08 Jun 2022
08 Jun 2022
Status: this preprint is currently under review for the journal ESurf.

Yukon River incision coupled to CO2 drawdown during late Cenozoic climate changes

Adrian M. Bender1, Richard O. Lease1, Lee B. Corbett2, Paul R. Bierman2, Marc W. Caffee3, James V. Jones1, and Doug Kreiner1 Adrian M. Bender et al.
  • 1U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA
  • 2University of Vermont, Rubenstein School of the Environment and Natural Resources, 180 Colchester Avenue, Burlington, Vermont 05405, USA
  • 3Purdue University, Department of Physics and Astronomy and Department of Earth, Atmospheric, and Planetary Sciences, 525 Northwestern Avenue, West Lafayette, Indiana 47907, USA

Abstract. 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 five million years (Ma). Here, we expand the terrestrial erosion record by dating terraces along the Charley River, 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 mid-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 Ma 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 explain CO2 drawdown across the Pliocene–Pleistocene and mid-Pleistocene climate transitions observed in many proxy records worldwide.

Adrian M. Bender et al.

Status: open (until 20 Jul 2022)

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Adrian M. Bender et al.

Data sets

Charley River Cosmogenic Isotope Data Collected 2019-2021 Adrian M. Bender

Adrian M. Bender et al.


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Short summary
To understand landscape evolution in the mineral resource-rich Yukon River basin (Alaska and Canada), we mapped and cosmogenic isotope-dated river terraces along the Charley River. Results imply widespread Yukon River incision that drove increased Bering Sea sedimentation and carbon sequestration during global climate changes 2.6 and 1 million years ago. Such erosion may have fed back to late Cenozoic climate change by reducing atmospheric carbon as observed in many records worldwide.