Yukon River incision drove organic carbon burial in the Bering Sea during global climate changes at 2.6 and 1 Ma
River erosion affects the carbon cycle and thus climate by exporting terrigenous carbon to seafloor sediment and by nourishing CO 2 -consuming marine life. The Yukon River–Bering Sea system preserves rare source-to-sink records of these processes across profound changes in global climate during the...
| Published in: | Earth Surface Dynamics |
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| Main Authors: | , , , , , , |
| Format: | Text |
| Language: | English |
| Published: |
2022
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/esurf-10-1041-2022 https://esurf.copernicus.org/articles/10/1041/2022/ |
| Summary: | River erosion affects the carbon cycle and thus climate by exporting terrigenous carbon to seafloor sediment and by nourishing CO 2 -consuming marine life. The Yukon River–Bering Sea system preserves rare source-to-sink records of these processes across profound changes in global climate during the past 5 million years (Ma). Here, we expand the terrestrial erosion record by dating terraces along the Charley River, Alaska, and explore linkages among previously published Yukon River tributary incision chronologies and Bering Sea sedimentation. Cosmogenic <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><msup><mi/><mn mathvariant="normal">26</mn></msup><mi mathvariant="normal">Al</mi></mrow><mo>/</mo><mrow class="chem"><msup><mi/><mn mathvariant="normal">10</mn></msup><mi mathvariant="normal">Be</mi></mrow></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="50pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="eaa31c44e7a402abc4a04e87022a8d92"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="esurf-10-1041-2022-ie00001.svg" width="50pt" height="15pt" src="esurf-10-1041-2022-ie00001.png"/></svg:svg> isochron burial ages of Charley River terraces match previously documented central Yukon River tributary incision from 2.6 to 1.6 Ma during Pliocene–Pleistocene glacial expansion, and at 1.1 Ma during the 1.2–0.7 Ma Middle Pleistocene climate transition. Bering Sea sediments preserve 2–4-fold rate increases of Yukon River-derived continental detritus, terrestrial and marine organic carbon, and silicate microfossil deposition at 2.6–2.1 and 1.1–0.8 Ma. These tightly coupled records demonstrate elevated terrigenous nutrient and carbon export and concomitant Bering Sea productivity in response to climate-forced Yukon River incision. ... |
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