3D Interpretation of a Broadband Magnetotelluric Data Set Collected in the South of the Chinese Zhongshan Station at Prydz Bay, East Antarctica

Enzhao Xiao,Lei Fu,Khalid Latif,Jingxue Guo,Feng Jiang,Bo Sun

doi:10.3390/rs14030496

Abstract

Antarctica is covered by a thick ice sheet, and the application of geophysical methods is necessary to image the subglacial structures for studying the hydrologic systems and tectonic deformations in the Antarctic continent. The magnetotelluric (MT) method is one of the best approaches to obtain the subglacial electrical resistivities. However, only a very small volume of data has been collected so far in Antarctica using this method. In this paper, we report on a broadband MT profile collected at 10 sites in the south of the Chinese Zhongshan Station at Prydz Bay, and a 3D resistivity model was constructed by inversion of these data. This 3D model shows two low resistivity zones at a depth shallower than 6 km. They are consistent with the low-velocity zones in the previous shear-wave model and can be interpreted as the result of interconnected fluids associated with a downward migration of subglacial water. In addition, a distinct eastward dipping low resistivity zoneis present in the crust, which extends from the top surface to the lower crust. Since its location coincides with the highly positive magnetization named Amery Lineament, it is proposed that this eastward dipping low resistivity zoneextending in the entire crust probably reveals the geometry structure of the Amery Lineament at depth. Besides, it can be inferred from this new 3D resistivity model that the Amery Lineament is at least a crustal-scale structure, which probably outcrops on the land surface but was covered by the ice sheets in the study area.

Highlights

The tectonic structure of the Antarctic continent is the least studied compared to the other continents on the Earth
By comparing our 3D resistivity model with the seismic velocity model reported in previous studies [25], we found that C3 in the shallow part
Zhongshan Station in the Prydz Bay area is constructed by the 3D inversion of a broadband

Summary

Introduction

Several authors [7,11,16] have reported that MT data collection on the Antarctic continent probably needs three important problems to be taken into consideration They are (1) the large contact resistance between the electrodes and the ice/slow ground, (2) the electromagnetic noises produced by the moving charged snow and ice particles induced by wind, and (3) the nonplanar magnetic source field, which conflicts with the fundamental assumption in the MT method. The rose diagram is a statistical result of the principal axis angles of the impedance tensor at different sites and periods This means that the geoelectrical strike is almost subparallel to the profile and implies that a 3D interpretation is required for these data, (2) The seawater to the north has few impacts on the MT data at periods longer than.

Results

Model Interpretations and Discussions

Conclusions