Cenozoic uplift and exhumation of the central South Tian Shan, Kyrgyzstan

The central South Tian Shan, marked by high elevation, high relief, an uplifted relict landscape and interspersed intermontane basins, offers an ideal setting to study the far-field tectonic response to Indian-Asian convergence, and the interplay of topographic growth, erosion and climatic aridification since the late Cenozoic. Previous thermochronology studies from the highest massifs of the central South Tian Shan - the Khan Tengri and Pobedi massifs - reported accelerated exhumation since the Late Miocene (~ 10 Ma), linked to the reactivation of inherited structures propagating towards the Tarim Basin to the south. Little is known about the spatial distribution, timing and rates of erosion along the main fault structures in this region. To better address this question, we study exhumation associated with the Pobedi Thrust, a major Paleozoic fault with significant inferred Late Cenozoic reactivation. New apatite and zircon (U-Th-Sm)/He (AHe and ZHe) as well as apatite fission-track (AFT) data was collected along an elevation profile from both the hanging wall and footwall of the western branch of the Pobedi Thrust to quantify the low-temperature thermal history. 
In contrast to enhanced Late-Miocene exhumation recorded in the Khan Tengri and Pobedi massifs, our samples from approximately 100 km to the west indicate dominant Mesozoic cooling and minimal Cenozoic exhumation, despite the region’s high (> 4 km) topography and significant (> 2 km) relief. Our southernmost sample provides a hint of exhumation associated with the South Tian Shan thrust (i.e., Maidan Fault), showing Late Paleogene AHe ages. 1D thermal history modeling suggests a phase of accelerated cooling of valley-bottom samples during the Late Miocene. Consistent with thermochronology data, mapping and interpolation of low-relief surfaces indicate Cenozoic tilting and deformation of the pre-Oligocene relict topography. These findings highlight spatially variable exhumation along the Pobedi Thrust and Maidan Fault and provide new insights into the complex Cenozoic tectonic activity of the central South Tian Shan and long-term landscape evolution processes.