北山造山带红柳河槽-跃进山地区石炭纪花岗岩成因及构造岩浆演化研究  

Genesis and tectonic magmatic evolution of Carboniferous granites in the Hongliuhecao-Yuejinshan area of Beishan orogenic belt

作　　者：白荣龙 虎金荣 赵甫峰[4] 岳雅慧[5] 周慧玲 BAI RongLong;HU JinRong;ZHAO FuFeng;YUE YaHui;ZHOU HuiLing(College of Resources and Environmental Engineering,Tianshui Normal University,Tianshui 741001,China;Key Laboratory of Strategic Mineral Resources of the Upper Yellow River,Ministry of Natural Resources,Lanzhou 730046,China;Gansu Nonferrous Geological Survey Institute,Lanzhou 730000,China;College of Earth Science,Chengdu University of Technology,Chengdu 610059,China;Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;Lanzhou Institute of Geotechnical Seismology,China Seismological Bureau,Lanzhou 730000,China)

机构地区：[1]天水师范学院资源与环境工程学院,天水741001 [2]自然资源部黄河上游战略性矿产资源重点实验室,兰州730046 [3]甘肃省有色地质调查院,兰州730000 [4]成都理工大学地球科学学院,成都610059 [5]中国科学院青藏高原研究所,北京100101 [6]中国地震局兰州岩土地震研究所,兰州730000

出　　处：《岩石学报》2022年第3期713-742,共30页Acta Petrologica Sinica

基　　金：甘肃省教育厅青年博士基金项目(2021QB-104);甘肃省教育厅创新基金项目(2021B-213);甘肃省基础地质调查项目联合资助。

摘　　要：北山造山带位于中亚造山带南缘,区内广泛发育古亚洲洋-陆演化的岩浆记录,是研究北山造山带构造-岩浆-成矿作用及其动力学背景的重要窗口。红柳河槽-跃进山地区是北山造山带中北部的重要组成部分,区内与成矿有关花岗岩的形成时代、成因及构造背景尚不明确,由此制约了对北山造山带内成岩成矿动力学背景的探讨。本次在系统、详细的野外地质调查、岩石(相)学观察的基础上,结合岩浆岩地球化学、锆石U-Pb年代学和Lu-Hf同位素等证据,深入剖析了北山造山带内红柳河槽-跃进山地区的花岗岩形成时代、类型、源区和动力学背景,取得了以下认识:(1)通过锆石LA-ICP-MS U-Pb定年测得与成矿有关的狼娃山二长花岗岩、红柳河槽正长花岗岩、跃进山北正长花岗岩、跃进山二长花岗岩形成时代分别为327.1±2.4Ma、326.7±2.4Ma、321.3±2.4Ma和309.7±2.2Ma,表明红柳河槽-跃进山地区铜、钨、钼、铅、锌等元素成矿与石炭纪(327.1~309.7Ma)岩浆活动有关;(2)通过花岗岩地球化学研究表明,红柳河槽-跃进山地区的花岗岩均属于钙碱性-高钾钙碱性、准铝质-弱过铝质系列,强烈富集LREE、LILE,亏损HREE、HSFE,具有典型弧岩浆的地球化学特征,花岗岩成因类型均为I型;(3)本次获得狼娃山二长花岗岩和红柳河槽正长花岗岩的εHf(t)值分别为5.90~9.92(平均值7.93)和5.87~10.28(平均值8.11),t DM2分别为0.703~0.959Ga和0.93~1.03Ga,且具有较低的Nb/Ta比值(5.1~14.2,平均值8.5),与典型新生下地壳来源岩浆(8.3)相似,表明岩浆物质可能源于新生下地壳岩石部分熔融;(4)根据锆石Ti温度计查明北山造山带红柳河槽-跃进山地区狼娃山二长花岗岩、红柳河槽正长花岗岩、跃进山北正长花岗岩、跃进山二长花岗岩的平均结晶温度分别为765℃、765℃、816.4℃、771.5℃,锆石Ce^(Ⅳ)/Ce^(Ⅲ)平均值分别为85.27、108.4、103.6、135.7,表明从石Beishan orogenic belt is located in the southern margin of the Central Asian Orogenic Belt.Magmatic records of paleo-Asian ocean-continent evolution widely existed in this area,and as a result,it is an important window to study the tectonic magmatic mineralization and dynamic background of Beishan orogenic belt.Hongliuhecao-Yuejinshan area is an important component of the middle-northern part of Beishan orogenic belt,however,the formation age,genesis and tectonic background of granites related to mineralization in the area are not clear,which seriously restricts the discussion of diagenetic and metallogenic dynamic backgrounds in Beishan orogenic belt.Based on systematic and detailed field geological survey and petrographic(facies)observation,combined with the evidence of magmatic rock geochemistry,zircon U-Pb chronology and Lu-Hf isotope,we analyzes the formation age,type,source area and dynamic background of granite in Hongliuhecao-Yuejinshan area in Beishan orogenic belt,from which the following conclusions can be obtained:(1)According to zircon LA-ICPMS U-Pb dating,the formation ages of Langwashan monzogranite,Hongliuhecao syenogranite,Yuejinshanbei syenogranite and Yuejinshan monzogranite related to mineralization are 327.1±2.4Ma,326.7±2.4Ma,321.3±2.4Ma and 309.7±2.2Ma,indicating that the mineralization of copper,tungsten,molybdenum,lead,zinc and other elements is related to the Carboniferous magmatism of 327.1~309.7Ma.(2)The geochemical study of granites shows that the granites in Hongliuhecao-Yuejinshan area are strongly enriched in LREE and LILE,while deficient in HREE and HSFE,which demonstrated that they have the geochemical characteristics of typical arc magma and the I-type granites,and belong to calc alkaline,high-K calc alkaline,quasi aluminous-weak peraluminous series.(3)TheεHf(t)values of Langwashan monzogranite and Hongliuhecao syenogranite are 5.90~9.92(average 7.93)and 5.87~10.28(average 8.11),respectively;and the t DM2 values are 0.703~0.959Ga and 0.93~1.03Ga,respectively;furthermore,they

关 键 词：北山造山带 红柳河槽-跃进山 地球化学 花岗岩成因 构造-岩浆演化 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]