.-

ANALYSIS OF MISSISSINEWA SHALE-LISTON

CP£EK LIMESTONE CONTACT IN NORTHEASTERN INDIANA

A THESIS

SUBMITTED TO THE HONOR'S COLLEGE

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS

for the

HONOR'S PROGRAM

by

L. DOUGL..4S MCKEE

Adviser - Dr. Harlan H. Roepke

~ /paz: 01 L-C;;~J/.~~/<1L. / c;:/>. BALL STATE UNIVERSITY

MUNCIE, INDIANA

MAY, 1983

,-

~Co\\~ \r\~::"-L,-'

LI>

ACKNOWLEDGEMENTS

I would like to take this opportunity to thank all those

who aided in this study. Special thanks is offered to'Dr.

Harlan H. Roepke, Honors Thesis advisor, for his aid in the

preparation and editing of this manuscript. Special thanks go

to Dr. Walter H. Pierce, who suggested this particular pro­

ject. Sj_ncere appreciation is also extended to the Ball State

DepartmEmt of Geology which provided research facilities and

to the Student-Faculty Research Committee which provided

funding for this project in the form of an undergraduate

research grant.

My appreciation is also extended to Dr. Henry E. Kane,

Dr. R. William Orr, and Dr. Alan Samuelson for all the geo­

logic knowledge they have imparted to me over the past four

years. And of course, I wish to thank the Ball State Honors

College for the stimulus for this entire research project.

---

l'ABLE OF CONTENTS Page

I. IN'TRODUCTION ....................................... 'I. 1

A. Purpose of Study........ .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .... 1 B. Significance ......................................................................... 8 C. Selection of Field Locaclities ................... 8

II. GEOLOGIC SETTING

A. Structural Setting ............................................................ 12 B. Stratigraphy of Wabash Formation ................. 15 C. Paleogeographic Setting .......................... 18 D. Depositional Model ............................... 18

III. FIELD METHODS AND LABORATORY PROCEDURES

A. Field Methods and Sampling ....................... 20 B. Laboratory Procedures ............................ 20

1 . Insoluble Res id ue Analys is ................... 21 2. Pipette Analysis ............................. 21

C. Procedure Reliability ........•................... 24

IV.. INTERPRETATION .. I ...................................... 26

V. CONCLUSIONS ....................................................... 34

VI • REFERENCES CITED ••..••.••••••.••••.•••..••.•.•••.••• 35

VII. APPENDIX A (Pipette Analysis Data Form) ............. J7

VIII. APPENDIX B (Stratigraphic Distribution of Total Detritus (percent insoluble) and Silt/Clay Ratios ... J9

IX. APPENDIX C (Stratigraphic Distribution of Silt/ Carbona te Ra tics) ...................................... 44

X. APPENDIX D (Stratigraphic Distribution of Clay/ Carbona te Ra tics) ...................................... 47

XI. APPENDIX E (Paleogeographic Setting of North America During Silurian ............................. 50

-ANALYSIS OF MISSISSINEWA SHALE-LISTON

CREEK LIMESTONE CONTACT IN NORTHEASTERN INDIANA

I. INTRODUCTION

ThE~ Wabash Formation, with its encompassed Mississinewa

Shale and Liston Creek Limestone Members, is a Silurian in­

terreef deposit of late Niagaran age (Shaver et. al., 1971)

(figure 1). In northeastern Indiana the contact between

these two members is exposed at several quarries, road, and

stream cuts. Existing contemporaneously with the deposition

of the Wabash Formation were numerous pinnacle reefs in addi­

tion to two major reef complexes along the edges of the Mich­

igan and Illinois basins (Shaver, 1978). These Silurian reefs

of the Midwest have been, over the last few years, the tar­

gets of petroleum exploration, and are prized as sources of

crushed stone and chemical-grade carbonates. In southwestern

Indiana, petroleum has been extracted from the overlying

strata which are usually domed due to differential compaction

of subsequently deposited layers. In some areas, such as in

Michigan and Illinois, but not in Indiana as yet, petroleum

has been produced directly from the reef bodies (Becker and

Keller, 1976).

A.Purpose of Study

The objective of this research is to determine how the

detrital component of the Wabash Formation varies in the

-

2

PINSAK AND SHAVER, 1964 DROSTE AND SHAVE R 1976 DROSTE AND SHAVER , 1982

illW~ illliJt'-'--'--'-Y~1 LJ....L.J...J.-~ i 11 j 11111111111 I ~ II 1 j I I 1

}U-J-g.l..ll.jrU-'--l...U..J...u..L.L...L-'-<?Xf::j Kenneth ~ a ~enneth Q.. ~ Kenneth .- Liston ::.:.:~'.~r- and - - ~ Liston and - z :::> <l: Liston r- ond -<l: Creek .:":Cfl:: Kokomo ~ ~ Creek Kokomo 0 ~ Creek Kokomo ~ Ls. Mbr. ~:w:'( Ls. Mbrs. a: Ls. Mbr. Ls. Mbrs. _ 0 0 Ls. Mbr. Ls. Mbrs.

fr :'.- ~~ ~ f2 1---------""------., .- a: u.. :r 1------<-<f U ~~ ~ a: :r S <l: (!) :r en M.issis- 9.<t":4 ~ ~ (f) Mississinewa ) ~ ~ ~ slnewa «flL ... ~ fT\ ~ Shale Member ) a: (l)

Sh. Mbr. t::·:·::~ (j) <l: (J) 0 <l: ~ t.lL .~~ 0 <l: ~ ~ u.. <l: ~ 1-------'-----7 ~.:: :.~ ::0 Z U en

<-.:. w . ~ c _ <t Z-.J

Mis sis sin e wa Shale Member

&w:·~ ~ ..J LL <l: _..J Z

E (:··~ 0 LOUISVILLE..J Z c:::: Louisville LOUISVILL \~'.~.) ~ <l: ~ _ ..J c:: 0 LlMESTONE~:.:-:·:.1 0 ....... (f) LIMESTONE W..J ~ equivalent

< •• ::.!< "r.. z <l:'-<l:

?:::'::~ I~II/)'o}- ~ <l: CJ) ~ ~~--------1 ~W-A-L-D-R-O-N-:F=-=M'-'--<-.. ? :.:'."::.} Illi-=> WALDRON FM. CJ) ~ e Waldron e~quivo~~

........ ~ brownn4'j:':":: ':'.:~ .L.ld.Llo'-'-loLlm.lJi-'-teLl.lJ...LL.L~~---=-:-,-: LL':-=I:=:'M=:-S'" E R LOS T) '" WQ..' Lim be r los t ' .... '-___ :~::.:. ________ ~'__D_O_LO_M_I_T_E __ _'~"_> _ _I: '""" ~ Dolomite Member

-.-. -.. : white •• dolomite

SALAMONIE DOLOMITE SALAMONIE DOLOMITE SALAMONIE DOLOMITE

Figure 1. - Chart showing the evolution of nomenclature of Middle (Niagaran) and Upper (Cayugan) Silurian rocks (from Droste and Shaver, 1982, Fig. 2).

3

vicinity of the Mississinewa-Liston Creek contact. As early

as 1927, in the work of Cumings and Shrock (1927), it was

noted that there was a decrease in the silica content of the

Mississinewa Member in a traverse from Yorktown to Kokomo

(30.28 percent at Yorktown to 15.90 at Kokomo).

Owens (1981) further developed this issue of using ter­

rigenous clastics as a research tool in his work on the Mis­

sissinewa Member. Owens determined two source areas for the

supply of detritus to the Mississinewa shale. Figure 2, a

map displaying the regional distribution of insoluble res­

idues in the Mississinewa Member, indicates these two source

areas. One of these, southeast of the Wabash Formation out­

crop area, was a clay-rich source. This source was supplied

via ocean currents carrying materials derived possibly from

the Appalachians, or exposed Ordovician sediments in the

Cincinnati area. Silt and clay from this source settled out

of suspension in high concentrations in the southeast of

Owens' study area (extreme southeastern Madison and Delaware

counties) (figures 3 and 4). Finer silt and clay remained in

suspension and was finally deposited further northwest in

substantially lower concentrations.

The second of Owens' sources was a sil~rich source

from the northwest (figures 3 and 4). Figure 5, a map illus­

trating the regional distribution of silt-clay ratios in the

Mississinewa Member of the Wabash Formation, shows the greater

potency of the northwestern source as a source of silt.

Owens believed this source was of aeolian origin, blown into

4

~; I~::: "-:-- ~ H~.:I •• t~n" --' 'I ," i!!Jt ." I / 6'>.8' /~/ W?erl!:l

~~2 ·';4.58~ I 0' 'I .60.01 )l{e . I A) ~ ~

,f QI f7//, I 'L~/ J

~ , +-1' -.J ~O ." 1 I I .,.,"'"

- . ---J \ -t-=7>!)~~ I' ~ Howard I I Blackford

, ___ ~::B_~ r" _" ~ j ,,1 /" M.d; ••• ; I 0.1.0.', ~

..".."", i 3~8 : 'I ".of;)O~ N

F /" :. m-m-:'7-to- n-~o': I

I, /A"" ~f;)" ~2J ' -- , ----I

32.20' ./ " ./%.~ 6 37,40 .,. 6.-' , __ .-...G, __ ,

Scale I I 1 o 5 10

mil ..

Figure 2. - Map displaying the regional distribution of insoluble residues in the Mississinewa Member of the 1rJabash Formation. Notice areas of higher concentration at the northwest and southeast corners. Black dots represent lo­calities where the entire stratigraphic sequence was sampled. Small tr~angles indicate sites where a single sample repre­sentative of the entire exposure was collected. Large black symbols indicate reef-proximal localities. Contour interval e~uals 10 percent (from Owens, 19~1, Fig. 9).

-

r-;;b~~ . j. . - . ~ . ---J wal Hunt ington

MIami '1 • ~48 . Y

I ~~ ?~!lY " ./ • • 2.8 /'

~~O i /~i~ ~ /_--...~ I A~ 42 . ",

,

. I .~.

IHowa~ ................. I Blackford

1)2.1 L . ..... ......

~TI.ton t--:?~O-d-i-Io-n' To',::,' ·I--N....J

I I (OmiItOn . rJ ~~. 4~.2 37. J' . ~ ~ I

fl' 0 . .

I ~ ~JlJ . L._.~·=~L.,

Seal. Contour Interval = 10% I A 1

o miles 10

Figure J. - Regional distribution of silt in the Mississin­ewa Member of the Wabash Formation. Notice increased silt in northwest and southeast corners. Values represent silt content as a percentage of total lithologic composition. Black dots represent localities where the entire stratigraph­ic sequence was sampled. Small triangles indicate sites where a singlE! sample representative of the entire exposure was collected (from Owens, 1981, Fig. 10).

6

N

I Mi~ I Wab:ab I Huntingto

6 . - 6.) ~ I 10 .9 -. I

I - 10 8 8. 9.1

eiiS"l •

I I L I Grant

r-- -~ -6.1 I Bl~kT-'~HOWard ! -S.3 --.lCOrd I

TiPt:n I Madison 1 Delaware -

I I

i HaJnil ;o;j 1 r :j I ~10 t4 ,-

• I AJ--~ SCALE

o 20

r- L;;;; J

1 inch = 20 miles

Figure 4. - Map illustrating the regional distribution of clay as a percentage of total lithologic composition. Notice areas of higher concentration of clay at the north­west and southeast corners. Contour interval equals 5 percent (from Owens, 1981, Fig. 12).

- -- -- .- .. _"

-

~~I .

. 1 ,.,

.

1

CONTOUR INTERVAL· 15.0 % I o

Scale

I 5

..,11 ..

1 10

Figure 5. - Map illustrating the regional distribution of silt-clay ratios in the Mississinewa Member of the Wabash Formation. Black dots represent localities where the entire stratigraphic sequence was sampled. Small triangles indicate sites where a single sample representative of the entire exposure was collected (from Owens, 1981, Fig. 11).

8

the marine waters from arid lands west of the Michigan basin.

The amount of detritus, from this source, decreased to the

southeast.

B. Significance

Should it be possible to determine some sort of pattern

in the silt and clay components of the Wabash Formation at

the Mississinewa-Liston Creek contact, it-might Bhed light

on the events that caused the abrupt lithic change at this

contact. Paleocurrents, paleowinds, and paleoclimatic events

might be deduced if this pattern could be applied over a

large area, such as northeastern Indiana.

C. Selection of Field Localities

Silurian rocks in Indiana crop out in a broad belt in

northeast Indiana, extending southward in some areas (fig­

ure 6). This general region became the basis for this study.

In. order to test Owens' data, and examine the upper

contact relationship of the Mississinewa with the overlying

Liston Creek, four sample areas were selected. Two of these

were in the vicinity of Wabash, at the northern end of the

Silurian outcrop area of Indiana. Two other localities were

selected at the southern edge of the Silurian outcrop belt

(figure 7). The exact locations of these localities are

as follows:

1. Wabash: Deep road cut on state road 13 on the south edge of Wabash, Indiana, North Reserve 55, T27N, R6E

2. Shanty Falls: 3 miles west of Wabash, Indiana, south­ern bank of the Wabash River, north Reserve 55, T27N, R6E

9

.-I

Fig~re 6. - Generali Indlana and parts 0 zed.g~ologic map of (from Pinsak and Shf adJolning states aver 1964 . , , Flg. 1).

- N

SCALE

o 20

~ b1Q1me:J 1 inch ~ 20 miles

Marion

Figure 7. - Map of study region showing sampling localities. site 1 - Wabash, site 2 - Shanty Falls, site 3 - Noblesville, site 4 - McCordsville Study region equals approximatelY 470 square miles.

10

3. Stony CreeK Stone Co., Inc., R. R. 4, Box 133A Noblesville, IN 46060, 4 miles E of Noblesville on S. R. 38, Riverwood Quad., SEiNEi sec. 3 T18N, R5E

11

4. Irving Materials, Inc., R. R. 1, Fortville, IN 46140, 3.5 miles N of McCordsville on C. R. 600 W., McCordsville Quad., NEiswi sec. 2, T17N, R5E

It was intended that the selection of these four field

localities would permit the discovery of any possible region-

al trend. By selecting two sites that were reasonably close

to each other, a limited check could be made on the accuracy

of the subsequent laboratory procedures. The choice of

localities was rather limited due to the fact that the Mis-

sissinewa-Liston Creek contact is exposed in so few places

at the surface. A more complete study would need access to

drill cores.

The southern two sites both are located in quarries~

The northern two sites lie in a region long noted for its

Silurian age deposits (Gorby, 1886; Elrod and Benedict,

1891).

- N

fI SCALE

20 o I tm"mw:J

1 inch ~ 20 miles Marlon

Figure 7. - Map of study region showing sampling localities. site 1 - Wabash, site 2 - Shanty Falls, site 3 - Noblesville, site 4 - McCordsville Study region equals approximately 470 square miles.

10

- 3. Stony Creek Stone Co., Inc., R. R. 4, Box 133A Noblesville, IN 46060, 4 miles E of Noblesville on S. R. 38, Riverwood Quad., SEiNEi sec. 3 T18N, R5E

11

4. Irving Materials, Inc., R. R. 1, Fortville, IN 46140, 3.5 miles N of McCordsville on C. R. 600 W., McCordsville Quad., NEiswi sec. 2, T17N, R5E

It was intended that the selection of these four field

localities would permit the discovery of any possible region-

al trend. By selecting two sites that were reasonably close

to each other, a limited check could be made on the accuracy

of the subsequent laboratory procedures. The choice of

localiti.es was rather limited due to the fact that the Mis-

sissinewa-Liston Creek contact is exposed in so few places

at the surface. A more complete study would need access to

drill cores.

The southern two sites both are located in quarries9

The northern two sites lie in a region long noted for its

Silurian age deposits (Gorby, 1886; Elrod and Benedict,

1891 ) .

II. GEOLOGIC SETTING

A. Structural Setting

Structurally, Indiana is dominated by two basins,

separated by a system of arches. The axis of the principal

arch, the Cincinnati Arch, trends northward along the Indi­

ana-Ohio State Line, then branches, with one branch that

trends northwestward, the other northeastward. In the vicin­

ity of Cass County, the northwestern branch joins the Kanka­

kee Arch, a southeastern extension of the Wisconsin Dome

(Becker, 1974). To the northeast of this feature is the

Michigan Basin, and to the southwest the Illinois Basin (fig­

ure 8). Some earlier authors such as Pinsak and Shaver (1964)

termed the entire Cincinnati-Kankakee Arch system simply the

Cincinnati Arch.

During the Silurian, the area between the Michigan

and Illinois Basins was so broad that Shaver (1978) has

termed· this area the Wabash Platform (figure 9). This plat­

form became the site of nilllerous pinnacle reefs. Along the

margins of the platform, barrier reef complexes developed.

The complex on the edge of the Michigan Basin has been termed

the Ft. Wayne Bank, and the one along the edge of the Illi­

nois Basin, the Terre Haute Bank. These banks and individual

reefs have been the topic of numerous articles such as those

,----------LAX! MICHIGAN

I

, Wl.

I I

I I I

HUNTINGTON

GRANT

S'iiUIo.--' I I

.J Of lAtl

AUfN

... : ...... -;:j

WEUl ADAiiiNi

IlACKFORD JAY

WOOOlPH

WAYNE

o 2S Miles

2S o 2S Km I I I I I r

Figure 8. - Map of Indiana showing county names and major structural features (from Carpenter, Dawson, and Keller, 1975, Fig. 1).

1.3

? •

o 200 Miles t-I --LI-rl _~--1-.1 ---,J o 300 Km +

Figure 9. Map of the Great Lakes area showing paleogeo­graphy and locations of some but not all known discrete

-reefs (dots and stars), carbonate banks or barrier reefs (stipples), and gross structural-sedimentational features, all composited for Silurian time. Individual reefs are not shown in bank areas; arrows represent reported forereef­to-backreef directions for given reefs (from Shaver, 1978, Fig. 1).

-I 15

by Carrozzi and Zadnik (1959), Textoris and Carrozzi (1964),

and Droste and Shaver (1980) to name but a few.

B. Stratigraphy of the Wabash Formation

The stratigraphy of the Wabash Formation and its adja-

cent formations have undergone a gradual evolution of nomen­

clature. The Mississinewa and Liston Creek Members were

originally described respectively as an irregularly fractured

"cement rock" of approximately 135 feet overlain by 60 feet

of cherty limestone or "quarry rock" (Elrod and Benedict,

1891) .

The current nomenclature for the Niagaran and Lower

Cayugan Series began to take form through the work of Pinsak

and Shaver (1964). They named the stratigraphic sequence for

Indiana (oldest to youngest) as the Salamonie Dolomite,

Waldron Formation, Louisville Limestone, and Wabash Formation.

The Salamonie Dolomite is named from the exposures of dolomite in the headwaters area of the Salamonie River in the vicinity of Portland, Jay County, in east-central Indiana. It is characteristically a ligh-colored medium­grained fossil-fragmental porous dolomite. The Waldron Formation in northern Indiana consists of distinctive mottled dark-gray and tan fine-grained to sublithographic argillaceous limestone or dolomitic limestone. The Louisville LImestone characteristically is tan and gray fine-to medium-grained thick-to medium-bedded fossil­fragmental limestone and dolomitic limestone. The Wabash Formation has two major subdivisions, the Mississinewa Shale Member and the Liston Creek Limestone Member. The Mississinewa Member generally is composed of gray fine-grained argillaceous silty dolomite and dolomitic siltstone and minor amounts of pyrite. The Liston Creek Member consists of a light-gray and tan fine-to mediurn­grained fossil-fragmental cherty limestone and dolomitic limestone (Pinsak and Shaver, 1964, pp. 24-39).

This nomenclature has been modified twice since its

inception by Droste and Shaver (1976) who proposed the name

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16

Limberlost Dolomite be used for the upper portion of the

Salamonie Dolomite. This unit was formerly termed the brown

upper part of the Salamonie Dolomite, but was renamed the

Limberlost Dolomite due to its differing lithology. In ad-

dition,

the Limberlost Dolomite represents the onset of restric­tive Salina influences within the Michigan Basin that transgressed in time onto the Wabash Platform as far south as Indianapolis (Droste and Shaver, 1976, p. 1).

Droste and Shaver (1982) further proposed the combin-

ation of the Limberlost, Waldron, and Louisville Limestone

Formations under the new name Pleasant Mills Formation. This

. proposed regrouping is designed to reflect, considering the

Great Lakes area as a whole, a complete facies relationship

that existed between the evaporites of the Michigan Basin

and the interbasin rocks of the Wabash Platform. The Pleasant

Mills and Wabash Formations are subsequently placed in the

Salina Group, a name previously applied only to the evapor-

ites of the Michigan Basin. Figure 1 shows this gradual ev-

olution of nomenclature.

In keeping with this new nomenclature, Droste and Shaver

'(1982) have extended the Wabash Formation northward into the

Michigan Basin

to include all rocks in the upper part of the Salina Group, that is, those Salina rocks lying above the Pleasant Mills Formation (Droste and Shaver, 1982 p. 21) .

Southwestward, the Wabash Formation is roughly correlated to

the upper Moccasin Springs Formation and lower Bailey Lime­

stone of the Illinois Basin. Figure 10 shows these correla-

tions.

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17

'Z ct (.)t/'I

a: uJ

wa: :i: W ctt/'l

Z z

<t (!)

=>

-----SOUTHWESTERN

AND

SOUTH-CENTRAL

11.

INDIANA

UJ Z o ~ (/)

UJ ::!!

>.! X.J:l

~:i! ~ Q)

u c o

c­o III ... (II

)- ~

.J

>­UJ .J

OIl E :i:.::i

.. <t" "0'"

u

z

UJ

.. ~ ..

cr 11. (/) . u u

ID :x: (/)

<[

UJ UJ .J Z .J 0 > ~ (/) Vl

AREA OF THIS REPORT, NORTH-SOUTHERN

CENTRAL AND WESTERN MICHIGAN

NORTHERN INDIANA OHIO

BASS IS. GR. i<.!)

Iu.. LL

Kenneth Liston and uJ Creek w Q.

Ls. Mbr. Kokomo ~

Ls. Mbrs. 0 0 ....................................... 0: ................... .

Mississinewa

--- Shale Member --- ro---------­<[

N Z I

Louisville <t

equivalent .J

(.)

N I

<t

....... .. ~ .... o . W

~ :i! •.. 0

z

o

z

::!:

w z o ~

Vl

.J .J

W. FM. UJ ~

OIl

:i! ~ o .J:l

Limber!ost Dolomite Member

o I

<t

.J ~ o :i! UJ o ~ ~

.J ~ <[ ~ o-cr w ~ cr z :'!!

<[ z .J SALAMONIE DOLOMITE C> 0 0<[0 ...J ~ 11. .J U 0 0 <[cr ~ 0

.••••.•.• ::!: ............................................................................................... . • 'U .... U 0 ~ <[ 0 - ......

o C1' OIl

o z o

Figure 10. - Chart showing the evolution of nomenclature of Middle (Niagaran) and Upper (Cayugan) Silurian rocks (from Droste and Shaver, 1982, Fig. 2).

Z <t (J) W W 0... -0 a: a: w ~ (J)

uJ

z c::x:

-1 0 0

0:: a..

Z

c::x:

> 0

-1

0

=> .J

Z

c::x:

~

u 0 .J

Z W

3:

OZ oc::x: z-c::x:O:: .JW -.J~ .!

.-I

18 "

C. Paleogeographic Setting

Du~ing the Silurian, paleogeographic evidence seems to

indicate that the Midwest region o£ the United States was

located somewhat south o£ the equator at approximately 10-

200 S latitude (see Appendix E). This was a period o£"rela-

tively rapid continental drift, as the same region was pre­

viously located at approximately 20-300 S latitude during

the Ordovician, and subsequently at 8-180 S latitude during

the Devonian, and 0-10 0 N latitude during the Carboni£erous

(Habicht, 1979).

D. Depositional Model

Prior to Owens' (1981) research, the depositional model

for the Silurian of Indiana was one in which terrigenous

clastic;s were deposited from the southeast in "surges"

(Shaver et. al., 1971). Shaver (1974) £urther stated that

both the rocks and fossils in the Liston Creek inter­reef facies suggest an environment of higher energy and shallower water than that of the Mississinewa (Shaver, 1974, p. 946).

Several researchers have tried to use the forereef-to-

backreef direction of Silurian reefs to determine the cur-

rent and wind directions during their deposition. Lowenstam

(1950) used the areal distribution o£ reef outwash and by-

passed terrigenous sediments at several reefs in the Niagar-

an archipelago (Terre Haute Bank) area of Illinois to de­

duce a prevailing southerly wind. Crowley (1973) in similiar

research on the Middle Silurian patch reefs of the Gasport

-

--I

19

Member (Lockport Formation) in New York came to the conclu­

sion that wind-generated currents from the northwest were

responsible for the north-to-south forereef-to-backreef re­

lationships that he found.

-III. FIELD METHODS AND LABORATORY PROCEDURES

A. Field Methods and Sampling

The Mississinewa-Liston Creek contact at the four

sample sites was deduced on the basis of differences in

lithology and weathering profile. Once the contact was ident­

ified, samples were taken above and below the contact. Above

the contact, samples were taken at six inch intervals be­

ginning at the top of the contact itself. This was continued

up section to three feet above the contact. Below the contact,

samples were taken at foot intervals beginning at the base

of the contact. This was continued down to three feet below

the contact. A total of eleven samples was taken at each

of the sampling sites.

For each sample collected, several pieces of rock were

taken for a total of approximately 500 grams. Great care was

taken to collect samples that were in place, not talus from

higher. layers, as this could badly confuse results.

B. Laboratory Procedures

Laboratory analysis was initiated with two goals in

mind. The first of these was to determine the percentage of

detritus in each sample. The second goal was to acquire a

grain-size distribution for each sample by the pipette method

of Folk (1968).

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21

1. Insoluble Residue Analysis

Insoluble resfdue analyses were conducted to deter­

mine the vertical distribution of insoluble detritus above

and below the contact at each site. The method used was sim­

iliar to that used by Owens (1981) with some personal mod­

ifications.

The detrital analysis of each sample began with weigh­

ing out approximately 100 grams of sample. This sample was

then crushed with a rock hammer to marble-sized chips. These

were sU~Jmerged in a 25% HCI solution, with additional acid

added when needed to completely dissolve the sample. Once

the carbonate was dissolved, the sample was filtered through

filter paper to catch the detritus. The filtered sample was

then "flushed" several times with distilled water to cleanse

it of any unreacted HCI that might cause flocculation in

the pipette process. The detritus was dried and weighed, and

its percentage as part of the original sample weight was

calculated (figure 11).

2. Pipette Analysis

Ten to fifteen gram samples of the insoluble residue

derived from the dissolution process were next run through

a 4~ wet sieve in order that the sand and mud fractions

might bl~ split. It was found that almost the entire amount

of each sample was less than 4% (silt and clay). What was

not, was dried and weighed to determine the mass of the sand

fraction.

Insoluble residues of the mud size range can be analyzed

by the procedures outlined by Folk (1968). The core of this

)

Calcite Digestion Dolomite Digestion

/~ I Crush > Add Recharge Recharge Filter, Calculate Sample 25% > Spent ) Spent > Wash ') Percent

HCL Hel HCl With Detrital (warm) Distilled

Figure 11 - Insoluble Residue Procedural Flow Chart (modified from Owens, 1981, Fig. 5)

Water, Dry

1\) 1\)

process is an equation derived from Stokes Law:

T = D 1500 x A x d 2

where: D is equal to the depth of pipette submersion

1500 is a constant

A is a constant dependent upon temper­ature at the time of the experiment and particle density (assumed to be that of quartz)

d is the diameter (mm) of the various particle sizes the experimenter wishes to retrieve

T is settling time (in minutes) required for the particle to settle a given distance beneath the surface

2J

The methodology of the procedure was to take each mud

fraction that passed through the wet sieve and place it in

a standard kitchen blender with additional dispersant solu-

tion. This solution had dissolved in it a calgon dispersing

agent .(7.4g/liter). The mud sample was then mixed for several

minutes and placed in a one liter graduated cylinder.

The graduated cylinder was next allowed to set out over-

night. The purpose of this was twofold. First, to see if the

dispersant was of sufficient concentration, and second, so

that the temperature of the water in the cylinder could

equalize with the room temperature. The following morning,

the cylinders (usually in groups of three) were placed in an

insulated ice chest. Alequots of 25 milliliters were drawn-off

-

--

24 c

by pipette at the required times calculated by the equation

given on the previous page, and placed in pre-weighed beakers.

After each withdrawal, the ice chest was sealed in order that

the initial temperature (the one the values for T were based

on) could be maintained. The beaker was next dried in 'an oven

and weighed. The mass of the dried sample was miltiplied by

40 (because the 25 milliliter alequot was 1/40th of the whole

liter) to find the mass of particles still in suspension.

The difference in mass between two successive alequots cor­

responds to an entire % size which has settled out of suspen­

sion. (figure 12). A sample data sheet is found in Appendix A.

c. Procedure Reliability

Two preparations of each rock sample were processed.

The data from these two trials were then compared for dis­

crepancies. This means that a total of 88 trials were run

through the above-discribed procedure.

) )

Weigh san1fSize Fraction

10-15' Gram ) Add Dispersent ) Wash through . > Place in Sample Solution and Wet Sieve Graduated

Check --~) Dispersion

Effective­ness.

Blend Cylinders

Figure 12. - Pipette Analysis Procedural Flow Chart (modified from Owens, 1981, Fig. 6)

~ Stir and Initiate Timing

~ Calculate Cumulative Percentages ~

Plot DistributiQns on Log-Probablllty Paper

l\) V\

-IV. INTERPRETATION

The data generated from laboratory analysis was used to

construet a series of graphs. In the plotting of these graphs

(see Appendixes B-D), along the ordinate was placed the rela­

tive position of the sample above or below the Mississinewa­

Liston Creek contact. Each foot interval over which the sam­

ples were taken was given a constant interval on the graph.

This interval was also used to separate the sample taken below

the contact from the one taken above the contact for an em­

phasis of the contact itself.

All four sequences of Mississinewa-Liston Creek samples

show some decrease in detrital content as the contact is

approached. The site that shows the least decrease in per­

cent detritus is the McCordsville site, which is the site

nearest the clay-rich source area southeast of the study area.

The other sites showed a much greater decrease in detritus

at the contact, especially the northern two sites near Wabash

(see Appendix B).

The silt/clay curves for the sites show a less pro­

nounced pattern (see Appendix B). At three of the sites

(Wabash, Shanty Falls, and Noblesville) there is a general

decrease in the ratio up section. At the McCordsville site,

the ratio actually increases somewhat above the contact.

-I

27

When the silt "and the clay content for the four sites

are plotted against the carbonate content (that is assuming

that the parameter of carbonate production is somewhat con­

stant) an interesting pattern emerges (see Appendixes C and

D). The northern two sites show almost no silt a~ter Missis­

sinewa depostion stops. The southern two sites, Noblesville

and McCordsville, show a somewhat higher level of silt versus

carbonate, but these higher levels characteristically appear

in surges at different distances above the Mississinewa­

Liston Creek contact. The clay versus carbonate of these two

southern sites also show surges· in clay content. These in­

creases in clay at Noblesville and McCordsville occur in the

same samples as do the surges in silt, and again, the McCords­

ville site shows somewhat higher levels than that of the

Noblesville site. The clay versus carbonate curves of the

northern two sites, Wabash and Shanty Falls, show generally

uniformly lew levels after the end of Mississinewa deposition.

A further analysis of the data was made by constructing,

for each sample, a grain-size distribution curve on prob­

ability paper. A comperison of these curves was made to that

of a cumulative grain-size distribution of a loess deposit,

the type of curve match on which Owens (1981) based his

theory of aeolian transport (figure 13). The curves of those

samples below the contact closely matched the loess deposit

curve, those above the contact did not.

It is this author's interpretation that after the end

of Mississinewa deposition, the supply of northern silt

28

4 5 7 9i SIZE

8 9 10

CUM % 99

Figure 1J. - Comparison of cumulative grain-size dis­tributions of a loess deposit, Nemaha Gouny, Kansaa (after Swineford and Frye, 1945) to those of samples below and above the Mississinewa-Liston Greek contact.

II' • • cumulative grain-size distribution of a loess deposi C

(8 E1 [!j typical cumulative grain-size distribution below Mississinewa-Liston Creek contact

e 9 9 typical cumulative grain-size distribution above Mississinewa-Liston Creek contact

stopped. This is suggusted by both the detritus and cumula­

tive grain-size distribution curves. What is left of the

terrigenous clastic supply is being supplied in surges from

the southeastern clay-rich source only. The bulk of this

material settles out. of suspension long before it reaches

the northern two sites of Wabash and Shanty Falls. In fact,

a great portion of silt-sized particles settled out be­

tween the sites of McCordsville and Noblesville.

Why did aeolian transport of the silt-rich source to

the northwest cease? A simple solution to this would be

vegetation growth in the source area slowing the rate of er­

osion. Such vegetative cover could have been provided by

lichens, of which Blatt, Middleton, and Murray (1980) stated,

it seems reasonable to suppose that the ability of li­chens to grow on bare rock is related to their occur­rence as one of the earliest colonizers of land in the Silurian Period (Blatt, Middleton, and Murray, 1980, p. 251).

A more satisfactory solution would be to model the wind

patterns of the Silurian after existing wind patterns of today.

If we accept a paleogeographic setting of 10-200 S latitude

for the Midwest of the United States, this would place the

study area in the monsoonal region (figure 14). The monsoonal

region refers to a region where

surface winds flow persistently from one quarter in the S~lmer and just as persistently from a different quarter in the winter (Ramage, 1971, p. 1).

Ramage (1971) further states that,

monsoons blow in response to the seasonal change that oc­curs in the difference in pressure-----resulting from the difference in temperature----between land and sea. Where continents border oceans, large temperature

-I

Figure 14. - Illustration of monsoonal regions. Hatched areas are monsoonal, heavy line marks northern limit of the region within the Northern Hemisphere with low fre­quencies of surface cyclone-anticyclone alternations in 9ummer and winter. Re<;:tangle encloses the monsoon region. \from Ramage, 1971, Flg. 1.2)

Figure 15. - Silurian paleogeography of the Great Lakes area A, Late Wenlockian to early Ludlovian (Niagaran) time. B, Pridolian (Cayugan)time (from Shaver, 1978, "Fig. 23)

30

differences and hence large differences in pressure might be expected. However, the shapes of continents and their topographies, as well as variations in sea­surface temperatures, all interact to produce consid­erable regional and temporal variability in the mon­soons.(Ramage, 1971, p.8) .

. During the summers in monsoonal regions, land masses

31 .

heat-up more rapidly than do the nearby bodies of water, and

subseqUE:mtly become areas of low pressure; such a region is

termed a cyclone. The wind direction of a cyclone is counter-

clockwise in the Northern Hemisphere, clockwise in the South-

ern Hemisphere. During the winter, the same land masses cool-

off more rapidly and become areas of high pressure; such a

region is termed an anticyclone. The wind direction of an

anticyclone is clockwise in the Northern Hemisphere, counter­

clockwise in the Southern Hemisphere (Ramage, 1971).

Desert regions are excellent examples of regions that

seasonally change temperature. Just such a region is theorized

by Shaver (1978) to have existed to .the northwest of the study

area (figure 15). This desert region, along with a paleo­

geographic setting of 10-200 S latitude would suggest a

modeling of the Silurian in this area after the present East-

ern Africa and Western Indian Ocean region.

The African continent spans the equator and so in Jan­uary radiational cooling results in high pressures over the Sahara and Arabia; radiational heating results in low pressure over the Kalahari Desert. The consequent north-south pressure gradient sets up a flow of air from north to south across the equator. The most intense heat lows overlie deserts and occupy the same latitude over the oceans. In contrast to January, radiational cooling res~lts in high pressure over the Kalahari Desert, and radiational heating, in low pressure over the Sahara.

The south-north pressure gradient sets up a southerly flow across the equator, eventually merging with the southeast trades over the southern Indian Ocean and with the southwest monsoon north of the equator. The upwelling effect, mentioned above contributes to the southerly monsoon being stronger than the northerly monsoon of January (Ramage, 1971, pp 11-16).

This seasonal variation in wind, besides being an ex-

cellent model, might explain the differences in wind dir-

ection cited by Lowenstam (1950) and Crowley (1973). At

the close of Mississinewa deposition this seasonal varia-

tion in wind must have been disrupted by continental drift

or some other mechanism.

The southeast current needed to supply detritus from

32

the clay-rich source to the southeast of the study area would

also exist in the Eastern Africa and Western Indian Ocean

region. Figure 16 shows a clockwise current existing in the

Indian Ocean today that would fit nicely.

-

--------- -~-- ---------.....,r

Figure 16. - Present world distribution of arid zones and ocean c~rrents. solid arrows-cold currents, dashed arrows­warm currents, dotted areas-deserts, diagonal lined areas­steppes (from Habicht, 1979, Fig. J).

JJ <

v. CONCLUSIONS

The Mississinewa-Liston Creek contact represents a

change in the depositional environment in the northeastern

Indiana region. It represents the transition of an area

being supplied by two terrigenous clastic sources, to an

area being supplied by onJ.y one source. The events that

triggered this change are only conjecture upon the part of

this author. Possible explainations for this change are

changes in the wind pattern caused by continental drift,

or vegetation growth in a terrestrial source area that existed

to the northwest.

-.

-

VI. REF'ERENCES CITED

Becker, Leroy E. 1974, Silurian and Devonian Rocks in Indiana Southwest of the Cincinnsti Arch: Indiana Geol .. Surv. Bull. v. 50, pp. 83.

Becker, Leroy E., and Keller, Stanley,J. 1976, Silurian Reefs in Southwestern Indiana and Their Relation to Petroleum ACGumulation: Indiana Geol. Surv. Occasional Paper 19, p. 11.

Blatt, Harvey, Middleton, Gerard, and Murray, Raymond. 1980, Origin of Sedimentary Rocks: Prentice-Hall Inc., Engle­wood Cliffs. New Jersey. p. 251.

Carpenter, G. L., Dawson. T. A .• and Keller, S. J. 1975, Pet­roleum Industry in Indiana: Indiana Geol. Surv. Bull. v. 42, p. 57.

Carrozzi, A. V. and Zadnik, V.E. 1959. Microfacies of Wabash, Indiana: Jour. of Sed. Pet .• V. 29, pp. 164-171.

Crowley. D. J. 1973. Middle Silurian Patch Reefs in Gasport Member (Lockport Formation), New York: Am. Assoc. Pet­roleum Geol. Bull. v. 57, pp. 283-300.

Cummings, E. R., and Shrock, R. R. 1928, Niagaran Coral Reefs of Indiana and Adjacent States and Their Stratigraphic Relations: Geol. Soc. Amer. Bull. v. 39. pp. 579-620.

Droste, John B., and Shaver, Robert H. 1976, The Limberlost Dolomite of Indiana; a Key to the Great Silurian Facies in the Southern Great Lakes Area: Indiana Geol. Surv. Occasional Paper 15. p. 21.

____ -= __ . 1980, Recognition of Buried Silurian Reefs in Southwestern Indiana; Application to the Terre Haute Bank: Jour. of Geol. V. 88, pp. 567-587.

______ ~. 1982, The Salina Group (Middle and Upper Silurian) of Indiana: Indiana Geol. Surv. Special Report 24, p. 41.

Elrod, M. N .• and Benedict, A. C. 1891, Geology of Wabash County: Indiana Dept. of Geology and Nat. Resources, Ann Report 17, pp. 192-272.

----!

Folk, Robert L. 1968, Petrology of Sedimentary Rocks: The University of Texas, pp.170.

36

Gorby, S. S. 1886, The Wabash Arch: Indiana Dept. of Geology and Nat. Resources, Ann. Report 15, pp. 228-242.

Habicht, J.K. A. 1979, Paleoclimate, Paleomagnetism, and Co~tinental Drift: Am. Assoc. Petroleum Geol. Studies in Geology no. 9, pp. 1-30.

Lowenstam, H. A. 1950, Niagaran Reefs of the Great Lakes Area: Jour. Geol. v. 58, pp. 430-487.

Owens, Robert N. 1981, Petrologic Analysis of the Mississinewa Member of the Wabash Formation and the Effect of Reef Proximity on interrreef Sedimentation: unpub. M. S. thesis, Ball State Univ., Muncie, Indiana, pp. 1-83.

Pinsak, A. P., and Shaver, R. H. 1964, The Silurian Formations of Northern Indiana: Indiana Geol. Surv. Bull v. 32, pp. 1-87.

Ramage, C. S. 1971, Monsoon Meteorology: Academic Press, New York and London, pp.296.

Shaver, et al. 1971, Silurian and Middle Devonian Stratigraphy of the Michigan Basin; a View from the Southwest Flank, in J. L. Forsyth, ed., Geology of the Lake Erie Islands and Adjacent Shbres: Michigan Basin Geol. Soc., pp. 37-59.

Shaver, R. H. 1974, The Silurian Reefs of Northern Indiana; Reef and Interreef Macrofaunas: Am. Assoc. Pet. Geol. Bull. v. 58, pp. 934-956.

, and others. 1978, The Search for a Silurian Reef Model Great Lakes Area: Indiana Geol. Surv. Special Report 15, pp. 1-36.

Swineford, A., and Frye, J. E. 1945, Petrographic Comparison of Some Loess Samples from Western Europe with Kansas Loess: Jour. of Sed. Pet. v. 25, pp. 3-23.

Textoris, D. A., and Carrozzi, A. V. 1964, Petrography and Evolution of Niagaran (Silurian) Reefs, Indiana: Am. Assoc. Petroleum Geol. Bull. v. 48, pp. 397-426.

Appendix A

Pipette Analysis Data Form

-I

) PIPETTE ANALYSIS DA~A FORM

1

SAMPLE NO. LOCATION ______________________________________________________ ___

EXPERIMENTER'S NAME REMARKS ______________________________ _

TEMPERATURE CONCENTRATION OF DISPERSENT ____________ _

rJ ,4';_""", P \..liOlU. depth(cm) time beaker no. sample and

beaker beaker sample wt. wt. X40

dIspers cum.~.

74 Z4

~ ~6

S2 Z8

~ < 10

weight obtained by wet sieving- ______ {Sl

100(S+(F-P) ) S+F

__ ilQQSl [S+F)

{f)

(p)

(rl __ 1._p.<-.1 __

{p)

-- ~(P,-,-)--.

(pl

\..oJ co

----I

Appendix B

Stratigraphic Distribution of Total Detritus (percent insoluble) and Silt/Clay Ratio

3~1"

r Ao:-,;e,

t-I '2.~

AtN<...

t R\.-t ~

Ab;1J~ <...NI)~(

BJow ~'fltac;

©;. ,~

2F6:t &/ow

3tcd &Io<.u

(

3~~

2~ f'ki,;4

1f::tx1-nb:i.~

!! .. ~ 141-

~/~ .. G..:.i\

i foot 8..~ON

~-2fe.z\ &!ie.1i

3~">t:i-~IOVJ

Tf'io...l ±l:.1 I

( ~

'\

Tria. I H(

MG coP-OS \.r~1-LE ) l=rlDTN'v'A -r('io..l ±:l.:2

40

b_'ic ;Ut 3 . .'10 I.{c/" :;";"'1,, (:<::i~ ?I)}.

fulc:t.. < .. urkd

Fk::tcen+- De +1' j' itt. i

\ ~--I-~!IIII

0..0 o.~ 08 j.1. L::> ,S 2 .. / I I I l-f

II) \;"~:.",,,r<d" II,,, C.nti""·,,. 5/1+;e.Iu.y 0 .. 6 0,10 08 1~7_ ;.5 I'~ :2.!

S;/i/C/QY

Noblesv i I Je~ J j: n cl. i'ClnCL

I {' i t.l I H. ( Tria. I ..Y 2. 41

3~t

(:-. Ab .. :l:

2#ee1" A~'~

I~ Abc"f!:,

Abc~'e c".,,,,",-

c .:?

1F=c.:r ~ Bt:,",-,

V 0

"2.~t -.J &If,,,,,

3n lX.jc~

2i:)'(., .'11;:11: 'tC1" ~c!.. be;:.

fkrcen+ De.t,'1/-k I f I .1 < I

-:;>'::;'1, I{:::/<. .:Xl. e-C.'Ii 7cl ..

~('ce/')-t- ~+I'i+c\.l

Tried t±/

'3~~T Ilb..;v e

2Nd' Abo.;lZ.

i ~a:J-Ab;.y(L i~

Abtl-<!o

C c:...:..lf1:4' <>

~ tkak\;.l

Gu\fu.c:t 0 0 I~Cl..i-

--.I Beio.u

, . ,,.-., '2~t \1 &ow

3Fe.i:: 8elc ......

o.~ t. ?> 0.'1 1.'1 1.:1 1.C6

5,' It/C/Q."j

,

(-:2.~t /1J:,.;;.<!.

, ~ .. f" AbG,«

Ab.. .. a Cc/)lI.<,;

RYcIO<J; C C-ol~t

,~

+- 1""4+

3 8dQo.lJ

'l.~ 0 -J &~

3V ~f!J0'<;

3~ Pix..€.

2M Abc...e

~~:e Abc~'e

C' "'lit;c.t -0 '- &lcv -+-d ~ v

I r=-~.,.. 0 -J &de-...;

- '2.~ /,1 6do~

3~.a-(klcv

S ha..nty Tfio...) ttl

'1 I I I

K? 2<:k 3:+ic 'tCk s:.,R (,q~

Pe,'ceT)t- Oe+l'jfa J

T (lj(".! at

~CL\15

I 7t7~

.3~ I. -.:.-.:!

,\h:~ Ix~

13~1c"" ~ ... 1b.c:t

42 Tf'icJ hI? -

» , I , .

i4'", 2Ci'., .~~;. <io.r~ .~t'.! co;;. 7Ck

fl:, ... t..e;') 1- Detrdc. .... t

Tf'io.../ #2.

0 .. ; O,b 0.9 ,~2 13 I-t> 2.'

Si/t/Ck)'

3Fe21

C I!b..ve.

'2~<rl AJ,cile

tFi:c+ Ab,;.c,.

~~ Ii!ICI.;l

C<1)iwr...+

I~f-G:k ...

Zr:c:et-6eit· ...

31e€t 8c!Jo~

(

~Ib!.T Abc.vc

(-d

Trio.. Itt I W(.L b(\.s~ ) Tnl.:l j'({ tl ~

to1o I I ,

10k ,:):"/. ~% 5C;~ &::ic . )(}" Percen+ Del-I' ," iu.1

TI' /0..1 ttl

~

/ , 0)1 I. 'l.. IS

S.!f/ C/a..y 1,/

3fJ:cl

'2~i ~~

l~t.

~L L<"l

Tf'iG\./ H: 2. 43

iclo 2c1: ,;:;;; 4D/, SC;J bd.. 74'.

Perce n+ Oe. tl' /'1cL (

fl'ia.1 ±t-z..

0.'3 o .. CI I.'l. 1.5 5;'/f/C k1

-

Appendix C

Stratigraphic Distribution of Silt/Carbonate Ratios

(~

( ,.

3h:<!t ~.'<-

~~fI.+ t.::... c..

I F'",t A~;e-

Ab;..:~ C",k,..

&iOJJ C,.l~

I tu;t' &feCI.'

2~t G:J~

3fc\1:t &lciJ)

3~­f\~.e,

2ka.~ flh;-I!

(~ L~ 3~t &Ic ....

Trio .. \ i!.1

0,1 (',,'--L C),3 C .. li (;.5 0 .. - (),./

S i It/ CQr bexl"'- f..c:...

Trra.J .i:i:(

; I ; I 0, I O~2. 0.::) 0. '+ C, ~- lU:> (l, J

ill ~Iilj,,",·tc-r' 1(. Ih.> C,.l1im, I., si 1+ /c..o.. I' l>Of)Qte

8 0::, j; .... c.:,,-)!!'.c..

45 triG\., 1 H2

a,i o.~s 0.9

I t '---i---I

o.i 0;2 0-.3 O~lJ o~·::;- 0..0 O~) C.() 0.-9 si j 1-/ Gel f'Cof) Q te....

(

· . . ..

M:i.e.. (.e;)inl.,.'i

BvG'" 6.,y~, .

1M Sdcw

L~ Px/t.:..J

0..1 0;:1. ~43 C.'t 0.5 0,6 0 .. 1

S i 1+ /ca.l'bCf\~ k

"2-&Ic ....

31-~t &.?Ie:...;

46

O.l 0;'). (),3 0 ··If O~5 (:))~ 0·7 o.~ c)'::! silt / CM.f' hen Cto·k.

fa.lls Tri'a..1 ~~

/). f;~1: OC.(ih.,

1 I I _._~l __ ~--~--+---+---~--+---~~~~~--, 0 .. 1 0;2 O,.~ 0.'1 0$ o.h 0,7 0/1 oR 0,/ D:1. C.:?1 O .. "i o,cr C),b 0 .. 7

si \+/CO-f' bOl)o...t-e...

· . .- ,. -<'

Appendix D

Stratigraphic Distribution of Clay/Carbonate Ratios

, •• r ...

(

(

( '1

3~t· 6..:Jc~

TriQ 1 .t! I

I i I I I

I(\;a.) i±. (

'--+---+~ I I , , 0-1 0,-1... 0.1.> 0" '-I 0.5" Q.h 6.7

:" '.L:Ii; ,,,",, ,.; '" ;;, ' , ,-,,;"",' r C ia.y /ca.t.bc.1a.i e

48 Tria. !!2

I I •

ti" lis Tf'iQ} ±l: 2.

i ~ , ~~

0,' 6,'1 c .. ? 0.'+ C'L5 O.G 0.7 ()~~ ('.9

C Ic-y I C .. ,. .bclie.. +c::..

. .. • - .. ,

( ~~

2~ """,.

Nx...:...

"3QE A/x.';e,

').k· PIx .• .....

liU:t f¥x· .. 'c

Ab.::ce. c::u)~r

f-.dcr:; U.tt:.:

Ikct e.:/c;u;

! 2M \ 8.{a:v r

~fQ1 (lxfow

Tr.-o... ( ±h {

I I • I 6.l Q.}.. o..~ o,o.i 0.5"' o,b 0.7

Ck"y /eorb+e..

49

Tr,'o..l ll2

o. i c;2 c.?> c.'j 0.5 0.6 e.7 o.'b c.9

G!o..y /cOJlbcl>at~

MG Gorc1sv j J)~

Tric ) :f± I

1 ) II J ' I I

C,' O.'.l. c.,? 0~'T oS 0.10 0.1 , I -r-- -.,+

.il .'·L:l""d·." I" .,.c, l.. ill;,,,.·, I" C h.y /CIl.rbcl)o..te... 0.2 b;~ 0.1./ 05 (J.b 0.7 o·D c!.'/

C.la.. Y /c..cLf buM!. +e

1 • • ...

--

Appendix E

Paleogeographic Setting of North America During Silurian