论山东胶东金矿形成的挤压-伸展构造环境  

On the Compression-extensional Tectonic Environment and Gold Mineralization in the Jiaodong Area, Shandong Province

作　　者：李逸凡[1] 李洪奎 陈国栋 耿科 曹丽丽 梁太涛 LI Yifan;LI Hongkui;CHEN Guodong;GENG Ke;CAO Lili;LIANG Taitao(College of Architecture and Civil Engineering,Weifang University,Weifang 261061,Shandong,China;Shandong Institute of Geological Sciences,Key Laboratory of Gold Mineralization Processes and Resources Utilization,Ministry of Natural Resources,Jinan 250013,Shandong,China)

机构地区：[1]潍坊学院建筑与工程学院,山东潍坊261061 [2]山东省地质科学研究院,自然资源部金矿成矿地质过程与资源利用重点实验室,山东济南250013

出　　处：《大地构造与成矿学》2019年第6期1117-1132,共16页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41572068);国家公益性专项(201511029);全国矿产资源潜力评价项目(1212010813014-01);山东地质勘查基金项目(2012028、2012032);国家重点研发计划项目(2016YFC0600107-5);山东省泰山学者建设工程专项联合资助

摘　　要：胶东地区沉积-岩浆-构造-成矿事件序列的时空演化,是在侏罗纪-白垩纪时期受太平洋板块向欧亚大陆俯冲作用的影响,而造成的挤压-伸展构造交互转换环境中形成的,金成矿作用发生在挤压与伸展转换过程中的伸展阶段。这一挤压-伸展联合作用过程表现在:①构造方面,表现为四期六阶段不同力学性质和方向的挤压-伸展特征:第一期近S-N向挤压及NW-SE向挤压,第二期NE-SW向挤压与NE-SW向引张,第三期NW向引张,第四期近E-W向挤压与近S-N向引张。②地层方面,在胶东各断陷盆地内发育的莱阳群、青山群和王氏群,以区域不整合、沉积间断和正常地层单元交互出现展现出挤压-伸展的过程。③侵入岩方面,分为三个侵入岩浆构造幕和四次岩浆侵入事件:第一幕(早期)为晚侏罗世玲珑片麻状二长花岗岩组合,SHRIMP锆石U-Pb年龄值集中在160~150 Ma,是区域构造挤压导致地壳增厚引起地壳重熔的产物,其后的伸展引张形成了各种密集分布的脉岩群;第二幕(中期)是早白垩世早期郭家岭花岗闪长岩组合,SHRIMP锆石U-Pb年龄集中在130~126Ma,之后的沉积岩建造组合代表构造应力体制由挤压为主向伸展为主转换;第三幕(晚期)包括两次岩浆侵入事件,一是伟德山花岗岩组合,指示了挤压向伸展转换环境,二是崂山A型晶洞过碱性正长花岗岩组合,形成于典型的后造山伸展构造环境。④火山岩方面,分为三个喷发亚旋回和七个喷发期,各亚旋回间均具有较长的时间间隔,代表了区域性挤压环境;各期次之间虽有短暂喷发间隔,但总体表现为伸展环境,火山喷发事件显示了挤压-伸展不同构造环境的交替发生。⑤岩石学方面,玲珑花岗岩中的片理、片麻理构造和郭家岭花岗闪长岩中的钾长石旋转眼球体、σ构造、S-C组构、压力影构造等,代表了挤压剪切的构造环境下形成的岩石特征;而崂山晶洞碱性正长岩组It is widely accepted that the spatiotemporal evolution of the Jurassic-Cretaceous sedimentary-magmatictectonic-metallogenic system in the Jiaodong area,Shandong province,was influenced by the subduction of Pacific plate,especially the resultant alternating compression-extensional tectonics.Many researchers believe that the gold mineralization was formed during the extrusion and extensional transition.The combined compression and extension in the area is characterized by(1)tectonically,the four periods and six stages of compression-extension;(2)stratigraphically,the regional unconformity and erosional hiatus in the sedimentary and volcanic strata in the faulted basins in the eastern Shandong province;and(3)in magmatism aspect,three intrusive magmatic tectonic episodes and four magmatic intrusive events,along with three eruption sub-cycles and seven stages of volcanism,can be recognized;moreover,(4)deformations such as the schistosity and gneissic structure of the Linglong granite,and the potash feldspar rotating eyeball,α-structure,S-C fabric and pressure shadow structure in the Guojialing granodiorite demonstrate stages of compressive shearing.The Late Jurassic and Early Cretaceous compression-extension as was exhibited by the strata sedimentation,magma intrusion,volcanic eruption formation,tectonic activity and ore mineralization in the Jiaodong area is favorable for the formation of large and super-large gold deposits in the area.

关 键 词：构造-岩浆事件 岩石组合 挤压-伸展 构造环境 金矿形成 胶东地区 山东 

分 类 号：P613[天文地球—矿床学] P542[天文地球—地质学]