STRUCTURE AND TECTONICS OF THE PROTEROZOIC ARAVALLI-DELHI FOLD BELT IN NORTHWESTERN INDIA FROM DEEP SEISMIC-REFLECTION STUDIES

Seismic imaging of the crust along a 400-km-long deep seismic reflecti on profile across the Palaeo/Mesoproterozoic Aravalli-Delhi Fold Belt, in the northwestern Indian Shield, brings into focus its complex stru cture and provides clues to understand the geological processes involv ed in the evolution of this belt. The reflectivity pattern varies cons iderably for different crustal units along the profile. The deep-crust al reflection data image two sets of oppositely dipping strong reflect ion bands, from upper-to lower-crustal levels. These are identified as the signatures of the collision corresponding to Aravalli and Delhi o rogeny. The data also exhibit a clear Moho and strong lower-crustal re flections near the collision boundaries. A stack of dipping reflection s from the top of the Moho to the surface is identified as a major thr ust fault indicating that the Proterozoic collision and deformation we re primarily thick-skinned in nature. (C) 1998 Elsevier Science B.V.