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

电话9615254 Wannamaker 摘要 该奖项支持一个项目，通过南极地区的大地电磁剖面图，扩大对南极地壳深部和上地幔的热状态和物理化学状态（流体、熔体）的了解。 在MT方法中，地球的天然电磁（EM）场的时间变化被用作源场，以探测1至100公里（km）或更大深度范围内的电阻率结构。 地球物理方法，如大地电磁法，适合于南极洲，因为南极洲的冰层很厚（占表面的95%），而且作业环境很困难。 这项工作将包括约16个站点，长度为90公里，偏离南极站约5公里，网格方向为东北-西南，垂直于横贯南极山脉（TAM）。 主要目的有三方面. 首先，该方法将测试东南极洲这一部分岩石圈100-150公里深处的电磁特性，并将其电阻率结构与同一研究小组在西南极洲中部的伸展成像进行比较。 第二，该实验将在南极现存的非常厚和冷的冰盖上进行，这些条件与CWA的条件非常不同，因此该项目应使MT测量在整个大陆上更加可行。 第三，研究结果将为南极下地幔深度的长期MT监测提供地壳响应基线。 这一实验将导致在了解南极大陆中部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.