NSFGEO-NERC: Developing A New Lower Cretaceous Time Scale: Foundation For The Next Generation Of Paleoceanographic And Biogeochemical Studies

在Aptian至Cenomanian异常温暖的温室条件下，黑色页岩沉积和/或碳同位素漂移（oae）反映了全球碳循环中的几个主要扰动。为了充分了解这个温室世界的海洋气候动力学，以及推动海洋缺氧和生态系统恶化的机制驱动因素，新的放射性同位素测年，以及地理上分散的高质量白垩纪沉积记录是必不可少的。日本野三群（TheYezo Group， YG）由一个面向太平洋的高纬度弧前盆地中的Aptian - Maastrichtian沉积物组成。与其他已被充分研究的下白垩纪层序不同，例如法国vocontan盆地（VB）， YG包含流纹岩凝灰岩，可以进行精确的U-Pb和40Ar/39Ar测年。我们建议根据新的锇（Os）和碳(C)同位素化学地层学，从YG获得新的放射性同位素年代。这种新的年代学和化学地层学可以导出并与Tethys的记录进行对比，包括VB记录，我们的目标是生成新的Os和C同位素地层学，以及一个以OAE1a临界起始区间为中心的天体年代学模型。我们建议通过整合法国和日本地层来更新和改进下白垩纪时间尺度，旨在纠正关键时间尺度的不准确性，并采用精细的时间尺度和新的替代数据来解决与白垩纪主要c -旋回扰动（如oae）相关的岩石圈-水圈-生物圈相互作用的基本问题。

During unusually warm greenhouse conditions of the Aptian to Cenomanian, several major perturbationsin the global carbon cycle are reflected by black shale deposits and/or carbon isotope excursions (OAEs).To fully understand the ocean-climate dynamics of this greenhouse world, and the mechanistic driversthat propel ocean anoxia and deterioration of ecosystems, new radioisotopic dating, in parallel with amore geographically dispersed array of high-quality Cretaceous sedimentary records are essential. TheYezo Group (YG), Japan comprises Aptian to Maastrichtian sediment deposited in a high latitude PacificOcean-facing fore arc basin. Unlike other well-studied Lower Cretaceous sequences, e.g., the VocontianBasin, France (VB), the YG contains rhyolitic tuffs amenable to precise U-Pb and 40Ar/39Ar dating. Wepropose to obtain new radioisotopic dates from the YG in concert with new osmium (Os) and carbon (C)isotope chemostratigraphy. This new chronology and chemostratigraphy can be exported and correlated torecords from Tethys, including the VB for which we aim to generate new Os and C isotopechemostratigraphy and an astrochronologic age model focused on the critical onset interval of OAE1a.Our proposed research to update and improve the Lower Cretaceous time scale by integrating French andJapanese strata is designed to rectify critical time scale inaccuracies, and employ refined time scales andnew proxy data to address fundamental questions concerning lithosphere-hydrosphere-biosphereinteractions associated with major Cretaceous C-cycle perturbations such as OAEs.