Paleozoic tectono-metallogeny in Tianshan-Altay area，Central Asia

Abstract：Paleozoic tectonics and endogenic metallogeny in Tianshan-Altay area of Central Asia constitute an important research topic in geology. The Altay area, as a collision zone of the Early Paleozoic (500-397 Ma), and the Tianshan region, as a collision zone of the early period in Late Paleozoic (Late Devonian - Early Carboniferous, 385-323 Ma), resulted from nearly NS-trending shortening and collision（according to recent magnetic orientation）. In the Late Devonian-Early Carboniferous (385-323 Ma), regional NW-trending faults exhibited features of the dextral strike-slip motion in Altay area and Junggar basin. In the Tianshan area, however, nearly EW-trending regional faults caused motions of the thrusts, thus belonging to the collision period of the Tianshan Mountains. However, in the Late Carboniferous-Permian (323-260 Ma), these areas suffered from weaker eastward compression, influenced by the long-distance effect of the Ural collision zone, which converted existent NW-trending faults into sinistral strike-slip in Altay and Junggar areas, and also converted existent nearly EW-trending faults into dextral strike-slip in Tianshan area. The rocks of that area in the Late Carboniferous - Permian period were moderately ruptured into a certain tension-shear form, thus forming a number of world-famous giant endogenic metal ore deposits in Tianshan-Altay area. As to the Central Asian continent, the most powerful collision period may not coincide with the most favorable endogenic metallogenic period. Therefore the “orogenic metallogeny hypothesis” should be treated with caution in that area.