投稿时间：2022-04-27
修订日期：2022-11-08
网络发布日期：2023-05-06
中文摘要:辽宁新岭铅锌银矿床位于华北克拉通东北缘，矿体赋存于古元古代辽河群变质岩中，受断裂构造控制。为了确定新岭矿床的成岩成矿时代、成矿流体和物质来源及其与中生代岩浆活动的关系，文章对新岭矿床开展了详细的矿床地质特征、年代学及同位素地球化学研究。结果表明，新岭矿床内与成矿有关花岗斑岩的LA-ICP-MS锆石U-Pb年龄为（227.3±1.5）Ma。5件闪锌矿样品的Rb-Sr等时线年龄为（222.9±2.9）Ma，初始Sr同位素比值为0.7104，确认新岭成岩成矿时代为晚三叠世。成矿流体的δ18OW值介于4.7‰~7.6‰，δDW值介于-97.7‰~-82.0‰，指示成矿流体主要为岩浆热液。黄铁矿3He/4He值介于0.15~0.21 Ra，进一步揭示成矿流体具有壳-幔混源特征。黄铁矿样品的LA-ICP-MS原位δ34S值介于+3.9‰~+7.2‰，均值为+5.5‰。6件闪锌矿样品的铅同位素组成为206Pb/204Pb=17.534~17.822，207Pb/204Pb=15.527~15.591，208Pb/204Pb=37.851~38.162。2件花岗斑岩样品的钾长石铅同位素组成为206Pb/204Pb=17.410~17.500，207Pb/204Pb=15.498~15.509，208Pb/204Pb=37.519~37.614。S-Pb同位素组成表明，新岭矿床成矿物质主要来源于晚三叠世岩浆，少量来源于辽河群变质岩地层。
Abstract:The Xinling Pb-Zn-Ag deposit is located in the northeastern North China Craton. The ore bodies are hosted in the Paleoproterozoic Liaohe Group metamorphic rock, and are controlled by faults. In order to obtain diagene-tic and metallogenic ages, source of ore-forming fluids and materials of the Xinling deposit and its genetic relationship with Mesozoic magmatic activity, a systematic studies of deposit geology, chronology and isotopic chemistry have been carried out in this paper. We present LA-ICP-MS zircon U-Pb age of (227.3±1.5)Ma for ore-related granite porphyry, Rb-Sr isochron age of (222.9±2.9)Ma for five sphalerite samples with initial Sr isotope ratio of 0.7104, which represent the Late Triassic diagenetic and metallogenic ages for the Xinling deposit. The δ18OW and δDW values of the ore-forming fluids vary from 4.7‰ to 7.6‰, and -97.7‰ to -82.0‰, respectively, indicating that the ore-forming fluid was mainly derived from magmatic fluid. The 3He/4He ratio of fluid inclusions in ore pyrite ranges from 0.15 to 0.21 Ra, further indicates that the ore-forming fluid was a mixing product of crustal and mantle-derived fluids. LA-ICP-MS in-situ δ34S values of pyrite sample range from +3.9‰ to +7.2‰, with an average of +5.5‰. The lead isotopic compositions of the six sphalerite samples are 206Pb/204Pb=17.534~17.822, 207Pb/204Pb=15.527~15.591, 208Pb/204Pb=37.851~38.162. The K-feldspar Pb isotopic compositions of the two granite porphyry samples are 206Pb/204Pb=17.411~17.500, 207Pb/204Pb=15.498~15.509, and 208Pb/204Pb=37.519~37.614. S-Pb isotope composition indicates that the ore-forming material was mainly derived from the Late Triassic magma with minor Liaohe Group metamorphic rock.
keywords:geochemistry zircon U-Pb dating Rb-Sr dating isotopic geochemistry Xinling deposit eastern Liaoning Province
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基金项目:本文得到中央级公益性科研院所基本科研业务费项目（编号：KK2106、KK2105）、国家自然科学基金项目（编号：41672066、41820104010）和中国地质调查局地质调查项目（编号：N2201-6）共同资助
引用文本：
何军成,刘军,王晓彤,侯可军.2023.辽东新岭铅锌银矿床成因：来自锆石U-Pb年龄、闪锌矿Rb-Sr年龄和H-O-S-Pb-He同位素证据[J].矿床地质,42(2):331~346HE JunCheng,LIU Jun,WANG XiaoTong,HOU KeJun.2023.Genesis of Xinling Pb-Zn-Ag deposit in eastern Liaoning Province: Evidences from zircon U-Pb age, sphalerite Rb-Sr age and H-O-S-Pb-He isotopic compositions[J].Mineral Deposits42(2):331~346
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