High-Resolution Stable Isotope Paleotopography of the John Day Region, Oregon, United States
نویسندگان
چکیده
The John Day region of central Oregon, United States contains ?50 million years near-continuous, fossiliferous sedimentation, representing one the world’s richest archives Cenozoic terrestrial ecosystems and climate. Stable isotope proxy data from this are commonly used to infer elevation history Cascades, which intercept westerly moisture in transit region. However, Blue Mountains, accreted Mesozoic, create a local high topography that can confound signals Cascades uplift. deposits, including Formation, divided into an eastern facies located within Mountains western adjacent plains. As result, may have supported gradients climate ecology between facies, constraining these is necessary for reconstructing past ecosystem change. In order define extent magnitude we use oxygen isotopes authigenic clay minerals construct spatially resolved map elevation. We find composition ?3‰ lower than plains, offset mostly constant throughout our record (spanning – 5 Ma). attribute topography, either directly upslope rainout or indirectly through effect on variations precipitation seasonality. Our results highlight importance topographic features regional paleotopography reconstructions provide important biogeographical context rich paleo-floral -faunal records preserved sediments.
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ژورنال
عنوان ژورنال: Frontiers in Earth Science
سال: 2021
ISSN: ['2296-6463']
DOI: https://doi.org/10.3389/feart.2021.635181