Case study: joint seismic reflection and CSAMT data interpretation for mineral explorations in Fujian, China

Acta Geophysica

article

Liu, Guofeng¹  Meng, Xiaohong¹  Tan, Handong¹  Chen, Zhaoxi¹  Ni, Jianhui²  Liu, Lanbo³ 

[1] School of Geophysics and Information Technology, China University of Geosciences;The Eighth Geology Team of Fujian Province;Integrative Geosciences Center, University of Connecticut

关键词: CSAMT;    Joint interpretation;    Mineral exploration;    PSDM on rugged topography;    Reflection seismic;    Thrust;   

DOI  :  10.1007/s11600-020-00477-2

学科分类：地球科学(综合)

来源: Polska Akademia Nauk * Instytut Geofizyki

【 摘 要 】

The Southwestern area of Fujian Province in China contains a major metallogenic belt. There have been three major tectonic movements since the Late Paleozoic, and the thrusts here are the main mineral deposits. These occurred between the Early Carboniferous and Late Permian eras. Due to dramatic undulations in the surface and associated complex underground structures, a single geophysical method cannot provide reliable imaging results. This is largely due to difficulties in data acquisition and processing. Seismic exploration provides one example. Using this method, raw shot gathers have a low signal-to-noise ratio because of the undulations in the topography. Furthermore, strong lateral velocity variation makes the migration process exceedingly difficult. This means that interpretations of the resulting reflection seismic profile give rise to uncertainty. For this reason, two-dimensional reflection seismology and controlled source audio-frequency magnetotellurics (CSAMT) electromagnetic sounding techniques were performed. After initially completing conventional processing on the seismic reflection data, subsequent pre-stack depth migration (PSDM) over the rugged topography yielded a much better image. It was able to identify thrust faults and magma intrusions. Then, using CSAMT, inversion was conducted with the same topography as the seismic reflection. By combining the migrated seismic profile, inverted resistivity profile, and borehole data, a vertical geological model was constructed. This proved the existence of an overlapped thrust, and it also indicated the possible presence of deeper mineralization.

【 授权许可】

Unknown