Abstract: There are two ophiolite belts, Armantai and Kelamaili ophiolite belts, in northeastern border of the Junggar basin, Xinjiang. Ages of the ophiolite and geological time of their emplacement of these two ophiolite belts are still not clear though many research works have be done since 1981. According to new data of isotopic age determination, microfossils in the ophiolite suite and regional tectonic analysis, this paper get following new knowledge: geologic time of development of these two palaeo-oceans representing by two ophiolite belts were close, and it might be from late Neo-proterozoic to early Silurian. The nascent oceans were formed in late Neo-proterozoic. The oceans were in a period of great prosperity from Cambrian to early-middle Ordovician. And they were withered and closed from late Ordovician to early Silurian. This new knowledge is important to reconstruction of Palaeo-Asian Ocean and understand continental crust evolution of Northern Xinjiang.

Key words: Eastern Junggar, ages of ophiolite, tectonic significance

摘要： 讨论了位于新疆准噶尔盆地东北缘的克拉麦里和阿尔曼太两条蛇绿岩带。侧重从蛇绿岩自身的同位素定年、伴生组分的微体古生物和蛇绿岩带的区域构造等方面系统阐述这两条蛇绿岩带的时代。作者得到的新认识是：这两条蛇绿岩带所代表的古洋发育的时代相近，可从新元古代晚期开始孕育，发育的鼎盛时期是寒武纪至早、中奥陶世，晚奥陶世到早志留世为其萎缩、闭合时期。这个新认识在重建古亚洲洋和认识北疆大陆地壳演化历史方面都有重要意义。

关键词: 东准噶尔, 蛇绿岩时代, 大地构造意义