Collaborative Research: Development of a New Late Mesozoic Time Scale based on U-Pb Geochronology of Volcanic Horizons from the Great Valley Group, Northern California

小行星9405772 中生代古海洋学、古生物学和构造学中一些最热门的问题的研究目前受到缺乏准确和精确的时间尺度的限制。 相关的例子包括估计生物化石的进化速度和控制它们的因素、有机物质的积累速度及其与海洋缺氧的关系、海底扩张和海洋地壳的生产速度及其古气候意义。 通过对北方加州大峡谷群早白垩世凝灰岩和碳酸盐岩的锆石U-Pb年代学研究，可以显著提高晚中生代时间尺度的精度。 由于在生物地层学上具有钙质超微化石、盘足类、Buchia和时间尺度，从而间接地确定了整个晚中生代（晚侏罗世至晚白垩世）的年代地层。 此外，更严格的绝对年龄控制将允许更窄的限制被放置在沉积旋回的周期性，从而提高了旋回地层学作为一种地层工具的适用性。

9405772 Bralower Investigation of some of the most topical problems in Mesozoic paleoceanography, paleobiology and tectonics are currently limited by the lack of an accurate and precise time scale. Pertinent examples include estimating rates of evolution of fossil organisms and the factors that control them, accumulation rates of organic matter and their relationship with oceanic anoxia, and sea floor spreading and oceanic crustal production rates and their paleoclimatic significance. We propose to significantly improve the precision of the Late mesozoic time scale by investigating the U-Pb zircon geochronology of Lower Cretaceous tuffs and bentonites from the Great Valley Group, Northern California. Because the biostratigraphically with calcareous nannofossils, the pelecypod, Buchia and time scale, and indirectly to a chronostratigraphy for the entire Late mesozoic (Late Jurassic to Late Cretaceous) interval. In addition, tighter absolute age control will allow narrower constraints to be placed on the periodicities of sedimentary cycles, thus enhancing the applicability of cyclostratigraphy as a stratigraphic tool.