Provenance of Early Triassic in Yanyuan Basin,Upper Yangtze and Its Implication for the Tectonic Evolution
Zhu Min
Chen Hanlin
Zhou Jing
Yang Shufeng
Abstract：The tectono-magmatic thermal event of Emeishan Large Igneous Province (ELIP)and the formation of Sanjiang Oro-gen caused by closure of Paleo-Tethys ocean along the western margin of the Upper Yangtze area during Late Paleozoic to Early Mesozoic shaped the unique pattern of basin-mountain system.For lack of cognition about the provenance and tectonic settings of Qingtianbao Formation in Yanyuan area,southwestern Sichuan,detrital compositions,major,trace elements and detrital zircon isotope ages of clastic rocks from Yantang section were tested and analyzed.The detrital components of Sandstone in Yanyuan region is volcanic clastic mainly and suggests that the provenance of Early Triassic strata was from a nearly source of volcanic rock,detrital zircons yield U-Pb ages of ca.261 Ma is consistent with the Emeishan mantle plume activity event and the geochemical characteristics of sandstone is similarity to those High Ti basalt of Emeishan LIP.Combined with the research findings of sedimentary and palaeo-geography in Yanyuan area,we suggest that the provenance of Qingtianbao Formation in Yanyuan region came from the Emeishan LIP,but may not came from the Sanjiang Orogen.Southwestern Upper Yangtze area was still a passive continental margin.
Keywords：Lower TriassicQingtianbao Formationprovenance analysistectonicYanyuan basinthe Upper Yangtze areastratigraphy
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 1309-1321 )