Late Quaternary vertical throw rates along the Gyaring Co fault in central Tibet

Abstract

Although normal components along the strike-slip faults have been widely found in central Tibet, poorly constrained vertical rates impede the recognition of their formation mechanism and tectonic implications. Herein, we systematically obtained spatial distribution of well-defined vertical throw rates along the Gyaring Co fault (GCF) using high-precision unmanned aerial vehicle topographic data and optically stimulated luminescence dating on oblique faulted fans and shorelines. Our integrated data indicated a southeastward decrease in Late Quaternary vertical throw rates from ∼0.12 to 0.05 mm/yr along the GCF. The vertical and horizontal movements of the GCF have shared similar rate gradient and have been partitioned with general steady ratios of 5–7.5 % since the Late Quaternary, which suggests that at least half of the motion on the GCF is accommodated by the southern linked Xainza rift. The vertical throws of the GCF are compatible with the conjugated Wuru Co fault, other strike-slip faults, and grabens in central Tibet but are tenfold slower than those of the southern linked rifts. Thus, our results indicate that the eastward motion of the conjugate strike-slip fault system could probably contribute to normal throws along the GCF. The disperse and slow normal faulting within the conjugate zones may initiated at the Middle Miocene as the secondary structures of the conjugate system in central Tibet, kinematically different from the considerably strong and independent southern linked rifts.