辽东矿集区大东沟金矿床成矿时代和成因:地质、年代学、地球化学和同位素制约  

Age and genesis of the Dadonggou gold deposit in the Liaodong mining district:Evidences from geology,chronology,geochemistry and isotope

作　　者：李浩[1,2] 韩吉龙 王功文 吕志成[3] 陈广镇[2] 刘泰冀[2] 杨帆 张朋 LI Hao;HAN JiLong;WANG GongWen;LV ZhiCheng;CHEN GuangZhen;LIU TaiJi;YANG Fan;ZHANG Peng(Frontiers Science Center for Deep-time Digital Earth,China University of Geosciences(Beijing),Beijing 100083,China;No.5 Geological Party Limited Liability Company of Liaoning Province,Dashiqiao 115100,China;Development and Research Center of China Geological Survey,Beijing 100037,China;College of Resources and Environment,Jilin Agricultural University,Changchun 130118,China;Shenyang Geological Survey Center,China Geological Survey,Shenyang 110034,China)

机构地区：[1]中国地质大学(北京)深时数字地球前沿科学中心,北京100083 [2]辽宁省第五地质大队有限责任公司,大石桥115100 [3]中国地质调查局发展研究中心,北京100037 [4]吉林农业大学资源与环境学院,长春130118 [5]中国地质调查局沈阳地质调查中心,沈阳110034

出　　处：《岩石学报》2024年第10期3191-3213,共23页Acta Petrologica Sinica

基　　金：辽宁省地质勘探矿业集团有限责任公司地质科研项目(KJ201802);中国博士后科学基金项目(2023M743306);深时数字地球前沿科学中心“深时数字地球”中央高校科技领军人才团队项目(2652023001)联合资助.

摘　　要：大东沟金矿位于华北克拉通北东缘辽东矿集区,矿体赋存于古元古代辽河群盖县岩组绢云千枚岩中,并与中生代石英闪长岩空间关系密切。为了深入揭示矿床成因与成矿地质背景,近期我们对其开展矿床地质、黄铁矿Re-Os和锆石U-Pb测年、成矿相关侵入岩的地球化学和Hf同位素以及硫化物S同位素工作。研究表明,其成矿可划分三期:第一期沉积成岩黄铁矿期(Ⅰ)、第二期为变质黄铁矿-毒砂期(Ⅱ)、第三期为热液期(Ⅲ)。其中,第三期又可划分黄铁矿-毒砂阶段(Ⅲ1)、多金属硫化物-石英阶段(Ⅲ2)和含黄铁矿石英-碳酸盐阶段(Ⅲ3)。热液期(Ⅲ)黄铁矿的Re-Os等时线年龄为130±18Ma(n=5,初始^(187)Os/^(188)Os=1.60±0.42),与成矿相关石英闪长岩的侵位年龄(133±1Ma)一致,指示金成矿作用发生在早白垩世。热液期Ⅲ1、Ⅲ2矿化阶段硫化物的δ^(34) S值为3.0‰~4.8‰,且明显不同于第一期沉积成因黄铁矿(8.9‰~10.2‰)和辽河群沉积-变质岩(7.0‰~23‰)的硫同位素组成,进一步揭示该矿床大规模成矿为岩浆热液作用形成,与石英闪长岩作用密切。石英闪长岩富集大离子亲石元素(Rb、Ba、U等),中度亏损高场强元素(Nb、Ta)、具有低的ε_(Hf)(t)值(-6.38~-2.82)以及弱氧化的属性;结合矿区内同期侵入岩数据,指示它起源于幔源镁铁质岩浆和壳源长英质岩浆的混合。结合区域地质资料,我们认为大东沟金矿床为中温热液型金矿床,成因上与同期弱氧化的闪长质岩浆有关,形成于早白垩世华北克拉通破坏峰期。The Dadonggou gold deposit is located in the Liaodong Mining District(LMD)at the northeastern margin of the North China Craton(NCC).Orebodies of the deposit are mainly hosted in the sericite phyllite of the Gaixian Formation of the Paleoproterozoic Liaohe Group,and they are are spatially related to the Mesozoic quartz diorite.In this paper,a combined study of deposit geology,pyrite Re-Os and zircon U-Pb dating,geochemical and Hf isotopic analyses upon ore-related intrusion,together with sulfur isotope of the sulfides was conducted to constrain the geological setting and ore genesis of the Dadonggou deposit.A paragenetic sequence with three periods has been identified as syngenetic/diagenetic pyrite(Ⅰ),metamorphosed pyrite-arsenopyrite(Ⅱ)and hydrothermal(Ⅲ)periods,among which the third period can be further subdivided into pyrite-arsenopyrite(Ⅲ1),polymetallic sulfide quartz(Ⅲ2)and pyrite-bearing quartz-carbonate(Ⅲ3)stages.Pyrites from stage Ⅲ yielded Re-Os isochron age of 130±18Ma(n=5,Initial ^(187)Os/^(188)Os=1.60±0.42),which is consistent with the emplacement age of ore-related quartz diorite(133±1Ma),indicating that Au-mineralization occurred in the Early Cretaceous.Sulfides from ore-stages Ⅲ1-2 haveδ^(34) S values ranging from 3.0‰to 4.8‰,which are distinct from those of sedimentary pyrite from the first period(8.9‰~10.2‰)and sedimentary-metamorphic rocks from the Paleoproterozoic Liaohe Group(7‰~23‰),suggesting that the S element was derived from a magmatic source.The ore-related quartz diorite is characterized by enrichment in large ion lithophile elements(i.e.,Rb,Ba and U),and moderately depleted in high field strength elements(i.e.,Nb and Ta)with lowε_(Hf)(t)values(-6.38~-2.82).Combined with geological data of synchronic intrusions in the district,the source of the pluton was likely derived from a magma mixing between the mantle-derived mafic and the crust-derived felsic magmas.Combining available data results in the district,we propose that the Dadonggou is a type of mesot

关 键 词：地球化学 矿床成因 早白垩世 大东沟金矿床 辽东 华北克拉通 

分 类 号：P597.3[天文地球—地球化学] P618.51[天文地球—地质学]