投稿时间：2014-10-27
修订日期：2016-12-15
网络发布日期：2017-03-11
中文摘要:青海省门源县浪力克地区毛藏花岗闪长岩岩体位于北祁连冷龙岭东段，文章通过开展年代学和岩石地球化学研究，对该岩体的形成时代进行厘定并探讨其成因。LA-ICP-MS锆石U-Pb测年结果表明，毛藏花岗闪长岩体形成时代为（471.9±8.6）Ma（MSWD=1.6），属早古生代奥陶纪；锆石Hf同位素分析结果显示，该类岩石εHf（t）值介于-13.3~5.26，TDM2为1112.4~2284.7 Ma，暗示岩浆可能是由壳幔混合作用形成，其壳源源区很可能是古元古代及中元古代古老地壳岩石。此外，岩石地球化学研究结果表明，该类岩石属弱过铝质中钾钙碱性系列的I型花岗岩，明显富集大离子亲石元素（如K、Ba、Rb）和活泼不相容元素（如Th、U），相对亏损高场强元素（如Nb、Ta、Ti、P），形成于俯冲消减环境，为火山弧花岗岩。
Abstract:The granodiorite pluton in Langlike area of Menyuan, Qinghai, is located in the eastern Lenglongling of North Qilian Mountain. The authors conducted a study of chronology and geochemistry to constrain its geochronology and petrogenesis. Zircon LA-ICP-MS dating yielded a concordant age of (471.9±8.6)Ma (MSWD=1.6), suggesting Ordovician in Early Paleozoic. Zircon Hf isotope analysis suggests that the calc-alkaline units have TDM2 values between 1112.4 and 2284.7 Ma, with εHf(t) values from -13.3 to 5.26, indicating that the magma sources were involved in crust-mantle mixing, the source region of the crust type was likely to be ancient crustal rocks of Paleoproterozoic and Mesoproterozoic. In addition, rock geochemistry indicates that the rock is a weak peraluminous potassium calc-alkaline series of I-type granites, obviously enriched in LILE (such as K, Ba, Rb) and incompatible elements such as Th and U, and relatively depleted in high field strength elements such as Nb, Ta, Ti and P, implying a volcanic arc granite formed in a subduction environment.
keywords:geochemistry potassium calc-alkaline intrusive rock petrogenesis zircon U-Pb age Maozang area of North Qilian Mountain
文章编号：
中图分类号：P597+3
文献标志码：
基金项目:本文受中国地质调查局"青海门源县银灿-浪力克1：5万成矿预测"项目（编号：1212011221043）和"青海门源县宁缠河-牛头山一带铜多金属矿调查评价"项目（编号：12120115022401）资助
引用文本：
白赟,郭周平,赵辛敏.2017.北祁连浪力克地区毛藏花岗闪长岩年代学、Hf同位素及地球化学特征[J].矿床地质,36(1):158~170BAI Yun,GUO ZhouPing,ZHAO Xin Min.2017.Geochronology,Hf isotopic and geochemical characteristics of Maozang granodiorite in Langlike area,North Qilian Mountain[J].Mineral Deposits36(1):158~170
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