Exploring sandstone body in weak electrical resistivity contrast with AMT data: a case study from the Yanchi sector, the mid of Erlian basin

AMT method with the economical and convenient superiority plays a key role in exploring the sandstone-type uranium deposits in China, which mainly meets to four problems such as the thickness of overlying strata, delineating the shape of the significant sand bodies, whether there are buried structures and knowing the basement relief. Exploring the sand body shape is the key one among such problems because sand body provides the room of uranium deposits and is the prerequisite for exploring uranium mineralization. Through an example of outlining the sandstone layer within the mudstone layers and analyzing the characters of the mainstream commercial MT inversion soft wares in dealing with AMT data in the mid of Erlian basin, a dynamic model-making method for inversion has been developed based on the observed AMT data. It is convenient to study the geo-electrical anomalies variations of different scale or dimensional models. A route to deal with such problem was given by inverting different scale models followed by checking whether the anomalies of each inversion are reliable. (authors)