| 胶东和小秦岭:两类不同构造环境中的造山型金矿省 |
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| 引用本文： | 蒋少涌,戴宝章,姜耀辉,赵海香,侯明兰.胶东和小秦岭:两类不同构造环境中的造山型金矿省[J].岩石学报,2009,25(11):2727-2738. |
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| 作者姓名： | 蒋少涌 戴宝章 姜耀辉 赵海香 侯明兰 |
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| 作者单位： | 1. 南京大学地球科学系内生金属成矿机制研究国家重点实验室,南京,210093
2. 中国冶金总局山东局,济南,250014 |
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| 基金项目： | 国家重点基础研究发展计划(973计划)课题 |
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| 摘 要： | 胶东和小秦岭是我国排名前两位的金矿产地,根据对这两个地区的实地野外考察、室内研究及对已有大量研究成果的总结,我们认为胶东与小秦岭地区的金矿床均可归入造山型金矿的范畴,它们分别形成于增生型造山体制和碰撞型造山体制.胶东金矿床形成于早白垩世(130～120Ma左右)与洋壳俯冲(增生)造山相关的活动大陆边缘环境,矿床主要产于中生代花岗岩岩体中,严格受断裂带(NNE向或NE向为主)控制,成矿流体具有低盐度高CO_2含量的特征,He-Ar同位素研究显示成矿过程有幔源物质的加入.综合金矿床及中生代岩浆岩(特别是与成矿近同时的早白垩世郭家岭花岗岩及基性岩脉)的地质地球化学特征与成岩成矿动力学,我们提出在俯冲的太平洋板块后退的背景下,胶东地区增厚地壳中的榴辉岩相下地壳及下伏岩石圈地幔发生两阶段拆沉,强烈的壳幔相互作用最终导致了早白垩世普遍的岩浆活动及金的爆发成矿的模式.小秦岭地区金矿床主要以大型含金石英脉的形式产出于太华群变质基底的脆性-韧性剪切带(EW向为主)中,而与区域内燕山期大型花岗岩岩基没有直接联系,矿床地质特征(如低盐度高CO_2,以变质流体为主的成矿热液)与造山型金矿吻合,He-Ar同位素特征表明金矿床形成时有幔源物质的加入.小秦岭地区脉状Au-Mo矿床印支期成矿年龄(215～256Ma,辉钼矿Re-Os)表明印支期是小秦岭地区金成矿的主要时期,小秦岭金矿属于陆陆(华北与扬子)碰撞造山过程中形成的造山型金矿.
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| 关 键 词： | 胶东金矿省 小秦岭金矿省 俯冲增生造山 陆陆碰撞造山 造山型金矿 |
| 收稿时间： | 2009/3/30 0:00:00 |
| 修稿时间： | 2009/5/29 0:00:00 |
Jiaodong and Xiaoqinling: two orogenic gold provinces formed in different tectonic settings |
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| JIANG ShaoYong,DAI BaoZhang,JIANG YaoHui,ZHAO HaiXiang and HOU MingLan.Jiaodong and Xiaoqinling: two orogenic gold provinces formed in different tectonic settings[J].Acta Petrologica Sinica,2009,25(11):2727-2738. |
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| Authors: | JIANG ShaoYong DAI BaoZhang JIANG YaoHui ZHAO HaiXiang and HOU MingLan |
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| Affiliation: | State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China;State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China;Shandong Bureau of China Metallurgical Geology Bureau, Jinan 250014, China |
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| Abstract: | Jiaodong and Xiaoqinling areas are two largest gold metallogenic provinces in China.On the basis of field observation and compilation and evaluation of available research progresses and data in these two areas,we argued that gold deposits in both Jiaodong and Xiaoqinling are orogenic gold deposits,but formed in different geological settings.The Jiaodong gold deposits formed in an accretionary orogeic setting while the Xiaoqinling was in a collisional orogeic setting.The Jiaodong gold deposits are likely formed in an active continental margin related to subduction of the Pacific plate in early Cretaceous(ca.130～120Ma).They are mainly hosted in Mesozoic granitoids and controlled by NNE-trend or NE-trend fault zones.The ore-forming fluids have low salinity and high CO_2 contents,and the He-Ar isotopic systematics in fluid inclusion show fingerprint of mantle-derived fluid input.As the consequence of roll-back of the Pacific slab and increase in density of lower crust when changed into eclogite after thickened by compression,part of the lithospheric mantle and lower crust were delaminated,which led to intensive crust-mantle interaction and extensive magmatism with formation of gold deposits in Jiaodong.In contrast,in the Xiaoqinling area gold deposits are mainly controlled by brittle-ductile shear zones(mainly EW-trend)in metamorphic basement rocks of Taihua Group,and show no close connection with Mesozoic granites.Geological features of these deposits(e.g.,hydrothermal fluid with low salinity and high CO_2 contents,and originated mainly from metamorphic water)are consistent with those of orogenic gold deposits worldwide.Some vein-type Au-Mo deposits have been dated at 215～256Ma through method of molybdenite Re-Os geochronology,which support the idea that the gold deposits in the Xiaoqinling area mainly formed in Indosinian period,when collision between North China Craton and Yangtze Block took place. |
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| Keywords: | Jiaodong gold province Xiaoqinling gold province Subduction-related accretion orogenesis Continental collision orogenesis Orogenic gold deposit |
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