Metamorphic Belts in Singhbhum, Manbhum and Chhota Nagpur, E. India

Earlier studies on metamorphic zones in the metamorphic belts of Singhbhum, Manbhum and adjoining parts of Chhota Nagpur around longitude 86°E and between latitudes 22°45 Nand 23°40 N have been synthesised. Maps of Barrovian zones delineated by different workers in small areas have been coordinated into a regional zonal map.

Broad structural data of earlier workers plotted on the map depict that the pattern of extension of the zones over the whole region has a direct correlation with the plunges of the regional fold axes; higher grade zones occupy anticlinal cores with the lower grade ones succeeding them in the direction of the stratigraphic younging.

Granites, late syntectonic with tbe major folds on S" accompany most sillimanite zone outcrops. Andalusite occurs (i) across the chlorite to the kyanite zones along the southern fringes of the Dalma basic volcanics, and (ii) also sporadically. within sillimanite zone schists in association with sillimanite and kyanite.