摘要
内蒙古白云鄂博地区阿木山组砂岩的碎屑锆石LA—ICP—MSU—Pb同位素年代学分析结果显示，早二叠世阿木山组的碎屑锆石主要由古生代（354—479Ma）和元古宙（934—1941Ma）及少量的古元古一新太古代（2330～2688Ma）碎屑锆石组成。结合该组模式剖面的实测和照化石再研究，笔者认为，阿木山组合934～1941Ma碎屑锆石的砂岩物源来自于佳蒙地块，而非华北板块；含有Spha．eroschwagerina化石带的阿木山组应当属于佳蒙地块的大陆边缘沉积。这一认识对于研究西拉木伦河缝合带和古亚洲洋的构造演化、以及将内蒙古草原一松花江地层区划归佳蒙地层大区等具有重要意义。
Based on the study of the detrital zircon U-Pb isotopic dating of the sandstone from the type section of Amushan Formation in Bayan Obo area, Inner Mongolia, the zircons from the Lower Permian sandstone include of ages of 354 ～479 Ma （Paleozoic）, 934 ～ 1 941 Ma （Proterozoic） and 2 330 ～ 2 668 Ma （ Siderian- Neo- archean）. Combined with the fusulinids of the type section, the authors conclude that the components of Proterozoic zircons （934 ～ 1 941 Ma） in the sandstone of the Amushan Formation should came from the Jiamusi -Mongolia block, rather than from the North China Plate. The Amushan Formation bearing fusulinids of the Biozone of Spha- eroschwagerina mights be deposited at the continental margins of the Jiamusi-Mongolia block. The present research would be helpful for investigating the tectonic evolution of the Xar Moron River Suture and the Paleo -Asian Ocean, and gives great support to assign the Inner Mongolia Grassland -Songhua River Stratigraphic Region to the Jiamusi - Mongolia Stratigraphic Superregion.
出处
《世界地质》
CAS
2015年第2期259-272,共14页
World Geology
基金
中国地质调查局项目(121201120966
1212011121086)资助
关键词
阿木山组
碎屑锆石
U—Pb同位素测年
佳蒙地块
地层区划
Amushan Formation
detrital zircons
U-Pb isotopic dating
Jiamusi- Mongolia block
strati-graphic regionalization
