Quantifying Seasonal Oceanic Temperatures and the Oxygen Isotopic Composition of Seawater Over the Last 150,000 Years

有孔虫化石的稳定同位素地球化学已成为重建地球过去古海洋和古气候波动不可缺少的工具。具体地说，同位素数据已被用于建立冰期-间冰期旋回，推断大陆冰盖的大小，并估计古海洋温度波动。尽管这些数据成功地应用于古气候问题，但可用于分析的大部分潜在数据仍未得到利用。在这项提案中，概述了一种访问这些未使用的信息以从海洋化石记录中提取新的古气候和古海洋信息的战略。利用在已单独分析的有孔虫化石贝类种群中发现的种内稳定同位素变异性，现在可以获得古海洋的绝对季节性海表面温度(SST)。此外，还提出了一种测定末次冰期旋回和倒数第二次冰川消融期间海水氧同位素组成(18Ow)的方法。180w是模拟大陆冰盖生长的一个关键参数。过去150,000年间关键时段SST和18Ow的绝对测定将为最后一次冰川周期的全球变化模型提供一套新的古气候信息。

The stable isotope geochemistry of fossil foraminifera has become an indispensable tool for reconstructing paleoceanographic and paleoclimatic fluctuations in the earth's past. Specifically, isotopic data have been used to establish glacial-interglacial cycles, infer the size of continental ice-sheets and to estimate paleoceanic temperature fluctuations. Despite the success in applying these data to paleoclimatic problems, a large portion of the potential data available for analysis remains unused. In this proposal, a strategy is outlined to access this unused information to extract new paleoclimatic and paleoceanographic information from the marine fossil record. Using the intraspecific stable isotopic variability found within populations of fossil foraminiferal shells which have been individually analyzed, it is now possible to obtain absolute seasonal sea surface temperatures (SST) for paleoceans. In addition, a procedure is proposed to determine the oxygen isotopic composition of seawater ( 18Ow) during the last glacial cycle and penultimate deglaciation. 18Ow is a critical parameter used to model the growth of continental ice sheets. Absolute determinations of SST and 18Ow during key intervals over the last 150,000 years will provide a suite of new paleoclimatic information for global change models of the last glacial cycle.