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 CO2-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 pa...

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Bibliographic Details
Published in:Earth Surface Dynamics
Main Authors: Bender, Adrian M., Lease, Richard O., Corbett, Lee B., Bierman, Paul R., Caffee, Marc W., Jones, James V., Kreiner, Doug
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2022
Subjects:
article
Verlagsveröffentlichung
Bering Sea
Yukon
Yukon river
Alaska
Online Access:https://doi.org/10.5194/esurf-10-1041-2022
https://noa.gwlb.de/receive/cop_mods_00063248
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00062352/esurf-10-1041-2022.pdf
https://esurf.copernicus.org/articles/10/1041/2022/esurf-10-1041-2022.pdf
Description
Summary:River erosion affects the carbon cycle and thus climate by exporting terrigenous carbon to seafloor sediment and by nourishing CO2-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 26Al/10Be 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. Carbon burial related to accelerated terrestrial erosion may contribute to CO2 drawdown across the Pliocene–Pleistocene and Middle Pleistocene climate transitions observed in many proxy records worldwide.

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