Reduced chemical weathering intensity in the Qaidam Basin (NE Tibetan Plateau) during the Late Cenozoic

•Detailed 15.3–1.8 Ma clay elemental geochemistry records for the northeastern Qaidam Basin are presented.•Long-term and persistent weakening of the chemical weathering intensity has occurred since the Middle Miocene.•Global cooling-related drying played a key role in the chemical weathering intensity.•Miocene uplift of the northern Tibetan Plateau might exert some influence on the weakened chemical weathering intensity at 12–8 Ma.