扬子北缘还是华北东南缘:胶东新元古代花岗片麻岩构造归属新议  

The northern margin of the Yangtze Craton or the southeastern margin of the North China Craton:new insights on the tectonic attribution of Neoproterozoic granitic gneisses in Jiaodong Peninsula

作　　者：王惠初 相振群[1,2] 任云伟 康健丽 初航 王智 滕菲 佟鑫 WANG Huichu;XIANG Zhenqun;REN Yunwei;KANG Jianli;CHU Hang;WANG Zhi;TENG Fei;TONG Xin(Tianjin Center,China Geological Survey,Tianjin 300170,China;Precambrain Geological Research Centre,China Geological Survey,Tianjin 300170,China;Department of Earth Sciences of NSFC,Beijing 100085,China;International Mining Research Center,China Geological Survey,Beijing 100037,China)

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]中国地质调查局前寒武纪地质研究中心,天津300170 [3]国家自然科学基金委员会地球科学部,北京100085 [4]中国地质调查局国际矿业研究中心,北京100037

出　　处：《地质学报》2022年第9期3012-3033,共22页Acta Geologica Sinica

基　　金：国家重点研发计划“深地资源勘查开采”重点专项项目(编号2016YFC0600107);中国地质调查局地调项目(编号DD20160042,D20190035);国家自然科学基金项目(编号4190020813)联合资助的成果。

摘　　要：苏鲁超高压变质带广泛发育新元古代花岗片麻岩,这些新元古代花岗片麻岩通常被认为与扬子克拉通具有亲缘性。本文基于新的调查资料,综合前人研究成果,提出新元古代花岗岩是华北克拉通新元古代时期大陆裂解产物、并在三叠纪华南与华北碰撞造山期间作为华北板块大陆边缘南向深俯冲的新认识。主要依据如下:(1)新元古代花岗岩与华北克拉通胶北地块为侵入接触关系,五莲-即墨-牟平断裂带并非北苏鲁超高压变质带与胶北地块的初始接触界线;(2)新元古代花岗片麻岩中有大量胶北地块的古老地壳物质,记录了~1.85 Ga的华北克拉通化变质事件;(3)胶北地块上晚侏罗世花岗岩中存在大量新元古代继承锆石,但缺少三叠纪的弧岩浆记录;(4)胶北地块东南缘存在三叠纪角闪岩相变质作用证据,指示胶北地块三叠纪的俯冲作用;(5)区域地球物理信息指示北苏鲁超高压变质带深部地壳属于华北克拉通和北东东向构造线方向。新的认识将有助于对华北克拉通新元古代构造演化和大别-苏鲁造山带形成过程的重新认识,为胶东中生代金成矿作用提供新视野。Neoproterozoic granitic gneisses are widely developed in the Sulu UHP metamorphic belt, which are commonly considered to have affinity with the Yangtze Craton. Based on new survey data and previous researches, this paper puts forward a new insight that the Neoproterozoic granites were the product of the continental breakup of the North China Craton in the Neoproterozoic, which deeply subducted southward as the continental margin of the Jiaobei Terrane during the Triassic collision between the South and North China blocks. Several lines of evidence are shown as follows:(1) The Neoproterozoic granites intruded into the metamorphic rocks of the Jiaobei Terrane of the North China Craton, and the Wulian-Jimo-Muping fault zone is not the initial boundary between the North Sulu UHP Metamorphic Belt and the Jiaobei Terrane.(2) The Neoproterozoic granitic gneisses contain a large amount of crustal rocks from the Jiaobei Terrane, recording the cratonization event of ~1.85 Ga in the North China Craton.(3) There is no Triassic arc magmatic record in the Jiaobei Terrane, but abundant Neoproterozoic inherited zircons have been identified in the Late Jurassic granites.(4) It is evident that the southeastern margin of the Jiaobei terrane underwent Triassic metamorphic event of amphibolite facies, consistent with Triassic subduction.(5) Regional geophysical information indicates that the deep crust of the North Sulu UHP metamorphic belt belongs to the North China Craton and its NE trending tectonic direction obliquely cut by the Wulian-Jimo-Muping fault. The new consideration will improve understanding the Neoproterozoic evolution of the North China Craton and the formation process of the Dabie-Sulu metamorphic belt, providing a new perspective for Mesozoic gold mineralization in the Jiaodong Peninsula.

关 键 词：华北克拉通 胶北地块 苏鲁超高压变质带 新元古代花岗片麻岩 构造属性 

分 类 号：P588.345[天文地球—岩石学] P548[天文地球—地质学]