The impact of neogene grassland expansion and aridification on the isotopic composition of continental precipitation

摘要: The late Cenozoic was a time of global cooling, increased aridity, and expansion grasslands. In the last two decades numerous records oxygen isotopes have been collected to assess plant ecological changes, understand terrestrial paleoclimate, determine surface history mountain belts. δ18O values these records, in general, increase from mid-Miocene Recent. We suggest that record an aridity grasslands midlatitude continental regions. use nondimensional isotopic vapor transport model coupled with soil water isotope evaluate role recycling transpiration by different functional types. This analysis shows associated grassland along biomechanistic changes grasses themselves conspires lower horizontal gradient atmospheric as air mass moves into interiors. resulting signal at given inland site is precipitation increasing matching general observed trend records. There are limits effect induced recycling, which we refer here “hydrostat.” modern climate, this hydrostatic limit occurs approximately boundary between forest ecosystems.