Hydrogeochemical characterization and CO2 consumption in the Maqu catchment of the Qinghai-Tibetan Plateau by multiple hydrogeochemical methods

•Both surface water and groundwater are of meteoric origin.•There is close contact between surface water (except wetlands) and groundwater.•Water in the wetlands is substantially evaporated (0–45%).•Carbonate and silicate weathering are the dominant sources of major cations.•Maqu catchment is an important carbon sink in the Yellow River Basin.