Application of gravity and magnetic methods for delineation of litho-structural information as an aid in uranium exploration : a case study from Alniyawas Area, Nagaur District, Rajasthan

Geophysical potential field methods play a vital role in uranium exploration by delineating litho contacts, structural features like faults/fractures and shear zones which have important bearing on the controls of movement of mineralized solutions and its precipitation. In the Bikaner-Nagaur Basin, towards the eastern margin, the Marwar Supergroup has faulted contact with the the metasediments/granitoids of the mesoproterozoic Delhi Supergroup. Regionally, the rocks of the Malani Igneous Suite (MIS) overlie the metasediments/ granitoids of the Mesoproterozoic Delhi Supergroup. The MIS in turn is unconformably overlain by the sediments of the Marwar Supergroup. The present paper discusses the results of regional magnetic and gravity surveys conducted in the Alniyawas area, Nagaur basin, Nagaur District, Rajasthan with an objective to delineate litho contacts between Delhi group of rocks and Erinpura granite and Marwar sediments over an area of 100 sq km