胶东金矿床成矿热液来源再分析及成矿动力学过程探讨

摘要

通过对胶东金矿成矿年龄和碳氢氧同位素等数据进行处理分析，结合硫、氦氩及放射性同位素数据并借鉴前人有关研究成果，总结了胶东金矿成矿热液来源，并对其成矿动力学过程进行了浅略探讨。分析指出胶东金矿成矿热液具壳幔混合特征，但以壳源为主，热液流体主要导源于早白垩世岩浆活动（郭家岭岩体、伟德山超单元），同期富集幔源岩浆（基性脉岩）也提供部分热液或成矿物质。古太平洋板块在向欧亚板块俯冲过程中所释放流体，交代并导致岩石圈地幔的部分熔融，形成富集岩石圈幔源基性岩浆，该岩浆对下地壳产生垫底作用导致下地壳部分熔融并形成郭家岭花岗岩（早白垩世早期）的母岩浆。随着板块持续俯冲，岩石圈地幔不断熔融，持续的高温幔源基性岩浆造成中—下地壳深度的部分熔融，并形成了伟德山超单元（早白垩世晚期）。早白垩世岩浆在上侵过程中析出流体，流体在壳内循环并萃取成矿物质，最终在有利的NNE 向拉张构造环境中同围岩发生反应或随着含矿热液温压条件的改变而导致矿质沉淀。%For purpose of making a clear acknowledge of nature and origin of the Jiaodong ore cluster ore-forming hydrothermal,date regarding mineralization ages,hydrogen and oxygen isotopes,sulfur isotope,argon,helium and radioactive isotopes were collected and reanalyzed briefly.The results showed that ore-forming hydrothermal was characterized by mainly crustal origin with minor proportions of mantle involvement.It was found that hydrothermal fluid was caused by early Cretaceous magmatic activities (Guojialing rock mass and Weideshan super-unit),acted the role of provider of the ore-forming hydrothermal.Over the same period enrichment mantle-derived magma (mafic dike) likewise provided partially or hydrothermal ore-forming materials.In the process of the Pacific plate to Eurasian plate subduction,fluid was released,which led to the partial melting of mantle lithosphere,the enrichment of lithospheric mantle source basic magma formation,and the bottom effect of magma resulted in partial melting of crust and formed parental magma for the Guojialing granite(Early Cretaceous).With continuous subduction plate,lithospheric mantle melted persistently,moreover,the sustained high temperature of mantle-derived basic magma caused the partial melting that happened at lower crust depth, and finally formed the mountain superelement Weideshan super-unite (late Early Cretaceous).Fluid appeared in the process the Early Cretaceous magmatic assault on precipitation,and the fluid circulated in the shell and extracted to ore-forming material.Finally,under the condition on favorable NNE pull-apart structure,the ore-forming material reacted with surrounding rock and become ore material precipitation as variation of ore-bearing hydrothermal temperature pressure conditions.