Exploring Sandstone Body in Weak Electrical Resistivity Contrast with AMT Data

Abstract

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, the ability can be improved to recognize the electrical resistivity anomaly among the weak electrical property contrast by adjusting the inversion model's scale. A route to deal with the problem was given by inverting different scale models followed by checking whether the anomalies of each inversion are reliable. Finally, the geo-electrical model was to be determined by comparing results of different scale model.

Analyses of Magnetic and Gravity Data in Search for Meteorite Impact Crater at Bukit Bunuh, Lenggong, Perak, Malaysia

“…3 In the same manner, electrical resistivity method uses contrast in resistivity distribution to distinguish between subsurface materials. 4 The magnetic method involves measuring the earth magnetic field at specific locations on earth's surface to determine locations of subsurface magnetic contrasts. The magnetic method works only when buried objects have different magnetic susceptibilities, which are caused by the object having a greater or lesser magnetism than the surrounding material.…”

Model Design for AMT Data Inversion

“…Moreover, some commercial software is bounded with several fixed models or will meet memory overflowing when inversing fine meshes. When studying the sand body anomaly among the weak resistivity contrast in uranium exploring by AMT data, an inversion process was outlined using different scale models with checking anomalies [8]. To meet such situations, a simple method of making different scale or dimensional model is required.…”