Thermal and Fluid State of the Lithosphere Beneath South Pole Region, East Antarctica, from Magnetotelluric Measurements

OPP 9615254 Wannamaker摘要该奖项支持一个项目，该项目旨在通过南极地区的大地电磁(MT)剖面法扩展对南极深部地壳和上地幔的热和物理化学状态(流体、熔体)的了解。在MT方法中，利用地球自然电磁场的时间变化作为源场，探测1到100公里(公里)或更深的深度范围内的电阻率结构。像大地电磁测深这样的地球物理方法在南极洲是合适的，因为厚冰覆盖的优势(95%的表面)和艰苦的作业环境。这项工作将由大约16个测点组成，全长90公里，距离南极站约5公里，定向网格为东北-西南方向，垂直于横贯北极的山脉()。主要目的有三个。首先，该方法将测试东南极这一部分100-150公里深度的岩石圈的克拉通特征，并将其电阻率结构与同一研究小组在西南极伸展中心(CWA)拍摄的电阻率结构进行比较。其次，这项实验将在南极现存的非常厚和寒冷的冰盖上进行，条件与CWA非常不同，因此这个项目应该会使整个大陆的大地电磁测量变得更加可行。第三，这些结果将为可能对南极下地幔深度进行长期大地电磁监测提供地壳响应基线。这项实验应该会在理解南极大陆中部的地壳和地幔结构方面取得重要进展。

OPP 9615254 Wannamaker Abstract The award supports a project to extend knowledge of the thermal and physico-chemical state (fluids, melts) of the deep crust and upper mantle of Antarctica with magnetotelluric (MT) profiling of the South Pole area. In the MT method, temporal variations in the Earth's natural electromagnetic (EM) field are used as source fields to probe the electrical resistivity structure in the depth range of 1 to 100 kilometers (km), or more. Geophysical methods such as MT are appropriate in Antarctica because of the predominance of thick ice cover (95% of the surface) and the difficult operating environment. The effort will consist of about 16 sites over a length of 90 km, offset from South Pole station about 5 km and oriented grid NE-SW, normal to the Transantarctic Mountains (TAM). The main purposes are three- fold. First, the method will test the cratonic character of the lithosphere of this part of East Antarctica to depths of 100-150 km and will allow comparison of its resistivity structure with that imaged in extensional central West Antarctica (CWA) by the same research group. Second, this experiment will be conducted over the very thick and cold ice sheet extant at South Pole, conditions that are very different those at CWA, so that this project should make MT surveying more feasible over the entire continent. Third, the results will provide the crustal response baseline for possible long-term MT monitoring to lower mantle depths at South Pole. This experiment should lead to important advances in understanding of the crustal and mantle structure of the central part of the Antarctic continent.