Cenozoic Foraminifera from the South Atlantic, DSDP Leg 36
1977; Linguagem: Inglês
10.2973/dsdp.proc.36.109.1977
Autores Tópico(s)Isotope Analysis in Ecology
ResumoCenozoic foraminifera occur in four sites drilled during Leg 36, one in the Drake Passage (Site 326), one in the Falkland Outer Basin (Site 328), and two on the eastern end of the Falkland Plateau (Sites 327 and 329).A calcareous section containing a well-preserved fauna was cored at Site 329.Planktonic foraminifera show that four Tertiary intervals were recovered, upper Paleocene-lower Eocene, Oligocene, lower Miocene, and upper Miocene.Some calcareous planktonics and benthonics are found in the Paleocene-lower Eocene of Site 327.The carbonate-free sediments of Site 328 only yielded an upper Cretaceous-lower Eocene arenaceous benthonic fauna.Planktonic species diversity and faunal composition at Site 329 indicate a progressive warming during the latest Paleocene culminating with the invasion of mid-latitude angular acarininids and keeled morozovellids.Species diversity of Oligocene assemblages is high relative to the latitudinal position of the site.Intense cooling is inferred from extreme low-diversity assemblages in the late Miocene with predominance of Globigerina bulloides.Four distinct benthonic assemblages occur in the Paleocene, lower Eocene, Oligocene, and upper Miocene.Comparison with low and mid-latitude assemblages from the South Atlantic suggests bathyal depth during the Paleocene.The remarkable stability of benthonic assemblages all through the Cenozoic with great similarities (on generic level) in faunal composition is a further indication for the absence of any substantial subsidence of the Falkland Plateau during the Cenozoic.
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