COLLABORATIVE RESEARCH: EAGER: Evaluating the Larsen basin's suitability for testing the Cretaceous Glaciation Hypothesis

智力优势：最近的地球化学，层序地层学和综合调查的海洋地层从几个大陆边缘和海洋盆地表明，短暂的冰盖可能存在于南极洲的部分白垩纪和早古近纪。然而，这一时期的大气二氧化碳估计值是现代水平的四倍。在这样的温室条件下，南极冰盖的存在意味着我们目前对地球的理解？的气候系统，特别是南极冰川和冰川消退的解释阈值应重新考虑。拟议的研究将比较南极半岛东部拉森盆地白垩纪沉积物的数量和物源，以及半岛和邻近地区潜在沉积物源岩的剥露年代和组成。新的露头地层分析与放射性同位素方法的年龄模型的改进，将被整合，以确定碎屑沉积物的数量流入拉森盆地之间的关键年代地层表面。石英砂和粉砂颗粒的显微结构分析将有助于确定拉森盆地碎屑沉积物是否起源于冰川风化。这些初步结果将测试的可行性，提出的方法来评估有争议的白垩纪南极冰川hypothes.Broader影响：拟议的工作将部分支持博士，硕士，和三个本科生在南卡罗来纳州的大学。PI将通过志愿者演讲活动以及视频和播客的开发来宣传这项工作。他们还承诺迅速公布结果，并及时向档案馆提交数据。拉森盆地年龄模型的发展和完善将有助于古生物学、古气候学和古地理学的研究。钙钛矿K-Ar和Rb-Sr计时器的开发可能是超出拟议研究直接范围的重要成果。

Intellectual Merit: Recent geochemical, sequence stratigraphic, and integrated investigations of marine strata from several continental margins and ocean basins suggest that ephemeral ice sheets may have existed on Antarctica during parts of the Cretaceous and early Paleogene. However, atmospheric carbon dioxide estimates for this time are as much as four times modern levels. With such greenhouse conditions, the presence of Antarctic ice sheets would imply that our current understanding of Earth?s climate system, and specifically the interpreted thresholds of Antarctic glaciation and deglaciation should be reconsidered. The proposed research will compare the quantity and provenance of Cretaceous sediments in the Larsen basin of the eastern Antarctic Peninsula with the exhumation chronology and composition of potential sediment source terranes on the peninsula and in adjacent regions. New outcrop stratigraphic analyses with improvements in the age models from radioisotopic approaches will be integrated to determine the amount of detrital sediment fluxed to the Larsen basin between key chronostratigraphic surfaces. Microtextural analysis of quartz sand and silt grains will help determine whether the Larsen basin detrital sediment originated from glacial weathering. These preliminary results will test the viability of the proposed approach to assess the controversial Cretaceous Antarctic glaciation hypothesis.Broader impacts: The proposed work will partially support a PhD, a MSc, and three undergraduate students at the University of South Carolina. The PIs will publicize this work through volunteer speaking engagements and the development of videos and podcasts. They also commit to prompt publication of the results and timely submission of data to archives. The development/improvement of the Larsen basin age model will benefit ongoing research in paleobiology, paleoclimate and biogeography. Development of the glauconite K-Ar and Rb-Sr chronometers could be an important outcome beyond the direct scope of the proposed research.