U-Pb, Pb-Pb and Sm-Nd ages of davidite within albitite zone from Bichun, Jaipur district, Rajasthan, India: possible link between uranium mineralization and Grenvillian orogeny

摘要

Uranium mineralization in Bichun area, Jaipur district, Rajasthan, India is hosted by albitites within the Banded Gneissic Complex (BGC). Detailed mineralogical and EPMA studies reveal the presence of davidite along with brannerite and uraninite. The U-Pb concordia upper intercept age of 933 +/- 13 Ma and Pb-Pb isochron age of 930 +/- 4 Ma, on pure davidite fractions indicate the timing of uranium mineralizing event to be ca. 930 Ma. The timing of uranium mineralization can be correlated with the Grenvillian orogeny (ca. 1000 Ma). The Sm-Nd model age (T-DM) of daviditeis varies from 1851 to 2200 Ma with epsilon(Ndi(930 Ma)) ranging from -10.7 to -15.5 which shows that the Palaeoproterozoic rocks with crustal component (either within BGC or basement granite) are the source for uranium.