辽东青城子矿集区大理岩碳—氧同位素组成及其对含矿层位对比及深部找矿的指示  

Carbon-oxygen isotopes of marbles from the Qingchengzi ore concentration area,eastern Liaoning Province:Implications for ore-hosted stratigraphic correlation and deep metallogenic prediction

作　　者：高森 张拴宏[1,3] 王宏宇 刘建民 胡国辉[1,3] 张琪琪[1] 王森 孔令昊 许继峰 刘洋 GAO Sen;ZHANG Shuanhong;WANG Hongyu;LIU Jianmin;HU Guohui;ZHANG Qiqi;WANG Sen;KONG Linghao;XU Jifeng;LIU Yang(Institute of Geomechanics,Chinese Academy of Geological Sciences,MNR Key Laboratory of Paleomagnetism and Tectonic Reconstruction,Beijing,100081;School of Earth Sciences and Resources,China University of Geosciences,Beijing,100083;SinoProbe Laboratory,Chinese Academy of Geological Sciences,Beijing,100037;Shenyang Center of China Geological Survey,Shenyang,110000)

机构地区：[1]中国地质科学院地质力学研究所,自然资源部古地磁与古构造重建重点实验室,北京100081 [2]中国地质大学地球科学学院,北京100083 [3]自然资源部深地科学与探测技术实验室,北京100037 [4]中国地质调查局沈阳地质调查中心,沈阳110000

出　　处：《地质论评》2024年第6期2127-2141,共15页Geological Review

基　　金：国家自然科学基金资助项目(编号:41920104004、U2244213);中国地质科学院基本科研业务费项目(编号:JKYZD202320)的成果。

摘　　要：辽东青城子矿集区金—多金属矿床严格受古元古代辽河群大石桥组大理岩及盖县组变质碎屑岩过渡带“硅—钙面”附近层间或近层间构造带控制,含矿层位的精确对比有助于区域及深部找矿预测。笔者等对青城子矿集区85件大理岩样品开展了碳—氧同位素测试,其中大石桥组中—下部厚层不含矿大理岩(普遍被古元古代基性岩床侵入)的δ^(13)C_(V-PDB)为2.1‰~6.1‰,普遍具有明显的碳同位素组成正漂移,其原岩沉积于洛马贡迪—贾图利(Lomagundi—Jatuli)事件后期;而大石桥组上部中薄层含矿大理岩的δ^(13)C_(V-PDB)为-6.4‰至3.0‰,碳同位素组成正漂移不明显,其原岩沉积于洛马贡迪—贾图利事件之后;矿区东南部原定的“南辽河群”“高家峪组”碎屑岩内大理岩夹层的δ^(13)C_(V-PDB)为-2.8‰至0,无明显碳同位素组成正漂移,与胶—辽—吉带北部“北辽河群”高家峪组大理岩强烈碳同位素正漂移特征明显不同,其原岩也沉积于洛马贡迪—贾图利事件之后。碳—氧同位素组成及岩性对比揭示,青城子矿集区东南部被认定为金—多金属矿体底板的“高家峪组”浅粒岩地层的层位与大石桥组上部地层相当,沉积时代晚于鞍山地区“北辽河群”高家峪组地层。结合前人研究及找矿勘查成果,认为林家三道沟、小佟家堡子、高家堡子—风银大地矿区深部可能存在有多个“硅—钙面”及含矿层位,具有很好的成矿潜力及找矿前景,深部勘探的终点应该到达大石桥组中—下部厚层大理岩段,即有变质基性岩床侵入、并具有碳同位素组成正异常的厚层状大理岩段。The gold and Pb—Zn—Ag ore deposits in the Qingchengzi ore concentration area in eastern Liaoning Province are strictly controlled by layer-parallel or layer-subparallel faults near the silicon—calcium surfaces within transitional zone between the Paleoproterozoic Dashiqiao and Gaixian formations of the Liaohe Group in the Jiao—Liao—Ji belt in NE China.Stratigraphic correlations of ore-hosted layers within the Dashiqiao and Gaixian formations are of great significances for regional and deep metallogenic predictions in the Qingchengzi ore concentration area.Here we present carbon—oxygen isotopes of 85 samples collected from the ore-hosted marbles and none ore-hosted marbles from the Dashiqiao Formation,and the previous named“Gaojiayu”Formation in the Qingchengzi ore concentration area.Our results show that the thick-layered none ore-hosted marbles from the middle—lower Dashiqiao Formation usually intruded by Paleoproterozoic metamorphosed mafic sills are characterized by positive carbon isotope excursion withδ^(13)C_(V-PDB) values of 2.1‰~6.1‰,and were deposited during late stage of the Lomagundi—Jatuli Event(LJE).In contrast,middle-to thick-layered ore-hosted marbles from the upper Dashiqiao Formation haveδ^(13)C_(V-PDB) values from-6.4‰to 3.0‰,and those from the previously named“Gaojiayu”Formation haveδ^(13)C_(V-PDB) values from-2.8‰to 0.Both the ore-hosted marbles from the upper Dashiqiao Formation and marbles from the previously named“Gaojiayu”Formation exhibit no positive carbon isotope excursion,indicating that their deposition occurred after the LJE.The carbon isotopic compositions of marbles from previously named“Gaojiayu”Formation in southeastern Qingchengzi ore concentration area are significantly different from those of marbles from the Gaojiayu Formation from Anshan area in northwestern part of the Jiao—Li—Ji Belt that are characterized by high positive carbon isotope excursion withδ^(13)C_(V-PDB) values of 10‰,indicating their depositional ages are di

关 键 词：辽河群 洛马贡迪—贾图利(Lomagundi—Jatuli)事件 青城子矿集区 深部找矿预测 胶—辽—吉带 华北克拉通 

分 类 号：P618.2[天文地球—矿床学]