Collaborative Research: East Antarctic Glacial Landscape Evolution (EAGLE): A Study using Combined Thermochronology, Geochronology and Provenance Analysis

合作研究：东南极冰川景观演化（EAGLE）：综合热年代学、地质年代学和起源分析的研究

• 批准号: 1443565
• 负责人: Sidney Hemming
• 金额: $ 26.69万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443565&HistoricalAwards=false
• 关键词: Collaborative; Research; East; Antarctic; Glacial

Antarctica is almost entirely covered by ice, in places over two miles thick. This ice hides a landscape that is less well known than the surface of Mars and represents one of Earth's last unexplored frontiers. Ice-penetrating radar images provide a remote glimpse of this landscape including ice-buried mountains larger than the European Alps and huge fjords twice as deep as the Grand Canyon. The goal of this project is to collect sediment samples derived from these landscapes to determine when and under what conditions these features formed. Specifically, the project seeks to understand the landscape in the context of the history and dynamics of the overlying ice sheet and past mountain-building episodes. This project accomplishes this goal by analyzing sand collected during previous sea-floor drilling expeditions off the coast of Antarctica. This sand was supplied from the continent interior by ancient rivers when it was ice-free over 34 million year ago, and later by glaciers. The project will also study bedrock samples from rare ice-free parts of the Transantarctic Mountains. The primary activity is to apply multiple advanced dating techniques to single mineral grains contained within this sand and rock. Different methods and minerals yield different dates that provide insight into how Antarctica?s landscape has eroded over the many tens of millions of years during which sand was deposited offshore. The dating techniques that are being developed and enhanced for this study have broad application in many branches of geoscience research and industry. The project makes cost-effective use of pre-existing sample collections housed at NSF facilities including the US Polar Rock Repository, the Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. The project will contribute to the STEM training of two graduate and two undergraduate students, and includes collaboration among four US universities as well as international collaboration between the US and France. The project also supports outreach in the form of a two-week open workshop giving ten students the opportunity to visit the University of Arizona to conduct STEM-based analytical work and training on Antarctic-based projects. Results from both the project and workshop will be disseminated through presentations at professional meetings, peer-reviewed publications, and through public outreach and media.The main objective of this project is to reconstruct a chronology of East Antarctic subglacial landscape evolution to understand the tectonic and climatic forcing behind landscape modification, and how it has influenced past ice sheet inception and dynamics. Our approach focuses on acquiring a record of the cooling and erosion history contained in East Antarctic-derived detrital mineral grains and clasts in offshore sediments deposited both before and after the onset of Antarctic glaciation. Samples will be taken from existing drill core and marine sediment core material from offshore Wilkes Land (100°E-160°E) and the Ross Sea. Multiple geo- and thermo-chronometers will be employed to reconstruct source region cooling history including U-Pb, fission-track, and (U-Th)/He dating of zircon and apatite, and 40Ar/39Ar dating of hornblende, mica, and feldspar. This offshore record will be augmented and tested by applying the same methods to onshore bedrock samples in the Transantarctic Mountains obtained from the US Polar Rock Repository and through fieldwork. The onshore work will additionally address the debated incision history of the large glacial troughs that cut the range, now occupied by glaciers draining the East Antarctic Ice Sheet. This includes collection of samples from several age-elevation transects, apatite 4He/3He thermochronometry, and Pecube thermo-kinematic modeling. Acquiring an extensive geo- and thermo-chronologic database will also provide valuable new information on the poorly known ice-hidden geology and tectonics of subglacial East Antarctica that has implications for improving supercontinent reconstructions and understanding continental break-up.

南极几乎完全被冰覆盖，厚度超过两英里。这种冰隐藏了一个不比火星表面知名的景观，代表了地球上一个未知的边界之一。冰渗透雷达图像可远程了解这一景观，其中包括大于欧洲阿尔卑斯山大的冰山和巨大的峡湾，其深度是大峡谷的两倍。该项目的目的是收集从这些景观中得出的沉积物样品，以确定这些特征何时何地形成了这些特征。具体而言，该项目试图在上覆盖的冰盖的历史和动态和过去的山区建设情节的背景下理解景观。该项目通过分析南极海岸以前的海底钻探探险中收集的沙子来实现这一目标。这条沙子是在3400万年前，后来由冰川冰上冰上的，由古老的河流从连续的内部提供。该项目还将研究跨北极山脉稀有部分的基岩样品。主要活性是将多种高级约会技术应用于该沙子和岩石中包含的单矿物颗粒。不同的方法和矿物质产生了不同的日期，这些日期可深入了解南极洲的景观如何在数千万年内发射，在该景观中，在其海上沉积了沙子。为这项研究开发和增强的约会技术在地球科学研究和行业的许多分支中都有广泛的应用。该项目可用于使用在NSF设施中存放的现有样品收集，包括美国极地岩石存储库，墨西哥湾沿岸核心库库和南极海洋地质研究机构。该项目将有助于两名研究生和两名本科生的STEM培训，其中包括美国四所大学之间的合作以及美国与法国之间的国际合作。该项目还以为期两周的开放研讨会的形式支持外展活动，这使十名学生有机会访问亚利桑那大学进行基于STEM的分析工作和基于南极的项目的培训。该项目和研讨会的结果将通过专业会议上的演讲，经过同行评审的出版物以及通过公共宣传和媒体进行分散。该项目的主要目的是重建南极亚冰川景观的年代学以了解构成构成和探索的构造和风格的构成，并在构成了冰上的冰上和动态上，并有影响了冰上的构成和动态。我们的方法着重于获取南极衍生的碎屑矿物颗粒和南极冰川发作之前和之后沉积在近海沉积物中的冷却和侵蚀史的记录。样品将取自现有的钻芯和海洋沉积物核心材料，来自海上威尔克斯陆地（100°E-160°E）和罗斯海。将使用多个地理和热基因计量器来重建源区域冷却历史记录，包括U-PB，裂变轨，以及（U-th）/HE的锆石和磷灰石日期，以及Hornblende，Mica和Feldspar的Hornblende，Mica和Feldspar的40AR/39AR日期。通过将相同的方法应用于从美国极地岩石存储库中获得的跨北极山脉中的陆上基岩样品和通过现场工作，将对离岸记录进行增强和测试。陆上的工作将介绍大量冰川麻烦的辩论切口历史，这些冰川麻烦削减了该范围，该山脉现在被冰川排干了东南极冰盖。这包括来自几个年龄段样本的样品，磷灰石4HE/3HE热表格计和Pecube热模型建模。获得广泛的地理和热教学数据库还将提供有关低冰川亚冰川东南极洲的冰冰贫困的地质​​和构造学的宝贵新信息，该信息对改善超大型重建和理解持续分手具有影响。