Maastrichtian Climatic History of the Southern Ocean

初步的锶、氧和碳同位素研究结果揭示了马斯特里赫特时期的逐渐冷却，以及显著的气候和海洋变化。有孔虫del 18O值的显著升高与海洋del 13C值的降低、有记录的海平面回归以及马斯特里克早晚期和晚期海水87Sr/86Sr比值的升高有关。这些事件的巧合，以及马斯特里赫特底栖有孔虫del18o值与始新世中期与冰筏碎屑相关的del18o值的相似性，表明马斯特里赫特的同位素变化可能与冰川-上升现象有关。本研究将基于有孔虫氧、碳同位素测量和有孔虫定量分析，调查和记录从马斯特里赫特晚期到白垩纪-第三纪边界的高纬度南大西洋和印度洋的气候和海洋学历史。我们将尝试确定气候/海洋学变化对有孔虫种群的影响。生物地层学、磁地层学和化学地层学的整合将加强深海剖面的地层对比。该数据集有望为晚白垩纪的气候重建提供基础，包括开发新的气候模型，这些模型不是基于白垩纪均匀、温暖和均匀气候条件的假设。

Results of preliminary strontium, oxygen and carbon isotope studies have revealed progressive cooling, and significant climatic and oceanographic variability during the Maastrichtian. Episodes of marked increases in foraminiferal del 18O values correlate with decreases in oceanic del 13C values, documented sea level regressions, and increases in seawater 87Sr/86Sr ratios in the early to late and latest Maastrichtian. The coincidence of these events, and the similarity between Maastrichtian benthic foraminifera del 18O values and those of middle Eocene age associated with ice-rafted debris, suggest that the Maastrichtian isotopic variations could be related to glacio-eustatic phenomena. The research proposed will investigate and document the climatic and oceanographic history of the high and mid-latitude South Atlantic and Indian Oceans from the latest early Maastrichtian to the Cretaceous-Tertiary boundary based on foraminiferal oxygen and carbon isotope measurements, and foraminiferal quantitative analyses. We will attempt to determine the effect of climatic/oceanographic changes on foraminiferal populations. Stratigraphic correlation of deep-sea sections will be enhanced by integration of biostratigraphy, magnetostratigraphy and chemostratigraphy. This data set is expected to provide a basis for climatic reconstruction of the Late Cretaceous including development of new climatic models that are not based on the assumption of uniform, warm, and equable climatic conditions during the Cretaceous.