Chapter 16 - Interpretation and resolution of multiple structures from residual gravity anomaly data and its application to subsurface mineralization

Abstract

The interpretation and resolution of residual gravity anomaly due to multiple bodies (viz. sphere, horizontal and vertical cylinder) and a combination of these were interpreted in this work. Residual gravity anomalies due to some multiple synthetic models were interpreted applying a global optimization method. In the case of a single structure, an increase in depth from the top of the subsurface structure decreases the resolution whereas an increase of amplitude increases the anomaly for spherical structure. It is the same for the horizontal cylinder but a vertical cylinder, the width of the anomaly changes with increasing depth. In the case of multiple structures, the amplitude increases or decreases with a change in the value of amplitude coefficient keeping fixed depth and vice versa for change in the amplitude with a change in the depth value. However, for multiple vertical cylinder-like structures, it is difficult to interpret the anomalies while changing the values of amplitude and depth. Moreover, a combination of these three structures often leads to the non-interpretation of one structure which may not show any anomalies associated with it. The efficiency of multiple structures for the delineation of residual gravity anomaly data is developed in this study using different synthetic models and field measurements from Beldih mine and South Purulia Shear zone associated with uranium mineralization.