挤压构造带变形样式的热年代学诊断
摘要
<p indent="0mm">Tectonic deformation, one of the main endogenic forces, dominates the lithospheric strain distribution and landscape evolution. Under the influences of both endogenic and exogenic processes, variable thin- and thick-skinned tectonic architectures developed in different compressional thrust belts, which is characterized by different spatio-temporal patterns of rock exhumation that can be recovered from thermochronometric age data. Given that the explanation for the thermochronologic data is nonunique, the application of such methods for exploring the deformation should take into account other geological and geophysical information. This study aims to explore the thermochronometric diagnostics of the various manners of deformation using five end-member examples in the Neo-Tethys orogenic belt, including the Himalayan frontal reverse and hinterland normal faulting, Alpine thick-skinned tectonics, Eastern Carpathian in-sequence thin-skinned thrusting, the Longmenshan basement-involved out-of-sequence thin-skinned thrusting, and the shallow folds in the southwestern Sichuan Basin. Comparison between the thermochronometric swath and crustal architecture of the Himalayan fold-and-thrust belt, it is found that the Miocene and younger thermochronometric ages are distributed south of the Yarlung Tsangpo suture zone, with the youngest between the south-verging Main Central Thrust and north-verging Southern Tibetan Detachment, suggesting more rapid and significant rock exhumation and extrusion between those two faults than in the suture zone and hinterland regions. The structural and thermochronometric swath across the relatively Alpine Orogen displays Miocene and younger ages and thus much more rock exhumation in the core part <sc>(~80 km</sc> wide) of the orogen than its marginal thrust belts, consistent with the doubly-vergent thrusting in both the southern and northern margins of the orogen. Such a pattern differs from that of the wide Himalayan belt, where