中国天山西段尤路都斯盆地构造地质特征

THE STRUCTURE GEOLOGY CHARACTERISTIC OF YULTUZ BASIN IN WESTERN TIANSHAN MOUNTAINS

尤路都斯盆地大地构造背景位于塔里木板块与伊犁—伊塞克湖板块的缝合位置，是天山西段南天山与中天山之间一个狭长型山间盆地，EW向延伸。北抵那拉提山，南为萨阿尔明山西段，面积7 600 km2。中间被NWW向延伸的艾尔宾山分隔为大、小尤路都斯盆地。其中大尤路都斯盆地面积4 700 km2，小尤路都斯盆地面积2 900 km2，现代盆地内为山间堆积平原，具有中间低凹、四周高的地形特征，海拔高程2 400(2 500 m。现今的盆地实际上是一个第三纪发育的断陷沉积盆地，其基底是前震旦系结晶基底和古生界褶皱基底；盆地边界及盆内各二级构造带主要受断层的控制；盆地的构造格架可划分大、小尤路都斯两个断陷，且大尤路都斯断陷可分为北部凹陷区、巴音背斜构造带、南部斜坡带等3个次级构造单元，巴音背斜构造带为大尤路都斯盆地内的最大二级构造单元；小尤路都斯断陷自北向南分布有北部(乌鲁木齐牧场)凹陷、西部凹陷、东南部凹陷、中部隆起带等三凹一隆4个二级构造单元。

Yultuz Basin is located subduction and suture zone between Tarim plate and Yili-Yisaikehu plate by macroscopic structure background, and it is situated between South Tianshan and Middle Tianshan in the west part of Tianshan Mountain, It is narrowed intermountain basin. Nowadays the basin was developed rift-depress in Tertiary period, its basement have pre-Sinian system crystal basement、Palaeozoic Erathem fold basement. Basin borderline and the secondly structure belts is controled by faults. The basin is divided big Yultuz and small Yultuz rift-depress, big Yultuz rift-depress is consisted north depress, Bayin structure belt, South slope belt etc three second structure units; small Yultuz rift-depress is also divided north depress, western depress, south-eastern depress, middle upwarp structure belt etc four secondly structure units.