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USGS · 70018974

Pliocene (3.2-2.4 Ma) ostracode faunal cycles and deep ocean circulation, North Atlantic Ocean

T. M. Cronin·M.E. Raymo·K.P. Kyle
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Abstract

Ostracode assemblages from Deep Sea Drilling Project Sites 607 (western Mid-Atlantic Ridge) and 610 (southeast Rockall Plateau) show rapid, systematic shifts during late Pliocene glacial-interglacial cycles that reflect deep-sea environmental change. Progressive decreases in North Atlantic deep-water taxa and increases in Southern Ocean taxa occur from 3.4 to 2.4 Ma, and high-amplitude faunal cycles begin near 2.8 Ma. Four ostracode assemblages, each with a characteristic phase relative to 41 k.y. obliquity glacial-interglacial δ 18 O cycles, characterize the benthic faunal record at Site 607. Cross-spectral analysis shows that the Site 607 glacial assemblage has a 41 k.y. periodicity significant at the 95% level; other assemblages show a less significant, but still obvious, concentration of variance at 41 k.y. Faunal patterns suggest climatically controlled reorganization of deep-sea benthic communities during glacial-interglacial cycles due to oscillating deep-sea environments.

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T. M. Cronin, M.E. Raymo, K.P. Kyle. 1996. Pliocene (3.2-2.4 Ma) ostracode faunal cycles and deep ocean circulation, North Atlantic Ocean. https://doi.org/10.1130/0091-7613(1996)024%3C0695%3Apmofca%3E2.3.co%3B2

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