The Maastrichtian record at Blake Nose (western North Atlantic) and implications for global palaeoceanographic and biotic changes
Kenneth G. MacLeod, Brian T. Huber, 2001. "The Maastrichtian record at Blake Nose (western North Atlantic) and implications for global palaeoceanographic and biotic changes", Western North Atlantic Palaeogene and Cretaceous Palaeoceanography, Dick Kroon, R. D. Norris, A. Klaus
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Widespread biological, geochemical and sedimentological shifts within the Maastrichtian are well documented, but data are limited for the low-latitude Atlantic. New observations from Ocean Drilling Program (ODP) sites located on Blake Nose in the subtropical western North Atlantic increase information concerning the Maastrichtian history of this critical region. Planktonic δ18O results suggest up to 6 °C of local surface water warming (or 4‰ decrease in salinity) at the same time as most of the globe was cooling. Benthic δ13O and δ13C values of both planktonic and benthic taxa show little if any directional trend or excursions on long time scales; however, planktonic and benthic taxa exhibit strong δ13C and δ18O cycles (up to 0.8 and 0.6‰, respectively) across a short interval of high-resolution sampling. Other portions of the cores have not yet been studied at high resolution. The last occurrence of inoceramid shell fragments on Blake Nose matches previously documented global patterns, i. e. a mid-Maastrichtian extinction event that occurred later in low latitudes than in high southern latitudes. Models for Maastrichtian change seem to be converging on variation in intermediate to deep water ocean circulation as a unifying process. Blake Nose data are consistent with this conclusion, but demonstrate new regional patterns and emphasize the importance of precise and accurate chronostratigraphic correlation in understanding Maastrichtian change.
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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.