Analysis of gravity and magnetic fields over a part of Krishna-Godavari basin, India-inference on structures and nature of the basement

Abstract

This study discusses the utility of joint interpretation of gravity and magnetic fields to delineate the basement features hidden beneath the volcanic layer in the Krishna-Godavari (KG) basin located on the east coast of India. Detailed gravity and magnetic (G-M) measurements over a part of the KG basin depicts anomaly trends which coincides with the major tectonic trends of the region. Gravity and magnetic anomaly maps primarily reflects the effect of basement relief depicting horsts and depressions. This study has clearly brought out NE-SW trending horst which separates the East Godavari sub basin into deep troughs towards the northwest and southeast. Integrated modeling of gravity and magnetic anomalies using constraints from borehole information reveals the minimum and maximum depth to the basement as 2.7 km and 6.5 km respectively. It is conjectured that the Charnockites constitute the Precambrian metamorphic basement in this region.