跃进山杂岩的地质年代学和地球化学证据及其构造演化意义  

Geochronological and geochemical constraints from the Yuejinshan Complex and its implications for the tectonic evolution of Northeast China

作　　者：韩伟 冯志强[1] 刘永江 周建波[4] 李小玉 张铁安 范修山 HAN Wei;FENG ZhiQiang;LIU YongJiang;ZHOU JianBo;LI XiaoYu;ZHANG TieAn;FAN XiuShan(Department of Earth Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Frontiers Science Center for Deep Ocean Multispheres and Earth System,MOE Key Lab of Submarine Geoscience and Prospecting Techniques,College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China;College of Earth Sciences,Jilin University,Changchun 130061,China;Heilongjiang Geological Science Institute,Harbin 150080,China)

机构地区：[1]太原理工大学地球科学与工程系,太原030024 [2]中国海洋大学深海圈层与地球系统前沿科学中心,海底科学与探测技术教育部重点实验室,海洋地球科学学院,青岛266100 [3]青岛海洋科学与技术国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266237 [4]吉林大学地球科学学院,长春130061 [5]黑龙江省地质科学研究所,哈尔滨150080

出　　处：《岩石学报》2022年第8期2489-2509,共21页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42130305、42072230、41602235、42002227);博士后基金项目(2019M661060);泰山学者计划(ts20190918);青岛市创新领军人才计划(19-3-2-19-zhc);青岛海洋科学与技术国家实验室鳌山科技创新计划项目(2015ASKJ01);国家重点研发计划项目(2017YFC0601300-01);国家重点基础研究发展计划项目(2013CB429802)联合资助。

摘　　要：那丹哈达地体是中国境内唯一保存的古太平洋板块俯冲-增生的直接记录,包括跃进山杂岩和饶河增生杂岩。跃进山杂岩出露于那丹哈达地体的西缘,属于地体早期阶段的增生产物,对揭示古太平洋板块的俯冲-增生历史以及古亚洲洋构造域、泛大洋和古太平洋构造域之间的转换过程具有重要意义。本文通过野外地质调查明确了跃进山杂岩是一套构造混杂岩,主要由硅质岩、石英片岩、大理岩、二云母片岩、石英-云母片岩、变玄武岩、辉长岩、纯橄榄岩、异剥橄榄岩和单斜辉石岩组成。LA-MC-ICPMS锆石年代学测试结果表明变玄武岩原岩和辉长岩的形成时代分别为303±2Ma和278±2Ma,此外前人报道了跃进山杂岩中最年轻的玄武岩形成于232±5Ma,这些年代学研究成果限定了镁铁质-超镁铁质岩形成于303~232Ma。大量地球化学研究数据证实了跃进山杂岩中的玄武岩为洋中脊玄武岩(MORB)和洋岛玄武岩(OIB)。糜棱岩化绿泥石-绢云母板岩的绢云母^(40)Ar/^(39)Ar测试结果为193±1Ma,根据跃进山杂岩中最年轻的原岩时代为~220Ma,本文限定了跃进山杂岩的最终就位时代为220~193Ma。结合中国东北地区中生代增生杂岩及佳木斯地块和松辽地块东缘晚古生代至中生代的岩浆弧,本文揭示了中国东北地区古亚洲洋和泛大洋构造域向古太平洋构造域的转换发生在晚三叠世至早侏罗世。The Nadanhada Terrane,the only direct record of Paleo-Pacific Plate subduction in NE China,is divided into Yuejinshan and Raohe accretionary complexes.The Yuejinshan Complex is considered as the first stage accretion of the Nadanhada Terrane.It can provide vital insights into the subduction-accretion of the Paleo-Pacific Plate and transition among the Paleo-Asian Ocean,the Panthalassa,and the Paleo-Pacific tectonic regimes in NE China.Field investigations define that the Yuejinshan Complex is a suit o tectonic mélange and consists of siliceous rocks,quartz schist,marble,two-mica schist,quartz-mica schist,meta-basalt,gabbro,dunite,wehrlite and clinopyroxenite.Zircon LA-MC-ICPMS results define two ages of 303±2Ma and 278±2Ma from meta-basalt and gabbro samples,respectively.These results,together with the youngest meta-basalt of 232±5Ma from the previous study,indicate tha the mafic-ultramafic rocks were formed at 303~232Ma.A summary of geochemistry data demonstrates that the meta-basalts have enriched mid-ocean ridge basalts,normal mid-ocean ridge basalts,and ocean island basalts affinities.Sericite ^(40)Ar/^(39)Ar data from a mylonitic chlorite-sericite slate sample give an age of 193±1Ma.This result,combined with the youngest protolithic age of ca.220Ma,constrains the final emplacement of Yuejinshan Complex at ca.220~193Ma.These pieces of evidence,in combination with the Mesozoic accretionary complexes in NE China and Late Paleozoic-Mesozoic magmatic arcs in the eastern margins of Jiamusi and Songliao blocks,suggest that the transition from the Paleo-Asian Ocean and the Panthalassa tectonic regimes to the Paleo-Pacific tectonic regime in NE China took place in the Late Triassic-Early Jurassic.

关 键 词：那丹哈达地体 跃进山杂岩 古太平洋板块 增生杂岩 构造域转换 

分 类 号：P588.145[天文地球—岩石学] P597.3[天文地球—地质学]