地质通报2024，Vol.43Issue(12)：2162-2180,19.DOI:10.12097/gbc.2024.07.070
中国阿尔泰造山带地壳改造与成熟化:岩浆-构造-变质视角
Crustal reworking and maturation in the Chinese Altai orogenic belt:Insights from magmatism,deformation and metamorphism
摘要
Abstract
Giant accretionary complexes form at active margins by scraping off oceanic sediments from the subducting plate.Whether or not those compositionally complicated accretionary complexes would be ultimately transformed into mature continent crust remains an unsolved question that calls for further investigation.The Chinese Altai section of the Central Asian Orogenic Belt(CAOB),the largest accretionary orogenic belt on the earth,preserves complicated tectono-thermal geological records and is characterized by formation of mature continental crust,making it a natural laboratory for studying the reworking of accretionary complexes and their evolution into mature continental crust.This paper focuses on the main orogenic period(Silurian-Devonian)of the Chinese Altai and systematically summarizes its recent research progresses in terms of metamorphism-deformation,anatexis,and granitization.① The Ordovician accretionary complex underwent multiple-stage deformation involving compression-extension-compression during the Silurian-Devonian period,accompanied by intense metamorphism and widespread anatexis during the extensional deformation stage;② The Ordovician accretionary complexes and most Silurian-Devonian granites in the region exhibited significant similarities in their geochemical characteristics.More importantly,the chemical compositions of Silurian-Devonian granites resemble those of the modelled partial melts of the accretionary complex under regional anatexis P-T conditions.③ Regional deformation processes facilitated crustal differentiation and the formation of mature continental crust.Together with regional available data,this contribution proposes that the intense crustal reworking during the Silurian-Devonian of the Chinese Altai Orogenic Belt was related to changes in the dynamics of the related supra-subduction system.The cyclic switching between subduction advance and retreat in accretionary orogenic belts could lead to changes of regional stress field and provide anomalous heat source for crustal anatexis,thus control the processes of crustal anatexis and mass redistribution.In these regards,anatexis of accretionary complexes,plays a pivotal role on transformation of active continental margin sediments into compositionally differentiated mature continental crust.This may be a key mechanism contributing to the peripheral continental growth in accretionary orogenic belts in general.关键词
中国阿尔泰/变形-变质/深熔作用/地壳分异/成熟大陆地壳Key words
Chinese Altai/deformation-metamorphism/anatexis/crustal differentiation/mature continental crust分类
天文与地球科学引用本文复制引用
汪晟,蒋映德,孙敏,Karel Schulmann,袁超..中国阿尔泰造山带地壳改造与成熟化:岩浆-构造-变质视角[J].地质通报,2024,43(12):2162-2180,19.基金项目
国家自然科学基金项目《中国阿尔泰造山带志留—泥盆纪挤压-伸展构造体制转换年代学研究》(批准号:42302052)、中国科学院国际合作局一带一路专项《中哈俄蒙增生体系地壳演化与成矿耦合》(编号:132744KYSB20190039)、安徽建筑大学校引进人才及博士启动基金项目《复合造山带早期构造转换过程年代学限定——以中国阿尔泰为例》(编号:2022QDZ30)和安徽省高等学校科学研究项目《荒漠沙物源解析及针对性资源化、功能化研究》(编号:2024AH050248) （批准号:42302052）
