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黄金科学技术 ›› 2015, Vol. 23 ›› Issue (5): 20-27.doi: 10.11872/j.issn.1005-2518.2015.05.020

• 矿产勘查与资源评价 • 上一篇    下一篇

南秦岭白马山岩体Sr、Nd、Pb同位素组成及源区示踪

张永华1,王建中1,2,钱壮志2,徐刚2,姜超2   

  1. 1.武警黄金第五支队,陕西  西安   710100;
    2.长安大学西部矿产资源与地质工程教育部重点实验室,陕西  西安   71005
  • 收稿日期:2015-02-15 修回日期:2015-05-12 出版日期:2015-10-28 发布日期:2015-12-09
  • 作者简介:张永华(1978-),男,河北保定人,工程师,从事金矿勘查工作。602107261@qq.com
  • 基金资助:

    中央高校基本科研业务费专项资金“造山带后碰撞伸展背景下的岩浆铜镍硫化物矿床成矿作用”(编号:CHD2011SY014)资助

he Sr,Nd,Pb Isotopic Compositon and its Implication for the Magmatic Source of the Baimashan Rock Mass,Southern Qinling

ZHANG Yonghua1,WANG Jianzhong1,2,QIAN Zhuangzhi2,XU Gang2,JIANG Chao2   

  1. 1.No.5 Gold Geological Party of  CAPF,Xi’an    710100,Shaanxi,China;
    2.Key Laboratory of Western China’s Mineral Resources and Geological Engineering,Ministry of  Education,Chang’an University,Xi’an    710054,Shaanxi,China
  • Received:2015-02-15 Revised:2015-05-12 Online:2015-10-28 Published:2015-12-09

摘要:

研究了南秦岭晚三叠世(~200 Ma)7个花岗岩类岩体的Sr、Nd、Pb同位素组成,包括白马山岩体在内的南秦岭花岗岩类以低放射成因Pb同位素组成为特征,初始87Sr/86Sr比值范围为0.70495~0.70908,εNd(t)值变化于-2.40~-8.55之间,Nd同位素模式年龄(TDM)变化于1.2~1.7 Ga之间,从东部到西部,呈现εNd(t)逐渐降低而TDM逐渐增高的变化规律。白马山岩体的初始87Sr/86Sr比值为0.70637,εNd(t)=-6.75,具有较高的TDM值(1.53 Ga),暗示其岩浆源区主要来自于南秦岭的大陆下地壳,岩浆源区以类似南秦岭耀岭河群基性火山岩为主,南秦岭较古老的地壳物质仅有少量参与。基性下地壳增厚,岩石圈地幔拆沉,软流圈上涌,下地壳部分熔融形成有利于铜、金成矿的白马山“C”型埃达克岩。

关键词: 同位素组成, 岩浆源区, 基性下地壳, 白马山岩体, 埃达克岩, 南秦岭

Abstract:

This paper studies Sr,Nd,Pb,isotopic compositions of 7 granitoids from South Qinling,which were all formed about 200 Ma B.P.The results indicate that the granitic rocks including the Baimashan rock mass from the South Qinling are characterized by low radiogenic Pb isotopic composition.Their initial(87Sr/86Sr)t ratios range from 0.70495 to 0.70908,εNd(t) values from -2.40 to -8.55,and Nd isotopic model ages(TDM) from 1.2 Ga to 1.7 Ga.their εNd(t) values gradually decrease from east to west,whereas TDM values gradualy increase.The Baimashan rock mass has much lower (87Sr/86Sr)t (0.70637),lower εNd(t)(-6.75) and much higher TDM(1.53 Ga).This study reveals that the magmatic source of the Baimashan rock mass was derived from the deep continental crust.In the magmatic source,basic magmatic material in the crust similar to the Yaolinghe Group basic volcanic rocks in South Qinling,is the major source for the formation of granitoids with less significant old continental crust material.The Baimashan adakite which is in favor of copper and gold mineralization,may resulted from partial melting of mafic lower crust in the thickened lower crust due to the lithospheric delamination and the asthenospheric upwelling,which can provide some clues to the direct copper-gold prospecting.

Key words: isotopic composition, magmatic source, basic lower crust, Baimashan rock mass, adakite, Southern
Qinling

中图分类号: 

  • P597

[1] 张宏飞,肖龙,张利,等.扬子陆块西北缘碧口块体印支期花岗岩类地球化学和Pb-Sr-Nd同位素组成:限制岩石成因及其动力学背景[J].中国科学(D辑),2007,37(4):360-370.
[2] 张国伟,张本仁,袁学诚,等.秦岭造山带与大陆动力学[M].北京:科学出版社,2001:1-885.
[3] 秦江峰,赖绍聪.秦岭造山带晚三叠世花岗岩成因与深部动力学[M].北京:科学出版社,2011:1-266.
[4] Sun W D,Li S G,Chen Y D,et al.Timing of synorogenic granotoids in the south Qinling,central China:Constraints on the evolution of the Qinling-Dabie orogenic belt[J].Journal of Geology,2002,110(4):457-468.
[5] 李先梓,严阵,卢欣祥,等.秦岭—大别山花岗岩[M].北京:地质出版社,1993:1-218.
[6] 王建中,钱壮志,姜超,等.南秦岭白马山金矿区石英闪长岩地球化学特征及其构造意义[J].黄金科学技术,2014,22(5):30-38.
[7] 田伟,董申保,陈咪咪,等.南秦岭造山印支期花岗岩带的“地幔印记”[J].地学前缘,2009,16(5):119-128.
[8] 王晓霞,王涛,卢欣祥,等.北秦岭老君山和秦岭梁环斑结构花岗岩及构造环境——一种可能的造山带型环斑花岗岩[J].岩石学报,2003,19(4):650-660.
[9] 王晓霞,王涛,Happala I,等.秦岭环斑结构花岗岩中暗色包体的岩浆混合成因及岩石学意义——元素和Nd、Sr同位素地球化学证据[J].岩石学报,2005,21(3):935-946.
[10] 张成立,张国伟,晏云翔,等.南秦岭勉略带北光头山花岗岩体群的成因及其构造意义[J].岩石学报,2005,21(3):711-720.
[11] 张宏飞,靳兰兰,张利,等.西秦岭花岗岩类地球化学和Pb-Sr-Nd同位素组成对基底性质及其构造属性的限制[J].中国科学(D辑),2005,35(10):914-926.
[12] 刘志鹏,李建威.西秦岭金厂石英闪长岩的岩浆混合成因:岩相学和锆石U-Pb年代学证据及其构造意义[J].地质学报,2012,86(7):1077-1090.
[13] 柳世强,王建中,党满宏,等.甘肃白马山金矿床成因初探[J].黄金科学技术,2013,21(4):32-38.
[14] 张智兴,辛存林.甘肃金厂矽卡岩型铜金矿地质特征及成因探讨[J].甘肃冶金,2004,26(2):23-25.
[15] Liew T C,Hofmann A W.Precambrian crustal components,plutonic associations plate environment of the Hercynian Fold Belt of central Europe:Indications from a Nd and Sr isotopicstudy[J].Contribution to Mineral and Petrology,1988,98 (2) :129-138.
[16] 张宏飞,欧阳建平,凌文黎.南秦岭宁陕地区花岗岩Pb、Sr、Nd同位素组成及深部地质信息[J].岩石矿物学杂志,1997,16(1):22-31.
[17] 邵世才,张本仁,李泽九.秦岭造山带东江口花岗岩体群的地球化学研究及其构造环境[J].矿产与地质,1994,25(5):424-429.
[18] 张宏飞,张本仁,赵志丹,等.东秦岭商丹构造带陆壳的俯冲和碰撞:花岗质岩浆源区同位素示踪证据[J].中国科学(D 辑),1996,26(3):231-236.
[19] 张宏飞,张本仁,凌文黎,等.南秦岭新元古代地壳增生事件:花岗质岩石钕同位素示踪[J].地球化学,1997,26(5):16-24.
[20] Huang X,Wu L R.The Study on the Granitoids in  Shanxi Province by Nd-Sr isotopes[M]//Advances in Geosciencea.Beijing:China Ocean Press,1992:211-219.
[21] 张旗,王焰,熊小林,等.埃达克岩和花岗岩:挑战与机遇[M」.北京:中国大地出版社,2008.
[22] 张本仁,骆庭川,高山,等.秦巴岩石圈构造及成矿规律地球化学研究[M].武汉:中国地质大学出版社,1994:1-446.
[23] Zartman R E,Doe B R.Plumbotectonics:The model[J].Tectonophysics,1981,75(1/2):135-162.
[24] 张宗清,张国伟,唐索寒,等.南秦岭变质地层同位素年代学[M].北京:地质出版社,2002:1-256.
[25] 陈衍景,张静,张复新,等.西秦岭地区卡林—类卡林型金矿床及其成矿时间、构造背景[J].地质论评,2004,50(2):134-152.
[26] Defant M J,XU J F,Kepezhinskas P,et al.Adakites:Some variations ona theme[J].Acta Petrologica Sinica,2002,18(2):129-142.
[27] Oyarzun R,Marquez A,Lillo J,et al.Giant versus small porphyry copper deposits of Cenozoic age in northern Chile:Adakitic versus normal calc-alkaline magmatism[J].Mineralium Deposita,2001,36(8):794-798.
[28] Thieblemont D,Stein G,Lescuyer J L.Gisements epithermaux et porphyriques:La connexion adakite[J].Earth and Planetary Science,1997,325(1):103-109.
[29] 曲晓明,江军华,辛洪波,等.西藏冈底斯造山带几乎同时形成的两套埃达克岩为什么一套含矿一套不含矿[J].矿床地质,2010,29(3):381-394.
[30] 罗照华,卢欣祥,陈必河,等.透岩浆流体成矿作用导论[M].北京:地质出版社,2009:1-179.

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