Collaborative Research: Potential Direct Geologic Constraint of Ice Sheet Thickness in the Central Transantarctic Mountains during the Pliocene Warm Period

合作研究：上新世温暖期横贯南极中部山脉冰盖厚度的潜在直接地质约束

• 批准号: 1443329
• 负责人: Gregory Balco
• 金额: $ 9.81万
• 依托单位: Berkeley Geochronology Center
• 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: 2015-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443329&HistoricalAwards=false
• 关键词: Collaborative; Research; Potential; Direct; Geologic

This investigation will reconstruct past behavior of the East Antarctic Ice Sheet during periods of warmer-than-present climate, such as the Pliocene, in order to better project the likely response of Earth's largest ice sheet to anthropogenic warming. Containing the equivalent of ~55 m sea-level rise, the future evolution of the East Antarctic Ice Sheet has clear societal ramifications on a global scale as temperatures continue to rise. Therefore, determining ice-sheet sensitivity to climate on the scale predicted for the next two centuries is a matter of increasing urgency, particularly in light of evidence suggesting the East Antarctic Ice Sheet is more dynamic than previously thought. This research will provide a terrestrial geologic record of long-term ice-sheet behavior from sites immediately adjacent the East Antarctic Ice Sheet in the Transantarctic Mountains, with which the project will help ascertain how the ice sheet responded to past warm periods. The project will focus primarily on the Pliocene warm period, 5 to 3 million years ago, as this represents the closest analogue to 21st Century climate conditions.The proposed research will investigate glacial deposits corresponding to the East Antarctic Ice Sheet in the central Transantarctic Mountains in order to expand the geologic record of past ice-sheet behavior. The overarching research objectives are to improve understanding of the East Antarctic Ice Sheet's configuration during periods of warmer-than-present climate, such as the Pliocene warm period, and to determine whether the ice sheet underwent significant volume changes or remained relatively stable in response to warming. To address these goals, the investigation will map and date glacial deposits preserved at mountain sites immediately adjacent the ice sheet. Specifically, we will: (i) employ multiple cosmogenic nuclides (10Be, 26Al, 21Ne) to establish more fully ice-thickness histories for the upper Shackleton and Beardmore Glaciers, where they exit the ice sheet; (ii) use this record to identify periods during which the East Antarctic Ice Sheet was at least as extensive as today; and (iii) use these data to assess long-term ice-sheet variability in East Antarctica, with particular emphasis on Pliocene warm episodes. This research will require Antarctic fieldwork, glacial-geologic mapping, and cosmogenic surface-exposure dating.

这项调查将重建南极冰盖在温暖的气候（例如上新世）期间的过去行为，以便更好地投射地球最大的冰盖对人为变暖的可能反应。随着温度不断升高，东南冰原的未来进化含量相当于约55 m的海平面上升，在全球范围内具有明显的社会影响。因此，在接下来的两个世纪中确定对气候对气候的敏感性是提高紧迫性的问题，特别是鉴于表明东南极冰盖的证据比以前认为的更具动态性。这项研究将提供陆地地质记录的长期冰片行为的地质记录，该地点紧邻跨二行山脉的东南极冰盖，该项目将有助于确定冰盖对过去温暖时期的反应。该项目将主要集中于5至300万年前的上新世暖时期，因为这代表了与21世纪气候状况的最接近的类似物。拟议的研究将研究与跨北极山脉中部南极冰盖相对应的冰川沉积物，以扩大过去的冰淇淋行为的地质记录。总体研究目标是在温暖的气候（例如上新近温暖的时期）中提高对东南极冰盖的配置的理解，并确定冰盖发生重大体积变化还是在响应温暖的情况下保持相对稳定。为了解决这些目标，调查将绘制和日期冰川沉积物在紧邻冰盖附近的山地保存。具体而言，我们将：（i）使用多个宇宙核素（10be，26al，21ne）来建立上层沙克尔顿和比尔德莫尔冰川的更全面的冰厚历史，在那里它们退出冰盖； （ii）使用此记录来确定东南极冰盖至少与今天一样广泛的时期； （iii）使用这些数据评估南极东部的长期冰盖变异性，特别强调上新世暖发作。这项研究将需要南极野外作业，冰川地质图和宇宙性的表面暴露日期。