天山两侧前陆冲断系构造样式与前陆盆地演化

Evolution and Structural Style of Tianshan and Adjacent Basins, Northwestern China

天山造山带呈W形结构,由V形结构的南天山和北天山复合而成。两者具有不同的造山模式。南天山自震旦纪开始张裂,扩展为被动大陆边缘和洋盆,在志留—泥盆纪时俯冲,延续至石炭纪碰撞,旋回时限达400Ma以上,应属威尔逊旋回造山模式。北天山应自泥盆纪开始弧后扩张,形成泥盆—石炭纪边缘海小洋盆,在石炭纪晚期闭合,旋回时限约100Ma,应属于弧后造山模式。前陆褶皱-冲断带的变形主要分为两期:早期由于楔冲作用所产生的薄皮褶皱和冲断层;后期则由于天山隆升重力滑动所产生的褶皱及重力正断层和逆断层。

The Tianshan orogenic belt has a W-shape, composed of the V-shape Southern Tianshan and Northern Tianshan with different orogenic models. The Southern Tianshan broke off from the Sinian, forming a passive Continental margin and ocean, and closed during Silurian and Devonian. It belongs to the Wilson cycle orogenic model. The net duration is abo 400 Ma. The Northern Tianshan began back-are spreading during Devonian, forming the Devonian-Carboniferous marginal sea, and closed during Late Carboniferous. It belongs to the non-Wilson cycle orogenic model or back-are orogenic model. The duration is abo 100Ma. Deformation of the foreland fold -thrust belt occurred in two stages: in the early stage, folds and thrusts were formed by wedge - thrusting and lateral compression, while in the later stage, folds, gavitational normal faults and reverse faults were formed by the uplift of the Tianshan range and by gravity - gliding.