Foraminiferal Paleoecology and Paleoceanography of the Cretaceous Western Interior Seaway: Northern San Juan Basin

浮游有孔虫种群结构的显著波动，特别是来自陆表海的组合，被认为记录了水体性质的变化。白垩纪西部内陆海道代表了广泛变化的水团之间的动态界面，这些水团对海平面上升波动、幕式构造运动和沉降以及气候变化做出了响应。白垩纪海相序列富含有孔虫，为严格评价有孔虫古生态学提供了难得的机会。假设保存完好的有孔虫组合记录了水团边界的变化和/或水团结构的性质随时间的变化，pi将检验西边缘的间歇性海岸线迁移影响了海道的古海洋学的假设，并且可以在近海泥岩相中观察到这种假设。通过对浮游和底栖有孔虫种群结构的详细分析，结合粘土矿物学和其他沉积学和地球化学技术，将建立西部内陆海道白垩纪有孔虫的古生态模型。这种模型将有助于评价未勘探地区的资源潜力。

Marked fluctuations in the population structure of planktonic foraminifera, particularly in assemblages from epicontinental seas, are believed to recrod changes in water-mass properties. The Cretaceous Western Interior Seaway represented a dynamic interface between widely varying water masses responding to eustatic sealevel fluctuations, episodic tectonism and subsidence, and climatic variability. The Cretaceous marine sequences are rich in foraminifera and represent a rare opportunity to rigorously evaluate foraminiferal paleoecology. With the assumption that well-preserved foraminiferal assemblages recrod shifts in water mass boundaries and/or changes in water mass structure of properties through time, PIs will test the hypothesis that episodic shoreline migrations of the western margin influenced the paleoceanography of the seaway, and can be observed as such in offshore mudrock facies. Detailed analyses of planktonic and benthic foraminiferal population structure, coupled with clay mineralogy and other sedimentologic and geochemical techniques, will be used to develop robust paleoecologic models for Cretaceous foraminifera of the Western Interior Seaway. Such models will be useful for evaluating the resource potential of unexplored areas.