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The Yulinshan accumulations of volcanic rocks and interbedded weathered mantles provide a unique chance for studying the processes and environment of the formation of the planation surface in central Tibetan Plateau. Geochemical, 40Ar/39Ar and K/Ar geochronologic investigations of the weathered mantles and high-potassium volcanic rocks reveal that the volcano-weathered mantle accumulations formed under arid or semi-arid subtropic environment in 30-24 Ma. The sole planation surface of the Qiangtang region finally formed in about 20 Ma.
The Yulinshan accumulations of volcanic rocks and interbedded weathered mantles provide a unique chance for studying the processes and environment of the formation of the planation surface in central Tibetan Plateau. Geochemical, 40Ar / 39Ar and K / Ar geochronologic investigations of the weathered mantles and high- potassium volcanic rocks reveal that the volcano-weathered mantle accumulations formed under arid or semi-arid subtropic environments in 30-24 Ma. The sole planation surface of the Qiangtang region finally formed in about 20 Ma.