地质学报2017，Vol.91Issue(4)：849-863,15.
云南格咱岛弧带休瓦促Mo-W-Cu矿床两期岩浆作用的锆石U-Pb年龄、Hf同位素组成及构造意义
Zircon U-Pb Age and Hf Isotopic Composition of The Two-Period Magmatism of the Xiuwacu Mo-W-Cu Deposit in the Geza Arc Belt, Yunnan, and Their Tectonic Significance
摘要
Abstract
The LA-ICP-MS zircon U-Pb dating results show that theore-bearing granodiorite from the Xiuwacu Mo-W-Cu deposit formed at 202 ± 3.5 Ma during which the Ganzi-Litang oceanic crust subducted westward;and monzonitic granite formed at 83.3 ± 1.7 Ma in a collisional orogenic environment in the Late Triassic.In-site Hf isotope analysis results show that the zircon in granodiorite has εHf (t) of from -2.87 tO 4.12 (0.09 on average),TDM1age of 541 ～ 828Ma,and TDM2age of 719 ～ 1109Ma.It shows that the intrusion was sourced from the crust with addition of mantle material.The zircons in monzonitic granite have εHf(t) values of-7.96～-2.75 (-5.54 on average),TDM1 age of 820～1019Ma and TDM2 age of 1102～1391Ma,indicating that monzonitic granite was the product of partial melting of ancient crust.Zircon U-Pb dating and in-situ Hf isotope analysis of two ore-bearing intusions in Xiuwacu show that there were two-period tectonic-magmatic-mineralization activities in the area in Late Triassic and Late Cretaceous respectively.The granodiorite magmatic intrusion and Cu polymetallic mineralization were related to oceanic subduction orogenesis in the Late Triassic,while the monzogranite magmatic intrusion and Mo polymetallic mineralization were mainly formed in the tectonic setting of continental-continental collisional orogeny in the Late Cretaceous.The study shows that the tectonic-magmatic-mineralization occurred from the subduction of oceanic crust in Late Triassic to the post-orogenic extension in Late Cretaceous,and the Late Triassic tectonic-magmatic activity was superimposed by the diagenesis and mineralization in Late Cretaceous.This provides a typical example for the study of compound superimposed diagenetic mineralization.关键词
锆石U-Pb年龄/Hf同位素组成/晚三叠世/晚白垩世/休瓦促/格咱岛弧Key words
zircon U-Pb age/Hf isotopic composition/Late Triassic/Late Cretaceous/Xiuwacu/Geza island arc引用本文复制引用
刘学龙,李文昌,杨富成,张娜,彦廷龙,罗云..云南格咱岛弧带休瓦促Mo-W-Cu矿床两期岩浆作用的锆石U-Pb年龄、Hf同位素组成及构造意义[J].地质学报,2017,91(4):849-863,15.基金项目
本文为云南省科技领军人才培养计划项目(编号:2013HA001)、云南省教育厅基金项目(编号:2015Y066)、国家自然科学基金项目(编号:41502076)、中国地质调查局项目(编号:12120114013701)资助的成果. （编号:2013HA001）
