Provenance of newly discovered Upper Ordovician black rock units in the West Kunlun Orogen, China: Constraints from detrital zircon U-Pb chronology and whole-rock geochemistry

We present new detrital zircon U-Pb chronological and whole-rock geochemical data for the newly discovered black rock units in West Kunlun Orogen in an attempt to constrain the provenance variations of the siliciclastic rocks and the tectonic history of NW China. Geochemical data indicate these black rock units could have formed in an active continental margin to continental arc setting during the Late Ordovician and source rocks could have undergone modest chemical weathering under a relatively warm and humid climate during the deposition of the black rock units. U-Pb dating of 170 detrital zircons defines five major age populations at 459-545 Ma, 710-900 Ma, 1,300-900 Ma, 1,814-1,641 Ma, and 2,153-2,845 Ma, demonstrating that the black rock units deposited during the Late Ordovician and the tectonic events that occurred in the West Kunlun Orogen were related to the assembly and breakup of the supercontinents of Columbia and Rodinia. Prevalence of Early Palaeozoic magmatic zircons further indicates the black rock units were derived from a proximal source, most likely from the South Kunlun arc.