Collaborative Research: Seismic Traverse of the Byrd Subglacial Basin-Field Test

该奖项支持在南极洲西部进行的原地和短导线地震反射/折射和大地电磁实验。这项合作实验涉及四个机构的四个奖项。其四个目的是1)调查伯德冰下盆地的一部分，2)测试这项工作的技术，这项工作可以在长导线上完成，3)确定大地电磁方法在厚(电阻)冰盖上的可行性，以及4)评估宽反射与窄折射地震研究在岩石圈成像方面的相对优点。将采用的地球物理技术能够成像冰盖、大陆岩石圈和上地幔，以及确定部分岩石圈和地幔的物理性质。过去30年来，对西南极和横贯北极山脉露头地质的研究导致了最近的解释，即地壳是由许多不同的岩石圈块体组成的。地震反射工作是对地壳进行详细成像的唯一方法，而折射工作是确定反射工作所确定的层和块的物理性质的唯一方法。大地电磁的工作在科学上是有风险的，因为它在电阻冰盖上使用时可能不会产生有用的信息；然而，如果它有效，它有可能成像地壳和上地幔中的熔岩。在南极洲西部这样的大陆裂谷地区，岩石圈中可能存在熔融，如果被记录下来，可能会对冰盖动力学产生非常重要的影响。该奖项支持的研究工作预计将对从冰盖动力学模型到岩石圈减薄和裂谷的构造和运动学模型的一系列地壳过程模型提供限制。

This award supports an in situ and short traverse seismic reflection/refraction and magnetotelluric experiment in West Antarctica. This collaborative experiment involves four awards at four institutions. The four-fold purpose is 1) to investigate part of the Byrd Subglacial Basin, 2) to test techniques for this work that could be done in a long traverse, 3) to determine the viability of the magnetotelluric method on a thick (electrically resistive) ice sheet, and 4) to evaluate the relative merits of refraction with wide reflection versus reflection with narrow refraction seismic studies in imaging the lithosphere. The geophysical techniques that will be employed are capable of imaging the ice sheet, the continental lithosphere, and the upper mantle, as well as determining physical properties of parts of the lithosphere and mantle. Investigations of outcrop geology over the last thirty years in West Antarctica and the Transantarctic Mountains have lead to recent interpretations that the crust is made up of many different lithospheric blocks. Seismic reflection work is the only way to image the crust in detail and the refraction work is the only way to determine physical properties of the layers and blocks defined by the reflection work. The magnetotelluric work is scientifically risky because it may not yield useful information when used over the electrically resistive ice sheet; however, if it works it has the potential to image molten rock in the crust and upper mantle. In a continental rift region such as West Antarctica, the presence of melt in the lithosphere is likely and, if documented, has very important ramifications to ice sheet dynamics. Research work supported by this award is expected to provide constraints to models of a range of crustal processes from models of ice sheet dynamics to tectonic and kinematic models of lithospheric thinning and rifting.