Petrogenesis for Neoproterozoic granitic rocks in Altyn Qiemo-Ruoqiang area, and implications for determining the timing of Rodinia supercontinent's convergence

The Neoproterozoic granitic magma activity was widespread in the Altyn orogenic belt, with formation ages around 800~1000 Ma.These magmatic events are thought to be associated with the convergence of the Rodinia supercontinent.Therefore, the study of Neoproterozoic granitic magma is of great significance for gaining insights into the evolution processes of the Altyn orogenic belt.In this study, we present precise results from petrological, geochronological and geochemical investigations of the granitic rocks from the Qiemo-Ruoqiang area in the southern Altyn block.Our findings indicate that: ①In comparison to the enrichment of light rare earth elements(LREE), heavy rare earth elements(HREE)exhibit a pronounced right-leaning characteristic, accompanied by a distinct negative Eu anomaly(δEu=0.14~0.6).These rocks are enriched in large ion lithophile elements like Th, U, and K, while simultaneously showing depletion in high field strength elements such as Ba, Ti, Nb, Ta, and Sr.②Zircon U-Pb ages fall within the range of approximately 899 Ma to 915 Ma.Comprehensive studies have shown that the three categories of granitic rocks in the Qimo-Ruoqiang region were formed in a syn-collision tectonic environment, which were the products of subduction and collision between plates during the convergence stage of the Rodinia supercontinent.