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Extending the record of Antarctic landscape evolution into the Pliocene with neon-21 measurements

通过 Neon-21 测量将南极地貌演化记录延伸至上新世

基本信息

批准号：
0838958
负责人：
Gregory Balco
金额：
$ 4.73万
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：
2009
资助国家：
美国
起止时间：
2009-06-01 至 2010-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838958&HistoricalAwards=false
关键词：
Extending record Antarctic landscape evolution

项目摘要

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The proposal seeks limited funds to develop the capability of the Berkeley Geochronology Center to measure the stable cosmogenic nuclide 21Ne, and to use this capability to measure 21Ne concentrations in an existing set of bedrock and sediment samples from the Antarctic Dry Valleys (DV). These samples were collected during two previous Antarctic field seasons and concentrations of the cosmogenic radionuclides 26Al and 10Be was measured in order to determine whether the observed antiquity of DV surface sediments and landforms was the result of vanishingly small erosion and degradation rates or of long periods of cover by cold-based glaciers. If the former hypothesis is confirmed, measure the degradation rates of these processes. These results quantify existing stratigraphic observations that many DV landscape surfaces are very old and erode very slowly. One consequence of the results is that, unlike in most environments worldwide where relatively rapid surface erosion limits the period about which cosmogenic-nuclide measurements can provide information, surfaces in the DV are sufficiently stable that the factor governing this time scale is not surface erosion, but the radioactive decay of 26Al and 10Be. The research results will have important implications in understanding Antarctic ice sheet and climate evolution.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该提案寻求有限的资金，以发展伯克利地质年代学中心测量稳定的宇宙成因核素21 Ne的能力，并利用这一能力测量南极干谷现有一套基岩和沉积物样本中的21 Ne浓度。这些样品收集在前两个南极领域的季节和宇宙成因的放射性核素26铝和10铍的浓度进行了测量，以确定是否所观察到的古老的DV表层沉积物和地貌是由于侵蚀和退化率微乎其微或长期覆盖的冷基冰川。如果前一个假设得到证实，则测量这些过程的降解速率。这些结果量化了现有的地层观测，许多DV景观表面非常古老，侵蚀非常缓慢。结果之一是，不像在世界上大多数环境中，相对快速的表面侵蚀限制了宇宙成因核素测量可以提供信息的时间，DV中的表面足够稳定，控制这个时间尺度的因素不是表面侵蚀，而是26 Al和10 Be的放射性衰变。研究结果对认识南极冰盖和气候演变具有重要意义。