LIU Xiao-zhen1,2, HU Yu-zhao1,2*, ZHENG Shuang1, WANG Zhan-feng1
(1.Kunming University of Science and Technology, Kunming 650093, China;
2.Yunnan Mineral Resources Laboratory, Kunming 650093, China)
Abstract: Many geologists are interested in the massive thick turbidites of Middle Triassic flysch formation in the Nanpanjiang basin. However, the understanding on provenance of clastic rocks in this flysch formation of the basin remains contentious. In order to trace the source of clastic rocks of the Nanpanjiang basin, we have chosen turbidites of the second Member of Middle Triassic Xuman Formation in the Weiruo area of the northern Nanpanjiang Basin as research object to explore the provenance of sediments of the turbidite by utilizing LA-ICP-MS dating of detrital zircons. The testing results show that there are five ranges of detrital zircon U-Pb ages, including 239~340Ma, 340~570Ma, 710~990Ma, 990~2300Ma, and 2300~2800Ma, suggesting the complicated provenance of detritus sediments of the second Member of Triassic Xuman Formation in the northern Nanpanjiang basin. Based on the comparison of these detrital zircon U-Pb ages in this study area and other U-Pb ages of zircons of possible provenances in surrounding areas of the Napanjiang basin and the combination of regional lithofacies paleogeography and regional tectonic evolution history, it is believed that the source of massive thick turbidites in the northern Nanpanjiang basin could be mainly sourced from the Song Ma suture zone and the Ailaoshan shear zone in the southwest, as well as the Yunkai ancient land containing the Qin-Fang orogenic belt in the southeast.
Keywords: Nanpanjiang basin; detrital zircons; Song Ma suture belt; Qin-Fang orogenic belt; Yunkai ancient land
ACTA MINERALOGICA SINICA Vol. 41, No.1, 2021, page 69-77