OLR (1981) 28 (12) D. Submarine Geology and Geophysics 871

Bureau des Recherches Geol. et Minieres, BP6009, 45018 Orleans Cedex, France.

DI40. Submarine hydrology (springs, hy- drothermal deposits, etc.)

81:6560 Haymon, R.M. and Miriam Kastner, 1981. Hot

spring deposits on the East Pacific Rise at 21°N: preliminary description of mineralogy and gene- sis. Earth planet. Sci. Letts, 53(3):363-381.

Approximately 135 kg of hydrothermal sulfide- sulfate precipitates collected from 8 active and inactive vents during the 1979 RISE expedition were examined. Sample mineralogy is correlated with the stage of chimney formation and the biology of the community surrounding the vent; geologically very short-lived, the chimneys plug up, are abandoned, and soon become reduced to weathered basal mounds of sulfide aggregates honeycombed with fossilized worm tubes. Scripps Inst. of Oceanog., La Jolla, Calif. 92093, USA. (hbf)

81:6561 Monin, A.S., E.A. Plakhin, A.M. Podrazhansky,

A.M. Sagalevich and O.O. Sorokhtin, 1981. Visual observations of the Red Sea hot brines. Nature, Lond., 291(5812):222-225.

Hydrophysical studies of the Atlantis II, Discovery, Chain and Valdivia deeps with the Pisces XI submersible confirmed previous findings (1967-80), and showed a surface-to-bottom increase in both temperature (40.9-62.3°C) and salinity (67.6-275.0 ppt). P.P. Shirshov Inst. of Oceanology, USSR Acad. of Sci., 117218 Moscow, USSR. (izs)

81:6562 Styrt, M.M. et al., 1981. The mineralogy and the

isotopic composition of sulfur in hydrothermal sulfide/sulfate deposits on the East Pacific Rise, 21°N latitude. Earth planet. Sci. Letts, 53(3): 382-390.

High temperature (~350°C) vents are rich in Cu-Fe sulfides; low temperature ( (300°C) vents show a high proportion of Zn sulfide. All contained anhy- drite (whose S is isotopically identical to that of seawater); the sulfides' isotopic composition is best explained by reduction of seawater sulfate and basaltic magma sulfur during magma/seawater interaction. Dept. of Earth and Plan. Sci., MIT, Cambridge, Mass. 02139, USA. (sir)

D170. Historical geology, stratigraphy

81:6563 Ager, D.V., 1981. Major marine cycles in the

Mesozoic. J. geol. Soc., Lond., 138(2):159-166.

Fischer's (1979) theory of 32 Ma cycles is examined in light of the Mesozoic record of 8 major trans- gressions and regressions and the associated changes in the shallow-water benthos, especially brachio- pods. Dept. of Geol., Univ. College of Swansea, Singleton Park, Swansea SA2 8PP, UK. (hbf)

81:6564 Archibald, J.D., 1981. The earliest known Palaeocene

mammal fauna and its implications for the Cretaceous-Tertiary transition. Nature, Lond., 291(5817):650-652.

The sequence at several localities in NE Montana (USA) in combination with previously known latest Cretaceous localities argues for gradual terrestrial extinctions and faunal changes at the C/T boundary. Dept. of Biol., Yale Univ., New Haven, Conn. 06520, USA.

81:6565 Barker, P.F. et al., 1981. Deep-Sea Drilling Project

Leg 72: southwest Atlantic paleocirculation and Rio Grande Rise tectonics. Bull. geol. Soc. Am., 92(5)(I):294-309.

Four sites were drilled. Site 515 in the Brazil Basin yielded 617 m of terrigenous and siliceous muds and mudstones. At Site 516, basement was reached penetrating 21 m of Santonian-Coniacian basalt after 1250 m of mostly calcareous sediments on the Rio Grande Rise crest. Sites 517 and 518 on the lower western flank of the rise contained calcareous sediments. Results elucidate deep and intermediate SW Atlantic paleocirculations and a mid-plate rise's evolution. Dept. of Geol. Sci., Univ. of Birmingham, P.O. Box 363, Birmingham B15 2TT, UK. (bas)

81:6566 Blackwelder, B.W., 1981. Late Cenozoic marine

deposition in the United States Atlantic coastal plain related to tectonism and global climate. Palaeogeogr. Palaeoclimatol. Palaeoecol., 34(1/2):87-114.

Molluscan faunal changes at erosional unconformi- ties generally coincide with periods of global cooling. Six such hiatuses are recognized and dated from the Early Miocene to the Pleistocene, and several more within the past half million years. Although the Georgia coastal plain appears to have remained relatively stable since the Early Pliocene, it is estimated that the Cape Fear Arch has undergone at