Collaborative Research: Development of a Suite of Proxies to Detect Past Collapse of the West Antarctic Ice Sheet

合作研究：开发一套代理来检测南极西部冰盖过去的崩塌

• 批准号: 1443437
• 负责人: Joseph Stoner
• 金额: $ 41.71万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443437&HistoricalAwards=false
• 关键词: Collaborative; Research; Development; Suite; Proxies

Collapse of the West Antarctic ice sheet (WAIS) could raise global sea level by up to 3 meters, at a rate of up to ~1 meter per century, yielding major societal impacts. The goal of this project is to determine if such a collapse occurred in the recent past. This will include development of new geochemical tools to evaluate the sedimentary geologic record around the WAIS to evaluate WAIS behavior during past warm periods. The primary activities to be carried out by the research team are to: 1) characterize the chemistry and magnetic properties of sediments being discharged from different portions of the WAIS and use these properties to ?fingerprint? inputs from different sources on the continent; 2) measure these same properties in a marine sediment core to document major changes in the WAIS over the last 150,000 years. Determining if the WAIS has collapsed in the recent past can provide important information on WAIS potential to grow unstable in the future. The tools to be developed here can then be used on older records around the WAIS to examine the frequency of ice sheet instability in the past. The project will support a postdoctoral researcher as well as undergraduate students. This project will develop sediment provenance proxies to trace the sources of sediment discharged by the West Antarctic Ice Sheet (WAIS) to the continental rise. Specific questions to be addressed are: 1) the degree that sediment from different WAIS terranes can be geochemically and magnetically differentiated; 2) the ability of terrane provenance proxies to detect WAIS collapse in the late Quaternary. The WAIS erodes sediments from various West Antarctic geologic terranes that are deposited in adjacent drift sites. The geochemistry and magnetic properties of drift sediments reflect the tectonic and metamorphic history of their source terranes. Deglaciation of a terrane during WAIS collapse should be detectable by the loss of the terrane?s geochemical and magnetic signature in continental-rise detrital sediments. Continental shelf late-Holocene sediments from near the current WAIS groundling line will be analyzed for silt- and clay-size Sr-Nd-Pb isotopes, magnetic properties, and major-trace elements. The suite of cores includes the eastern Ross Sea to the northern tip of the Antarctic Peninsula and will establish provenance signatures of the Ross and Amundsen Provinces of Marie Byrd Land, Pine Island Bay, Thurston Island/Eight Coast Block, Ellsworth-Whitmore Crustal Block, and Antarctic Peninsula terranes. Many of these terranes have similar tectonic and metamorphic histories but Sr-Nd isotope data from detrital sediments suggest at least 3 distinct provenance signatures. An initial down core study of Ocean Drilling Program Site 1096 in the Bellingshausen Sea will be conducted to detect if the WAIS was unstable during the last interglacial period.

西南极冰盖（WAIS）的崩溃可能会使全球海平面上升3米，速度高达每世纪1米，产生重大的社会影响。 该项目的目标是确定这种崩溃是否发生在最近的过去。这将包括开发新的地球化学工具，以评估WAIS周围的沉积地质记录，以评估WAIS在过去温暖时期的行为。 研究小组将开展的主要活动是：1）表征从WAIS不同部分排放的沉积物的化学和磁性特性，并利用这些特性来？指纹？从大陆上不同来源的输入; 2）测量海洋沉积物核心中的这些相同属性，以记录WAIS在过去15万年中的主要变化。确定WAIS在最近的过去是否已经崩溃，可以提供有关WAIS未来可能变得不稳定的重要信息。 这里开发的工具可以用于WAIS周围的旧记录，以检查过去冰盖不稳定的频率。该项目将支持博士后研究人员以及本科生。该项目将开发沉积物来源代理，以追踪西南极冰盖排放到大陆隆起的沉积物的来源。需要解决的具体问题是：1）不同WAIS沉积物的地球化学和磁学差异程度; 2）WAIS物源代用指标检测晚第四纪WAIS塌陷的能力。WAIS侵蚀沉积物，这些沉积物来自南极西部的各种地质遗迹，沉积在邻近的漂流地点。漂流沉积物的地球化学和磁性特征反映了其源区的构造和变质历史。在WAIS崩溃期间，冰融的消退应该可以通过冰融的损失来检测？的地球化学和磁性特征。大陆架晚全新世沉积物附近的当前WAIS接地线将进行分析，粉砂和粘土大小的Sr-Nd-Pb同位素，磁性和主要微量元素。岩芯组包括罗斯海东部至南极半岛北方端，并将建立玛丽伯德地的罗斯省和阿蒙森省、松岛湾、瑟斯顿岛/八海岸地块、埃尔斯沃-惠特莫尔地壳地块和南极半岛地块的物源特征。许多这些岩石具有相似的构造和变质历史，但碎屑沉积物的Sr-Nd同位素数据表明至少有3个不同的物源标志。将在别林斯高晋海的大洋钻探计划1096站点进行初步的下芯研究，以检测WAIS在末次间冰期是否不稳定。