SHRIMP U-Pb zircon ages and major element, trace element and Nd-Sr isotope geochemical studies of a Neoproterozoic granitic complex in western Sichuan:Petrogenesis and tectonic significance
川西新元古代花岗质杂岩体的锆石SHRIMP U-Pb年龄、元素和Nd-Sr同位素地球化学研究:岩石成因与构造意义

Neoproterozoic magmatism was very intense at the western margin of the Yangtze block.The origin of the magmas has great significance for the study of the evolution of the supercontinent Rodinia.At present,there are two divergent views as to the interpretation of the origin and tectonic setting of the magmas:the mantle plume origin and island arc origin.The authors performed SHRIMP U-Pb zircon dating and major element and trace element and Sr-Nd isotope studies of the Mosuoying granitic complex and its surrounding small granitic intrusions as well as basic dikes in these intrusions exposed in the Xichang area,Sichuan,in the Sichuan-Xikang-Yunnan rift. These studies indicate that:(1)these acid and basic rock bodies all formed at 842 ~ 790 Ma and are in the main contemporaneous intrusions;(2)intermediate enclaves are pervasive in the granite batholith is the manifestation of magma mingling;and(3)granite was derived from the older lower crust,while basic rocks were derived from the depleted asthenospheric mantle.This study supports the view that South China was located in the supercontinent Redinia between the continents Australia and Laurentia in the Neoproterozoic.