Zircon SHRIMP U-Pb dating and neoproterozoic metamorphism of Kangding and Yuanmou intrusive complexes, Sichuan and Yunnan

Abstract

To clarify the relationship of the metamorphic intrusions along the west margin of the Yangtze craton and their metamorphic history after crystallization, the petrochemical and trace element geochemical characters, zircon SHRIMP U-Pb dating, and the chemical compositions of coexisting hornblendes and plagioclases from Neoproterozoic metamorphic intrusions in Kangding (康定), Sichuan (四川) Province, and Yuanmou (元谋), Yunnan (云南) Province, were studied. Combined with the former published data, it is indicated that the Kangding granitic plutons and Yuanmou complex in the west margin of the Yangtze craton generally formed at the same period. Metamorphic event at ∼700 Ma existed extensively, at least covering from Kangding area in Sichuan to the Eshan (峨山) area in Central Yunnan. Moreover, amphibolite facies may represent the peak regional metamorphic condition.

Keywords

Yangtze craton / Kangding-Yuanmou complex / SHRIMP / metamorphic history

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