EFFECTIVE UTILIZATION OF GEOMORPHOLOGY IN URANIUM EXPLORATION - A SUCCESS STORY FROM MEGHALAYA, NORTHEAST INDIA

The southern fringe of Meghalaya plateau displays a spectacular develo pment of erosional landforms in the thick sedimentary cover of Cretace ous-Tertiary formations. Mahadek formation, the lower member of this s equence, comprises both continental and marginal marine sediments whil e all the overlying formations are mainly of marine origin. In the stu dy area all the Tertiary formations are eroded away, leaving exposed t he continental part of the Mahadek formation, which comprises channel- filled and floodplain sediments. Geomorphologically, both these units express themselves as cuestas but significant textural differences wer e observed, enabling us to discriminate them in aerial photographs. It is known that the channel-filled sedimentary unit incorporates many f avourable geological and geochemical characters to host uranium minera lization. The Domiasiat uranium deposit occurs in this unit only. By v irtue of its distinct geomorphology, three domains of channel-filled s ediments were demarcated in aerial photographs. Follow-up radiometric field checks on one of these domains, near the confluence of Wah Blei and Kynshiang rivers, have led to the discovery of significant uranium occurrences, opening up promising new avenues for uranium exploration in Meghalaya.