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Environmental Indicators and Impact Assessment
University of Nebraska - Lincoln
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
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Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell
Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Well-preserved nannofossil assemblages in late Albian and Cenomanian hemipelagic sections from Ocean Drilling Program (ODP) Leg 171B preserve a record of the early history and adaptive radiation of the calcareous nannofossil genus Prediscosphaera. There was a significant rise in the abundance of the genus (from an average of 2% in the early late Albian to about 6% in the latest Albian and Cenomanian. This rise, and other shorter term pulses of increased generic abundance, corresponds to black shale deposition episodes. Twelve distinct morphotypes that were derived from the long-ranging Prediscosphera columnata and Prediscosphaera spinosa, are recognized and differentiated …