地质与勘探2017，Vol.53Issue(2)：283-299,17.
格咱岛弧带热林二长花岗岩的岩石成因及动力学背景:岩石地球化学、年代学及Hf同位素约束
Rock Genesis and Dynamic Background of the Relin Monzogranite in the Geza Arc Belt, Yunnan: Constrains from Petrogeochemistry, Chronology, and Hf Isotope
摘要
Abstract
The Geza arc belt is one of the newly discovered important Cu-polymetallic metallogenic belts in the southwestern Sanjiang Tethyan tectonic zone.With collision-type magmatic intrusion activity,porphyry-skarn Mo (Cu) and hydrothermal W (Mo) deposits were formed during the late Yanshanian period in this region.Among them,the Relin Mo-Cu deposit is representative of the diagenesis and mineralization.This paper presents the analyses of petrochemistry,zircon LA-ICP-MS U-Pb dating and Lu-Hf isotope in this typical deposit.The results show that Relin monzogranite is rich in SiO2 (69.88％ ～ 74.58％) and K2O + Na2O(7.24％ ～ 8.62％),which belongs to high-K calc-alkali and quasi-aluminous granite(A/CNK =0.93～1.05,less than 1.1).The rock has high ΣREE (ΣREE are 80.72×10-s ～284.85×10-6,190.86×10-6 on average) and negative Eu anomaly (δEu =0.46 ～ 0.83),and high fractionation degree of LREE and HREE.It is also enriched in LREE and LILE (K,Rb) and depleted in HFSE (Nb,Ta,P,Ti)and HREE,implying a characteristic of adakite affinity.The zircon U-Pb ages of two samples are 79.4 ±2Ma (MSWD =1.1) and 78 ± 1.6Ma (MSWD =1.8),respectively,which represent the crystallization age of monzogranite magma as late Yanshanian.The value of εHf(t) from two simples range from-12.12 to-4.41 (less than zero),and the peak value of tDM2 age is between 1.35 ～ 1.4Ga,which reveals that the Relin monzongranite originated from the deep melting of the Mesoproterozoic crustal basement.The research shows that the Relin monzongranite is the product of crustal magma emplacement in an intracontinental extensional environment after the collision in late Yanshanian,and developed Mo-Cu polymetallic mineralization with ore-forming hydrothermal solution,which finally formed Mo-Cu polymetallic deposit.Thus the diagenesis and mineralization in the Relin Mo -Cu deposit was closely related to the collisional orogeny.关键词
二长花岗岩/动力学背景/燕山晚期/热林/格咱岛弧带Key words
monzogranite/dynamic background/late Yanshanian period/Relin/Geza arc belt分类
天文与地球科学引用本文复制引用
杨富成,李文昌,刘学龙,彦廷龙,王帅帅,罗云..格咱岛弧带热林二长花岗岩的岩石成因及动力学背景:岩石地球化学、年代学及Hf同位素约束[J].地质与勘探,2017,53(2):283-299,17.基金项目
云南科技领军人才计划项目(编号:2013HA001),国家自然科学基金项目(编号:41502076),云南省教育厅科学研究基金(编号:2015Y066)和昆明理工大学省人培训项目(编号:KKSY201421042)联合资助. （编号:2013HA001）
