华北克拉通阜平杂岩新太古代-古元古代多期地质事件及其构造性质  

Neoarchean-Paleoproterozoic Multi-Stage Geological Events and Their Tectonic Implications in the Fuping Complex, North China Craton

作　　者：杜利林[1] 杨崇辉[1] 宋会侠[1] 王建龙 段庆松 黄智强 程海峰 耿元生[1] 任留东[1] Du Lilin;Yang Chonghui;Song Huixia;Wang Jianlong;Duan Qingsong;Huang Zhiqiang;Cheng Haifeng;Geng Yuansheng;Ren Liudong(Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;histitute of Regional Geological Survey of Hebei Province,Langfang 06500,China)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]河北省区域地质调查院,河北廊坊065000

出　　处：《地球科学》2020年第9期3179-3195,共17页Earth Science

基　　金：国家自然科学基金项目(Nos.41772191,41572175);中国地质调查局地质调查项目(No.DD20190003)。

摘　　要：本文收集了阜平杂岩新太古代早期-古元古代晚期基底岩石的岩石地球化学、锆石U-Pb年代学、同位素地球化学和变质作用资料,以期对阜平杂岩早寒武纪演化历史进行初步总结.阜平新太古代早期~2.7 Ga片麻岩原岩为英云闪长岩,具有TTG质片麻岩的地球化学特征;其锆石εHf(t)具有较高的正值(+5.44^+7.50),单阶段模式年龄为2 745~2 824 Ma,表明新太古代早期为阜平杂岩强烈的地壳生长时期.新太古代晚期片麻岩的时代集中于2 543~2 484 Ma,主要岩石类型为英云闪长岩-奥长花岗岩-花岗闪长岩(TTG),同时区域内还存在二长花岗岩.TTG质片麻岩的εNd(t)值为-1.64^+0.96,单阶段模式年龄为2.76~3.04 Ga;锆石εHf(t)值为-1.9^+7.91,单阶段和两阶段模式年龄分别为2 546~2 888 Ma和2 548~3 119 Ma.这些TTG岩石主要为新太古代早期岩石的部分熔融,并有少量中太古代地壳物质参与.近于同期具有岛弧性质的辉长岩和变质作用暗示阜平杂岩新太古代晚期可能经历了俯冲和弧-陆或陆-陆碰撞.古元古代中期(2.1~2.0 Ga)阜平地区花岗质岩浆活动强烈.该阶段花岗岩具有A型花岗岩特征,与同期的火山-沉积岩系形成于华北克拉通古元古代中期伸展的陆内裂谷环境中.阜平杂岩中基性麻粒岩包体记录的变质作用时代为1.89~1.85 Ga,并具有顺时针演化的P-T轨迹,其代表了古元古代晚期裂谷闭合的陆内造山过程,表明华北最终克拉通化.In this paper, we summarize the evolutionary history on Fuping Complex from the early Neoarchean to late Paleoproterozoic by comprehensive analyses of data collected on its geochemistry, zircon U-Pb dating, isotopic geochemistry and metamorphism. It is found that the protolith of ca. 2.7 Ga gneisses are tonalite with the geochemical features of TTG, and zircons in these gneisses show positive εHf(t) values of 5.44 to 7.50, with single stage model age(TDM) of 2 745-2 824 Ma, which indicates the intensive crustal growth in early Neoarchean in the Fuping Complex. The late Neoarchean gneisses yield the age of 2 543-2 484 Ma and are mainly composed of tonalite-trondjemite-granodiorite(TTG) besides some monzogranite. TTG gneisses have εNd(t)values ranging from-1.64 to +0.96, with single stage model age(TDM) of 2.76-3.04 Ga, and zircon εHf(t) of-1.9-+7.91,with single stage model age(THf1) and two stage model age(THf2) of 2 546-2 888 Ma and 2 548-3 119 Ma, respectively. Thus,these TTG are derived from partial melting of the early Neoarchean rocks with some addition of Mesoarchean crust. Gabbro coeval with TTG gneisses displays the features of island arc magma and ca. 2.5 Ga metamorphism in Neoarchean supracrustal rocks,suggesting that the Fuping Complex underwent subduction and arc-continent or continent-continent collision in late Neoarchean.2.1-2.0 Ga granitoids widely occur in the Fuping Complex with the feartures of A-type granite and the simultaneous volcanicsedimentary rocks formed intra-continental rift environment in middle Paleoproterozoic. Mafic granulite enclaves in the Fuping Complex yield metamorphic age of 1.89-1.85 Ga and show clockwise P-T paths, which represents closure of intra-continent rifts and cratonization of the North China Craton in late Paleoproterozoic.

关 键 词：阜平杂岩 新太古代早期-古元古代晚期 TTG片麻岩 A型花岗岩 P-T轨迹 克拉通化 地球化学 

分 类 号：P581[天文地球—岩石学]