Semi-rigid behavior of the Gonghe Block, northeastern Tibetan Plateau, inferred from cosmogenic 10Be erosion rates along the Qinghai Nanshan

How crustal strain is distributed and propagated within continental interiors remains a central question in continental tectonics and mountain building. Framed by the East Kunlun Fault, Altyn Tagh Fault, and North Qilian thrust belt, the northeastern Tibetan Plateau represents a key region to investigate how deformation is transferred across an evolving plateau margin. The Qinghai Nanshan Fault, situated within the Gonghe Block, plays a critical role in mediating strain transferring between the plateau interior and its northern foreland. Cosmogenic 10Be concentrations in river sediments from ten small catchments were measured along the southern flank of the Qinghai Nanshan in this study. Assuming a near-steady-state topography, the derived catchment-wide erosion rates can be interpreted as the first-order minimum proxies for the fault’s vertical slip rate. The results indicate a vertical slip rate of ∼0.05 mm/a for the central segment of the Qinghai Nanshan Fault, whereas the recalculation of previously published data suggests a rate of ∼0.1 mm/a for the western segment. These estimates indicate that both segments are characterized by low late Quaternary vertical slip rates that are broadly comparable in magnitude, reflecting weak but persistent deformation within the Gonghe Block interior. Integrating our results with prior geodetic and geologic studies, it can be inferred that the Gonghe Block behaves in a semi-rigid manner, with most strain localized along block-bounding structures and limited yet persistent deformation along the internal thrust faults (e.g., the Qinghai Nanshan Fault). More broadly, the northeastern Tibetan Plateau deforms in a pervasive but non-homogeneous manner, as deformation is widespread but not uniformly distributed.