TANG JingTian,
ZHANG LinCheng,
WANG XianYing et al
.2018.Subsurface electrical structure of the Fanshan-Jiangjunmiao area in the Lujiang-Zongyang Ore District derived from 3-D inversion of audio-magnetotelluric data.Chinese Journal Of Geophysics,61(4): 1576-1587,doi: 10.6038/cjg2018L0121
Subsurface electrical structure of the Fanshan-Jiangjunmiao area in the Lujiang-Zongyang Ore District derived from 3-D inversion of audio-magnetotelluric data
1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education, Central South University, Changsha 410083, China;
2. School of Geosciences and Info-physics, Central South University, Changsha 410083, China;
3. College of Earth and Planetary Sciences University of Chinese Academy of Sciences, Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049, China;
4. Anhui Province Geological Survey, Heifei 230001, China
The Lujiang-Zongyang ore district is an important polymetallic ore deposit district in the Middle and Lower Reach of Yangtze Metallogenetic Belt. In order to reveal the geological structure of the Fanshan-Jiangjunmiao area, a part of the Lujiang-Zongyang ore district, a 3-D audio magnetotelluric (AMT) data acquisition was carried out. The Rhoplus technique was applied to correct the distorted data caused by AMT high-frequency dead-band for guaranteeing the data quality, and the dimensional characteristics of underground media were analyzed using the phase tensor method. Then, a 3-D inversion of the data was carried out by a modular code which is referred to as ModEM. Through 3-D inversion, a high-resolution 3-D electrical resistivity model was established.The study area is a two-layer structure of a volcanic basin. Combined with geological data, the 3-D inversion results show that the main features in the electrical resistivity model corresponded well to the known geological features and the near-surface conductive layers and high-resistivity uplift zones at depth, which delineate the thickness of volcanic formation and distribution of intrusions. Meanwhile, a near-surface high-conductive body was found beneath the Xiaoling Mountain, which was considered to be an ore-bearing secondary volcanic edifice.
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