Application of audio magnetotelluric method in prospecting for deep hidden manganese ore: A case study in the Pujue manganese mine in Songtao, Guizhou, China

Abstract

The Pujue manganese deposit is a typical Datangpo-type sedimentary deposit of Nanhua period in eastern Guizhou. In the Pujue mining area the early-formed sedimentary manganese deposits were significantly influenced by the subsequent structures in aspects of burial and preservation. Analyzing the deep tectonic framework and its relationship with the manganese-bearing rock series is of great importance to the ore-prospecting prediction and deep exploration of the manganese deposits in the area as well. Our aim is to find out the spatial distribution of metallogenic geological bodies and fault structures and their relationship in the Pujue Manganese mining area. We used audio magnetotelluric method to study the characteristics of underground electrical structure and tectonic framework in the area, and built a theoretical model similar to the geoelectric structure of the study area based on the physical property analysis. Through inversion calculation under different schemas, we gave preference to a two-dimensional inversion method of nonlinear conjugate gradient TM model, which is suitable for Occam-TE one-dimensional inversion as the initial model. We used the above inversion method to invert the measured data from the area, and thus identified the spatial distribution characteristics between the tectonic framework and the manganese-bearing rock series and their contact relationship. It demonstrates that the fault F0 hasn't damaged the manganese-bearing rock series in the deep. Our research results show that AMT is of great significance in guiding the deep prospecting prediction in the Pujue manganese mining area and its adjacent areas.

Keywords

• pujue manganese deposit
• audio magnetotelluric method
• inversion
• tectonic framework