PDF《三江北段纳日贡玛花岗闪长斑岩成岩时代的 确定及地质意义》

2011 年3月地球学报Mar.

2011 第32 卷第2期: 154-162 Acta Geoscientica Sinica Vol.32 No.2: 154-162 www.cagsbulletin.com www.地球学报.com 本文由中国地质调查局 青海省地质调查综合研究 (编号: 1212010918044)和 青海省岩浆岩的时空分布与成矿作用研究工作项目 (编号: 科〔2011〕01-06-02 号)联合资助. 收稿日期: 2011-01-31;

改回日期: 2011-03-17.责任编辑: 魏乐军. 第一作者简介: 宋忠宝, 男,

1963 年生.研究员.主要从事岩石矿产及同位素地质年代学研究.通讯地址: 710054, 西安市友谊东路

438 号.

电话: 029-87821557.E-mail: [email protected]. 三江北段纳日贡玛花岗闪长斑岩成岩时代的 确定及地质意义 宋忠宝, 贾群子, 陈向阳, 陈博, 张雨莲, 张晓飞, 全守村, 栗亚芝 西安地质矿产研究所, 陕西西安

710054 摘要: 纳日贡玛斑岩型铜钼矿是近年来在三江北段发现的与侵入岩有关的斑岩型铜钼矿. 作者首次利用锆 石U-Pb 方法测得纳日贡玛花岗闪长斑岩的形成年龄为 41.44±0.23 Ma, 属于喜马拉雅早期. 纳日贡玛斑岩型 铜钼矿成矿主要在 40.8±0.4 Ma~40.86±0.85 Ma 之间.在多期热液叠加, 多期成矿作用中, 纳日贡玛斑岩型 铜钼矿的热液应是纳日贡玛黑云花岗斑岩(41.53±0.2 4Ma~43.8±0.4 Ma)、 纳日贡玛花岗闪长斑岩(41.44±0.23 Ma)和纳日贡玛斜长花岗斑岩(41.00±0.18 Ma)共同提供的. 由于该区有较多的中酸性岩体存在, 因而, 这些侵 入体的形成年龄确定, 为印度板块与亚洲板块在 65~45Ma 碰撞提供依据, 对于在该区寻找斑岩型铜钼矿不仅有重要 的理论意义,而且有重要的现实意义. 关键词: 花岗闪长斑岩;

铜钼矿;

成岩时代;

41.44±0.23 Ma;

印度板块与亚洲板块的碰撞时间;

三江北段 中图分类号: P588.121;

P597.1 文献标志码: A doi: 10.3975/cagsb.2011.02.03 The Petrogenic age of Narigongma Granitic Diorite-porphyry in the Northern Part of the Sanjiang Region and Its Geological Implications SONG Zhong-bao, JIA Qun-zi, CHEN Xiang-yang, CHEN Bo, ZHANG Yu-lian, ZHANG Xiao-fei, QUAN Shou-cun, LI Ya-zhi Xi'

an Institute of Geology and Mineral Resources, Xi'

an, Shaanxi

710054 Abstract: The Narigongma porphery molybdenite copper deposit related to intrusive rocks was discovered recently in the northern part of the Sanjiang Region. U-Pb dating shows that the formation age of Narigongma granodiorite porphyry is 41.44±0.23 Ma, belonging to early Himalayan period. Metallogenic ages of the Narigongma porphery molybdenite copper deposit are mainly in the range of 40.8±0.4 Ma~40.86±0.85 Ma. During multiperiodic hydrother- mal activities and multistage ore-forming processes, the metallogenetic hydrothermal solution was provided by Narigongma granitite porphyry (41.53±0.24 Ma), Narigongma granite diorite-porphyry (41.44±0.23 Ma) and Narigongma plagioclase porphyry (41.00±0.18 Ma). Due to occurrence of many intermediate-acid mass, the age of these intrusive bodies provide evidence for collision function between India plate and Eurasian plate in 65~45 Ma, which has theoretical and practical meaning to forecast of porphyry copper-molybdenum deposit in the region. Key words: granodiorite porphyry;

Cu-Mo deposit;

petrogenic age;

41.44±0.23Ma;

time of India-Asia continental colli- sion;

northern part of the Sanjiang Region 关于印度板块与亚洲板块的碰撞时限问题目前 尚有争议(莫宣学等, 2003, 2006, 2007;

李荣社等, 2008;