图书馆知识库

The elevation history of the Tibetan Plateau promises insight into the mechanisms and dynamics that develop and sustain high topography over tens of millions of years. We present the first nearly continuous Cenozoic elevation history from two sedimentary basins on the southern Tibetan Plateau within the latest Cretaceous to Eocene Gangdese arc. Oxygen-isotope and Delta(47) clumped-isotope compositions of nonmarine carbonates allow us to constrain carbonate formation temperature and reconstruct the paleoprecipitation record of the Eocene to Pliocene Oiyug Basin and Paleocene to Eocene Penbo Basin. We exploit the systematic decrease of surface temperature and meteoric water delta O-18 values with elevation to derive paleoelevation estimates for these basins. Minimally altered and unaltered pedogenic and lacustrine carbonates from the Oiyug Basin yield Delta(47,) (CDES) (relative to the carbon dioxide equilibrium scale [CDES]) values of 0.625% to 0.755%, which correspond to temperatures of 1-30 degrees C using a Delta(47) thermometer for low-temperature carbonates. Similarly, the Penbo Basin yielded Delta(47), CDES values of 0.701% to 0.726%, corresponding to temperatures of 6-12 degrees C. The apparent evidence for survival of primary clumped-isotope values in the face of substantial burial and heating is an important result for the field of carbonate clumped-isotope thermometry.