Geochronology,Petrogenesis,and Tectonic Significance of the Neoproterozoic Diabases in the Jinkouhe Area,Western Sichuan Province
[Objective]An extensive suite of Neoproterozoic diabase dykes is exposed in the Jinkouhe area of west-ern Sichuan province,offering crucial insights into the tectonic evolution of the western Yangtze Craton.These dia-bases bear key implications for understanding the early tectono-magmatic history of the Yangtze Craton and its rela-tionship with the assembly and fragmentation of the Rodinia supercontinent.[Methods]Sensitive High-Resolution Ion MicroProbe(SHRIMP)zircon U-Pb geochronology and whole-rock geochemistry analyses were performed on the Jinkouhe diabases.[Results]SHRIMP zircon U-Pb dating of the diabase samples yields an age of 823±10 Ma(MSWD=1.30,n=10).The diabases are classified as a tholeiitic basalt series,displaying Nb-Ta depletion and nega-tive Eu anomalies.Their geochemical signatures are indicative of both island arc and intraplate basaltic affinities.[Conclusions]The Jinkouhe diabases are interpreted to have originated from partial melting of a spinel-garnet lher-zolite mantle source,which was metasomatized by subduction-related melts.Combined with regional geological data,these diabases were most likely formed within a post-collisional extensional setting,reflecting tectonic processes asso-ciated with the final amalgamation of the Yangtze Craton within the context of the Rodinia supercontinent assembly.
万方数据
维普
