Provenances of the Ediacaran sedimentary rocks in the Zhuguangshan area and their implications for granitoid-related uranium mineralization in South China

Abstract

The terrigenous clastic sedimentary rocks in the Zhuguangshan uranium ore field of the Cathaysia Block, South China, were selected to reveal their petrogenesis and implications for granitoids-related uranium mineralization in South China. LA-ICP-MS U-Pb dating of detrital zircons shows that the Ediacaran terrigenous clastic sedimentary rocks in the Zhuguangshan area are characterized by a significant age peak at ca. 1023 Ma and that the Grenville-aged detritus in the Zhuguangshan area originated from northern India and eastern Antarctica. Elemental geochemical features show that the Ediacaran terrigenous clastic sedimentary rocks in the Zhuguangshan area were derived from a recycled sedimentary source and were deposited in a passive continental margin. The geochemical composition of the source rock is similar to that of intermediate-felsic rocks which are likely composed of andesite-granite. Petrographic and geochemical features unravel that the Ediacaran terrigenous clastic sedimentary rocks in the Zhuguangshan area underwent mildly-intensive chemical weathering. Through the comparison of the terrigenous clastic rocks between the Cathaysia Block and the southeastern margin of the Yangtze Block, we suggest that the high maturity and high U and Th contents of the terrigenous clastic rocks might be the key factors causing the granite-related uranium mineralization in the Cathaysia Block.