Investigation of early Eocene water-vapor transport and paleoelevation using oxygen isotope data from geographically widespread mammal remains

摘要: The oxygen isotope composition (δ 18 O) of apatite from mammalian tooth enamel can be used to infer the δ O value ingested water, which is in turn related that precipitation stored surface reservoirs. Therefore, phosphate fossil these reservoirs past. In this paper, a semiaquatic mammal taxon ( Coryphodon ) collected five early Eocene localities North America construct patterns values river water for time period. At all localities, r estimated have been higher during relative present-day American rivers, although vs. latitude gradient was shallower Eocene. Higher are consistent with warmer air masses being able hold more vapor and an increase poleward transport both moisture latent heat. regular decrease indicates global atmospheric circulation hydrological were not much different those present, may reflect regional differences precipitation, evaporation, recharge. scale, provide insight into topographic relief case intermontane basins Wyoming, average between indicate Laramide mountain on order 475 m. It suggested anomalously low reported previously do unambiguous evidence permanent snow at elevations instead brief episodes cooler winters and/or altered patterns.