Evidence for Pre-Grenvillian high-pressure granulite metamorphism from thenorthern margin of the Sausar mobile belt in Central India

Distinct lithological associations, structural relationships, and petrograp hic and geothermobarometric results indicate the presence of reworked granu lites of Pre-Grenvillian age from the northern margin of the Sausar mobile belt (SMB) in Central India. In rare residual zones, the mafic granulite-fe lsic migmatite gneiss association preserves early structures and high-P (si milar to 10.5 kbar at similar to 775 degrees C) granulite histories which a ppear to pre-date and bear no relation to similar to 1000 Ma old Sausar oro geny. An isothermal decompression through similar to 5.5 kbar at 750 degree s C from maximum recorded P-T condition, possibly signifies extensional col lapse of the crust, previously thickened through collision. During the Saus ar orogeny, the granulites were further tectonically interleaved with young er lithological associations. Widespread retrogression in amphibolite and f inally in greenschist facies conditions have all but obliterated granulite mineralogy and structure except in rare low-strain domain.