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

智力价值：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岩芯中的石英砂中的宇宙成因核素，获得关于南极长期气候和地貌演变的新信息。这两个岩芯已经在5.5米和30.6米深的冰胶结、富含沙子的永久冻土中进行了钻探，目前正在华盛顿大学的冷库中。这些岩心被认为记录了沙子的单调积累，这些沙子被吹到比肯山谷下游，并随着时间的推移膨胀了地表。堆积的速度和堆积中的任何中断被认为在一定程度上反映了泰勒冰川的进退。对5.5米深的石英砂中宇宙生成的铍(10Be)和铝(26Al)的初步测量表明，在过去的100万年里，它一直以2.5m/Myr的速度增长。此外，在此之前，下比肯河谷很可能被泰勒冰川覆盖(不受大气层影响，因此在石英中没有宇宙成因核素或产生的宇宙核素很少)，从1到3.5Myr BP。这些初步测量还表明，30.6米的核心可能提供了超过1000万年的记录。重点是对30.6米永久冻土核心的充分描述和宇宙成因核素(包括宇宙成因霓虹石)的分析，以建立沙子的埋藏史，并可能记录泰勒冰川的消长。这将使我们能够在麦克默多干燥山谷(MDV)对我们目前对地表动力学和气候历史的理解进行新的测试，这是基于数百万年来一直积累和膨胀表面的风沙的过时地层学。这是一种新的地表膨胀过程，其程度尚未被很好地记录下来，并有可能发展出持续的地表埋藏和冰川膨胀历史。该项目将为了解干旱山谷的气候历史提供一个新的替代物，并将测试Beacon山谷永久冻土演化的模型。广泛的影响：麦克默多干旱山谷的景观历史很重要，因为那里的地质沉积构成了南极洲可获得的最丰富的陆地记录。通过检验这些沉积物目前的年龄模型，我们将加深对南极洲S在全球气候变化中的作用的理解。该项目将培养一名研究生和一名本科生，内容涉及地球化学、地质年代学、冰川和冰缘地质学。他们将实质性地参与研究，并有望形成自己的原创想法。这项工作的结果将被纳入本科生和研究生的教学课程，将发表在同行评议的文献中，数据将被公开。

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.