黑龙江虎林杂岩变形样式与时代:对中国东北东部早白垩世古太平洋板块俯冲的启示  

Deformation pattern and age of Hulin complex in Heilongjiang Province: Implications for subduction of the Palaeo-pacific plate during the Early Cretaceous, eastern NE China

作　　者：梁琛岳[1,2] 刘永江 宋志伟 张骞[1] 杨岩 LIANG ChenYue;LIU YongJiang;SONG ZhiWei;ZHANG Qian;YANG Yan(College of Earth Sciences,Jilin University,Changchun 130061,China;MNR Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Jilin University,Changchun 130061,China;MOE Key Lab of Submarine Geoscience and Prospecting Techniques,Institute for Advanced Ocean Study,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)

机构地区：[1]吉林大学地球科学学院,长春130061 [2]吉林大学东北亚矿产资源评价自然资源部重点实验室,长春130061 [3]中国海洋大学海底科学与探测技术教育部重点实验室,海洋高等研究院,海洋地球科学学院,青岛266100 [4]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

出　　处：《岩石学报》2020年第3期685-702,共18页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2017YFC0601300-01、2017YFC0601401);国家自然科学基金项目(41730210、41872192、41972215);青岛市创新领军人才计划(19-3-2-19-zhc);泰山学者计划(ts20190918)联合资助。

摘　　要：黑龙江虎林盆地位于兴凯地块北部,盆地内部中央隆起区出露一套呈NE走向展布的虎林杂岩,岩石强烈韧性变形,对其变形样式及其动力学背景的探讨,为进一步研究兴凯地块乃至中国东北东部中生代构造属性和古太平洋构造体制下构造演化过程提供一个独特的视角。虎林杂岩主体由云母片岩和侵位其中的花岗质岩脉组成,塑性变形特征明显,发育倾向NW向片麻理,走向NE-SW的低角度矿物拉伸线理。岩石矿物组合、微观构造特征和石英EBSD组构分析显示岩石表现中低温变形样式,变形温度为350~450℃,石英变形机制以位错滑移和膨凸重结晶为主。结合宏观变形样式可知,虎林杂岩早期变形以NW倾向片麻理为标志,指示NW-SE向伸展作用,晚期变形以NE倾伏低角度矿物拉伸线理为标志,指示NE-SW向左行走滑事件。侵位的变形闪长玢岩的锆石年代学研究限定晚期左行走滑事件晚于闪长玢岩就位时间107.0±1.7Ma。早白垩世期间,伊泽奈崎板块(古太平洋)NW向斜向俯冲和板片后撤,导致东北东部乃至整个中国东部NW-SE向伸展,造成大陆岩石圈减薄、岩浆活动和虎林伸展断陷盆地的形成。在早白垩世末(104Ma之后),伊泽奈崎板块高速向欧亚大陆俯冲由NNW转向N,由低角度俯冲替代高角度俯冲,使得中国东部再次遭受区域性挤压,导致虎林杂岩发育大规模NE向压扭性左行走滑变形和持续性隆升。The Hulin basin in Heilongjiang Province is located in the north of the Khanka block.A series of Hulin complex with NE trending emerges in the central uplift zone of the Hulin basin,and all the exposed rocks have strong ductile deformation fabrics.The discussion of the deformation pattern and its dynamic background provides a unique perspective for further understanding the Mesozoic evolution process of the Khanka block and even the eastern NE China under the paleo-Pacific tectonic domain.The Hulin complex is composed of mica schist and intrusive granite which have obvious deformation characteristics with mylonitic foliation and NE-trending subhorizontal stretching lineation.Mineral assemblages,microstructural and quartz EBSD fabrics indicate that the deformation occurred in the low-greenschist facies under low-middle temperatures of 350~450℃.Dislocation creep with subgrain-rotation recrystallization sustained to be the dominant deformation mechanism of quartz.Combining with the mesostructures,two phases of deformation were identified.The early-stage deformation of the Hulin complex is marked by gneiss schistosity that trends NW,which indicates an NW-SE extension,and the late-stage deformation is symbolized by NE-trending subhorizontal stretching lineation,which indicates that a NE-SW sinistral shearing.New zircon U-Pb age of the deformed diorite porphyrite shows that the left strike-slip event is later than 107.0±1.7Ma of its emplacement.During the Early Cretaceous,the NW subduction and roll-back of the Izanagi(paleo-Pacific)plate led to the NW-SE extension in the NE China and even the eastern China,which resulted in the lithospheric thinning and destruction,magmatic activities,and the formation of rift basins including Hulin basin.At the end of the Early Cretaceous(after 104Ma),the Izazaki plate subducted towards Eurasia at a high speed and changed from NNW to N,and replaced high-angle subduction with low-angle subduction,together led to the large-scale NE sinistral strike-slip deformation and sustained upli

关 键 词：虎林杂岩 EBSD 锆石U-PB年龄 虎林盆地 兴凯地块 伊泽奈崎板块 

分 类 号：P542[天文地球—构造地质学] P597.3[天文地球—地质学]