyd

roth

erm

alM

n, s

ubm

etal

lic g

ray

to b

lack

,m

assi

ve

Tabl

e 6

cont

inue

d

D9

08°5

0.18

'08

°48.

32'

137°

35.0

7'13

7°35

.10'

8190

1060

Gra

nula

r, sm

ooth

, &

bot

ryoi

dal

surf

aces

on

mos

tly p

atch

ypa

tina

or th

in c

rust

s; 1

lay

er,

mas

sive

, bla

ck, p

orou

s, r

arel

yde

ndrit

ic &

aci

cula

r; 1

cobb

le o

fan

desi

te w

ith 2

0 m

m th

ick

vein

of h

ydro

frac

ture

d an

desi

te c

last

sin

hyd

roth

emia

l Mn

oxid

e,sm

ectit

e, a

nd p

hilli

psite

cem

ent;

crus

t thi

ckne

ss:

max

=15m

m, a

v=<3

mm

38%

lim

esto

ne, m

uddy

, mic

ritic

, pal

ebr

own,

var

iabl

e am

ount

s of

sm

ectit

e, M

nve

inle

ts, e

xten

sive

ly b

urro

wed

, int

erbe

dded

with

for

amin

ifera

l lim

esto

ne w

ith b

asal

tgr

ains

; 26%

and

esite

, 1.

mild

ly a

ltere

d,gr

ay, m

assi

ve, h

ighl

y ve

sicu

lar,

feld

spar

phyr

ic;

2. f

resh

gla

ssy

blac

k, h

ighl

yve

sicu

lar w

ith g

ray

rind

alte

red

toph

illip

site

, bot

h fe

ldsp

ar p

hyric

; 17

%br

ecci

a, 1

. and

esite

cla

sts

as in

#1

unde

ran

desi

te &

yel

low

-bro

wn,

gra

y, b

row

nal

tere

d vo

lcan

ic c

last

s in

cla

st s

uppo

rted

silt

& c

lay

volc

anic

last

ic m

atrix

; 2.

bla

ckgl

assy

and

esite

cla

sts,

as

in #

2 un

der

ande

site

s, &

oth

er v

olca

nic

rock

cla

sts

inbr

own

to y

ello

w-g

reen

sm

ectit

e m

atrix

,so

me

yello

w-g

reen

sm

ectit

e cl

asts

; 3. d

ark

gray

to p

ale

gray

aph

yric

to fe

ldsp

ar p

hyri

cba

salt

& a

ndes

ite c

last

s in

yel

low

-gre

enm

atri

x of

sm

ectit

e &

phi

llips

ite c

emen

t &ve

inle

ts, M

n ve

inle

ts &

gra

ins;

17%

tuf

for

tuff

aceo

us s

ands

tone

-silt

ston

e-m

udst

one,

bla

ck, b

row

n, y

ello

w-g

reen

,da

rk b

row

n la

yers

def

orm

ed b

y so

ftse

dim

ent d

efor

mat

ion

& b

urro

win

g,pe

pper

ed w

ith M

n ox

ide

grai

ns th

at a

lso

form

lam

inae

, gra

ded

beds

, cla

y ve

ins,

mos

tly s

mec

tite;

2%

vol

cani

clas

ticsa

ndst

one:

1. s

ands

tone

with

gra

ins

ofbl

ack

glas

sy a

ndes

ite; 2

. med

ium

to d

ark

gray

mas

sive

, Fe-

oxid

e ce

men

t & f

ine­

grai

ned

volc

anic

last

ic m

atrix

; pum

ice

pebb

le

'Lat

itude

s an

d lo

ngitu

des

for o

n an

d of

f bot

tom

2P

umic

e

Table 7. X-ray diffraction mineralogy of substrate rocks from KODOS 98-3 cruise

Sample Majorl Moderate Minor/Trace Rock/Sediment

Marshall Islands Fe-Mn crust leg

D1-5AD1-5BD1-10AD2-2ED2-4B

CFA2, plagioclaseCFA, plagioclaseCalciteSmectiteCFA

Smectite CFA -

-

Smectite Halite-

Phosphatized basalt clast from breccia3Phosphatized hyaloclastite clastPebbly phosphatic limestoneHighly altered basaltPhosphorite (Foraminiferal limestone)4

FSM Hydrothermal leg

D5-2B-CD5-2B-MD5-4A

D5-7A

D7-2-1A

D7-4-1A

D7-6-1A

D7-8-1AD7-9-1A

D7-10-1AD7-10-2AD7-10-2BD7-10-2CD7-13AD8-2AD8-4AD9-3-1AD9-3-1BD9-3-2AD9-3-2BD9-3-2CD9-3-2DD9-3-2ED9-4A

D9-6-2AD9-6-2B

D9-8CD9-8DD9-8ED9-11-1AD9-14A

Plagioclase, pyroxenePlagioclase, pyroxeneLizardite, pyroxene

Plagioclase

Plagioclase, pyroxene

Plagioclase, pyroxene

Plagioclase, pyroxene

CalciteCalcite

Phillipsite, plagioclaseCalciteCalcitePhillipsiteAmorphous, plagioclaseLizarditeLizarditePhillipsiteSmectite, phillipsiteSmectite, phillipsiteSmectiteSmectite, phillipsitePhillipsite, smectiteSmectite, phillipsiteTridymite, cristobalite

Cristobalite, plagioclasePhillipsite, plagioclase

Smectite, phillipsitePlagioclasePhillipsite, plagioclaseSmectite, plagioclaseCalcite

TridymiteTridymitePlagioclase

Pyroxene

-Plagioclase, phillipsiteSmectite-SmectiteCalciteCalciteMagnetiteMagnetiteMagnetite Phillipsite- -Plagioclase, pyroxenePyroxenePyroxene, magnetitePlagioclasePyroxene--Plagioclase

SmectiteSmectite, calciteSmectite, magnetite, talc, tridymiteTridymite, calcite, quartz, smectiteMagnetite, smectite, hematiteMagnetite, hematite, smectiteMagnetite, smectite, hematite-Smectite, hematite

SmectitePhillipsiteSmectiteSmectiteChromiteChromite, smectitePlagioclase, smectite - -Hematite, smectite

Smectite

-Hematite, smectiteAmphibole-High-Mg calcite, smectite

Volcaniclastic sandstone clast from brecciaAltered clay matrix of D5-2B-CSerpentinite

Amygdaloidal andesite

Pillow basalt with chill margins

Altered pillow basalt

Vesicular pillow basalt fragment

Breccia matrixBreccia matrix

Dark green matrix in brecciaWhite matrix in brecciaGreen matrix in brecciaBrown-rind on clast from brecciaVolcanic ash bed in limestoneSerpentiniteSerpentiniteSandy layer in bedded tuffMudstone layer in bedded tuffPale brown mudstone layer in bedded tuffGreen-gray sandstone layer in bedded tuffPale brown mudstone layer in bedded tuffBrown sandstone layer in bedded tuffMottled brown siltstone layer in bedded tuffAndesite

Black glassy andesiteGray rind on glassy andesite

Yellow and white vein in basaltBasaltVein in basaltVolcaniclastic sandstoneLimestone and micritic limestone

iMajor: >25%, Moderate: 5-25%, Minor: <5%; 2CFA and most are Volcaniclastic; 4Rock type in parentheses

is carbonate fluorapatite; 3AH breccias are sedimentary, is replaced by CFA

27

Table 8. Chemical composition of substrate rocks from Litakpooki Ridge, Marshall Islands Fe-Mn crust leg, KODOS 98-3 cruise

SiO2 wt%A12O3FeOFe2O3MgOCaONa2OK2OTiO2P205MnOLOI2Total

H20+H2O-CO2t-total

^total

FCl

Ba ppmCrNbRbSrYZrThU

CaO/P2O5

Rock type

D1-10A0.780.24

~0.220.3454.20.210.05

0.02410.00.0933.099.2

0.60.2032.49.000.20

0.9180.051

44<68<2<2650168

0.41.7

5.42

Phosphaticlimestone

D1-10A10.780.24

--0.220.3454.10.220.05

0.02410.00.0933.199.2

0.60.2032.39.010.19

0.9310.050

45<68

2<2653177

0.41.6

5.41

Phosphaticlimestone

D2-2E43.018.0<0.112.41.916.422.281.61

2.4902.980.037.1098.3

6.64.500.44

~----~

783401430

248147186--~

2.15

Alteredbasalt

D2-2E142.818.0<0.112.51.906.412.271.62

2.4982.990.037.0598.2

6.44.400.42

-- ~

773401329

249147185 ~

2.14

Alteredbasalt

D2-4B4.451.87<0.11.730.6248.71.270.13

0.16929.80.507.8097.1

2.40.604.92

----~

162<68

53

126025491 ~

1.63

Phosphorite

Duplicate analysis= loss on ignition at 925° C; dash means not analyzed

28

Table 9. Yttrium and rare earth element contents (in ppm) of a partly phosphatized limestone, Marshall Islands Fe-Mn crust leg, KODOS 98-3 cruise

YLaCePrNdSmEuGdTbDyHoErTmYbLuXREEs

Ce*Y/Ho

D1-10A168.75.71.35.81.40.381.70.21.50.371.20.21.30.2230.0

0.443

D1-10A1178.96.01.35.71.40.381.60.21.50.351.10.21.30.2230.2

0.449

Duplicate analysis;Ce* is Ce anomaly = chondrite-normalized

2Ce/La+Pr

29

Tabl

e 10

. C

hem

ical

com

posi

tion

of su

bstra

te ro

cks

from

FSM

hyd

roth

erm

al le

g, K

OD

OS

98-3

cru

ise

LO

SiO

2 W

t%A1

2O3

FeO

Fe20

3M

gOC

aON

a2O

K2O

TiO

2P2

Os

MnO

LO

I2T

otal

H20

+

H2cr

C0

2

As

ppm

Ba

Cr

Nb

Rb

Sb Sr W Y Zr

Au

ppb

Roc

k ty

pe

D5-

2B49

.814

.02.

05.

9610

.49.

791.

700.

520.

372

0.03

0.11

2.25

96.9

3

1.8

3.10

0.02 <2 <20

550 6 <2 <0.5 37 <2 11 30 16

Bre

ccia

D5-

4A42

.98.

52 3.5

5.11

22.4

6.63

0.69

0.19

0.20

00.

040.

136.

3596

.66

6.3

0.90

0.03 <2 <20

2390 5 4

<0.5

29 <2 2 24 <5

Serp

entin

ite

D7-

2-1A

46.4

13.1

6.4

8.49

4.73

9.32

2.97

0.52

3.17

90.

530.

250.

8096

.69

1.5

1.10

0.07 _ 22 68 15 5 167 66 192 -- B

asal

t

D7-

4-1A

46.2

18.8

2.5

10.5

1.51

11.1

3.91

0.46

1.51

10.

230.

191.

7098

.63

1.7

0.30

0.46 _ 41 270 8 6 298 24 75 ~ B

asal

t

D7-

6-1A

45.4

13.6

6.3

8.60 4.53

9.81

3.07

0.41

3.31

90.

620.

260.

55 96.4

7

1.3

0.08

0.07 __ 70 68 19 12 184 71 191 ~ B

asal

t

D7-

9-1A

38.3

11.3 11.7

3.13

14.7

2.18

2.34

2.08

10.

140.

21 12.9

98.9

8

3.2

<0.0

18.

70 _ 48 68 10 45 228 26 123 --

Bre

ccia

D8-

2A39

.50.

67 1.4

10.3

34.4

0.33

0.23

0.04

0.01

80.

060.

08 12.3

99.3

7

11.3

1.30

0.04 23 <20

3560 6 <2 1.4 12 <2 <2 14 <5

Serp

entin

ite

D9-

3-1A

46.8

13.7

<0.1

16.3

3.45

1.91

2.16

3.79

1.06

50.

080.

528.

0097

.88

7.6

5.70

0.04 7 112

68 12 64 4.0

104 4 9 208 15

Tuff

aceo

ussa

ndst

one

D9-

3-1B

48.2

16.4

<0.1

13.2

3.81

2.16

2.22

2.62

0.82

00.

110.

958.

5099

.09

6.8

6.10

0.07 9 170

140

11 37 3.2

138

<2 15 98 <5

Tuff

aceo

usm

udst

one

D9-

4A59

.515

.54.

03.

92 2.00

6.99

3.08

0.90

0.59

80.

260.

150.

3597

.25

0.9

0.30

0.04

<2 130

68 8 6<0

.531

9<2 24 63 <5

And

esite

D9-

6-2A

63.6

13.2

4.2

2.56 2.25

5.69

2.56

0.77

0.50

90.

160.

132.

7098

.33

3.1

0.40

0.01 <2 105

<68 6 7

<0.5

250

<2 14 60 <5

And

esite

D9-

11-1

A45

.812

.20.

119

.54.

243.

261.

423.

661.

154

0.09

0.88

7.40

99.6

9

-- - 0.07 6 122

140

14 82 5.3

130

<2 16 266

26

Sand

ston

e

Dup

lica

te a

naly

sis

2LO

I =

loss

on

igni

tion

at 9

25°

C; -

- = n

ot a

naly

zed

Table 11. Calculated growth rates and ages of bulk Fe-Mn crusts and crust layers that have <2% P content, KODOS 98-3 cruise

Sample Interval (mm)1

Type Growth rate (mm/Ma)2

Crust age(Ma)

Growth rate (mm/Ma)3

Crust age(Ma)

Marshall Islands Fe-Mn crust cruise

D1-1AD1-1A4D1-1BD1-1CD1-2BD1-2CD1-2DD1-4AD2-1BD2-1CD2-1C4D2-2BD2-4AD2-5AD2-6A

0-1000-1000-77-370-1010-2525-550-450-1010-6010-600-300-250-200-32

BulkBulkLayerLayerLayerLayerLayerBulkLayerLayerLayerLayerBulkLayerBulk

9.3 8.4 2.8 6.7 4.2 6.6 7.5 4.2 1.5 3.0 3.3 1.8 2.7 2.6 4.5

10.811.92.57

2.44.78.710.76.7

23.421.916.79.37.77.1

3.5 3.3 1.2 2.8 1.9 2.8 3.0 1.9 0.6 1.3 1.5 0.7 1.2 1.1 2.0

28.630.35.816.55.310.720.723.716.755.250.042.820.818.216.0

FSM Hvdrothermal cruise

D5-2AD5-2A4D7-11AD9-5-1AD9-6-1AD8-1A

0-8 Bulk0-8 Bulk0-5 Bulk0-5 Bulk0-9 BulkStratabound Mn

8.08.515.412.044.1

~

1.00.90.30.40.2

3.13.34.54.06.1

38.3

2.62.41.11.31.50.4

'Intervals measured from the outer surface of crusts2From equation of Puteanus and Halbach (1988); age of a layer is for the base of that layer3From equation of Manheim and Lane-Bostwick (1988)4Duplicate sample

31

Table 12. X-ray diffraction mineralogy of Fe-Mn crusts and hydrothermal deposits from Marshall Islands and FSM, KODOS 98-3 cruise

Sample Type & Interval (mm) 1

5-MnO2(%)2

Others(%)

Marshall Islands Fe-Mn crust leg

D1-1AD1-1BD1-1CD1-1DD1-2AD1-2BD1-2CD1-2DD1-2ED1-3AD1-4AD2-1AD2-1BD2-1CD2-1DD2-1ED2-2AD2-2BD2-2CD2-2DD2-3AD2-4AD2-5AD2-5BD2-6A

Bulk (0-100)Layer (0-7)Layer (7-37)Layer (37-102)Bulk (0-95)Layer (0-10)Layer (10-25)Layer (25-55)Layer (55-90)Bulk (0-62)Bulk (0-45)Bulk (0-142)Layer (0-10)Layer(10-60)Layer (60-100)Layer (100-150)Bulk (0-98)Layer (0-30)Layer (30-47)Layer (47-82)Bulk (0-1 10)Bulk (0-25)Layer (0-20)Layer (20-35)Bulk (0-32)

959899879196949585949795999982939010088749299946993

4-CFA, 1-goethite2-smectite1-goethite13-CFA,<1 -quartz6-CFA, 2-pyroxene , 1- smectite4-smectite2-plagioclase, 2-pyroxene, 1 -quartz, 1-goethite2-goethite, 1-plagioclase, 1 -quartz , <1- calcite12-CFA, 2-smectite, 1-goethite6-CFA3-K-feldspar5-CFA1 -calcite1-goethite1 6-CFA, 2-goethite5 -CF A, 1 -goethite, < 1 -quartz10-CFA~8-CFA. 3-phillipsite, 1-goethite26-CFA6-CFA, 2-smectite1-plagioclase4-smectite, 1-plagioclase, 1 -quartz14-CFA, 9-phillipsite, 7-plagioclase, 1-goethite5-CFA, 1-plagioclase, 1 -quartz

FSM Hydrothermal leg

D5-2AD5-16A

D7-11AD8-1AD9-5-1AD9-6-1A

Bulk (0-8)Mn sandstone

Bulk (0-5)Stratabound MnBulk (0-5)Bulk (0-9)

94?

949

9591

5-plagioclase, 1 -calcite25-birnessite, 50-plagioclase, 1 2-serpentine, 6-pyroxene, 4-amphibole, 3-quartz2-calcite, 2-plagioclase, 2-quartz78-birnessite, 17-smectite, 5-quartz3-plagioclase, 1 -calcite, 1 -quartz5-quartz, 2-calcite, 2-plagioclase

1 Intervals measured from the outer surface of crusts;2Percentages were determined by using the following weighting factors relative to quartz set at 1: 8-MnO2 70; todorokite 10; birnessite 12 (Hein et al., 1988); carbonate fluorapatite (CFA) 3.1; plagioclase 2.8; calcite 1.65; smectite 3.0; goethite 7.0; phillipsite 17.0; illite 6.0; pyroxene 5.0; halite 2.0 (Cook et al., 1975); the limit of detection for each mineral falls between 0.2 and 1.0%, except the manganese minerals which are greater, perhaps as much as 10% for 8-MnO2

32

Tabl

e 13

. C

hem

ical

com

posi

tion

of F

e-M

n ox

yhyd

roxi

de c

rust

s fr

om M

arsh

all I

slan

ds F

e-M

n cr

ust l

eg, K

OD

OS

98-3

cru

ise

Fe

wt%

Nfa

Fe/M

nSi N

aA

lK M

gCa Ti P S H

20'

LOI

As

ppm

B Ba Be Bi Cd a Co Cr Cu Ga

Hf

Li Ma

Mb

Ni

Pb Rb Sb Sc Sn Sr Te Th Tl U V w Zn Zr Au

ppb

Hg

Ir Os Pd Pt Rh

Ru Inte

rval

Type

DM

A18

.523

.70.

82.

71 1.08

0.34

0.36

0.89

5.79

1.30

51.

500.

21 16.6

18.7

198

178

3140

9.9

47.0

0.7

6560

3150

189

1150 61 8 3 497 37 2510

1310 15 34.9

6.6 6

1440

65.3

10.2

73.3

<0.5

646

<4 576

499 <2 <5 4 2 4 470 22 20

0-10

0Bu

lk

DM

A1

18.5

23.5

0.8

2.70

1.08

0.34

0.36

0.89

5.76

1.29

71.5

10.

21 16.3

18.6

170

184

3150

10.7

45.0 1.2

6440

3290

171

1180 63 7 3 515 36 2700

1360 16 27.8

6.7 8

1480

69.8

10.0

73.4

<0.5

727

<4 612

502

<2 <5 .. - - 0-

100

Bul

k

D1-

1B18

.926

.50.

73.

171.

300.

210.

42 1.04

2.66

1.27

30.

480.

2413

.9

20.1 - 228

1970

7.5

42.0

0.7

7230

6000 - 370 28 2 492 40 2990

1460 11 - 5.6 7

1400

56.4 152 - 648 528

513 5 9 2 2 6 130 12 20 0-7

Laye

r

D1-

1C20

.721

.7 1.0

4.77

1.25

0.89

0.52

0.97

2.90

1.65

90.

580.

1717

.6

17.9

200

204

2610

9.6

37.8

0.2

7850

3560

182

872

24 15 2 344

57 2300

1090 7

31.1 5.5 11 1300

64.3

6.5

91.0

11.5

556

74 635

652

<2 7 4 - 4 320

21 18 7-37

Laye

r

D1-

1D15

.718

.40.

92.

200.

840.

330.

200.

7412

.91.

064

4.19

0.27 15.0

16.5

185

147

2800

9.4

58.5

<0.2

5330

2230

183

1280 23 8 <1 423 31 1940

1300 9

32.1 5.4 9 1500

74.0

14.5

59.4 8.0

610

<4 549

367 6 <5 4 - 8 410 19 10

37-1

02La

yer

D1-

2A18

.119

.70.

94.

031.

070.

830.

420.

897.

721.

302

2.25

0.24

6.90 16.2

170

197

2860

11.1

45.8

0.8

6840

3320 <2 955

48 13 2 362 43 2840

1130 12 26.3

7.0 9

1500

71.8

<0.5

94.7

<0.5

676

<4 719

524

<2 6 -- - - - 0-95

Bul

k

D1-

2B20

.724

.40.

84.

03 1.31

0.50

0.47 1.02

2.59

1.60

80.

450.

18 10.5

17.9 - 242

2200

9.3

34.6 1.7

6950

4890 - 481 74 - 2 424

45 3190

1380 14 - 5.5 8

1340

56.6 - 122 - 704 - 626

481 - 16 - - - - - 0-10

Laye

r

D1-

2C19

.420

.90.

95.

841.

391.

340.

671.

003.

411.

603

0.71

0.17

11.3

16.3

165

202

3430

10.1

39.7

2.1

7430

3850 41 866

79 12 5 307 55 3250

1070 17 25.2

5.4 12 1260

80.1

<0.5

112

<0.5

624

<4 708

585

<2 9 .. - -- 10

-25

Laye

r

D1-

2D21

.021

.3 1.0

4.96

1.21

1.01

0.58

1.00

3.22

1.59

80.

620.

159.

40

17.0 - 206

2560

11.4

33.6 1.5

8250

3730 - 894

46 - 3 342

64 3200

1100 12 - 5.4 15 1260

76.6 - 104 705 - 741

685 - 8 - .. - - -

25-5

5La

yer

D1-

2E15

.315

.31.

03.

51 1.02

0.93

0.31

0.81 13.7

0.86

24.

670.

286.

30

14.7

135

155

2170

10.0

44.2

0.5

5290

1780 28 1170 40 13 5 281 27 2880

935 16 23.2 8.8 11 1440

57.4

6.3

60.4

13.2

552 <4 679

442 <2 6 -- .. - - -

55-9

0La

yer

D1-

3A18

.018

.41.

03.

961.

020.

850.

410.

849.

011.

268

2.76

0.26

8.60

16.3

206

188

2500

10.1

50.1 0.4

6650

3290

174

1210 26 12 2 398

45 2220

1170 13 31.7

8.3 8

1480

91.5

11.8

69.1

11.6

607

<4 627

488 <2 9 - - - - 0-62

Bul

k

D1-

4A19

.522

.80.

94.

82 1.19

1.02

0.56 1.03

2.59

1.73

30.

440.

188.

60

18.2

194

218

2700

10.0

38.2

0.9

7640

4970

162

937 33 14 3 383

55 3470

1330 11 30.6

6.5 12 1450

78.8

10.4

137

17.0

662

113

800

581 <2 <5 .. .. - 0-45

Bul

k

D2-

1A17

.322

.30.

82.

56 1.02

0.44

0.32

0.89

8.15

1.51

92.

270.

22 18.7

17.7

149

144

2900

10.1

48.8

0.4

7660

4240 <2 716 50 12 3 379 57 2830

1390 14 25.8

5.3 11 1230

118

11.8

116

<0.5

576 <4 520

471 <2 5 -- - - - - -

0-14

2B

ulk

D2-

1B16

.530

.1 0.5

2.26

1.23

0.01

0.37

1.09

2.89

1.16

20.

430.

198.

60

19.8 - 208

1680

6.9

38.1 2.4

7870

9790 - 410

61 - <1 583 39 5020

1610 13 - 4.8 8

1270

85.7 - 213 - 666 - 611

391 - 11 - - - - 0-10

Laye

r

Tabl

e 13

con

tinue

d

Fe

wt%

Mn

Fe/M

nSi N

aA

lK M

gCa Ti P S H

2Cf

LO

IA

s pp

mB Ba Be B

i Cd a Co

Cr

Cu

Ga

Hf

Li Mo

Nb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

Tl U V w Zn

Zr Au

ppb

Hg

Ir On Pd Pt Rh

Ru

Inte

rval

Typ

e

D2-

1C

19.3

25.6

0.8

3.40

1.22

0.62

0.46

1.05

2.87

1.56

00.

480.

2212

.2

18.7

169

188

2270

9.0

41.7 1.9

9770

5850 <2 917

58 11 2 449

58 4260

1210 19 23.1

5.7 12 1260

101

<0.5

176

<0.5

615

<4 692

566

<2 <5 -- - .. - -10

-60

Lay

er

D2-

1C1

19.2

25.4

0.8

3.40

1.22

0.63

0.46

1.04

2.85

1.55

30.

470.

1912

.3

18.8

157

200

2280

10.1

45.6 1.7

9550

5470 <2 940 47 10 2 426

59 4350

1100 20 22.6

5.4 13 1270

104

6.2

164

<0.5

659

<4 653

567 <2 <5 -- - - - - -

10-6

0L

ayer

D2-

1D

14.5

17.1

0.8

1.94

0.82

0.35

0.17

0.72

14.7

0.84

74.

930.

316.

30

16.0

171

153

2140

10.3

68.8

<0.2

6120

2420 <2 914

51 9 3 391 25 2430

1060 12 21.5

10.2 9

1460

72.7

14.7

87.9

<0.5

644

<4 557

375

<2 6 -- - - - - -60

-100

Lay

er

D2-

1E

18.4

22.1

0.8

2.86

0.96

0.43

0.39

0.80

6.97

1.65

91.

880.

279.

40

17.1

160

166

4180

15.2

81.0

<0.2

9090

3250 <2 730

55 11 2 553

55 2490

2170 19 32.7

5.7 9 1550

127

13.5

101

10.6

814

<4 633

510

<2 <5 -- - - -10

0-15

0L

ayer

D2-

2A

15.0

21.4

0.7

1.80

0.91

0.23

0.21

0.80

11.3

1.32

53.

490.

2614

.1

17.5

181

138

2730

8.4

54.6

<0.2

6670

4200

163

700

25 8 <1 419

42 2300

1440 17 31.0

5.0 10 1430

109

16.0

112

15.4

563

<4 511

359

<2 <5 6 2 6 620

29 14 0-98

Bul

k

D2-

2B

18.0

28.2

0.6

2.20

1.25

0.15

0.35

1.04

2.94

1.71

30.

380.

1917

.1

20.4

210

158

2430

7.0

53.0 1.4

9680

8030

158

993

31 11 <1 401 86 3720

1450 15 35.8

5.5 16 1280

158

14.4

172

<0.5

541

<4 621

543

45 5 14 2 10 1600

70 34 0-30

Lay

er

D2-

2C

14.5

24.6

0.6

1.37

0.91

0.06

0.22

0.85

9.86

1.25

32.

840.

3210

.0

18.8 - 143

2810

8.5

88.0

<0.2

7120

5430 - 947 34 - <1 591 38 2990

1820 10 - 6.6 9

1630

143 - 154 - 611 - 629

394 - 6 6 2 4

700 27 12

30-4

7L

ayer

D2-

2D

14.6

16.1

0.9

1.88

0.79

0.44

0.16

0.66

15.1

1.44

55.

190.

327.

30

14.9

184

136

3130

10.6

80.4

0.7

5710

2710

140

535

27 8 137

0 43 1400

1880 14 37.0

4.2 8

1750

125

9.8

82.8

<0.5

545

<4 536

310

<2 <5 4 .. 4 540 24 8

47-8

2L

ayer

D2-

3A

16.2

23.0

0.7

2.09

0.93

0.28

0.29

0.86

9.36

1.10

42.

770.

2815

.7

17.7

197

146

2920

8.1

53.7

0.5

6520

3600

145

914

29 8 3 581 30 2650

1350 15 28.5

6.0 6

1510

71.1

11.4

61.4

12.7

617

144

628

353

<2 <5 4 6 340 16 12

0-11

0B

ulk

D2-

4A

18.0

26.3

0.7

3.89

1.27

0.65

0.47

1.09

3.07

1.49

60.

460.

208.

80

18.5

172

211

1940

7.5

43.2

2.5

7350

6440 <2 434

51 5 348

642 50

1014

30 15 23.1

4.6 8

1210

73.4

<0.5

182

<0.5

631

<4 651

445

<2 8 -- - - - - 0-25

Bul

k

D2-

5A

18.2

26.5

0.7

3.60

1.29

0.59

0.50

1.08

2.64

1.43

70.

410.

209.

70

18.5

169

213

2000

7.8

40.4

2.0

7540

6640 <2 381

64 <1 2 486

45 4690

1500 16 25.7

4.4 8

1220

68.6

5.0

165

<0.5

646

<4 651

462

<2 8 - - 0-20

Lay

er

D2-

5B

15.7

10.2

1.5

10.9

1.60

3.69

1.62

1.47

5.65

1.31

71.

830.

146.

30

13.2

129

165

1040

5.4

11.7

2.3

5340

2190 58 685

49 13 30 102

49 4590

507 37 28.1

10.8 7 559

30.0

<0.5

55.4

<0.5

420

<4 633

464

<2 212 -- - - -

20-3

5L

ayer

D2-

6A

18.4

20.7

0.9

5.05

1.20

1.19

0.53

1.12

5.02

1.60

71.

200.

1812

.9

17.4

185

183

1780

7.1

24.8 1.6

7880

4580

136

607 27 12 8 308

54 3100

1170 19 30.8

7.3 7 1130

64.0

7.8

112

<0.5

490

<4 598

509 10 11 8 2 14 420

21 20 0-32

Bul

k

All

Ag

cont

ents

<0.

2ppm

; B

r <

lppm

^D

uplic

ate

anal

ysis

of

sam

ple

Cs

<3pp

m;

Ge

<10p

pm;

In <

0.5p

pm;

Se <

5ppm

; T

a <

lppm

Tabl

e 14

. Hyg

rosc

opic

wat

er-f

ree

(0%

H2O

") c

ompo

sitio

n of

Fe-

Mn

crus

ts fr

om T

able

13

Fe

wt%

Mn

Fe/M

nSi N

aA

lK M

gC

aT

i P S As

ppm

B Ba

Be

Bi Cd a Co

Cr

Cu

Ga

Iff

Li Kb

Nb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

Tl

U V W Zn

Zr

Au

ppb

Hg

Ir a Pd Pt Rh

Ru

Inte

rval

Typ

e

DM

A

22.1

28.4

0.8

3.25

1.29

0.41

0.43 1.07

6.94

1.56

41.

800.

25 237

213

3765

11.9

56.4

0.8

7866

3777

227

1379

73 10 4 596

44 3010

1571 18 41.8

7.9 7

1727

78.3

12.2

87.9

<0.6

775 <5 691

598

<2 <6 5 2 5 564

26 240-

100

Bul

k

DM

A'

22.1

28.1

0.9

3.23

1.29

0.40

0.43

1.07

6.88

1.54

91.

800.

25 203

220

3763

12.8

53.8 1.4

7694

3931

204

1410

75 8 4 615

43 3226

1625 19 33.2

8.0 10 1768

83.4

11.9

87.7

<0.6

869

<5 731

600

<2 <6 - - - - -0-

100

Bul

k

DM

B

21.9

30.8

0.7

3.69

1.51

0.25

0.49 1.21

3.09

1.47

90.

550.

28 -- 265

2288

8.7

48.8

0.8

8397

6969 - 430 33 - 2 571 46 3473

1696 13 - 6.5 8

1626

65.5 - 177 - 753 .. 613

596 6 10 2 2 7 151 14 23 0-7

Lay

er

D1-

1C

25.1

26.3 1.0

5.79

1.51

1.09

0.63

1.18

3.52

2.01

40.

700.

21 243

248

3167

11.7

45.9

0.2

9527

4320

221

1058 29 18 2 417

69 2791

1323 8

37.7

6.7 13 1578

78.0

7.9

110

14.0

675

90 771

791 <2 8 5 - 5 388

25 22 7-37

Lay

er

DM

D

18.4

21.6

0.9

2.59

0.99

0.39

0.23

0.87

15.1

1.25

24.

930.

32 218

173

3294

11.1

68.8

<0.2

6271

2624

215

1506

27 9 <1 498

36 2282

1529 11 37.8

6.4 11 1765

87.1

17.1

69.9

9.4

718

<5 646

432 7 <6 5 9 482

22 1237

-102

Lay

er

D1-

2A

19.5

21.2

0.9

4.33

1.15

0.89

0.45

0.95

8.29

1.39

82.

420.

26 183

212

3072

11.9

49.2

0.9

7347

3566 <2 1026

52 14 2 389

46 3050

1214 13 28.2

7.5 10 1611

77.1

<0.5

102

<0.5

726

<4 772

563

<2 6 .. -- - 0-95

Bul

k

D1-

2B

23.1

27.3

0.8

4.50

1.46

0.56

0.53

1.14

2.90

1.79

70.

510.

20 - 270

2458

10.4

38.7 1.9

7765

5464 - 537

83 - 2 474

50 3564

1542 16 6.1 9

1497

63.2 - 136 - 787 .. 699

537 - 18 -- .. - - 0-10

Lay

er

D1-

2C

21.8

23.6

0.9

6.59

1.56

1.51

0.76

1.12

3.84

1.80

70.

800.

19 186

228

3867

11.4

44.8

2.4

8377

4340 46 976 89 14 6 346 62 3664

1206 19 28.4

6.1 14 1421

90.3

<0.6

126

<0.6

703 <5 798

660

<2 10 - - - -10

-25

Lay

er

D1-

2D

23.2

23.5 1.0

5.47

1.33

1.11

0.64

1.11

3.55

1.76

40.

680.

17 - 227

2826

12.6

37.1 1.7

9106

4117 - 987

51 - 3 377

71 3532

1214 13 - 6.0 17 1391

84.5 - 115 - 778 - 818

756 - 9 -- - - - - -

25-5

5L

ayer

D1-

2E

16.3

16.4

1.0

3.74

1.08

0.99

0.33

0.86

14.6

0.92

04.

980.

30 144

165

2316

10.7

47.2

0.5

5646

1900 30 1249 43 14 5 300

29 3074

998 17 24.8

9.4 12 1537

61.3

6.7

64.5

14.1

589

<4 725

472

<2 6 .. -55

-90

Lay

er

D1-

3A

19.7

20.1 1.0

4.33

1.12

0.93

0.45

0.92

9.85

1.38

73.

020.

28 225

206

2735

11.1

54.8

0.4

7276

3600

190

1324

28 13 2 435

49 2429

1280 14 34.7

9.1 9

1619

100

12.9

75.6

12.7

664

<4 686

534

<2 10 -- - - - - 0-62

Bul

k

D1-

4A

21.3

24.9

0.9

5.27 1.31

1.12

0.62 1.13

2.84

1.89

60.

480.

20 212

239

2954

10.9

41.8 1.0

8359

5438

177

1025 36 15 3

419

60 3796

1455 12 33.5

7.1 13 1586

86.2

11.4

150

18.6

724

124

875

636

<2 <5 .. - - - - 0-45

Bul

k

D2-

1A

21.2

27.4

0.8

3.15

1.25

0.55

0.40

1.09

10.0

1.86

82.

800.

27 183

177

3567

12.4

60.0

0.5

9422

5215 <2 881 62 15 4 466

70 3481

1710 17 31.7

6.5 14 1513

145

14.5

143

<0.6

708 <5 640

579

<2 6 .- - - - -0-

142

Bul

k

D2-

1B

18.1

32.9

0.5

2.48

1.35

0.01

0.41 1.19

3.17

1.27

10.

470.

21 -- 228

1838

7.5

41.7

2.6

8611

1071

1- 44

967 - <1 63

843 54

9217

61 14 - 5.3 9

1389

93.8 - 233 - 729 - 668

428 - 12 -- - - - - - 0-10

Lay

er

Tabl

e 14

con

tinue

d

Fe

wt%

Mi

Fe/M

nSi N

aA

lK M

gCa Ti P S A

s pp

mB Ba B

e Bi Cd a Co

Cr

Cu

Ga

Hf

Li Nfo

Nb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

Tl U V W Zn

Zr

Au

ppb

Hg

Ir Os Pd Pt Rh

Ru

Inte

rval

Typ

e

D2-

1C22

.029

.10.

93.

871.

390.

710.

531.

203.

271.

777

0.54

0.25 192

214

2585

10.3

47.5

2.2

1112

866

63 <2 1044

66 14 251

1 66 4852

1378 22 26.3

6.5 14 1435

115

<0.6

200

<0.6

700

<5 788

645

<2 <6 -- - - - 10

-60

Lay

er

D2-

1C1

21.9

29.0

0.9

3.88

1.40

0.72

0.53

1.19

3.25

1.77

00.

540.

22 179

228

2600

11.5

52.0 1.9

1088

962

37 <2 1072 54 12 2

486 67 4960

1254 23 25.8

6.2

'15 14

4811

97.

118

7<0

.675

1 <5 745

647 <2 <6 - - - - -

10-6

0L

ayer

D2-

1D15

.518

.30.

92.

080.

880.

380.

180.

7715

.60.

904

5.26

0.33 182

163

2284

11.0

73.4

<0.2

6531

2583 <2 975 54 11 3

417 27 2593

1131 13 22.9

10.9 10 1558

77.6

15.7 94 <0.5

687 <4 594

400

<2 6 - - - - -60

-100

Lay

er

D2-

1E22

.226

.61.

03.

451.

150.

520.

470.

978.

412.

002

2.26

0.33 193

200

5042

18.3

97.7

<0.2

1096

539

20 <2 881

66 13 2 667

66 3004

2618 23 39.4

6.9 11 1870

153

16.3

122

12.8

982

<5 764

615

<2 <6 -- - -- -- - -10

0-15

0L

ayer

D2-

2A17

.424

.90.

82.

101.

060.

270.

240.

9313

.11.

543

4.06

0.30 211

161

3178

9.8

63.6

<0.2

7765

4889

190

815

29 10 <1 488

49 2678

1676 20 36.1

5.8 12 1665

127

18.6

130

17.9

655 <5 595

418

<2 <6 7 2 7 722 34 16 0-98

Bul

k

D2-

2B21

.834

.00.

82.

651.

500.

180.

421.

263.

542.

067

0.46

0.23 253

191

2931

8.4

63.9

1.7

1167

796

8619

111

98 37 14 <1 484

104

4487

1749 18 43.2

6.6 19 1544

191

17.4

207

<0.6

653

<5 749

655

54 6 17 2 12 1930 84 41 0-30

Lay

er

D2-

2C16

.127

.30.

71.

521.

010.

070.

240.

9411

.01.

392

3.16

0.36 - 159

3122

9.4

97.8

<0.2

7911

6033 1052 38 .. <1 657

42

33

2220

22 11 - 7.3 10 1811

159 - 171 - 679 - 699

438 - 7 7 2 4

778 30 13

30-4

7L

ayer

D2-

2D15

.817

.41.

02.

030.

850.

480.

170.

71 16.3

1.55

95.

600.

35 198

147

3376

11.4

86.7

0.8

6160

2923

151

577 29 9 1

399

46 1510

2028 15 39.9

4.5 9

1888

135

10.6 89 <0.5

588 <4 578

334 <2 <5 4 - 4 583 26 9

47-8

2L

ayer

D2-

3A19

.227

.30.

82.

471.

110.

330.

341.

0211

.11.

309

3.28

0.33 234

173

3464

9.6

63.7

0.6

7734

4270

172

1084 34 10 4 689-

36 3144

1601 18 33.8

7.1 7

1791

84.3

13.5 73 15.1

732

171

745

419

<2 <6 5 - 7 403 19 14

0-11

0B

ulk

D2-

4A19

.728

.80.

84.

261.

390.

710.

521.

193.

371.

640

0.51

0.22 189

231

2127

8.2

47.4

2.7

8059

7061 <2 476

56 6 353

346 54

9315

68 16 25.3

5.0 9

1327

80.5

<0.6

200

<0.6

692

<4 714

488

<2 9 -- - - - 0-25

Bul

k

D2-

5A20

.129

.30.

83.

991.

430.

660.

551.

202.

931.

591

0.46

0.22 187

236

2215

8.6

44.7

2.2

8350

7353 <2 422

71 <1 2 538

50 5194

1661 18 28.5

4.9 9

1351

76.0

6.1

183

<0.6

715 <4 721

512

<2 9 - - -- - - 0-20

Lay

er

D2-

5B16

.710

.91.

611

.71.

703.

941.

731.

576.

031.

405

1.95

0.15 138

176

1110

5.8

12.5

2.5

5699

2337 62 731 52 15 32 109

52 4899

541 39 30.0

11.5 7 597

32.0

<0.6

59 <0.5

448

<4 676

495 <2 226 -- - -

20-3

5L

ayer

D2-

6A21

.123

.71.

05.

801.

381.

360.

611.

295.

771.

845

1.37

0.21 212

210

2044

8.2

28.5 1.9

9047

5258

156

697 31 15 9 354

62 3559

1343 22 35.4

8.4 8

1297

73.5 9.4

129

<0.6

563 <5 687

584 11 13 9 2 16 482 24 23 0-32

Bul

k

All

Ag

cont

ents

<0.

2ppm

; B

r <l

ppm

; D

uplic

ate

anal

ysis

of

sam

ple

Cs

<3pp

m;

Ge

<10p

pm;

In <

0.5p

pm;

Se <

5ppm

; T

a <

lppm

Table 15 Statistics for 25 bulk Fe-Mn crusts and crust layers from Marshall Islands Fe-Mn crust leg KODOS 98-3 cruise; hygroscopic water-free data from Table 14

Fe wt. %MnFe/Mn4SiNaAlKMgCaTiPSH2O'

LOIAs ppmBBaBeBiCdClCoCrCuGaHfLiMoNbNiPbRbSbScSnSrTeThnuVwYZnZrAu ppbHgIrOsPdPtRhRuDepth5Thickness

N2525252525252525252525252525202525252525252520252520252525252525202525252520252025202525252125106101010102525

Mean20.024.90.84.041.270.780.491.087.531.5782.120.2611.317.4201204

286510.554.5-1.282005001-10291149-12-4

47153

35351513

1733.07.011

153696.6-9.7130-6.1697

-23.1287708543 5-17

728

6483120

187847

Median20.126.30.83.741.310.560.451.116.031.5641.800.2510.017.7196210

293110.748.8-0.880594340-10797651-13-2

47449

34731542

1633.66.610

155884.5-11.0126-0.6703 5

271699537 2-6527

5232619

180535

SD 12.65.40.52.080.220.770.300.194.68

0.3131.750.063.861.703035

7952.419.80.9

1571217992

3081946

13016

1026396

66.01.73

25836.36.4507.19547697511411444

0.14

4842098437

Min215.510.91.4

1.520.850.010.170.712.84

0.9040.460.156.3013.2138147

11105.812.5<0.256461900<2

42227<1<110927

1510541

822.94.57

59732.0<0.559

<0.5448<4195578334<2<5224

151149

18057

Max325.134.00.7

11.681.703.941.731.5716.272.0675.600.3618.720.4253270

504218.397.82.7

11677107112271506891832

689104

5493261839

43.211.519

188819118.623318.698217139387579154

22617216

19308441

1970142

Standard deviation; Minimum; depth in meters; 6Crust thickness

Maximum; Ratio of means, in millimeters

not a mean of the summation of ratios; JWater

37

Table 16. Statistics for 9 bulk Fe-Mn crusts from Marshall Islands Fe-Mn crust leg KODOS 98-3 cruise; hygroscopic water-free data from Table 14

Fe wt.%MnFe/Mn4SiNaAlKMgCaTiPSH2OLOIAs ppmBBaBeBiCdClCoCrCuGaHfLiMoNbNiPbRbSbScSnSrTeThTlUVWYZnZrAu ppbHgITOsPdPtRhRuDepth5Thickness6

N9999999999999999999999999999999999999999999999943444499

Mean20.125.20.83.881.230.730.451.077.931.6062.190.2612.317.6210202299010.451.7-1.080974786-1249674512-448551

3404149117

33.47.210

157194.7-10.4121-7.5693-36288712535 3-8629

5432619

187879

Median19.724.90.84.261.250.710.451.078.291.5642.420.2612.917.7212210307210.954.8-0.878664889-17210253613 346649

3144156817

33.87.19

161184.3-12.2129-0.6708 5304691563 2-6627

5232520180595

SD11.53.10.51.240.120.370.120.123.500.2221.240.054.230.921276031.611.40.873011299428816321061189317734.71.3216725.06.1418.36164588178322

0.15136658740

Minz17.420.10.92.101.060.270.240.922.841.3090.480.206.9016.218316120448.228.5<0.272763566<2476286<135436

2429121412

25.35.07

129773.5<0.573<0.5563<4205595418<2<5525

4031914

180525

Max"22.128.80.85.801.391.360.621.2913.11.8964.060.3318.718.7237239376512.463.72.794227061227137973159

68970

549317102241.89.114

179114518.620018.67751713668756361113921672234241970142

Standard Deviation; L Minimum; depth in meters; 6Crust thickness

""Maximum; "Ratio of means, in millimeters

not a mean of the summation of ratios; ''Water

38

Table 17. Statistics for 16 Fe-Mn crust layers from Fe-Mn crust leg KODOS 98-3 cruise; hygroscopic water-free data from Table 14

Fe wt. %MnFe/Mn4SiNaAlKMgCaTiPSH20LOIAs ppmBBaBeBiCdClCoCrCuGaHfLiMoMbNiPbRbSbScSnSrTeThTlUVwYZnZrAu ppbHgIrOsPdPtRhRuDepth5Thickness6

N16161616161616161616161616161116161616161616111616111616161616161116161616111611161116161612166366661616

Mean19.924.70.94.131.300.800.521.087.311.5632.080.2510.717.4194206279510.556.1-1.382575122-8488052-12-446354

3608152517

32.67.011

151697.6-9.0135-4.9699-12286707548-7-22727

7193420187729

Median21.026.50.83.711.370.540.481.133.701.5750.750.249.8517.5192207270610.547.3-1.283634330-4697652-14 247950

3502153615

30.06.510

154085.8-7.9124-0.6702~5263710525~2~8 o

526

5322618

180530

SD13.16.40.52.470.260.930.370.225.330.3602.010.073.642.035398962.723.51.01912262291324204814419

11164847

7.12.03

30042.16.8546.211226767413215555

0.13

62925128517

Min^15.510.91.41.520.850.010.170.712.900.9040.460.156.3013.213814711105.812.5<0.256461900<242227<1<11092715105418

22.94.57

59732.0<0.659<0.5448<4195578334<2<5224

151149

18057

Max"25.134.00.711.681.703.941.731.5716.272.0675.600.3617.620.4253270504218.397.82.6

11677107112211506891832667104549226183943.211.519

188819117.423314.1982903938187915422617212

19308441197065

Standard Deviation; Minimum; depth in meters; 6Crust thickness

Maximum; Ratio of means, in millimeters

not a mean of the summation of ratios;

39

Table 18. Concentrations of yttrium and rare earth elements (ppm) in Fe-Mn crusts from Marshall Islands (Dl, D2) and Fe-Mn crusts and Mn stratabound deposits from FSM (D5-D9), KODOS 98-3 cruise

YLaCePrNdSmEuGdTbDyHoErTmYbLuIREECe*Interval2

DMA264345

145054.024043.110.152.27.9

46.29.8029.64.3

28.64.5423252.3

B 0-85

DMA1

280359151057.424743.310.756.48.2

47.09.9430.84.5

28.54.6624172.3

B 0-85

D1-1B233 '28175544.8199

37.19.8050.67.7

47.510.732.34.8

31.34.9815171.5

L 0-7

D1-1C11124884141.9179

34.48.6742.26.5

36.57.7923.73.4

20.33.3414971.8

L 7-37

DMD248352

156055.522140.39.5147.47.2

39.98.3624.63.8

24.43.9123982.4

L 37-102

D1-3A220271124046.5193

36.49.2844.86.7

37.68.2023.63.5

23.73.8219482.5

B 0-62

D1-4A187279103048.220740.110.349.47.5

42.58.8725.83.7

25.13.9517812.0

B 0-45

D2-1C210318

117052.923243.110.151.28.0

46.39.3729.34.2

29.34.3420082.0

B 0-9

D2-2A313373

147052.921637.09.0446.77.0

40.89.0327.94.0

27.14.2423252.2

B 0-98

D2-2B175253142039.616430.47.6337.75.9

34.17.5722.43.3

21.33.4120503.1

L 0-30

YLaCePrNdSmEuGdTbDyHoErTmYbLuIREECe*Interval

D2-2C343359

179057.023140.29.6851.37.8

44.39.6630.04.5

30.04.4326692.7

L 30-47

D2-2D344398

175052.220832.58.1645.96.6

37.68.9626.93.7

24.64.1926072.6

L 47-82

D2-3A256333

123056.2233

41.19.9650.87.6

43.19.4427.84.0

27.24.0620772.0

B 0-110

D2-6A31927371046.720940.510.653.78.0

47.010.430.24.1

26.74.5914741.4

B 0-32

D5-2A20429971862.125853.813.061.99.4

50.410.228.83.6

27.64.1016001.2

B 0-8

D5-2A 119229866358.824751.312.658.99.0

48.19.5428.03.9

25.83.9015181.1

B 0-8

D5-16A24

23.155.15.1

21.54.81.305.80.94.91.103.00.42.0

0.511301.2

Mn SS

D7-11A20729059458.824752.911.158.69.1

50.210.127.93.4

30.54.0614481.0

B 0-5

D8-1A109.46.31.77.11.9

0.862.10.31.7

0.441.30.20.6

0.22340.4

Strat. Mn

D9-5-1A22430767363.927155.613.665.49.8

54.111.0313.7

32.24.4715961.1

B 0-5

Duplicate analysis of sampleIntervals measured from the outer surface of the crust; B = bulk, L = layer; Ce* = 2Ce/La+Pr from chondrite-normalized data

40

Tabl

e 19

. C

orre

latio

n co

effic

ient

mat

rix f

or 9

bul

k cr

usts

list

ed in

Tab

le 1

4; n

=9, e

xcep

t for

Cd,

Li =

8; T

h =

7; C

r, H

g =

6; Ir

, Pd,

Pt,

Rh, R

u, a

nd U

= 4

; the

zer

o co

rrel

atio

ns fo

r 9 p

oint

s, 8

poin

ts,

7 po

ints

, 6 p

oint

s, an

d 4

poin

ts a

t the

95%

con

fiden

ce le

vel

are

10.6

651,

10.

7061

, 10

.753

1, 1

0.81

31,

10.9

621,

res

pect

ivel

y;

stat

istic

ally

sig

nific

ant c

orre

latio

ns a

re in

bol

d; --

= in

suff

icie

nt c

orre

latio

n pa

irs

Mi

Fe/M

nSi N

aA

lK M

gC

aTi P S L

OI

As

B Ba

Be

Bi Cd a Co

Cr

Cu

Ga

Hf

Li Mo

Mb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

Tl U V Y Zn

Zr

Hg

Ir Pd Pt Rh

Ru

Dep

thT

hick

Fe 0.25

0.16

10.

509

0.66

0.36

30.

633

0.62

-0.6

020.

636

-0.6

2-0

.558

0.36

90.

097

0.53

90.

095

0.31

1-0

.439

-0.0

620.

511

0.01

50.

202

0.25

80.

535

0.38

40.

393

-0.1

170.

440.

184

-0.0

83-0

.104

0.28

10.

38-0

.057

-0.2

11-0

.252

-0.7

620.

037

0.02

50.

211

-0.1

510.

335

0.85

8-0

.085

-0.0

420.

197

-0.4

42-0

.448

0.85

80.

342

-0.0

81

Mn

-0.8

12-0

.371

0.50

7-0

.537

-0.1

670.

404

-0.1

930.

269

-0.2

43-0

.144

0.88

90.

057

-0.0

720.

267

-0.1

70.

252

0.30

50.

390.

529

0.36

2-0

.283

0.56

3-0

.555

0.14

30.

673

-0.0

70.

548

0.82

10.

321

0.04

4-0

.624

-0.0

39-0

.017

0.08

50.

132

0.40

30.

564

0.38

80.

145

-0.1

17-0

.15

-0.1

68-0

.957

-0.8

18-0

.213

-0.3

28-0

.015

-0.4

710.

177

Fe/M

n

0.75

10

0.85

30.

546

0.10

9-0

.208

0.06

5-0

.174

-0.3

-0.6

80.

081

0.37

1-0

.564

-0.1

16-0

.664

-0.0

2-0

.046

-0.2

55-0

.488

0.14

5-0

.536

0.59

30.

271

-0.7

170.

273

-0.2

59-0

.839

-0.1

320.

048

0.75

7-0

.144

-0.3

41-0

.331

-0.6

13-0

.231

-0.5

43-0

.605

-0.1

310.

220.

412

0.58

40.

870.

982

-0.2

97-0

.187

0.50

10.

365

-0.5

27

S

0.54

60.

968

0.95

30.

615

-0.7

770.

468

-0.7

6-0

.837

-0.4

17-0

.193

0.80

1-0

.697

-0.2

31-0

.944

0.48

30.

257

0.23

4-0

.445

-0.1

9-0

.143

0.45

60.

368

-0.6

950.

425

0.34

2-0

.679

-0.2

51-0

.218

0.38

9-0

.026

-0.6

64-0

.534

-0.8

420.

289

0.02

2-0

.414

-0.3

750.

533

0.69

20.

465

0.71

80.

882

-0.3

76-0

.286

0.70

30.

309

-0.7

52

Na

0.40

30.

643

0.92

9-0

.76

0.76

1-0

.796

-0.8

470.

445

-0.2

170.

539

-0.4

37-0

.343

-0.6

310.

712

0.70

50.

702

-0.1

34-0

.499

0.39

1-0

.03

0.56

2-0

.18

0.50

10.

728

0.16

80.

231

-0.0

91-0

.198

0.03

3-0

.748

-0.2

07-0

.671

0.67

80.

621

-0.2

17-0

.014

0.08

80.

505

0.30

30.

522

0.64

3-0

.228

-0.1

690.

924

-0.2

39-0

.478

Al

0.87

10.

509

-0.6

080.

408

-0.5

86-0

.714

-0.5

27-0

.202

0.64

8-0

.716

-0.2

48-0

.932

0.36

0.24

0.14

2-0

.569

-0.1

98-0

.322

0.56

70.

407

-0.7

990.

461

0.18

1-0

.739

-0.1

72-0

.19

0.45

60.

016

-0.6

41-0

.45

-0.7

550.

201

-0.0

01-0

.566

-0.2

470.

441

0.60

80.

519

0.84

50.

961

-0.2

95-0

.19

0.57

40.

254

-0.7

04

K

0.71

4-0

.871

0.54

9-0

.864

-0.8

92-0

.266

-0.2

950.

848

-0.5

63-0

.134

-0.8

990.

558

0.34

50.

302

-0.3

71-0

.22

0.09

30.

418

0.33

9-0

.583

0.42

90.

481

-0.5

59-0

.317

-0.2

970.

248

0.01

8-0

.638

-0.5

48-0

.883

0.37

50.

171

-0.2

01-0

.436

0.63

40.

763

0.14

60.

561

0.78

3-0

.487

-0.4

150.

753

0.29

9-0

.64

Mg

-0.7

210.

634

-0.7

58-0

.832

0.33

4-0

.216

0.49

5-0

.498

-0.4

41-0

.745

0.76

30.

684

0.59

6-0

.351

-0.5

310.

295

0.06

0.76

4-0

.202

0.41

10.

679

00.

317

-0.1

46-0

.084

-0.1

48-0

.756

-0.3

92-0

.748

0.54

10.

523

-0.3

080.

089

0.16

90.

456

0.41

60.

561

0.78

3-0

.487

-0.4

150.

753

-0.2

99-0

.476

Ca

-0.5

250.

997

0.95

40.

008

0.16

9-0

.934

0.50

50.

249

0.74

1-0

.718

-0.2

44-0

.527

0.11

70.

275

-0.2

51-0

.003

-0.1

310.

262

-0.2

17-0

.717

0.26

50.

325

0.26

90.

058

0.02

0.56

20.

589

0.81

-0.5

63-0

.364

-0.0

290.

542

-0.6

44-0

.619

0.01

-0.3

-0.5

140.

419

0.38

3-0

.897

-0.2

570.

72

Ti

-0.5

42-0

.631

0.38

3-0

.324

0.32

-0.1

420.

06-0

.49

0.21

30.

860.

517

-0.2

07-0

.322

0.22

0.46

0.41

1-0

.443

0.88

30.

368

0.22

50.

051

0.03

7-0

.119

0.58

3-0

.537

0.23

8-0

.353

0.58

80.

721

-0.1

92 0 0.12

0.67

7-0

.158

0.75

30.

699

0.13

90.

218

0.85

-0.1

06-0

.165

P

0.95

8-0

.039

0.18

7-0

.915

0.50

10.

260.

732

-0.7

51-0

.287

-0.5

560.

117

0.30

4-0

.291

0.01

6-0

.166

0.23

7-0

.23

-0.7

470.

224

0.28

70.

279

0.08

40.

030.

586

0.57

20.

824

-0.5

84-0

.364

-0.0

270.

514

-0.6

1-0

.61

-0.0

1-0

.289

-0.5

110.

438

0.40

3-0

.889

-0.2

090.

699

S

0.00

50.

253

-0.8

440.

647

0.38

10.

865

-0.7

85-0

.407

-0.6

110.

285

0.44

8-0

.154

-0.0

85-0

.376

0.42

3-0

.378

-0.7

140.

260.

113

0.25

90.

062

-0.0

270.

745

0.51

30.

788

-0.6

47-0

.478

0.23

70.

335

-0.4

77-0

.603

-0.2

27-0

.636

-0.7

60.

256

0.18

1-0

.854

-0.0

820.

769

LO

I

0.26

2-0

.269

0.44

5-0

.002

0.28

10.

025

0.52

50.

287

0.43

6-0

.053

0.47

8-0

.28

0.34

50.

585

0.11

70.

195

0.84

80.

512

0.42

9-0

.346

0.01

20.

110.

255

0.12

30.

159

0.61

20.

276

0.42

7-0

.29

-0.0

27-0

.069

-0.8

12-0

.738

-0.0

4-0

.145

0.30

8-0

.424

0.35

5

As

-0.1

120.

27-0

.078

0.18

-0.3

34-0

.33

-0.4

350.

566

0.62

4-0

.258

-0.1

640.

151

0.50

4-0

.464

-0.4

560.

048

0.25

10.

789

0.48

7-0

.555

0.55

5-0

.295

-0.2

09-0

.641

-0.7

490.

119

0.20

80.

021

-0.1

450.

475

-0.8

88-0

.635

-0.4

78-0

.578

0.03

10.

215

-0.0

13

B

-0.4

8-0

.092

-0.6

910.

548

-0.0

390.

274

0.03

8-0

.044

0.20

90.

042

-0.1

34-0

.337

0.08

10.

526

-0.5

11-0

.524

-0.2

480.

142

-0.0

96-0

.427

-0.6

59-0

.781

0.36

20.

117

0.09

6-0

.683

0.68

90.

651

-0.0

440.

176

0.36

-0.3

31-0

.314

0.93

80.

537

-0.7

27

Ba

0.75

40.

75-0

.781

-0.1

07-0

.549

0.74

20.

640.

405

0.06

5-0

.351

0.51

3-0

.162

-0.5

260.

446

-0.0

910.

463

0.02

20.

145

0.83

10.

392

0.47

9-0

.509

0.25

60.

736

0.16

2-0

.094

-0.0

26-0

.793

-0.9

6-0

.984

0.13

50.

014

-0.2

630.

223

0.88

4

Be

0.42

2-0

.793

-0.0

85-0

.609

0.84

60.

685

0.45

70.

441

-0.5

21-0

.049

0.17

2-0

.51

-0.0

3-0

.492

0.23

20.

282

0.35

10.

534

0.36

80.

194

-0.4

07-0

.229

0.62

1-0

.187

0.07

10.

44-0

.729

-0.7

81-0

.848

0.27

20.

164

0.22

0.60

50.

677

Bi

-0.6

13-0

.352

-0.3

290.

524

0.36

40.

163

-0.3

72-0

.594

0.66

2-0

.409

-0.3

860.

568

-0.0

30.

154

-0.2

80.

092

0.73

90.

566

0.79

6-0

.358

-0.3

030.

550.

113

-0.4

02-0

.579

-0.5

42-0

.803

-0.9

220.

287

0.18

8-0

.664

-0.0

960.

768

Cd

0.19

90.

793

-0.5

22-0

.833

0.05

1-0

.481

0.34

6-0

.144

0.00

80.

865

0.00

10.

277

-0.4

7-0

.53

-0.1

7-0

.795

-0.4

53-0

.922

0.76

30.

997

-0.4

2-0

.042

0.01

5-0

.10.

436

0.99

0.95

10.

132

0.37

60.

545

-0.4

36-0

.739

a

0.51

2-0

.544

-0.4

530.

187

0.39

90.

642

-0.2

530.

831

0.33

90.

385

0.38

4-0

.006

-0.1

580.

407

-0.5

540.

346

-0.2

830.

478

0.88

1-0

.329

0.31

3-0

.146

0.39

40.

073

0.85

40.

961

-0.2

76-0

.17

0.57

6-0

.501

0.05

Co

-0.6

41-0

.858

0.04

9-0

.342

0.22

5-0

.046

0.32

40.

888

0.40

30.

137

-0.5

09-0

.716

0.29

9-0

.706

0.06

2-0

.049

0.93

70.

984

-0.2

72-0

.149

0.02

5-0

.068

0.08

20.

933

0.81

80.

151

0.26

5-0

.066

-0.5

8-0

.488

Cr

0.73

90.

798

-0.5

84-0

.504

0.40

7-0

.432

-0.4

630.

343

-0.1

710.

827

-0.0

11-0

.129

0.58

70.

138

0.28

2-0

.352

-0.2

050.

682

-0.0

59-0

.234

0.12

-0.4

93-0

.648

-0.7

850.

430.

333

0.31

20.

577

0.54

5

Cu

0.09

0.24

4-0

.367

0.22

6-0

.287

-0.7

32-0

.227

-0.3

160.

628

0.68

2-0

.236

0.76

6-0

.071

-0.1

14-0

.836

-0.8

520.

512

-0.1

160.

155

0.24

2-0

.263

-0.8

85-0

.767

-0.1

48-0

.258

0.18

10.

729

0.39

6

Ga

-0.2

13-0

.196

0.25

90.

025

0.30

60.

285

-0.1

05-0

.029

-0.2

34-0

.034

-0.0

03 0-0

.067

0.17

70.

515

0.61

9-0

.081

-0.0

50.

365

-0.5

18-0

.57

-0.5

150.

013

-0.0

670.

607

0.15

50.

341

Hf '

0.23

9-0

.677

0.68

4-0

.424

-0.4

18-0

.181

0.14

80.

575

0.40

9-0

.071

0.16

8-0

.523

-0.2

290.

125

-0.2

430.

032

0.24

10.

638

-0.1

670.

870.

982

-0.2

97-0

.187

0.50

10.

30.

143

Tabl

e 19

con

tinue

d

K)

Mo

Nb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

Tl U V Y Zn

Zr

Hg

Ir Pd Pt Rh

Ru

Dep

thT

hick

Li-0

.195

0.37

30.

073

0.06

30.

874

0.33

0.20

7-0

.245

-0.4

87-0

.172

-0.6

880.

088

0.40

4-0

.69

0.80

3-0

.304

0.14

20.

673

10.

985

-0.0

110.

240.

419

-0.5

39-0

.227

Mo

-0.6

580.

048

0.60

10.

175

0.20

7-0

.291

-0.4

220.

568

-0.0

340.

291

-0.2

55-0

.189

0.57

80.

082

-0.0

94-0

.542

-0.2

37-0

.964

-0.8

11-0

.299

-0.4

06-0

.484

-0.2

30.

376

Nb

0.10

70.

070.

05-0

.039

0.03

90.

681

-0.5

40.

473

-0.2

040.

427

0.50

7-0

.398

0.09

2-0

.08

0.59

3-0

.089

0.95

0.84

30.

206

0.31

20.

571

-0.1

42-0

.015

Ni

0.19

8-0

.075

-0.6

36-0

.628

0.04

5-0

.669

-0.2

55-0

.527

0.84

90.

657

-0.0

17-0

.374

0.25

60.

061

0.00

40.

480.

803

-0.7

48-0

.675

0.44

6-0

.354

-0.5

22

Pb 0.39

80.

162

-0.6

630.

293

0.17

50.

581

0.67

70.

296

0.59

90.

256

0.34

1-0

.426

-0.3

78-0

.279

-0.6

83-0

.891

0.48

50.

396

-0.6

3-0

.594

0.45

6

Rb

0.41

4-0

.058

-0.3

09-0

.193

0.11

40.

108

-0.0

220.

067

-0.5

260.

921

-0.6

84-0

.354

0.76

51

0.90

10.

147

0.26

50.

296

-0.6

990.

081

Sb

0.50

6-0

.223

0.47

90.

031

-0.0

77-0

.571

0.04

20.

051

0.51

7-0

.247

0.14

70.

328

-0.3

42-0

.435

0.34

0.27

90.

70.

233

0.24

5

Sc

-0.3

920.

18-0

.311

-0.7

25-0

.73

-0.8

23-0

.171

0.04

90.

139

0.43

80.

390.

215

0.51

9-0

.636

-0.6

030.

759

0.55

6-0

.052

Sn

-0.1

040.

70.

401

0.47

40.

805

0.01

-0.1

690.

025

0.22

5-0

.818

0.35

-0.0

650.

877

0.90

3-0

.33

-0.0

430.

21

Sr

0.11

80.

48-0

.729

-0.2

290.

653

0.02

60.

066

-0.2

74-0

.654

-0.9

45-0

.954

0.06

7-0

.046

-0.5

270.

369

0.63

4

Te

0.74

40.

119

0.18

3-0

.037

0.26

-0.5

87-0

.199

-0.3

620.

023

-0.3

60.

814

0.80

4-0

.565

-0.3

50.

605

Th

0.04

90.

237

0.16

10.

271

-0.5

74-0

.691

-0.6

02-0

.26

-0.5

940.

721

0.67

9-0

.661

-0.3

40.

617

Tl

0.91

8-0

.207

-0.2

220.

045

0.09

7-0

.115

0.87

80.

585

0.60

20.

694

0.22

-0.3

99-0

.446

U

0.21

20.

126

0.26

60.

185

-1 1 1 1 1-0

.181

-0.0

97

V

-0.4

20.

356

0.09

2-0

.94

-0.9

82-0

.91

-0.0

69-0

.189

-0.1

280.

452

0.48

1

Y

-0.7

15-0

.295

0.57

90.

903

0.62

70.

556

0.65

20.

208

-0.5

410.

353

Zn

0.44

2-0

.514

-0.3

890.

048

-0.9

63-0

.987

0.01

40.

522

-0.3

62

Zr

Hg

Ir

Pd

Pt

Rh

Ru

Dep

th

-0.3

660.

250.

357

-

0.90

1-0

.157

-

0.14

7 -0

.292

-0.1

35

-

0.26

5 -0

.176

0.

993

0.98

6 -

0.29

6 0.

329

0.01

2 0.

035

0.57

6 -0

.418

-0

.522

-0

.508

0.

104

0.02

7 0.

634

-0.1

8 -0

.539

-0

.906

-0

.961

0.

162

0.05

2 -0

.563

-0

.078

Tabl

e 20

. C

orre

latio

n co

effic

ient

mat

rix

for

5 bu

lk c

rust

s >8

5mm

list

ed in

Tab

le 1

4; n

=5, e

xcep

t for

Cd,

Li,

and

Th =

4; t

he z

ero

corr

elat

ions

for

5 a

nd 4

poi

nts

at th

e 95

% c

onfid

ence

leve

l are

10.

8831

and

10.

9621

, res

pect

ivel

y; s

tatis

tical

ly s

igni

fican

t cor

rela

tions

are

in

bold

; -

= in

suff

icie

nt c

orre

latio

n pa

irs

Mn

FeM

n S

N

a A

l K

M

g C

a Ti

P S L

OI

As

B

Ba

Be

Bi Cd a Co

Cu

Ga

Hf

Li Mo

Nb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

TI V Y Zn

Zr

Dep

thT

hick

Fe0.

511

-0.1

16

0.48

6 0.

882

0.14

1 0.

629

0.98

2 -0

.83

0.54

8 -0

.877

-0

.803

0.

493

0.08

2 0.

624

0.8

0.77

2 -0

.346

-0.0

660.

44-0

.216

0.66

90.

950.

278

0.48

20.

130.

286

0.63

40.

026

-0.2

310.

306

0.66

7-0

.209

-0.1

64-0

.156

-0.8

42-0

.128

0.80

6-0

.346

0.19

30.

850.

458

0.39

3

Mn

-0.8

96-0

.495

0.

649

-0.7

68

-0.3

2 0.

522

-0.0

49

0.39

5 -0

.118

0.

041

0.98

1 0.

612

-0.2

21

0.91

9 -0

.04

0.61

3-0

.628

0.50

80.

355

0.37

80.

301

-0.3

730.

989

0.73

10.

101

0.31

70.

792

0.65

90.

696

0.05

-0.1

970.

288

0.2

-0.9

84-0

.119

0.34

30.

453

-0.3

390.

039

-0.3

280.

471

Fe/M

n

0.80

8 -0

.408

0.

943

0.68

6 -0

.134

-0

.366

-0

.34

-0.3

06

-0.3

89

-0.9

2 -0

.566

0.

582

-0.6

65

0.33

2 -0

.867

0.73

-0.4

72-0

.616

-0.0

280.

060.

494

-1 -0.6

5-0

.132

-0.0

44-0

.96

-0.9

07-0

.672

0.36

4-0

.035

-0.2

64-0

.448 -

-0.1

040.

087

-0.7

760.

639

0.29

80.

612

-0.4

06

S

0.18

4 0.

926

0.97

70.

467

-0.7

9 0.

082

-0.7

69

-0.8

16

-0.5

18

-0.5

09

0.85

3 -0

.125

0.

778

-0.9

630.

739

-0.1

-0.6

140.

315

0.62

0.65

2-0

.877

-0.5

450.

124

0.36

3-0

.805

-0.9

36-0

.441

0.66

7-0

.081

-0.3

98-0

.419

-0.7

77-0

.094

0.50

9-0

.874

0.63

20.

780.

779

-0.0

75

Na

-0.1

1 0.

32

0.87

3 -0

.541

0.

833

-0.6

05

-0.6

34

0.70

4 0.

014

0.29

9 0.

827

0.71

5 -0

.057

-0.3

160.

70.

198

0.38

70.

862

0.25

70.

577

0.04

20.

576

0.54

80.

396

0.10

60.

436

0.26

40.

149

-0.3

540.

271

-0.5

640.

260.

468

0.06

3-0

.289

0.74

70.

167

0.56

8

Al

0.84

5 0.

144

-0.5

09

-0.0

26

-0.4

72

-0.5

84

-0.7

75

-0.7

08

0.64

9 -0

.479

0.

613

-0.9

240.

625

-0.1

81-0

.497

-0.0

160.

320.

718

-0.9

51-0

.742

0.15

0.21

6-0

.868

-0.9

62-0

.68

0.39

50.

121

-0.5

01-0

.287

-0.3

650.

069

0.17

1-0

.826

0.55

90.

557

0.62

3-0

.141

K

0.62

9 -0

.84

0.17

1 -0

.836

-0

.838

-0

.361

-0

.449

0.

841

0.05

4 0.

824

-0.8

90.

671

0.03

7-0

.558

0.38

50.

710.

669

-0.8

16-0

.419

0.17

30.

529

-0.6

97-0

.898

-0.3

940.

719

-0.1

17-0

.384

-0.3

92-0

.831

-0.1

30.

617

-0.8

890.

644

0.83

20.

721

0.08

Mg

-0.7

54

0.59

7 -0

.812

-0

.727

0.

492

-0.0

07

0.52

4 0.

785

0.76

9 -0

.286

-0.3

160.

556

-0.1

020.

555

0.90

30.

384

0.57

70.

123

0.37

70.

768

0.07

6-0

.254

0.18

10.

591

-0.1

23-0

.242

-0.0

55-0

.831

-0.0

670.

747

-0.3

830.

194

0.81

50.

327

0.54

2

Ca

-0.1

51

0.99

6 0.

94-0

.017

-0

.034

-0

.953

-0.4

34

-0.7

5 0.

753

-0.7

490.

067

0.69

-0.7

92-0

.881

-0.2

380.

279

0.06

80.

051

-0.3

280.

50.

57-0

.16

-0.9

090.

433

0.03

50.

572

0.86

20.

366

-0.8

810.

625

-0.5

37-0

.865

-0.8

630.

101

Ti

-0.2

18

-0.3

87

0.50

3 -0

.418

-0

.052

0.

465

0.67

4 0.

047

-0.4

830.

902

0.59

2-0

.18

0.59

20.

541

0.37

8-0

.331

0.92

40.

547

0.48

50.

109

0.08

9-0

.225

0.67

-0.7

490.

718

-0.0

430.

739

-0.0

530.

19-0

.578

0.58

6-0

.159

0.76

P

0.93

7-0

.085

-0

.03

-0.9

21-0

.497

-0

.775

0.

709

-0.6

62-0

.019

0.62

8-0

.783

-0.9

1-0

.266

0.18

40.

041

-0.0

07-0

.402

0.43

30.

543

-0.1

67-0

.893

0.40

40.

064

0.51

70.

873

0.33

6-0

.89

0.61

1-0

.506

-0.8

84-0

.813

0.01

2

S

0.01

1 0.

203

-0.9

-0

.346

-0

.897

0.

793

-0.5

92-0

.089

0.51

2-0

.592

-0.9

32-0

.41

0.30

90.

345

-0.2

23-0

.31

0.44

50.

562

-0.1

08-0

.717

0.12

30.

324

0.32

0.64

50.

039

-0.6

80.

52-0

.298

-0.9

66-0

.833

0.01

1

LO

I

0.54

8 -0

.246

0.

896

0.01

0.

613

-0.6

030.

559

0.43

30.

308

0.32

7-0

.351

0.96

70.

618

0.20

90.

249

0.84

30.

715

0.74

1-0

.047

-0.0

660.

183

0.31

3-0

.822

0.03

20.

246

0.56

-0.4

930.

077

-0.3

290.

472

As

-0.0

26

0.52

1 -0

.524

0.

447

0.01

8-0

.366

-0.2

570.

634

-0.0

83-0

.915

0.57

70.

897

-0.6

99-0

.356

0.32

0.59

70.

798

0.29

2-0

.768

0.91

3-0

.462

-0.4

19-0

.70.

409

0.38

60.

05-0

.339

0.01

4-0

.366

B

0.16

6 0.

659

-0.8

810.

925

-0.3

16-0

.834

0.73

0.73

50.

203

-0.5

6-0

.205

-0.1

930.

109

-0.7

11-0

.673

0.05

90.

894

-0.4

560.

002

-0.6

89-0

.795

-0.4

010.

777

-0.6

740.

615

0.77

30.

969

-0.3

49

Ba

0.29

4 0.

252

-0.4

320.

479

0.08

50.

621

0.63

7-0

.198

0.90

40.

595

0.12

70.

444

0.53

20.

363

0.67

0.37

8-0

.297

0.19

10.

001

-0.9

31-0

.20.

635

0.16

5-0

.123

0.40

10.

030.

426

Be

-0.6

80.

189

0.45

4-0

.146

0.24

30.

892

0.72

7-0

.239

-0.5

290.

606

0.57

4-0

.273

-0.5

75-0

.144

0.43

20.

263

-0.6

760.

068

-0.4

660.

315

0.43

6-0

.496

0.11

10.

976

0.54

20.

368

Bi

-0.8

530.

303

0.71

1-0

.327

-0.5

34-0

.505

0.87

60.

595

0.00

7-0

.099

0.88

10.

887

0.35

5-0

.642

0.12

30.

31 0.5

0.64

60.

119

-0.4

350.

779

-0.5

89-0

.703

-0.8

730.

317

Cd

-0.8

03-0

.943

0.51

10.

209

-0.1

39-0

.73

-0.3

38-0

.498

-0.8

5-0

.867

-0.6

140.

032

0.85

6-0

.446

0.19

5-0

.792

-0.9

93-0

.409

0.50

8-0

.612

0.65

40.

328

0.94

9-0

.9

a

0.75

6-0

.312

0.36

70.

531

0.54

4-0

.105

0.88

0.73

10.

627

0.17

8-0

.062

-0.3

360.

636

-0.6

460.

784

-0.0

80.

649

-0.1

150.

168

-0.4

980.

337

-0.4

770.

96

Co

-0.7

2-0

.276

0.17

80.

582

-0.0

550.

683

0.23

20.

811

0.56

3-0

.052

-0.8

540.

762

-0.4

480.

959

0.65

0.74

8-0

.673

0.61

5-0

.7%

-0.2

95-0

.87

0.71

1

Tabl

e 20

con

tinue

d

Ga

Hf

Li Mo

Mb

Ni

Pb Rb

Sb Sc Sn Sr Te Th

Tl V Y Zn

Zr

Dep

thT

hick

Cu

0.60

7-0

.377

0.21

20.

493

-0.4

990.

024

-0.2

28-0

.102

0.58

50.

894

-0.8

250.

548

-0.7

56-0

.83

-0.7

370.

932

-0.2

760.

483

0.44

50.

688

-0.3

3

Ga

0.36

80.

131

-0.1

370.

360.

494

-0.1

18-0

.334

0.26

30.

639

-0.0

8-0

.318

-0.1

36-0

.692

0.01

80.

715

-0.3

550.

130.

958

0.61

60.

263

Hf

-0.4

44-0

.721

0.73

60.

68-0

.295

-0.6

9-0

.741

-0.0

170.

607

-0.8

870.

36-0

.048

0.54

4-0

.066

-0.5

760.

125

0.57

10.

073

0.56

7

Li

0.72

90.

137

0.37

80.

961

0.98

0.65

6-0

.279

-0.0

770.

267

0.38

9-

-0.0

080.

217

0.97

9-0

.682

-0.1

9-0

.577

0.52

9

MD

-0.5

560.

006

0.44

40.

548

0.57

10.

221

-0.6

880.

824

-0.3

15-0

.592

-0.6

740.

399

0.26

20.

129

-0.3

94-0

.257

-0.0

12

Mb

0.54

90.

358

-0.0

46-0

.26

-0.4

230.

872

-0.9

180.

831

0.19

80.

887

-0.3

170.

093

-0.5

450.

448

-0.2

880.

784

Ni

0.11

2-0

.364

-0.3

650.

218

0.18

3-0

.453

0.23

6-0

.562

0.13

20.

36-0

.492

0.22

70.

498

-0.1

350.

844

Pb 0.87

20.

493

-0.5

690.

308

0.01

90.

680.

646

0.35

9-0

.30.

799

-0.7

72-0

.3-0

.745

0.55

3

Rb

0.69

8-0

.531

0.05

10.

368

0.40

60.

766

0.12

4-0

.336

0.94

8-0

.736

-0.5

37-0

.60.

075

Sb

0.16

5-0

.395

0.51

8-0

.131

-0.2

94-0

.247

0.32

10.

614

-0.3

780.

020.

122

-0.2

25

Sc

-0.7

480.

329

-0.8

31-0

.939

-0.7

150.

953

-0.6

750.

769

0.58

60.

814

-0.2

86

Sn -0.8

70.

904

0.64

30.

985

-0.7

280.

273

-0.6

650.

07-0

.454

0.54

Sr

-0.6

61-0

.279

-0.8

570.

345

0.16

40.

325

-0.5

050.

065

-0.5

69

Te

0.62

60.

904

-0.6

930.

533

-0.8

22-0

.1-0

.714

0.69

6

Th

0.62

-0.9

710.

878

-0.7

99-0

.592

-0.6

03-0

.167

Tl

V

-0.6

780.

355

-0.5

32-0

.745

0.

629

0.14

3 0.

594

-0.3

87

0.65

70.

509

-0.0

74

Y

Zn

Zr

Dep

th

-0.8

77-0

.492

0.

183

-0.5

54

0.53

7 0.

665

0.01

1 -0

.303

0.

241

-0.5

44

Tabl

e 21

. C

orre

latio

n co

effic

ient

mat

rix fo

r 4 b

ulk

crus

ts <

62m

m li

sted

in T

able

14;

n=4

; th

e ze

ro c

orre

latio

n fo

r 4 p

oint

s at

the

95%

co

nfid

ence

leve

l is

10.9

621;

sta

tistic

ally

sig

nific

ant c

orre

latio

ns a

re in

bol

d

Mi

Fe/M

nSi N

aA

lK M

jCa Ti P S LO

IAs B Ba Be Bi C

d a Co Cu Ga

Hf

Li Ma

Nb

Ni

Pb Rb Sb Sc Sn Sr Te Tl V Y Zn Zr

Hg

Dep

thTh

ick

Fe-0

.011

0.26

0.93

20.

379

0.82

80.

901

0.46

-0.4

550.

925

-0.4

19-0

.575

0.44

80.

192

0.28

50.

165

0.02

8-0

.779

-0.0

910.

775

0.01

2-0

.026

-0.3

720.

740.

557

-0.7

240.

969

-0.1

22-0

.079

0.17

70.

531

0.19

60.

499

-0.0

42-0

.489

0.03

4-0

.196

0.31

40.

593

0.92

3-0

.18

0.06

6-0

.146

Mi

-0.9

1-0

.06

0.80

8-0

.348

0.4

0.63

3-0

.857

0.36

8-0

.89

-0.7

950.

866

-0.9

760.

727

-0.4

37-0

.63

-0.1

830.

872

0.35

90.

996

-0.8

710.

93-0

.68

0.00

70.

603

-0.1

910.

993

0.96

90.

052

-0.8

47-0

.966

0.14

9-0

.602

-0.6

270.

999

0.29

8-0

.196

0.22

8-0

.268

-0.2

55-0

.604

-0.8

71

Fe/M

n

0.40

6-0

.492

0.67

-0.0

91-0

.255

0.73

7-0

.118

0.75

30.

522

-0.6

080.

895

-0.7

940.

145

0.32

3-0

.226

-0.6

550.

037

-0.8

720.

622

-0.9

60.

795

0.40

8-0

.844

0.47

2-0

.915

-0.9

770.

322

0.93

50.

985

-0.2

930.

272

0.24

8-0

.906

-0.6

290.

564

-0.3

130.

379

0.50

10.

302

0.59

9

S

0.47

10.

949

0.87

0.61

8-0

.302

0.82

7-0

.292

-0.5

560.

446

0.18

50.

007

-0.1

41-0

.22

-0.9

310.

044

0.88

8-0

.007

-0.1

56-0

.419

0.71

50.

816

-0.8

30.

974

-0.1

45-0

.207

0.51

40.

573

0.29

60.

153

-0.2

94-0

.64

-0.0

27-0

.532

0.63

50.

266

0.77

20.

185

-0.1

92-0

.26

Na

0.23

70.

739

0.96

6-0

.775

0.63

8-0

.82

-0.9

430.

967

-0.7

710.

427

-0.6

83-0

.845

-0.7

150.

887

0.82

0.85

3-0

.935

0.58

-0.2

760.

589

0.05

40.

297

0.78

10.

652

0.54

6-0

.438

-0.6

28-0

.062

-0.8

58-0

.965

0.81

4-0

.247

0.37

40.

075

0.01

50.

143

-0.8

16-0

.971

Al

0.67

0.44

10.

015

0.61

70.

024

-0.2

790.

166

0.43

6-0

.289

-0.1

12-0

.11

-0.8

47-0

.155

0.74

7-0

.288

0.05

4-0

.653

0.83

0.82

8-0

.957

0.93

9-0

.414

-0.5

0.56

80.

769

0.57

-0.0

21-0

.187

-0.4

6-0

.321

-0.6

810.

741

0.06

70.

723

0.36

3-0

.097

-0.0

34

K

0.76

4-0

.732

0.98

1-0

.723

-0.8

70.

79-0

.244

0.46

8-0

.157

-0.3

44-0

.866

0.34

50.

923

0.43

2-0

.452

0.03

50.

387

0.62

5-0

.458

0.82

30.

305

0.29

20.

322

0.14

7-0

.193

0.39

1-0

.399

-0.7

860.

437

-0.1

890.

336

0.52

10.

685

-0.1

32-0

.302

-0.5

56

Mg

-0.6

220.

638

-0.6

7-0

.878

0.88

6-0

.606

0.21

3-0

.748

-0.8

68-0

.849

0.81

20.

909

0.69

5-0

.87

0.37

5-0

.103

0.77

7-0

.17

0.43

70.

607

0.43

40.

723

-0.2

3-0

.412

-0.1

98-0

.896

-0.9

990.

637

-0.4

790.

596

-0.0

530.

084

0.34

-0.8

45-0

.912

Ca

-0.7

570.

996

0.91

6-0

.911

0.72

7-0

.897

0.10

40.

359

0.38

7-0

.603

-0.5

56-0

.845

0.65

5-0

.644

0.23

8-0

.08

-0.2

61-0

.247

-0.7

89-0

.852

0.09

10.

507

0.78

3-0

.55

0.36

10.

635

-0.8

83-0

.374

0.23

-0.6

43-0

.261

0.51

40.

314

0.71

5

Ti

-0.7

33-0

.827

0.73

5-0

.186

0.56

80.

028

-0.1

76-0

.766

0.22

30.

832

0.38

4-0

.332

0.00

90.

431

0.48

1-0

.428

0.82

0.26

0.30

40.

139

0.16

8-0

.192

0.55

9-0

.23

-0.6

640.

41-0

.026

0.17

50.

673

0.76

9-0

.307

-0.1

3-0

.444

P

0.93

3-0

.937

0.77

4-0

.867

0.18

70.

435

0.40

8-0

.669

-0.5

77-0

.883

0.71

7-0

.683

0.28

8-0

.119

-0.2

82-0

.219

-0.8

29-0

.869

0.02

60.

546

0.80

8-0

.477

0.43

60.

68-0

.912

-0.3

240.

182

-0.5

75-0

.20.

449

0.39

20.

772

S

-0.9

890.

69-0

.645

0.40

10.

618

0.70

1-0

.726

-0.8

26-0

.819

0.79

5-0

.516

0.11

7-0

.469

-0.0

02-0

.441

-0.7

33-0

.69

-0.3

090.

352

0.62

9-0

.269

0.63

90.

888

-0.8

160.

031

-0.1

81-0

.401

-0.2

770.

151

0.57

70.

861

LOI

-0.7

870.

639

-0.4

83-0

.692

-0.6

350.

815

0.77

10.

891

-0.8

690.

625

-0.2

590.

427

0.12

40.

312

0.81

90.

760.

323

-0.4

75-0

.715

0.18

8-0

.703

-0.8

90.

881

-0.0

170.

159

0.31

60.

132

-0.1

14-0

.655

-0.9

19

As

-0.5

840.

560.

711

0.10

7-0

.923

-0.2

7-0

.979

0.90

2-0

.965

0.8

-0.0

03-0

.677

0.34

1-0

.995

-0.9

31-0

.134

0.91

0.95

50.

045

0.67

30.

593-

-0.9

64-0

.216

0.13

9-0

.024

0.46

20.

104

0.69

40.

877

B

0.27

90.

030.

009

0.31

10.

171

0.67

7-0

.34

0.61

4-0

.266

-0.3

480.

445

0.03

80.

659

0.83

2-0

.52

-0.5

26-0

.761

0.78

50.

043

-0.2

280.

755

0.74

1-0

.629

0.81

90.

252

-0.8

290.

072

-0.3

89

Ba

0.96

60.

483

-0.8

21-0

.487

-0.5

090.

808

-0.4

020.

435

-0.6

49-0

.069

0.08

6-0

.495

-0.2

24-0

.864

0.36

40.

290.

769

0.96

10.

726

-0.4

070.

666

-0.6

870.

677

0.51

7-0

.758

0.97

70.

769

Be 0.56

1-0

.926

-0.6

08-0

.695

0.92

8-0

.539

0.46

3-0

.637

-0.1

240.

008

-0.6

66-0

.428

-0.7

910.

467

0.47

10.

578

0.99

70.

851

-0.6

090.

533

-0.5

910.

466

0.41

-0.5

80.

999

0.90

8

Bi

-0.3

83-0

.981

-0.2

520.

479

0.15

5-0

.434

-0.9

320.

659

-0.8

23-0

. 124

0.01

8-0

.735

-0.3

13-0

.077

0.09

0.62

30.

861

-0.2

030.

654

-0.7

62-0

.048

-0.5

-0.3

770.

538

0.55

9

Cd 0.49

80.

909

-0.9

930.

806

-0.6

640.

361

0.41

6-0

.162

0.89

90.

736

0.50

4-0

.733

-0.7

69-0

.321

-0.9

05-0

.796

0.85

5-0

.174

0.25

1-0

.22

-0.4

460.

25-0

.915

-0.9

72

a

0.42

1-0

.593

0.01

60.

314

0.86

3-0

.522

0.77

30.

296

0.17

30.

662

0.15

3-0

.109

0.00

6-0

.663

-0.9

20.

381

-0.5

230.

650.

151

0.47

40.

253

-0.5

79-0

.674

Co

-0.9

110.

911

-0.6

630.

092

0.55

3-0

.153

0.99

0.94

30.

142

-0.8

23-0

.941

0.08

6-0

.67

-0.6

880.

993

0.21

1-0

.107

0.17

4-0

.27

-0.1

75-0

.669

-0.9

12

Tabl

e 21

con

tinue

d

Ga

Hf

Li Nfo

Nb

Ni

Pb Rb

Sb Sc Sn Sr Te Tl V Y Zn

Zr

Hg

Dep

thT

hick

Cu

-0.7

620.

578

-0.4

32-0

.328

0.04

7-0

.885

-0.7

25-0

.532

0.67

0.74

50.

269

0.91

60.

858

-0.8

590.

204

-0.2

950.

156

0.34

-0.2

360.

913

0.99

3

Ga

-0.8

96-0

.254

0.84

5-0

.539

0.95

90.

942

-0.0

86-0

.983

-0.9

770.

018

-0.4

86-0

.36

0.91

40.

413

-0.3

610.

051

-0.5

62-0

.238

-0.5

27-0

.72

Hf

0.38

4-0

.927

0.83

4-0

.758

-0.7

040.

072

0.95

60.

788

0.28

50.

393

0.07

7-0

.646

-0.3

220.

340.

299

0.86

30.

018

0.47

30.

489

Li

-0.6

860.

679

-0.0

14-0

.229

0.91

60.

369

0.24

8-0

.428

-0.6

93-0

.779

0.01

1-0

.882

0.94

4-0

.306

0.27

30.

685

-0.6

31-0

.48

Mo

-0.8

680.

660.

716

-0.4

4-0

.92

-0.7

790.

029

-0.0

490.

188

0.57

90.

645

-0.6

67-0

.021

-0.7

21-0

.355

-0.1

29-0

.25

Nb

-0.2

88-0

.292

0.33

10.

683

0.39

40.

31-0

.069

-0.4

63-0

.151

-0.4

040.

498

0.40

10.

892

0.03

50.

036

-0.0

65

Ni

0.95

80.

08-0

.894

-0.9

70.

051

-0.6

31-0

.597

0.98

50.

272

-0.1

840.

123

-0.3

81-0

.186

-0.6

45-0

.87

Pb

-0.1

96-0

.881

-0.9

920.

313

-0.3

9-0

.43

0.97

10.

524

-0.4

320.

363

-0.2

55-0

.46

-0.4

-0.7

22

Rb

0.14

80.

163

-0.7

41-0

.823

-0.7

110.

035

-0.9

370.

959

-0.6

39-0

.131

0.88

7-0

.802

-0.5

31

Sb

0.93

30.

048

0.40

40.

212

-0.8

25-0

.448

0.42

30.

039

0.67

80.

217

0.46

20.

609

Sc

-0.2

080.

426

0.40

3-0

.961

-0.4

950.

417

-0.2

510.

376

0.38

60.

449

0.72

7

Sn

0.56

60.

170.

193

0.74

5-0

.666

0.98

90.

664

-0.9

390.

617

0.19

Sr 0.88

-0.5

830.

575

-0.6

380.

448

0.34

4-0

.595

0.99

40.

903

Te

-0.6

330.

47-0

.59

0.02

4-0

.117

-0.3

20.

826

0.90

3

Tl

V

0.31

3-0

.206

-0

.988

0.27

4 0.

673

-0.2

19

0.00

9-0

.287

-0

.928

-0.5

8 0.

551

-0.8

65

0.20

6

Y

Zn

Zr

Hg

Dep

th

-0.5

750.

074

0.70

70.

876

-0.8

98

-0.3

71-0

.602

0.

51

0.44

3 -0

.612

-0.3

11

0.06

8 0.

223

-0.1

92

0.88

7

Table 22. Chemical composition of Fe-Mn oxyhydroxide crusts and stratabound Mn deposits from FSM hydrothermal leg, KODOS 98-3 cruise

Fe wt.%MnFe/MnSiNaAlKMgCaTiPSH2OLOIB ppmBaBeBiCdClCoCuGaLiMoNbNiPbRbScSnSrTeTlVZnZrHg ppbIntervalType

D5-2A19.021.10.96.401.191.490.481.503.22

0.9330.410.177.7017.221314206.211.11.8

90903700763518

36444

35301080

1910.8

6116039.511753161948015

0-8Bulk

D5-2A119.021.10.96.401.191.490.481.493.21

0.9300.41

17.522514207.29.61.5

3600749548

36144

39801100209.26

1090 Ill58660748015

0-8Bulk

D5-16A7.906.971.1

17.11.053.340.4111.22.94

0.2820.060.042.109.9059

2671.72.12.7

56303098731885595

1520804

19.9<21492.2

37.62173538416

MnSandstone

D7-11A23.820.31.2

5.891.36

<0.010.671.242.83

0.7520.460.208.7016.622211806.712.11.4

93102950541285

35268

29001010407.25

115031.180.756850557816

0-5Bulk

D8-1A1.5043.10.032.760.982.350.672.551.02

0.0360.060.062.0019.256

115200.6

<0.515.37160889197058175359

26280

54113.7<26390.857.750616102518

StrataboundMn

D9-5-1A19.920.90.96.401.291.280.601.162.81

0.8950.450.1910.216.922214207.015.41.1

84003110620283

33739

25701020218.35

114034.086.9523493504

90-5

Bulk

D9-6-1A18.720.40.97.011.361.540.641.183.14

0.9000.610.207.8016.921913006.814.10.9

79402480507405

27737

3370863216.74

88228.972.0552452462240-9

BulkAll Ag contents <0.2ppm; Ge <10ppm; In <0.5ppm Duplicate analysis of sample

47

Table 23. Hygroscopic water-free (0% H2O~) composition of Fe-Mn crusts and stratabound Mn deposits from Table 22

Fe wt.%MnFe/MnSiNaAlKMgCaTiPSB ppmBaBeBiCdClCoCuGaLiMoNbNiPbRbScSnSrTeTlVYZnZrHg ppbIntervalType

D5-2A20.522.80.96.941.291.610.521.633.481.0110.440.1823115386.712.02.0

98484009827559

39448

3824117021

11.77

125742.812757522167152016

0-8Bulk

D5-2A120.522.80.96.941.291.610.521.613.481.0070.44

24415387.810.41.6

3900811599

39148

4312119222

10.07

1181~

12063520865852016

0-8Bulk

D5-16A8.077.121.1

17.41.083.420.4211.53.01

0.2880.060.0460

2731.72.12.8

57513168921887605

1553824

20.3<21522.2

38.422225

3618616

MnSandstone

D7-11A26.022.21.2

6.451.49

<0.010.741.353.10

0.8230.500.2224312927.313.31.5

101973231593315

38674

31761106447.95

126034.188.462222755363318

0-5Bulk

D8-1A1.5344.00.032.811.002.400.692.601.04

0.0370.060.0657

117550.6

<0.515.673069072010

59179366

26408

55113.8<26520.858.951610

16432618

StrataboundMn

D9-5-1A22.123.30.9

7.131.441.430.671.293.13

0.9970.510.2124715817.817.11.2

93543463690313

37543

28621136239.26

126937.996.858224954956110

0-5Bulk

D9-6-1A20.322.20.9

7.611.471.670.691.283.40

0.9770.660.2223814107.415.31.0

86122690550435

30040

3655936237.34

95731.378.1599249490501260-9

BulkAll Ag contents <0.2ppm; Ge<10ppm; In <0.5ppm Duplicate analysis of sample

48

Table 24. Statistics for 4 bulk Fe-Mn crusts from the Yap convergent margin hydrothermal leg KODOS 98-3 cruise; data from Table 23

Fe wt.%MnFe/Mn4SiNaAlKMgCaTiPSH2CTLOIB ppmBaBeBiCdClCoCuGaLiMoNbNiPbRbScSnSrTeTlVYZnZrHg ppbDepth5Thickness6

N44444444444444444444444444444444444444444

Mean22.222.61.07.031.42-1.180.651.393.280.9520.530.218.6016.924014567.3114.431.4295033348665406

36451

33791087289.05

118636.59859523756655417

24087

Median20.522.20.96.941.44-1.430.671.293.130.9770.500.217.8016.923814107.3413.251.2293543231593315

37543

31761106237.95

125734.18858222754952016

25045

SD1

10.210.11.03.170.640.860.300.641.480.4320.250.093.977.61076613.296.740.7342911570316213167271559494164.43

54616.94726710726125310

10994

Min'

20.322.20.96.451.29<0.010.521.283.100.8230.440.187.7016.623112926.7212.030.9886122690550313

300402862936217.34

95731.37857522149050110

20295

MaxJ

26.023.31.17.611.491.670.741.633.481.0110.660.2210.217.224715817.8017.151.95101974009827559

39474382411704411.77

126942.812762224967163326

25509

Standard deviation; Minimum; Maximum; Ratio of means, not a mean of the summation of ratios; Water depth in meters; Crust thickness in millimeters; LOI and H2O" from Table 22

49

160C

166

14C

RE

PU

BL

IC O

FJM

AR

SHA

LL

ISL

AN

D~

o~

« °~

u

172'

Figu

re 1

. A

tolls

and

sea

mou

nts

com

pris

ing

the

Mar

shal

l Isl

ands

with

the

two

boxe

d ar

eas

encl

osin

g L

omili

k Se

amou

nt a

nd

Lita

kpoo

ki R

idge

, whi

ch w

ere

stud

ied

durin

g cr

uise

KO

DO

S 98

-3; n

ote

the

loca

tion

of C

TD 2

bet

wee

n L

omili

k an

d L

itakp

ooki

se

amou

nts.

The

box

ed r

egio

ns in

the

inse

t map

sho

w lo

catio

ns in

Fig

ures

1 a

nd 4

160°30'E 160°35 'E 160°40'E 160°45 'E 160°50'E

&oo '

OO

o OO

o(So OO

OO

o OO

Figure 2. SeaBeam bathymetry, dredge (D), CTD, and piston core (PC) locations for Litakpooki Ridge, located south of Ujlan Atoll in the Marshall Islands group; D14 and D15 from KODOS 97-4 (Hein, Moon, et al., 1998); contour interval is 200m

51

161°

20'E

161°

25 'E

161°

30'E

161°

35 'E

161°

40 'E

161°

45 'E

Figu

re 3

. Se

aBea

m b

athy

met

ry f

or L

omili

k Se

amou

nt, l

ocat

ed w

est o

f Ane

wet

ak A

toll;

D4-

D13

fro

m K

OD

OS

97-4

(H

ein,

Moo

n, e

t al.,

199

8);

cont

our i

nter

val i

s 10

0m

136C

140

145C

Figu

re 4

. A

toll

and

isla

nd n

ames

with

in th

e Ex

clus

ive

Econ

omic

Zon

e of

the

wes

tern

Fed

erat

ed

Stat

es o

f Mic

rone

sia,

incl

udin

g th

e Y

ap c

onve

rgen

t mar

gin

and

the

wes

tern

edg

e of

Car

olin

e R

idge

; hat

chur

ed li

nes

are

basi

ns;

boxe

d ar

ea w

as s

urve

yed

durin

g K

OD

OS

98-3

; con

tour

inte

rval

is

100

0 m

; mod

ified

fro

m C

hase

et a

l. (1

988)

.

137°

30'E

137°

45'E

138°

00'E

138°

15'E

138°

30'E

138°

45 'E

Yap

Arc

Yap

Tre

nch

00

§0

Wes

t Car

olin

e R

idge

Figu

re 5

. Se

aBea

m b

athy

met

ry, d

redg

e (D

), C

TD, p

isto

n co

re (

PC),

box

core

(B

C),

and

mul

tiple

cor

e (M

C)

loca

tions

for

Yap

-Car

olin

e R

idge

co

nver

gent

mar

gin;

con

tour

inte

rval

is 2

00 m

100-,

Iu1. 10 H

A.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

wrj

1"E,

0.1-

0.01B.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Figure 6. REE plots of phosphatized limestone sample D1-10A, Litakpooki Ridge:(A) Chondrite (Anders and Grevesse, 1989) normalized, and (B) Post Archean AustralianShale (PAAS, McLennan, 1989) normalized

55

A. (Co+Ni+Cu)xlO

Bulk crusts, Litakpooki Ridge < 60 mm o Bulk crusts, Litakpooki Ridge > 60 mm Bulk crusts, Yap Arc+ Bulk crusts, SW Caroline Ridge Stratabound Mn, Yap Arc

Mn-cemented SS, Yap Arc

Fe Mn

B.(Co+Ni+Cu)xlO

Non-phosphatized crust layers (P < 1%) o Phosphatized crust layers (P > 1%)

Fe Mn

Figure 7. Mn-Fe-(Co+Ni+Cu)xlO ternary diagram after Bonatti et al. (1972) for: (A) bulk crusts, and (B) crust layers

56

ilooo-

100-

10-A.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

lOOn

10-

B.La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Figure 8. Range of REE plots for 13 Fe-Mn samples from Litakpooki Ridge: (A) Chondrite normalized, and (B) PAAS normalized

57

1000-

I I

100-

10-A.

I I I I I I I I I I I I V I

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

lOO-i

on

"cL 10-

c/3

B.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Figure 9. REE plots of bulk crusts and layers from dredge Dl, Litakpooki Ridge: (A) Chondrite normalized, and (B) PAAS normalized

58

1000-

I

C/3

C/3

|"a.

C/3

100-

10-

D2-2A D2-2B D2-2C D2-2D D2-3A D2-6A D2-1C*

A.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

lOO-i

10-

D2-2A D2-2B D2-2C D2-2D D2-3A D2-6A D2-1C*

B.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Figure 10. REE plots of bulk crusts and layers from dredge D2, Litakpooki Ridge: (A) Chondrite normalized, and (B) PAAS normalized

59

Fact

or 1

: CFA

pha

se

38.6

% o

f sam

ple

vari

ance

0.1

-0.1

-0.2

-0.3

0.5

0.4

0.3

o I

0.2

-o.i

-0.2

Al

Fact

or 2

: A

lum

inos

ilica

te p

hase

40

.2%

of s

ampl

e va

rian

ce

K

Si

ON O

0.8

fi

o o on i_i 1

0.6

UH

0.4

0.2

Fact

or 3

: Res

idua

l bio

geni

c ph

ase

13.6

% o

f sam

ple

vari

ance

0.4

0.3

0.2

0.1

-0.1

-0.2

-0.3

-0.4

Fact

or 4

: 5 M

nC>2

pha

se

6.5%

of

sam

ple

vari

ance

nu

n

iniiiii

Tl

Co

Ni

Ga

Mn

Pb

Na

Bi

P C

u A

l H

f

Figu

re 1

1. F

our

Q-m

ode

fact

ors

for 9

bul

k cr

usts

from

Lita

kpoo

ki R

idge

. Th

e fo

ur fa

ctor

s ac

coun

t for

98.

9% o

f the

var

ianc

e.

Fact

or s

core

s be

twee

n 0

and

10.14

1 ar

e no

t inc

lude

d be

caus

e ra

ndom

noi

se m

akes

it d

iffic

ult t

o re

solv

e th

e or

ient

atio

n of

the

fact

or to

with

in 1

0° o

f an

abso

lute

dire

ctio

n in

var

iabl

e sp

ace.

~ 0.1

-0.1

-0.2

-0.3

0.7

0.6

2 0.5

Factor 1: Aluminosilicate phase 39.6% of sample variance

0.4

0.2

0.1

w Factor 2: Mixed 6 MnO2 and residual biogenic phases 29.9% of sample variance

Zn Mn Cu

III III 11II11

1I

XI 03

'C!

Factor 3: CFA-diagenetic phase 29.9% of sample variance

Ca Co Nb Pb Ti Bi

-0.1

-0.2

-0.3

Figure 12. Three Q-mode factors for 5 bulk crusts >85mm from Litakpooki Ridge. The three factors account for 99.4% of the variance. Factor scores between 0 and 10.141 are not included because random noise makes it difficult to resolve the orientation of the factor to within 10° of an absolute direction in variable space.

61

lOOOn

I o

3 100-

10-

lOOn

10-

D5-2AD7-11A D9-5-1A

A.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

D5-2AD7-11AD9-5-1A

B.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Figure 13. REE plots of bulk crusts from dredges D5, D7, and D9, FSM: (A) Chondrite normalized, and (B) PAAS normalized

62

loo­

c o

JGy0>

10--

A.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

10-r

0.1--

0.01

D5-16A D8-1A

B.

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Figure 14. REE plots of hydrothermal Mn-cemented sandstone (D5) and stratabound Mn layer (D8) from Yap Arc: (A) Chondrite normalized, and (B) PAAS normalized

63