中蒙边境地区主要蛇绿岩带特征及地质意义  

Characteristics and geological implications of the Ophiolite Belts in the Sino-Mongolian Border Region

作　　者：滕学建 付超 李俊建 李志丹 唐文龙 TENG Xuejian;FU Chao;LI Junjian;LI Zhidan;TANG Wenlong(Tianjin Center,China Geological Survey(North China Center of Geoscience Innovation),Tianjin 300170,China)

机构地区：[1]中国地质调查局天津地质调查中心(华北地质科技创新中心),天津300170

出　　处：《华北地质》2024年第3期1-13,共13页North China Geology

基　　金：国家重点研发计划:“蒙古古生代岩浆活动与铜(金钼银)成矿作用(2022YFE0119900)”。

摘　　要：【研究目的】中国与蒙古的交界地区构造位置上位于中亚造山带,沿边境两侧断续出露呈团块、带状分布的蛇绿(混杂)岩带。蛇绿岩作为古大洋岩石圈的残片,是研究岩石圈地幔演化、俯冲带物质循环和重建古地理格局的天然实验室。【研究方法】本文依托中蒙合作1/100万系列地质图件编制项目成果,结合前人针对该地区蛇绿(混杂)岩带的研究成果,进一步厘定中亚造山带的构造演化和恢复其构造格局。【研究结果】在研究区划分出十四条蛇绿(混杂)岩带,综合阐述了其时空分布特征,建立了蛇绿(混杂)岩带的时空分布格架。【结论】研究结果表明,中蒙边境蛇绿岩带自西向东呈年龄逐渐年轻的趋势(新元古代-早二叠世),揭示了中亚造山带西段和东段大洋岩石圈地幔演化的差异性。多数蛇绿(混杂)岩带属于与俯冲作用密切相关的SSZ(supra-subduction zone)型蛇绿岩,但弧前和弧后的构造背景的争议仍需进一步研究加以限定。This paper is the research of ophiolite.[Objective]Ophiolites,as fragments of ancient oceanic lithosphere,serve as a natural laboratory for studying the evolution of the lithospheric mantle,material cycling in subduction zones,and reconstructing paleogeographic patterns.The China-Mongolia border region is located within the Central Asian Orogenic Belt(CAOB),where ophiolite(mélange)belts intermittently crop out along both sides of the boundary,exhibiting blocky and zonal distributions.[Methods]To further clarify the tectonic evolution of the CentralAsian Orogenic Belt and restore its structural framework,this paper relies on the results of the China-Mongolia collaborative 1/1000000 geological map series compilation project,combined with previous studies on the ophiolite(mélange)belts in this region.[Results]Fourteen ophiolite(mélange)belts were identified in the study area.A comprehensive explanation of their spatial-temporal distribution characteristics was provided,and a spatial-temporal framework for the distribution of the ophiolite(mélange)belts was established.[Conclusions]The results indicate that the ophiolite belts along the China-Mongolia border exhibit a trend of progressively younger ages from west to east(Neoproterozoic to Early Permian).This reveals differences in the evolution of the oceanic lithospheric mantle between the western and eastern segments of the Central Asian Orogenic Belt.Most ophiolite(mélange)belts are of the SSZ(supra-subduction zone)type,closely related to subduction processes.However,the tectonic settings of fore-arc and back-arc environments remain controversial and require further study.

关 键 词：中蒙边界 中亚造山带 蛇绿岩 时空分布 构造演化 

分 类 号：P587[天文地球—岩石学] P597.3[天文地球—地质学]