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

合作研究：EAGER：评估拉森盆地测试白垩纪冰川假说的适用性

• 批准号: 1241574
• 负责人: Sidney Hemming
• 金额: $ 11.07万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1241574&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; EAGER; Evaluating; Larsen

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.

知识价值：最近的地球化学、层序地层学和对几个大陆边缘和海洋盆地的海洋地层的综合调查表明，在白垩纪和古近纪早期的部分时间里，南极可能存在短暂的冰盖。然而，这一次大气中二氧化碳的估算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？S气候系统的理解，特别是对南极冰川和冰川消融的解释阈值应该得到重新考虑。这项拟议的研究将把南极半岛东部拉森盆地白垩纪沉积物的数量和来源与半岛及其邻近地区潜在沉积源地体的折返年代学和成分进行比较。新的露头地层学分析和放射性同位素方法年龄模型的改进将结合起来，以确定在关键年代地层面之间流入拉森盆地的碎屑沉淀量。对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。这些初步结果将检验评估有争议的白垩纪南极冰川假说的拟议方法的可行性。更广泛的影响：拟议的工作将部分支持南卡罗来纳大学的一名博士、一名理学硕士和三名本科生。国际志愿人员将通过志愿者演讲以及制作视频和播客来宣传这项工作。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利于正在进行的古生物学、古气候和生物地理学的研究。海绿石K-Ar和Rb-Sr计时仪的发展可能是超出拟议研究直接范围的一个重要成果。