秦岭造山带中秦岭杂岩的早古生代幔源岩浆作用  

Early Paleozoic mantle-derived magmatism from the Qinling complex of the Qinling orogenic belt

作　　者：时毓[1,2,3] 于津海[3] 裴小利[1,2] 刘希军[1,2] 朱昱桦 

机构地区：[1]桂林理工大学广西矿冶与环境科学实验中心,广西桂林541004 [2]桂林理工大学广西隐伏金属矿产勘查重点实验室,广西桂林541004 [3]南京大学内生金属矿床成矿机制研究国家重点实验室,南京210093

出　　处：《桂林理工大学学报》2014年第2期207-217,共11页Journal of Guilin University of Technology

基　　金：国家自然科学基金项目(41302155);南京大学开放基金项目(19-14-1);广西八桂学者创新团队项目(许继峰;2013);广西自然科学基金项目(2012GXNSFCA053007)

摘　　要：秦岭造山带是华北克拉通和扬子克拉通的缝合带，经历了复杂的碰撞-扩张-聚合的演化，以商-丹断裂带为界被分为北秦岭和南秦岭。本文对北秦岭秦岭岩群（杂岩）中的斜长角闪岩和角闪黑云斜长片麻岩进行了地球化学、锆石U-Pb年代学和锆石Hf同位素研究，斜长角闪岩（变质玄武岩）中含有大量新元古代早期（888～957 Ma）和中元古代（～1424 Ma）的捕获锆石，其原岩的形成时代应早于新元古代早期；角闪黑云斜长片麻岩中的变质锆石指示秦岭岩群（杂岩）在早古生代经历了变质-热事件，其锆石εHf（t）值变化于9.0～12.0，指示其原岩源于亏损地幔。The Qinling orogenic belt,located between the North China Craton and the Yangtze Craton,has a complex evolution of collision-expansion-aggregation.The Qinling orogenic belt is composed of the Northern Qinling Belt and the Southern Qinling Belt,separated by Shangnan-Danfeng suture.This study presents geochemical data,zircon U-Pb ages and Hf isotopes for the amphibolite and hornblende-biotite-plagioclase gneiss from the Qinling complex in Northern Qinling Belt.The results show that the amphibolite （meta-basalt）contains a lot of zircons with the early Neoproterozoic （888 -957）and Mesoproterozoic （-1 424 Ma）ages, which were probably captured.The protolith of the amphibolite was probably formed earlier than early Neoprot-erozoic.The metamorphic zircons from the hornblende-biotite-plagioclase gneiss indicated a metamorphic-thermal event in the Qinling complex in early Paleozoic.TheεHf（t）values of zircons suggests that the protolith was originated from the depleted mantle.

关 键 词：秦岭岩群(杂岩) 地球化学 锆石U—Pb年代学 锆石HF同位素 幔源岩浆作用 秦岭造山带 

分 类 号：P581[天文地球—岩石学]