LANDSAT THEMATIC MAPPER DATA APPLIED TO STRUCTURAL STUDIES OF THE EASTERN GHAT GRANULITE TERRANE IN PART OF ANDHRA-PRADESH

LANDSAT TM data have been used as an aid to studying the regional geol ogy of the granulite terrane in the southern part of Eastern Ghats. Th e technique in conjunction with regional traverses proved to be useful in identifying regional structural elements. such as shear zones, fol d patterns of different scales and other lineament patterns, in poorly exposed and inaccessible areas. A major crustal scale ductile shear z one, designated as Sileru shear zone, with a dextral sense is highligh ted and lies at the western margin of the high grade terrane. The othe r shear zones within the granulite terrane, characterised by migmatiti c gneisses and typical L-S mylonitic fabrics, are associated with tran spressional tectonics. Fold patterns varying from tight upright isocli nal folds to refolded large scale recumbent folds, along with complex fold interference structures on mesoscopic to regional scale are descr ibed. The interpretation of LANDSAT data, followed by limited ground b ased traverses from Sileru to Visakhapatnam in Visakhapatnam district and from Chinturu to Eleswaram in East Godavari district are the const raints in precisely defining the regional structures and understanding the tectonic processes that fashioned shear zones and fold patterns i n granulite terranes. A fold thrust thin-skinned tectonic model involv ing two tectono-thermal events for the study area is envisaged.