Mid- to Late Eocene organic-walled dinoflagellate cysts from ODP Leg 171B, offshore Florida
Caroline A. Van Mourik, Henk Brinkhuis, Graham L. Williams, 2001. "Mid- to Late Eocene organic-walled dinoflagellate cysts from ODP Leg 171B, offshore Florida", Western North Atlantic Palaeogene and Cretaceous Palaeoceanography, Dick Kroon, R. D. Norris, A. Klaus
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The well-calibrated mid- to late Eocene sediment record of ODP Leg 171B (Site 1053A, Blake Nose) allows a detailed stratigraphic and palaeoenvironmental analysis of the dinoflagellate cyst (dinocyst) content. The recovered assemblages are a mixture of inner neritic, outer neritic and oceanic species. The autochthonous dinoflagellates, principally those of the Impagidinium group, indicate an oceanic milieu, with possibly some shallowing of water depth towards the top of the section. This trend is also indicated by a corresponding increase of inner neritic dinocysts. The close agreement in the abundance peaks of inner neritic dinocysts and terrestrial palynomorphs indicats that both are allochthonous. This is confirmed by the much higher number of neritic species found in JOIDES Holes 1 and 2, on the continental shelf of eastern Florida, immediately to the west of the Blake Nose. Lower-latitude species found in Hole 1053A, but not occurring at higher latitudes during late Eocene time, are Diphyes colligerum and Thalassiphora delicata. The presence of these, and other lower-latitude species, confirms that warmer-water conditions persisted during mid- to early late Eocene time in the vicinity of Site 1053. Eighteen new taxa are described, two of them formally: Charlesdowniea proserpina sp. nov. and Oligosphaeridium anapetum sp. nov.
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Palaeogene and Cretaceous palaeoceanography has been the focus of intense international interest in the last few years, spurred by deep ocean drilling at Blake Nose in the North Atlantic as well as the need to use past climate change as input for modelling future climate change. This book brings together a number of review papers that describe ancient oceans and unique events in the Earth’s climatic history and evolution of biota. The papers show evidence of periods characterized by exceptional global warmth such as the Late Palaeocene Thermal Maximum and Cretaceous anoxic events. Geochemical records and modelling will make the reader aware that these periods were forced by greenhouse gases. This information is essential for understanding the response of the ocean—climate system to the current input of fossil fuels. In this sense, the book contributes to the understanding of fundamental aspects of Earth’s climate, the carbon cycle, and marine ecosystems. A number of papers describe massive mass wasting deposits resulting from the energy released by the bolide impact at the Cretaceous—Tertiary boundary as well as the geochemistry of the boundary itself. Additional papers cover aspects of cyclostratigraphy and biostratigraphy of Palaeogene and Cretaceous records.
This book will be of interest to a broad audience of Earth Scientists interested in Palaeogene—Cretaceous palaeoceanography, extreme climate modelling, Cretaceous—Tertiary boundary, Late Palaeocene Thermal Maximum, Cretaceous anoxic events, as well as those specifically interested in radiolarian, dinoflagellate and coccolithophorid stratigraphy.