南天山—北山—索伦—长春缝合带的性质与演化  

Nature and evolution of the South Tianshan Mountains—Beishan Mountains—Solonker—Changchun Suture

作　　者：李皓东 周建波[1] 李功宇 王斌[1,2] 陈卓 王红燕 LI Haodong;ZHOU Jianbo;LI Gongyu;WANG Bin;CHEN Zhuo;WANG Hongyan(College of Earth Sciences,Jilin University,Changchun,130061;Shandong Provincial No.6 Exploration Institute of Geology and Mineral Resources,Weihai,Shandong,264209)

机构地区：[1]吉林大学地球科学学院,长春130061 [2]山东省第六地质矿产勘查院,山东威海264209

出　　处：《地质论评》2022年第3期797-816,共20页Geological Review

基　　金：国家自然科学基金资助项目(编号:41730210)的成果。

摘　　要：南天山—北山—索伦—长春缝合带作为古亚洲洋的最终闭合位置,其形成与演化特征一直以来都是中亚造山带相关研究的焦点与热点问题。对于该缝合带形成时代以及俯冲极性等方面的研究,有利于揭示中亚造山带的增生与演化历史,为古亚洲洋构造演化模型的建立提供理论支持。笔者等依据南天山—北山—索伦—长春缝合带内的大地构造背景、构造岩石组成、闭合方式和闭合时代的差异,自西向东将其分为4段:(1)南天山缝合带位于缝合带西段,形成于塔里木板块向北俯冲与哈萨克斯坦—伊犁地块发生拼贴的过程中,根据高压变质年龄、钉合岩体以及不整合盖层等证据来综合分析,其闭合时代应为晚石炭世;(2)北山缝合带位于缝合带中段,形成于敦煌地块和阿拉善地块向北俯冲与北部图瓦—蒙古板块发生拼贴的过程中,根据带内蛇绿岩的年代学证据限定其闭合时代应为早—中二叠世。阿拉善地块北缘的两条蛇绿岩带作为北山缝合带与索伦—长春缝合带之间的连接带,分别代表了古亚洲洋在该区域闭合时形成的缝合带和弧后盆地,其形成时代应当为中二叠世—晚二叠世早期;(3)索伦—长春缝合带位于缝合带中—东段,古亚洲洋在该地区同时发生了南北两侧的双向俯冲,两侧地块在中二叠世—早三叠世完成拼贴;(4)长春—延吉缝合带形成于中三叠世前后华北板块与佳木斯—兴凯地块的俯冲增生过程中,其较西侧索伦—长春缝合带的形成时间(270~250 Ma)晚20~30 Ma。因此长春—延吉缝合带与索伦—长春缝合带的形成时代与构造背景存在显著的差异,不属于其东延部分。在上述分析基础上,笔者等认为古亚洲洋沿南天山—北山—索伦—长春缝合带自西向东发生了4个阶段的演化过程,闭合时代自西向东逐渐变年轻,整个过程从晚石炭世一直持续到了三叠世,其中长春—延�The formation and evolution of the South Tianshan Mountains—Beishan Mountains—Solonker—Changchun Suture, as the final closure position of the Paleo-Asian Ocean, has been the focus of research of the Central Asian Orogenic Belt. Studies on the formation age and subduction polarity of this suture zone can help us to reveal the accretionary and evolutionary history of the Central Asian Orogenic Belt and provide theoretical support for the establishment of a tectonic evolutionary model of the Paleo-Asian Ocean. In this paper, the South Tianshan Mountains —Beishan Mountains —Solonker—Changchun Suture is divided into four segments based on the differences in geotectonic setting, rock composition, closure mode and closure era, and they are, from west to east: the South Tianshan Suture, the Beishan Suture, the Solonker—Changchun Suture, and the Changchun—Yanji Suture. The South Tianshan Suture is located in the western section of this suture zone and is a result of the northward subduction of the Tarim block, which collapsed with the Kazakhstan—Yili block, and it was formed in the Late Carboniferous based on the evidences of high-pressure metamorphic age, intrusive dike and unconformity cover, etc. The Beishan Suture is located in the middle section, formed during the northward subduction of Dunhuang and Alxa blocks, which collapsed with the Tuva—Mongolia block, and it was formed in the Early—Middle Permian based on the chronological evidences of the ophiolites. The two ophiolite belts at the northern margin of the Alxa block, as the connecting belt between the Beishan Suture and the Solonker—Changchun Suture, represent the suture zone and the post-arc basin formed during the closure process of the Paleo-Asian Ocean, and they were formed in the middle Permian—early Late Permian. The Solonker—Changchun Suture is located in the middle—eastern section, where the Paleo-Asian Ocean underwent simultaneous southward and northward subduction in both directions, and the amalgamation of two sides was

关 键 词：中亚造山带 南天山—北山—索伦—长春缝合带 分段演化 俯冲极性 构造域转换 

分 类 号：P542.2[天文地球—构造地质学]