Delineation of structural lineaments from marine magnetic anomalies off Lawson's Bay (Visakhapatnam), east coast of India

Abstract

Marine magnetic surveys have recorded total field anomalies that correspond to structural lineaments extending from the coast into the sea. The significant anomalies recorded in this area are along wavelength high amplitude negative anomaly and short wavelength negative anomalies on either side of the broad central anomaly. While the central anomaly appears to continue into deeper waters, the anomalies on its flanks are recorded only up to 20 m water depth. Two dimensional modelling of these anomalies has revealed an upliftment in the basement corresponding to the central broad anomaly, 2 intrusives cutting across the basement corresponding to the negative anomalies on either side of the central anomaly and a low in the basement uplift at shallow depths. These structural elements correlate well with the major geological features over the adjoining coastal areas.