Geodynamics and Thermal Regime across the Central Transantarctic Mountains from Analysis of Magnetotelluric Measurements

从大地电磁测量分析中跨南极中部山脉的地球动力学和热力状况

• 批准号: 1243559
• 负责人: Philip Wannamaker
• 金额: $ 17.33万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2016-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1243559&HistoricalAwards=false
• 关键词: Geodynamics; Thermal; Regime; across; Central

Intellectual Merit: The PIs propose to analyze a transect of 57 high-quality magnetotelluric (MT) soundings acquired over two Antarctic field seasons to examine competing hypotheses for the mechanism of extension and creation of the Transantarctic Mountains. These data will also be used to characterize the thermal regimes of rifted West Antarctica and stable East Antarctica. In the MT method, temporal variations in the Earth's natural electromagnetic field are used as source fields to probe the electrical resistivity structure in the depth range of 1 to 200 km below Earth's surface. Raw MT soundings contain significant information related to the thermal regime beneath the Transantarctic Mountains as it relates to support mechanisms and composition. This information will enable comparison to other rift-platform transitions, such as in the western United States. The distinct character of the MT data will also be correlated with regional aeromagnetic trends and tied to outcrops in terms of distinct lithologies such as meta-sedimentary terranes and plutonic complexes. Specifically, the goals of this research are: to establish the location of the tectonic transition between East and West Antarctica, which may help infer a support mechanism for the Transantarctic Mountains; to use MT data to estimate crustal heat flux into the ice sheet base; and to determine if regional-scale resistivity properties be used as a proxy for lithological discrimination, to support facies extrapolation and terrane reconstruction.Broader impacts: This project involves international collaborations between University of Utah, GNS Sciences Wellington NZ, and Tokyo Institute of Technology Japan. It will support a female post-doc who will gain experience in state of the art geophysical instrumentation, parameters of field survey design, practical logistical matters in remote settings, modern methods of MT inversion, and the relationship between electrical resistivity and physico-chemical state in the Earth. Heat flow estimates could improve models of ice sheet stability.

智力优势：PI建议分析一个断面的57个高质量的大地电磁（MT）探测获得了两个南极领域的季节，以检查竞争的假设的机制，延长和创建的跨南极山脉。这些数据还将用于确定断裂的西南极洲和稳定的东南极洲的热状况。在MT方法中，地球天然电磁场的时间变化被用作源场，以探测地球表面以下1至200 km深度范围内的电阻率结构。原始MT探测包含重要的信息有关的热制度下的跨南极山脉，因为它涉及到支持机制和组成。这些信息将能够与其他裂谷-地台过渡进行比较，例如在美国西部。MT数据的独特性还将与区域航磁趋势相关，并与不同岩性（如变质沉积岩和深成杂岩）的露头相关。具体而言，本研究的目标是：确定东南极和西南极之间的构造转换位置，这可能有助于推断横贯南极山脉的支撑机制;并且为了确定区域尺度电阻率特性是否被用作岩性鉴别的替代，更广泛的影响：该项目涉及犹他州大学、新西兰惠灵顿GNS科学公司和日本东京工业大学之间的国际合作。它将支持一名女博士后，她将获得最先进的地球物理仪器、实地调查设计参数、偏远地区的实际后勤事项、MT反演的现代方法以及电阻率与地球物理化学状态之间的关系方面的经验。热流估算可以改进冰盖稳定性模型。