摘要
勉略缝合带是华北与华南大陆于印支期完成拼合的主要拼接带,在中国大陆的形成与演化中占据重要地位。但是,勉略带的东、西延伸至今没有确定的结论,尤其陕西省勉县以东到湖北随州一带,还没有找到确凿的缝合带的证据。已发表的文章多认为勉略带在勉县以东到达宁陕县两河口之后向南转折,沿着高川岩片的位置顺大巴山弧形构造带向东延伸到湖北随州一带。本文的研究表明,高川岩片是一个独立于大巴山构造带的外来地质体,称之为高川地体。高川地体是一个由近南北向右行走滑断层与轴向近南北向的走滑剪切褶皱构造组成的右行走滑构造系统,是大巴山冲断推覆构造向南推覆过程中从原勉略缝合带中挤过来的一片,仅仅是被挟持在大巴山冲断-推覆构造带与大巴山前陆构造带之间的地壳浅层地质体。因此,高川地体现在的位置不能代表勉略带向东的延伸,大巴山弧形构造带也不是中国南北大陆最终碰撞拼贴的位置。
The Mianlue tectonic belt, trending from west to east, was regarded as the suture zone between the North China and South China continent during the Indochina movement and it is very important for the formation and evolution of China continent. But the extension of the belt eastwards and westwards hasn＇t been got an affrmative conclusion. Especially, from east Mianxian of Shaanxi Province to Suizhou of Hubei Province, there have been no any evidences about the suture zone. In previous important papers, it is regarded the Mianlue suture zone turns to south from Lianghekou town of Ningshan County, then it goes through the Gaochuan slab and stretched along the arc belt of Dabashan to Suizhou of Hubei Province eastwards. In our paper, it is proped that the Gaochuan slab is an allochthonous geological terrane and named as the Gaochuan Terrane. The Gaochuan Terrane is a dextral strike slipping system composed of some strike slipping faults trending in nearly south to north and some strike slipping shearing folds with axes trending in nearly south to north. It is suggested that the terreane was wedged into the Dabashan belt from original the Mianlue suture zone when the Dabashan thrust belt thrust towards south. It is only a shallow geological slab of the crust under duress between the Dabashan thrust belt and the Dabashan foreland belt. The present location of the Gaochuan terrain doesn＇t represent the eastern extension of the Mianlue suture zone. Therefore, the arc Dabashan tectonic belt isn＇t the location of the final collision of the south and north China continents.
出处
《地质通报》
CAS
CSCD
北大核心
2008年第12期2031-2044,共14页
Geological Bulletin of China
基金
国家自然科学基金项目(编号:40830314、40272097)资助。
关键词
大巴山构造带
高川地体
勉略缝合带
Dabashan tectonic belt
Gaochuan Terrane
Mianlue suture zone
