Delineating the Lithotectonic Domains in the Eastern Ghats Mobile Belt: Implication for the Regional Exploration of the Metasediment Hosted Graphite and Manganese Ore Horizons

ABSTRACT The present work documents and discusses the spatial disposition and lithotectonic control of graphite and manganese mineralization associated with metasediments of the Proterozoic Eastern Ghats Mobile Belt (EGMB) of eastern Indian shield and attempts to evolve a working model for furthering their exploration activities. Detailed satellite image based trendline mapping was done for the part of EGMB north of the Godavari Rift to map the marker horizons and demarcate structural discontinuities. Based on the contiguity of mineralised zones and their disruption due to structural discontinuities in EGMB, a lithotectonic map has been prepared. Five lithotectonic domains having distinct disposition patterns of mineralisation have been made which are (i) the southernmost, Vizianagaram - Rajahmahendravaram Domain bounded on its east by the N-S trending Nagavalli Shear Zone (NSZ), (ii) the Nagavalli - Vamsadhara Domain lying between NSZ and Vamsadhara Shear Zone (VSZ), (iii) the central Daspalla - Phulbani Domain bounded by VSZ in the south and the Mahanadi Shear Zone (MSZ) in the north, (iv) the northernmost Angul - Redhakhol Domain located north of the MSZ and (v) the western Balangir Domain between the eastern margin of the Bastar Craton and the Tel Shear Zone (TSZ). The disposition of the mineralised zones is unique in each domain, primarily controlled by the second and third generation folding often modified by high strain zones. Based on this, a working model for exploration in brownfield and greenfield areas has been proposed.