Orogenies can have a
regional or even global influence on climate, but means to assess these
influences can be masked in the stratigraphic record. Extracting oxygen
isotopes from a diverse set of vertebrate phosphate materials, Suarez et al. explore
the effect of the Sevier Orogeny on regional climate and paleohydrology, as
recorded in the Cretaceous Cedar Mountain Formation. The results within the
Cedar Mountain Formation suggest a regional rainshadow effect from the Sevier
Orogeny. Compared to the average meteoric water values for this paleolatitude
as determined by pedogenic carbonates, meteoric water values determined from
crocodiles and turtles are within the range of values for 34°N paleo-latitude. The
Sevier Orogeny had a major effect on the isotopic composition of river water, the
result of significant depletion in runoff of high altitude water or snow. These
sorts of analyses that distinguish between regional paleoclimatic effects of
orogeny and those of global climatic factors are essential for evaluating
perturbations to the global carbon cycle and the related changes in temperature
(e.g. mid-Cretaceous global warming).
Multi-taxa isotopic investigation of paleohydrology in the Lower Cretaceous Cedar Mountain Formation, eastern Utah, U.S.A.: deciphering effects of the Nevadaplano Plateau on regional climate by Celina A. Suarez, Luis A. González, Gregory A. Ludvigson,
James I. Kirkland, Richard L. Cifelli, and Matthew J. Kohn
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