Collaborative Research: Pacific Coast Campanian-- Maastrichtian Chronostratigraphy

9405684我们建议对南加州和下加利福尼亚州上白垩统罗萨里奥组的生物地层学、磁性地层学和锶同位素地层学进行研究。人们早就知道，在罗萨里奥组的不同层位中都有极其丰富的大型化石。然而，到目前为止，对这些剖面的生物地层学研究相对较少，特别是在下加利福尼亚州露出的露头。我们已经确定了位于下加利福尼亚的三个目标区段，这些区段有望极大地提高我们对太平洋海岸上白垩统年代地层学的了解。我们最近发现，这些地区的软体动物化石是由太平洋沿岸特有物种和墨西哥湾沿岸和欧洲物种的混合组合组成的。其中最重要的是欧洲地带性菊石，这是太平洋沿岸地区首次发现的菊石。我们的目标地段已经进行了部分磁性地层学采样。通过将更完整的磁性地层学采样与修订的生物地层学相结合，我们将首次在太平洋海岸上白垩统地层与欧洲的层型剖面之间以及与墨西哥湾沿岸、西部内陆和大西洋海岸平原的特提斯剖面之间建立一级对比。

9405684 Ward We propose to investigate the biostratigraphy, magnetostratigraphy, and strontium isotope stratigraphy of the Upper Cretaceous Rosario Formation of southern California and Baja California. It has long been known that macrofossils are extremely abundant from various horizons of the Rosario Formation. Nevertheless, there has been relatively little study to date investigating the biostratigraphy of these sections, especially outcrops exposed in Baja California. We have identified three target sections located in Baja California that hold the promise of greatly increasing our understanding of Upper Cretaceous chronostratigraphy of the Pacific Coast. We have recently discovered that molluscan fossils from these sections are composed of a mixed assemblage of Pacific Coast endemics and Gulf Coast and European species. Of greatest importance are European zonal index ammonites, recognized here for the first time form the Pacific Coast region. Our target sections have already been partially sampled for magnetostratigraphy. By integrating a more complete magnetostratigraphic sampling with a revised biostratigraphy, we will produce, for the first time, a first order correlation between Pacific Coast Upper Cretaceous strata and the stratotype sections in Europe, and with Tethyan sections of the Gulf Coast, Western Interior and Atlantic Coast Plain.