Collaborative Proposal: Age, Origin and Climatic Significance of Buried Ice in the Western Dry Valleys, Antarctica

合作提案：南极洲西部干谷埋冰的年龄、起源和气候意义

• 批准号: 0338291
• 负责人: David Marchant
• 金额: --
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0338291&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Age; Origin; Climatic

This project will determine the age, origin, and climatic significance of buried ice found in the western Dry Valleys of Antarctica. Previous studies indicate that this ice may be over a million years in age, making it by far the oldest ice yet discovered on Earth. An alternative view is that this ice is represents recently frozen groundwater. To distinguish between these hypotheses and characterize the ice, we are undertaking an interdisciplinary research program focused on: 1) understanding the surface processes that permit ice preservation; and 2) testing the efficacy of cosmogenic nuclides and 40Ar/39Ar analyses in dating both tills and volcanic ash associated with the ice. Our plan calls for the analysis of a minimum of six cosmogenic depth profiles to determine if and how cryoturbation reworks sublimation tills and assess the average rate of ice sublimation for three debris-covered glaciers. We will model through finite- element analyses at least three buried glaciers and compare flow rates with those based on radiometric dating of surface deposits. Ten ice cores will also be collected for measurement of d18O, dD, ice fabric, ice texture, total gas content/composition. Better understanding of surface processes above buried ice will permit researchers to gain access to a record of atmospheric and climate change that could well cover intervals that predate Quaternary time. The work may also add valuable insight into Martian history. In terms of broader impacts, we have recruited three female PhD students and developed interdisciplinary collaborations among geochemists at Columbia University, planetary geologists at Brown University, geomorphologists at Boston University, and numerical modelers at the University of Maine.

该项目将确定在南极洲西部干谷发现的埋藏冰的年龄、起源和气候意义。先前的研究表明，这些冰的年龄可能超过100万年，使其成为迄今为止在地球上发现的最古老的冰。另一种观点是，这些冰是最近冻结的地下水。为了区分这些假设并描述冰的特征，我们正在进行一项跨学科的研究计划，重点是：1）了解允许冰保存的表面过程; 2）测试宇宙成因核素和40 Ar/39 Ar分析在确定冰碛物和与冰相关的火山灰的年龄方面的有效性。我们的计划要求分析至少六个宇宙成因的深度剖面，以确定冷冻扰动是否以及如何改造升华，并评估三个碎片覆盖的冰川的冰升华的平均速率。我们将通过有限元分析模拟至少三个埋藏的冰川，并将流速与基于地表沉积物放射性测年的流速进行比较。还将收集10个冰芯，用于测量d18 O、dD、冰组构、冰结构、总气体含量/成分。更好地了解埋冰上方的表面过程将使研究人员能够获得大气和气候变化的记录，这些记录可以很好地覆盖第四纪之前的时间间隔。这项工作也可能增加对火星历史的宝贵见解。在更广泛的影响方面，我们招募了三名女博士生，并在哥伦比亚大学的地球化学家、布朗大学的行星地质学家、波士顿大学的地貌学家和缅因州大学的数值建模师之间开展了跨学科合作。