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Using multiple isotope systems, we examine the complex effects of drainage reorganization in the Laramide Foreland in the context of stable isotope paleoaltimetry. Strontium, oxygen and carbon isotopic data from lacustrine carbonates formed in the southwestern Uinta Basin, Utah between the Late Cretaceous and late Middle Eocene reveal a two stage expansion in the drainage basin of Lake Uinta beginning at ~Â 53Â Ma culminating in the Mahogany highstand at 48.6Â Ma. A marked increase in 87Sr/86Sr ratios of samples from the Main Body of the Green River Formation is interpreted as the result of water overflowing the Greater Green River Basin in Wyoming and entering Lake Uinta from the east via the Piceance Creek Basin...
Carbon and nitrogen isotope ratios of human fingernails were measured in 490 individuals in the western US and 273 individuals in southeastern Brazil living in urban areas, and 53 individuals living in a moderately isolated area in the central Amazon region of Brazil and consuming mostly locally grown foods. In addition, we measured the carbon and nitrogen isotope ratios of common food items to assess the extent to which these isotopic signatures remain distinct for people eating both omnivorous and vegetarian diets and living in different parts of the world, and the extent to which dietary information can be interpreted from these analyses. Fingernail δ13C values (mean ± standard deviation) were −15.4 ± 1.0 and...
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Isotopic and elemental records of authigenic calcite from lacustrine deposits in the intraforeland basins of Utah were analyzed in an effort to reconstruct the regional paleoclimate, paleohydrology, and paleotopography of the early Cenozoic central North American Cordillera. Isotopic profiles for Paleogene Lakes Uinta, Flagstaff, and Claron show relatively large oxygen isotopic shifts that are diachronous among basins with an ~7{per thousand} decrease in {delta}18Ocalcite values at ca. 45 Ma in Lake Flagstaff, an ~5{per thousand} decrease in {delta}18Ocalcite values between ca. 42 and 35 Ma in Lake Claron, and an ~6{per thousand} decrease in {delta}18Ocalcite values between ca. 44 and 43 Ma in Lake Uinta. We interpret...
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In the past decade, we and others have compiled an extensive dataset of O, C and Sr isotope stratigraphies from sedimentary basins throughout the Paleogene North American Cordillera. In this study, we present new results from the Piceance Creek Basin of northwest Colorado, which record the evolving hydrology of the Eocene Green River Lake system. We then place the new data in the context of the broader Cordilleran dataset and summarize implications for understanding the synorogenic evolution of large-scale drainage patterns. The combined data reflect (1) a period of throughgoing foreland rivers heading in the Sevier fold-and-thrust belt and flowing east, (2) ponding of freshwater lakes in the foredeep as Laramide...
    map background search result map search result map Synorogenic evolution of large-scale drainage patterns: Isotope paleohydrology of sequential Laramide basins The effect of drainage reorganization on paleoaltimetry studies: An example from the Paleogene Laramide foreland Paleogene landscape evolution of the central North American Cordillera: Developing topography and hydrology in the Laramide foreland The effect of drainage reorganization on paleoaltimetry studies: An example from the Paleogene Laramide foreland Paleogene landscape evolution of the central North American Cordillera: Developing topography and hydrology in the Laramide foreland Synorogenic evolution of large-scale drainage patterns: Isotope paleohydrology of sequential Laramide basins