胶东中生代岩浆岩金等元素组成及其对金成矿的启示  

Composition of Gold and Other Elements in the Mesozoic Magmatic Rocks of the Jiaodong Peninsula and Their Implications for Gold Mineralization

作　　者：董磊磊 白鑫 宋明春 DONG Leilei;BAI Xin;SONG Mingchun(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;College of Earth Sciences,Hebei GEO University,Shijiazhuang 050031,Hebei,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083 [2]河北地质大学地球科学学院,河北石家庄050031

出　　处：《黄金科学技术》2024年第5期768-780,共13页Gold Science and Technology

基　　金：国家自然科学基金NSFC-山东省联合基金项目“胶东深部金矿断裂控矿机理”(编号:U2006201);河北省人才项目“冀北地区金成矿系统及深部找矿技术”(编号:HBQZYCXY0010)联合资助。

摘　　要：胶东地区是我国最大的金成矿区,但是关于其巨量金的来源一直不明。通过对成矿前的晚侏罗世玲珑期岩体(玲珑、昆嵛山)、早白垩世早期郭家岭期岩体及其暗色包体(郭家岭、丛家)以及成矿后的早白垩世晚期伟德山型岩体及其暗色包体(崂山、牙山、艾山等)的Au、Cu和Ag等元素含量进行分析,发现这些亲铜元素相对于大陆地壳较为亏损。此外,玲珑期和伟德山期样品中Cu/Ag比值与Cu含量具有明显的正相关性。而郭家岭期岩体及其包体中以及伟德山期岩体中的暗色包体中,Cu/Ag比值与Au含量具有正相关性,表明在岩浆演化过程中,单硫化物固溶体从岩浆中持续分离,造成中生代岩浆岩具有较低的Cu/Ag比值和金属含量。这些硫化物的堆晶在中下地壳形成了富集Au等元素的矿源层,为胶东金成矿提供了物质基础。研究还表明,单硫化物固溶体分离是岩浆演化过程中普遍发育的现象,这种现象也可能是导致大陆地壳相对于地幔亏损Cu等元素的原因。The Jiaodong Peninsula is the largest gold-producing region in China,however,the sources of its substantial gold reserves remains uncertain.Analyzing the trace elements in pre-mineralization Late Jurassic Linglong-type plutons(Linglong,Kunyushan),Early Cretaceous Guojialing-type plutons(Guojialing,Congjia),syn-to post-mineralization Early Cretaceous Weideshan-type plutons,and the mafic dioritic enclaves within the latter two plutons reveals that these formations generally exhibit lower concentrations of elements such as Cu,Au,Ag,Sb,and As compared to the average values of the continental crust.Specifically,the gold content is typically below 0.5×10−9,aligning with prior test results and suggesting a depletion process of elements such as gold during magmatic evolution.Furthermore,a significant positive correlation is observed between the Cu/Ag ratio and Cu content in both Linglong-type and Weideshan-type samples.In Guojialing-type plutons and their enclaves,a positive correlation between the Cu/Ag ratio and Au content has been observed.This relationship suggests that during magma evolution,monosulfide solid solution continuously separates from the magma.Consequently,Mesozoic magmatic rocks exhibit lower Cu/Ag ratios and reduced metal content.The accumulation of these sulfides in the middle to lower crust forms an enriched source layer of gold and other elements,thereby providing ore-forming materials essential for gold mineralization in the Jiaodong region.The study also suggests that the separation of monosulfide solid solutions during magma evolution may be a common process,which could also explain why the continental crust is depleted in copper and other elements compared to the mantle.

关 键 词：胶东 金成矿 硫化物堆晶 玲珑岩体 郭家岭岩体 伟德山岩体 

分 类 号：P618.51[天文地球—矿床学]