GPS velocity field for the Tien Shan and surrounding regions

Measurements at similar to 400 campaign-style GPS points and another 14 continuously recording stations in central Asia define variations in their velocities both along and across the Kyrgyz and neighboring parts of Tien Shan. They show that at the longitude of Kyrgyzstan the Tarim Basin converges with Eurasia at 20 +/- 2 mm/yr, nearly two thirds of the total convergence rate between India and Eurasia at this longitude. This high rate suggests that the Tien Shan has grown into a major mountain range only late in the evolution of the India-Eurasia collision. Most of the convergence between Tarim and Eurasia within the upper crust of the Tien Shan presumably occurs by slip on faults on the edges of and within the belt, but 1-3 mm/yr of convergence is absorbed farther north, at the Dzungarian Alatau and at a lower rate with the Kazakh platform to the west. The Tarim Basin is thrust beneath the Tien Shan at similar to 4-7 mm/yr. With respect to Eurasia, the Ferghana Valley rotates counterclockwise at similar to 0.7 degrees Myr(-1) about an axis at the southwest end of the valley. Thus, GPS data place a bound of similar to 4 mm/yr on the rate of crustal shortening across the Chatkal and neighboring ranges