博格达山晚古生代坳拉谷(Aulacogen)的初步研究

博格达地区在晚古生代不是与哈尔里克相联的岛弧,而是坳拉谷.它发育较完整的滨浅海→陆棚→陆坡→坡角→盆地平原相的沉积相序.建造类型和充填序列与国内外坳拉谷很相似,而与岛弧建造相差甚远.早期具多旋回的火山喷发,中期发育多种重力流沉积组分,晚期出现复理石和磨拉石建造.东与兴蒙大洋相联,西端伸入准噶尔小板块内部.从中泥盆世开始由巴里坤一带逐渐向乌鲁木齐地区发育.

INITIAL STUDIES ABOUT BOGDA MT. LATE PALAEOZOIC AULACOGEN

In the late Palaeozonic.Bogda was not a island arc which connected with Haer-lick island arc, was a aulacogen.This aulacogen initiated at the middle Devonian and closed in the late Permian, East, It connected with Xinmeng ocean and extended into the Junggar plate in the west. Facies, volcanic rocks, strata and so on indicat this aulacogen devolopmen-ted from east to west.Its formations and vertical sequence are: volcanic-sedimentary formation, carbonate-terrigenous fragment formation, volcanic-carbonate-fragment rock complex formation, brat siliceous-mud formation, flysch formation, molasse formation, relevant sedimentary environments was shore, shelf, slope, flat, slope , shelf, shore, continental. These samilar with other aulacogens in home and abroad. This imply that they had samilar tectonic setting and evolution.