Ivr. Murthy et Pr. Rao, Magnetic anomalies and basement structure around Vizianagaram, Visakhapatnam and Srikakulam districts of Andhra Pradesh, India, GONDWANA R, 4(3), 2001, pp. 443-454
A systematic regional magnetic survey was carried out in the districts of V
izianagaram, Visakhaptnam and Srikakulam in Andhra pradesh, India comprisin
g an area of 15,000 sq. km of eastern migmatite zone of Eastern Ghat Mobile
Belt. The magnetic anomalies are very noisy, varying between -1300 nT and
+700 nT in amplitude and correlate very poorly with the surface geology Upw
ard continuation of these anomalies brought out distinct magnetic anomaly t
rends, running along NE-SW on the south and turning later to E-W on the nor
th, consistent with the folding pattern of Eastern Ghats. Based on the term
ination of anomaly closures and displacement of anomaly trends, five faults
, all striking approximately in the N-S direction, were inferred. From inve
rsion of anomaly profiles, it is established that the anomalies are produce
d by structures in the magnetic basement composed of charnockites.