New U-Pb SHRIMP Zircon Ages of the Dhamda Tuff in the Mesoproterozoic Chhattisgarh Basin, Peninsular India: Stratigraphic Implications and Significance of a 1-Ga Thermal-Magmatic Event

Abstract

AbstractMagmatic zircons from two samples of the Dhamda Tuff in the Tarenga Formation of the Mesoproterozoic Chhattisgarh Supergroup in central India were dated by U-Pb SHRIMP methods, which yielded a concordia upper-intercept age of Ma. The samples are from outcrops located about 10 km apart, approximately along strike and stratigraphically near the top of the Chhattisgarh Succession in the western Hirri Subbasin. These results indicate that the Dhamda Tuff is coeval with the Sukhda Tuffs of the eastern Baradwar Subbasin, which previously yielded ages of 990–1020 Ma. The new ages confirm the prediction of geologists of the Indian Statistical Institute who, when creating a new mapping of part of the Chhattisgarh Basin, suggested that the Sukhda and Dhamda tuffs are correlative. The new data also confirm that deposition in the Chhattisgarh Basin occurred essentially between ca. 1400 and ca. 1000 Ma. The Eastern Ghats Mobile Belt (EGMB), then a part East Antarctica, docked with the southern Indian block at ...