西天山尤路都斯盆地构造演化与原型盆地古环境分析

TECTONIC EVOLUTION OF YULTUZ BASIN WESTERN TIANSHAN MOUNTAINSAND PALEOENVIRONMENTAL ANALYSISON THE PROTOTYPE BASIN

尤路都斯盆地位于天山西段南天山与中天山之间 ,呈 EW向延伸的狭长型山间盆地。通过最新资料研究 ,提出大、小尤路都斯盆地分属不同的板块体系 ,塔里木板块向伊犁—伊塞克湖板块俯冲带沿那拉提断裂至巴音布鲁克 ,沿艾尔宾山南缘向东延伸 ;划分大尤路都斯盆地归属南天山—塔里木板块 ,而小尤路都斯盆地属于伊犁—伊塞克板块。自新元古代以来 ,盆地经历了古生代盆地基底演化阶段、中新生代盆地形成阶段。从晚二叠世开始至中生代 ,那拉提断裂带—艾尔宾山以南是泥盆—石炭系的露头区 ,基本无沉积。构造线以北属中—新生代原型盆地分布范围应该以巴音布鲁克为中心 ,西北延伸至巩乃斯 ,东南到现在的小尤路都斯 ;受断裂控制 ,沿着 NW向断裂体系发育有河流、沼泽。

Yultuz Basin is situated between South Tianshan and Middle Tianshan in the west part of Tianshan Mountains,It is a long narrowed intermountain basin distributed E- W.Studing on the latest data, the author indicates that the Dayultuz and Xiaoyultuz Basins belong to different plate systems,the subduction zone between Tarim plate and Yili- Yisaikehu plate extends eastward along Nalati fault to Bayanbulag and then the south edge of Erbeng Mountain;The Dayultuz Basin belongs to South Tianshan- Tarim plate and the Xiaoyultuz Basin belongs to Yili- Yisaike plate.Since neoproterozoic,the basins have undergone the stages of basemental evolution in poleozoic and basin forming in Meso- Cenozoic from Late Permian to Mesozoic,south to Nalati fault belt- Erbeng Mountain in the outcrop region of Devonian- Carboniferous.There is basically no sediment north to the structural lineament in the prototype basin of Mewso- Cenozoic,the basin takes Bayanbulag as its center,extends northwest to Kunes and southeast to present Xiaoyltuz.Controled by the fault,There is a paleodrainage of river,swamp and sag pond developed along the northwest fractural system