麻豆传媒

B.Sc. (Honours) Thesis

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Offshore Newfoundland reflects the Cretaceous and Cenozoic sediments deposited offshore eastern Newfoundland and the rift and post-rift history of the North Atlantic. Site 1276 of Leg 210 of the Offshore Drilling Program was drilled to study the rift and subsequent post-rift sedimentation of the Newfoundland鈥揑beria system. Key biostratigraphic ages and paleoenvironments for the Creteceous-Paleogene section in 1276 were originally based on nannofossil, foraminifera and palynomorphs, all of wich are microfossils. In this study, I have utilized dinoflaglellate cysts, tiny unicellular organisms. Dinoflagellates have distinctive morphological features, such as tabulation patterns and excystment openings (archeopyles), which allow them to be assigned to genera and species, which have restricted stratigraphic ranges. These ranges allow the sediments to be dated, and dinocyst assemblages, for example, show changes that allow the Paleocene-Eocene thermal maximum (PETM) to be recognized. This event saw a significant rise in global average temperatures. In the present study, three broad intervals can be identified through the dinocyst assemblages: Selandian to Thanetian, late Ypresian to middle Lutetian, and middle Lutetian to early Priabonian. Peridinioid/ gonyaulacoid (P-Cyst/G-cyst) ratios have yielded a distinctive trend indicating an outer-neritic paleoenvironment with oceanic influence followed by a mass influx of inner-neritic species induced by the Paleocene Eocene thermal maximum and possibly the mid Eocene Climatic Optimum. Evidence for reworking among dinocysts has been recorded throughout the section.

Keywords: Palynology, Paleogene, dinoflagellates, PETM, paleoenvironments, dinocysts
Pages: 57
Supervisor: Rob Fensome & Graham Williams