Contemporary localized orogenic process along the central segment of Altyn Tagh Fault using continuous GPS observation in Northern Tibetan Plateau
Monday, 15 December 2014
Modern space geodesy with high-precision continuous GPS time-series data can reveal contemporary slow tectonics processes and crustal deformations in three dimensions within several years temporal scale in localizable region of continents boundary, accompanying with mountain building in geological temporal scale. 11 continuous GPS stations have been installed crossing the central segment of Altyn Tagh fault and Qimen Tagh thrust fault near Mangnai town of Qinghai province in northern margin of Tibetan Plateau. Within approximately 2.5 years time stage, we analyze and eliminate common mode errors of residual time series through considerations of correlation analysis with seasonal temperature and mass loading in localizable basins, including of southwestern part of Qaidam Basin, Xorkol basin and Ayakkum keli basin with identical elevation and climate conditions in the southern uninhabited region of Qimen Tagh Mountain. Thus, we estimate a approximate horizontal velocity of 6-8mm/yr. along central segment of Altyn Tagh fault and vertical relative velocity of 1~2mm/yr. near the peak of Altyn Tagh mountain using continuous GPS stations, crossing the central segment of Atlyn Tagh Fault with respect to the lowest velocity of GPS station which is noted as ATFD, while it might be on the Qimen Tagh thrust fault plane. Some analysis show that crustal uplift velocity profile is better curvilinear correlation with the topography of Akato Tagh Mountain, which is defined as major orogenic belt in Northern Tibetan Plateau. We analyze geological setting and deformation model among Akaoto Tagh bend, Kadzi Fault and Huatugou fold. The result indicates modern episode of Akato Tagh is uplifted with left lateral oblique slip affected by tectonic activity between Qimen Tagh and central segment of Altyn Tagh Fualt, accompanying with the collision between India and Eurasia. We estimate a sustained uplift and localized orogenic process is still occurred, according to explicitly constrains between our continuous GPS records in short-term geodetic observation and some terraces studies of Yaziquan spring within long-term geological temporal scale since at least Quaternary near the norhtern front of Qimen Tagh Mountain .