摘要
出露在准噶尔盆地东北缘的老君庙变质岩 ,主要由绿片岩相的石英片岩构成 ,其上残存含前泥盆纪床板珊瑚和海百合茎化石的大理岩。对石英片岩中的白云母进行的4 0 Ar/ 39Ar定年 ,获得了(4 6 1.5± 0 .2 )Ma的坪年龄和 (4 6 2 .0± 4 .1)Ma等时线年龄 ,表明该变质岩的变质时代不晚于中奥陶世晚期 ,准噶尔盆地东部具有前晚奥陶世的陆壳基底。结合区域地质资料 ,推测准噶尔盆地的基底主体是古生代期间的陆块。
The Laojunmiao metamorphic complex, exposed on the northeastern margin of the Junggar basin,consists mainly of quartz schists of greenschist facies, with some marbles bearing pre Devonian tabulates and crinoids resting on it. 40 Ar/ 39 Ar dating of muscovite from the complex yields a plateau age of 461.5±0.2 Ma and an isochron age of 462.0±4.1 Ma, indicating that its metamorphism occurred in the late Middle Ordovician. In combination with regional geology, it is supposed that the basement of the basin is composed of the Paleozoic continental crust.
出处
《中国区域地质》
CSCD
2000年第3期297-302,共6页
Regional Geology of China
基金
国家科技攻关项目资助!(96 - 915 )
关键词
准噶尔盆地
基底
前晚奥陶世
陆壳
Laojunmiao metamorphic complex
muscovite 40 Ar/ 39 Ar dating
basement of the Junggar basin
Paleozoic continental crust
