Late Cenozoic structural deformation and tectono-geomorphic features along the Gobi-Tianshan Fault System

Abstract: The Gobi-Tianshan Fault System (GTFS) extending over 700 km long is one of the largest strike-slip faults in the Central Asia Orogenic Belt (CAOB), which was considered to accommodate the eastward extrusion of Tibet. On the basis of tectono-geomorphic interpretation of satellite remote sensing images along GTFS, this study aims to document the Late Cenozoic structural deformation and geomorphic features. Geomorphic features, such as fault scarps, displaced rivers and varied restraining bends, are well developed around the GTFS. Visible fault scarps cutting across Late Cenozoic alluvial sediments, whereas low mountain-front sinuosities and deeply incised narrow canyons in the range front can indicate Late Cenozoic fault activity. The authors identified a ca. 2000 m-long lateral offsets of rivers, which are related to prolonged geomorphic growth of the GTFS. Historical earthquake data are consistent with deforming continental interior region, with tectonic loading shared amongst a network of faults, which indicates a complex earthquake prediction. Meanwhile, three restraining bends were identified in the study area: Karlik Tagh, Gurvan Sayhan and Nemgt Uul, of which the first two restraining bends are located in the two termination zones of the strike-slip fault, whereas the last one occurs in the converging and overlapping position of two separate strike-slip fault segments. Strike-slip fault cutting through the regions of restraining bend mountain ranges might have been an important mountain-building process in the CAOB.