大兴安岭南段黄岗梁地区早白垩世正长花岗岩成因及构造启示:锆石U−Pb年龄、岩石地球化学和Sr−Nd−Pb同位素证据  

Petrogenesis and tectonic implications of the Early Cretaceous syenogranite in Huanggangliang area,southern Great Hinggan Range:Evidence from zircon U−Pb ages,petrogeochemistry and Sr−Nd−Pb isotopes

作　　者：顾玉超[1] 陈仁义[2] 杜继宇[1] 鞠楠[1] GU Yuchao;CHEN Renyi;DU Jiyu;JU Nan(Shenyang Center,China Geological Survey(Geosciences Innovation Center of Northeast China),Shenyang 110034,Liaoning,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]中国地质调查局沈阳地质调查中心(东北地质科技创新中心),辽宁沈阳110034 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质通报》2025年第1期91-116,共26页Geological Bulletin of China

基　　金：中国地质调查局项目《吉黑东部成矿带战略性矿产调查》(编号:DD20240060);国家自然科学基金项目《碱性岩浆作用中铌钽元素富集机制研究:以辽东地区赛马铌钽矿床为例》批准号:42102087)。

摘　　要：【研究目的】大兴安岭南段黄岗梁锡铁矿区及外围发育大面积花岗岩类,加强其成岩时代、岩石成因类型、成岩成矿物质来源等研究,有利于探究该区成岩与成矿关系和早白垩世碰撞造山机制。【研究方法】采集大兴安岭南段黄岗梁锡铁矿区及外围样品,进行岩相学、锆石U−Pb测年、岩石地球化学及Rb−Sr、Sm−Nd、Pb同位素研究。【研究结果】获得岩浆结晶年龄为141.9~139.1 Ma,较成矿年龄早约3 Ma,形成于早白垩世。岩石具有高硅、低铝、低镁、富钾少钠特征,为高钾钙碱性A型花岗岩。(^(87)Sr/^(86)Sr)_(i)和^(143)Nd/^(144)Nd值分别介于0.70031~0.70543和0.512572~0.512636之间,ε_(Nd)(t)值为0.07~1.18,Nd同位素模式年龄T_(DM2)为926~838 Ma。【结论】黄岗梁矽卡岩型锡铁矿床成岩物质于新元古代从亏损地幔分离,在上升侵位过程中受到地壳物质混染。大兴安岭南段地区在早白垩世经历了蒙古–鄂霍次克洋碰撞闭合伸展作用和古太平洋高角度俯冲作用叠加。[Objective]A large area of granitoids had been developed in the huanggangliang tin-iron mining and its surrounding area in the southern Great Hinggan Range.Thus,the study on its diagenetic age,petrogenetic type and source of diagenetic and ore-forming materials provides important insights to the mechanism of Early Cretaceous collision orogeny in this area and its relationship with mineralization.[Methods]Samples were collected from the Huanggangliang tin−iron mining area and its surrounding areas in the southern Great Hinggan Range for petrography,zircon U−Pb geochronology,rock geochemistry,and Rb−Sr,Sm−Nd,Pb isotope studies.[Results]The crystallization ages of these samples range from 141.9 Ma to 139.1 Ma,which was formed during the Early Cretaceous and was about 3 Ma earlier than the mineralization age.The rocks are belong to high potassium calcium alkaline A−type granites with characteristics of high silicon,low aluminum,low magnesium,high potassium and low sodium.The ratios of(^(87)Sr/^(86)Sr)_(i)and^(143)Nd/^(144)Nd are 0.70031~0.70543 and 0.512572~0.512636,respectively,the value ofε_(Nd)(t)_(i)s 0.07~1.18,and the Nd isotope model age T_(DM2)ranges from 926 Ma to 838 Ma.[Conclusions]The diagenetic materials of the Huanggangliang skarn tin−iron deposit were separated from the depleted mantle in Neoproterozoic,and experienced crustal contamination during ascending emplacement process.The southern Great Hinggan Range area experienced high−angle subduction of the Paleo−Pacific Ocean plate after post−collisional extension of the Mongol−Okhotsk Ocean closure.

关 键 词：Sr−Nd−Pb同位素 花岗岩 碰撞后伸展环境 锆石U−Pb年龄 黄岗梁地区 大兴安岭 

分 类 号：P534.53[天文地球—古生物学与地层学] P597[天文地球—地质学] P588.12