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.

知识分子的优点：该项目将从南极洲的两个独特的永久冻土核心中的宇宙基因核中的宇宙核素的测量中产生有关南极长期气候和景观进化的新信息。 这两个核心已经在5.5和30.6米的深度涂层，富含沙质的多永久冻土中钻出，目前正在华盛顿大学冷藏。据信，岩心记录了砂的单调积聚，该沙子被吹入下标准谷，并随着时间的流逝而膨胀了表面。据信，积累速率和积累中的任何中断率部分反映了泰勒冰川的前进和撤退。 在5.5米深核心中，宇宙生产的铍（10BE）和铝（26AL）的初步测量表明，它在过去一百万年内一直以2.5米/MYR的速度吸收。此外，在此之前，泰勒冰川从1至3.5 Myr BP覆盖了下部标准谷（从石英中遮盖了大气中，因此没有或非常低的宇宙核素产生）。 这些初步测量还表明，30.6米的核心可能会提供超过1000万年的记录。重点是核心的全部表征和在30.6米冻土核心中的宇宙核素（包括宇宙基因霓虹灯）的分析，以发展沙子的埋葬历史，并有可能记录泰勒冰川的上蜡和减弱。 这将允许我们根据McMurdo干谷（MDV）（MDV）的当前了解我们目前对基于Eolian Sand的过时的地层研究的表面动力学和气候历史的了解，而Eolian Sand的日期分层已经积累并膨胀了数百万年的表面。这是一个新的表面通胀过程，其范围尚未得到充分证明，并具有发展表面埋葬和冰川膨胀的连续历史的潜力。该项目将为理解干山谷的气候历史提供新的代理，并将测试信标谷中多年冻土演变的模型。Broader的影响：McMurdo Dry Valleys的景观历史很重要，因为地质矿床也构成了Antarctica可获得的最丰富的地面记录。 通过测试这些沉积物的当前年龄模型，我们将提高对南极在全球气候变化中的作用的理解。 该项目将培训一名毕业生和一名地球化学，年代学以及冰川和冰川地质的本科生。他们将实质上参与研究，并有望发展自己的原始想法。这项工作的结果将纳入本科和研究生教学课程中，将在同行评审的文献中发布，并将数据公开。