南天山:晚古生代还是三叠纪碰撞造山带?

South Tianshan:a Late Paleozoic or a Triassic orogen?

伊犁-哈萨克斯坦板块和塔里木-卡拉库姆板块之间的南天山造山带是‘中亚型造山带’的典型代表之一,经历了复杂的构造演化与地壳增生过程。传统上,它被视为华力西期褶皱带或晚古生代碰撞造山带。但近年来,部分学者提出它可能为三叠纪碰撞造山带。本文在综述南天山造山带的蛇绿岩、高压变质岩、花岗岩类等方面研究成果的基础上,讨论了其碰撞造山的时限。我国境内南天山西段碰撞造山可能开始于早石炭世(345Ma),结束于晚石炭世末(300Ma左右)。二叠纪时期,南天山至整个中亚地区进入后碰撞演化阶段。现有资料证实南天山为一晚古生代碰撞造山带,并非一三叠纪碰撞造山带。

The South Tianshan Orogen between the Yili-Kazakhstan and Tarim-Karakum plates is one of the representatives of the Central-Asia type＇ Orogen and has undergone complicate tectonic evolution and crustal growth processes. It has been traditionally regarded as a Hercynian foldbelt or a Late Paleozoic collisional orogenic belt. However, some researchers have proposed that it may be a Triassic collisional orogenic belt recently. Here, we have summarized the age dating data of ophiolites, high-pressure metamorphic rocks and granites and discussed its collisional time. The collisional orogenesis in the western segment of Chinese South Tianshan Orogen may start in early Carboniferous （345Ma） and end at the end of late Carboniferous （ca. 300Ma）. The South Tianshan and the whole Central Asia may have evolved into a post-collisional stage in Permian. The data obtained up to now have demonstrated that the South Tianshan Orogen is a late Paleozoic collisional orogenic belt, not a Triassic one.