The general strike of the Tian Shan ranges is East-Northeast, but there are significant deviations, especially near the major Talas-Fergana fault. A striking feature of western Tian Shan is the large number of basins containing Cenozoic rocks, prominent basins include the Fergana Basin in the southwest, the Issyk-Kul Basin in the east and Naryn Basin in the south. On the edges of the Tian Shan, there are foreland basins with Cenozoic sediments several kilometers thick. The Talas-Fergana fault is an active strike slip fault in which Quaternary offset is about 10 km and the total offset since the Paleozoic is about 200 km.