Erosion and asymmetric relief evolution of the Central Asian Pamir Plateau

点击翻译按钮获取中文摘要

Continental plateaus constitute first-order topographic features of Earth’s surface that set basic patterns of climate, ecology, and even culture. Understanding the processes triggering the evolution of plateaus is fundamental to understand the dynamic link between tectonics, climate, and erosion. However, its relationship remains elusive. I propose to study spatial-temporal variations in the plateau uplift and exhumation of the Central Asian Pamir. I want to test, if plateau evolution is only controlled by tectonic and deep crustal processes triggering uplift, topography and relief evolution, or, alternatively, if long-term erosion gradients have played a first-order role in modifying the plateau evolution by dissecting its western and central sectors. For example, it is unknown if climate-enhanced erosion during Pliocene/Quaternary time has caused the relief asymmetry between the western and central compartments of the Pamir plateau as observed today. I propose an integration of multiple low-temperature thermochronometers, and thermo-kinematic models to test two controversial hypotheses related to plateau evolution. I will test, if asymmetry in topographic relief between the western and central Pamir evolved (1) abruptly as a result of rapid incision over the last ~3 Ma, or, alternatively, (2) continuously since the plateau was initially uplifted sometime between 20 and 10 Ma. With ~30 new zircon and apatite (U-Th-Sm)/He, apatite fission-track cooling ages, respectively, extending over two E-W traverses oriented perpendicular to strong climate gradients, I will constrain the spatial and temporal variations in exhumation over geologic timescales. Thereby 3D thermo-kinematic models will simulate the thermal, structural, and erosional evolution of end-member scenarios that test for different plateau evolution histories.