The horizontal boundary and top depth estimates of buried source using gravity data and their applications

Abstract

A new method of the horizontal location of boundaries and the estimates of top depth of gravity anomaly sources is presented to meet the need of the quick interpretation of potential field data. On the basis of the theory of Tilt angle and Tilt-depth, we derive new Tilt-depth method for gravity anomaly from the forward formula of the upright dyke model, namely Tilt-depth2. This method combines the second order of horizontal and vertical gradient of gravity data. It not only indicates the horizontal locations of boundaries according to the 0° contour line, but also estimates the top depths of buried sources calculated from the horizontal distances from 45° and 90° contour line to 0° contour line. In the synthetic model tests, 2D and 3D combined designed model is used to show effectiveness of the Tilt-depth2, where the results are more in accordance with the true parameters. In a case study of Nanmeitou ore deposit in China, the geological bodies' boundaries are well identified and the depth estimates of the focus area are relatively consistent with the drilling data, which can provide effective reference for subsequent drilling target selection.