Ancient landscape-active Surfaces: Periglacial Hyperinflation in soils of Beacon Valley, Antarctica

古代景观活跃表面：南极洲灯塔谷土壤中的冰缘过度膨胀

• 批准号: 1341680
• 负责人: Ronald Sletten
• 金额: $ 23.91万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341680&HistoricalAwards=false
• 关键词: Ancient; landscape; active; Surfaces; Periglacial

Intellectual Merit: This project will yield new information on the long term Antarctic climate and landscape evolution from measurements of cosmogenic nuclides in quartz sand from two unique permafrost cores collected in Beacon Valley, Antarctica. The two cores have already been drilled in ice-cemented, sand-rich permafrost at 5.5 and 30.6 meters depth, and are currently in cold storage at the University of Washington. The cores are believed to record the monotonic accumulation of sand that has been blown into lower Beacon Valley and inflated the surface over time. The rate of accumulation and any hiatus in the accumulation are believed to reflect in part the advance and retreat of the Taylor Glacier. Preliminary measurements of cosmogenically-produced beryllium (10Be) and aluminum (26Al) in quartz sand in the 5.5 meter depth core reveal that it has been accreting at a rate of 2.5 meter/Myr for the past million years. Furthermore, prior to that time, lower Beacon Valley was most likely covered (shielded from the atmosphere thereby having no or very low production of cosmogenic nuclides in quartz) by Taylor Glacier from 1 to 3.5 Myr BP. These preliminary measurements also suggest that the 30.6 meter core may provide a record of over 10 million years. The emphasis is the full characterization of the core and analysis of cosmogenic nuclides (including cosmogenic neon) in the 30.6 meter permafrost core to develop a burial history of the sands and potentially a record the waxing and waning of the Taylor Glacier. This will allow new tests of our current understanding of surface dynamics and climate history in the McMurdo Dry Valleys (MDV) based on the dated stratigraphy of eolian sand that has been accumulating and inflating the surface for millions of years. This is a new process of surface inflation whose extent has not been well documented, and holds the potential to develop a continuous history of surface burial and glacial expansion. This project will provide a new proxy for understanding the climatic history of the Dry Valleys and will test models for the evolution of permafrost in Beacon Valley.Broader impacts: The landscape history of the McMurdo Dry Valleys is important because geological deposits there comprise the richest terrestrial record available from Antarctica. By testing the current age model for these deposits, we will improve understanding of Antarctica?s role in global climate change. This project will train one graduate and one undergraduate student in geochemistry, geochronology, and glacial and periglacial geology. They will participate substantively in the research and are expected to develop their own original ideas. Results from this work will be incorporated into undergraduate and graduate teaching curricula, will be published in the peer reviewed literature, and the data will be made public.

智力优势：该项目将通过测量在南极洲灯塔谷收集的两个独特的永久冻土核心的石英砂中的宇宙成因核素，获得关于南极长期气候和景观演变的新信息。 这两个岩心已经在5.5米和30.6米深的冰胶结、富含沙子的永久冻土中钻取，目前存放在华盛顿大学的冷藏库中。这些岩芯被认为记录了沙子的单调堆积，这些沙子被吹到了比肯山谷的下游，并随着时间的推移使地表膨胀。堆积的速度和堆积过程中的任何间断被认为部分地反映了泰勒冰川的前进和后退。 对5.5米深处的石英砂中宇宙生成的铍（10 Be）和铝（26 Al）的初步测量表明，在过去的一百万年里，它一直以2.5米/百万年的速度增生。此外，在此之前，下比肯谷很可能在100万至350万年前被泰勒冰川覆盖（与大气隔绝，因此石英中没有或非常低的宇宙成因核素）。 这些初步的测量也表明，30.6米的核心可能提供了超过1000万年的记录。重点是充分表征的核心和宇宙成因的核素（包括宇宙成因氖）在30.6米的永久冻土核心开发的埋藏历史的沙子和潜在的记录的盈亏泰勒冰川的分析。 这将允许我们目前对麦克默多干谷（MDV）的地表动力学和气候历史的理解进行新的测试，这些知识基于风成沙的年代地层学，风成沙已经积累和膨胀了数百万年。这是一个新的地表膨胀过程，其程度尚未得到很好的记录，并有可能发展一个连续的地表埋藏和冰川扩张的历史。该项目将提供一个新的代理人，了解干旱山谷的气候历史，并将测试模型的演变比肯Valley.Broader影响：景观历史的麦克默多干旱山谷是重要的，因为地质沉积物有最丰富的陆地记录从南极洲。 通过测试这些沉积物目前的年龄模型，我们将提高对南极洲的了解？在全球气候变化中的作用。 该项目将在地球化学、地质年代学、冰川和冰缘地质学方面培训一名研究生和一名本科生。他们将实质性地参与研究，并有望发展自己的原创思想。这项工作的结果将纳入本科和研究生教学课程，将在同行评议的文献中发表，数据将公开。