Biostratigraphic implications of mid-latitude Palaeocene–Eocene radiolarian faunas from Hole 1051A, ODP Leg 171B, Blake Nose, western North Atlantic
Annika Sanfilippo, Charles D. Blome, 2001. "Biostratigraphic implications of mid-latitude Palaeocene–Eocene radiolarian faunas from Hole 1051A, ODP Leg 171B, Blake Nose, western North Atlantic", Western North Atlantic Palaeogene and Cretaceous Palaeoceanography, Dick Kroon, R. D. Norris, A. Klaus
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Abundant well-preserved radiolarians were recovered from Ocean Drilling Program Leg 171B Hole 1051A, western North Atlantic, and range from upper middle Eocene radiolarian Zone RP16 through lower Palaeocene Zone RP6. This mid-latitude fauna contrasts with tropical faunas in lacking many tropical zonal markers and in its high proportion of diachronous first and last occurrences. The sequence from Hole 1051A contains the lower Eocene-middle Eocene and Palaeocene-Eocene (P-E) boundaries, and the only known record of a well-preserved Late Palaeocene Thermal Maximum (LPTM) radiolarian assemblage. There is no gross change observed in the composition of the fauna, only a minor increase in the number of first and last occurrences across the LPTM interval and P-E boundary. Calcareous evidence indicates two hiatuses, each 1–2 Ma long, one in the lowermost middle Eocene sequence and a second in the upper Palaeocene sequence. Presence of the middle Eocene hiatus is corroborated by an abnormally large radiolarian turnover. Twenty-six events are documented and show that most of radiolarian Zone RP10 and a substantial part of Zone RP9 are missing. Seven new species are described: Spongatractus klausi, Calocyclas aphradia, Lychnocanoma (?) parma, Sethocyrtis austellus, Sethocyrtis chrysallis, Thyrsocyrtis (Pentalacorys) krooni and Thyrsocyrtis (Thyrsocyrtis) norrisi.
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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.