Deep canyons along the Salmon, Snake, and Clearwater rivers in central Idaho, USA suggest long-lasting transient incision, but the timing and drivers of this incision are not well understood. The perturbation of the Yellowstone hotspot, eruption of flood basalts, and drainage of Lake Idaho all occurred within or near to this region, but the relationship among these events and incision is unclear. Here, we utilized in situ 10Be cosmogenic radionuclide concentrations for 46 samples (17 new) of fluvial sediment across the region to quantify erosion rates, calibrate stream power models, and estimate incision timing. We estimate that transient incision along the Salmon River began prior to ca. 10 Ma. However, canyon age decreases to ca. 5 Ma or earlier farther to the north. For a group of tributaries underlain by basalt, we use the age of the basalt to estimate that local transient incision began between ca. 11.5 and 5 Ma. Based on these timing constraints, the canyons along the Salmon and Clearwater rivers predate the drainage of Lake Idaho. We argue that canyon incision was triggered by events related to the Yellowstone hotspot (e.g., basalt lava damming, subsidence of the Columbia Basin, reactivation of faults, and/or lower crustal flow). Furthermore, our models suggest basalt may be more erodible than the other rock types we study. We show that lithology has a significant influence on fluvial erosion and assumptions regarding river incision model parameters significantly influence results. Finally, this study highlights how geodynamic processes can exert a significant influence on landscape evolution.
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Research Article|
March 16, 2023
Late Miocene or older canyon incision in the northern U.S. Cordillera shown by erosion rates, incision models, and basalt flow ages
Nate Mitchell;
Nate Mitchell
1
Department of Earth and Atmospheric Sciences, Indiana University, 1001 East 10th Street, Bloomington, Indiana 47405-1405, USA
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Brian Yanites;
Brian Yanites
1
Department of Earth and Atmospheric Sciences, Indiana University, 1001 East 10th Street, Bloomington, Indiana 47405-1405, USA
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Alison Duvall;
Alison Duvall
2
Department of Earth and Space Sciences, University of Washington, Johnson Hall Room-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310, USA
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Eugene Humphreys;
Eugene Humphreys
3
Department of Earth Sciences, University of Oregon, 100 Cascade Hall, 1272 University of Oregon, Eugene, Oregon 97403, USA
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Jonathan Perry-Houts;
Jonathan Perry-Houts
3
Department of Earth Sciences, University of Oregon, 100 Cascade Hall, 1272 University of Oregon, Eugene, Oregon 97403, USA
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Philip Schoettle-Greene;
Philip Schoettle-Greene
2
Department of Earth and Space Sciences, University of Washington, Johnson Hall Room-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310, USA
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Seth Williams
Seth Williams
2
Department of Earth and Space Sciences, University of Washington, Johnson Hall Room-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310, USA
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Nate Mitchell
1
Department of Earth and Atmospheric Sciences, Indiana University, 1001 East 10th Street, Bloomington, Indiana 47405-1405, USA
Brian Yanites
1
Department of Earth and Atmospheric Sciences, Indiana University, 1001 East 10th Street, Bloomington, Indiana 47405-1405, USA
Alison Duvall
2
Department of Earth and Space Sciences, University of Washington, Johnson Hall Room-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310, USA
Eugene Humphreys
3
Department of Earth Sciences, University of Oregon, 100 Cascade Hall, 1272 University of Oregon, Eugene, Oregon 97403, USA
Jonathan Perry-Houts
3
Department of Earth Sciences, University of Oregon, 100 Cascade Hall, 1272 University of Oregon, Eugene, Oregon 97403, USA
Philip Schoettle-Greene
2
Department of Earth and Space Sciences, University of Washington, Johnson Hall Room-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310, USA
Seth Williams
2
Department of Earth and Space Sciences, University of Washington, Johnson Hall Room-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310, USA
Publisher: Geological Society of America
Received:
22 Mar 2022
Revision Received:
09 Oct 2022
Accepted:
26 Nov 2022
First Online:
16 Mar 2023
Online ISSN: 1943-2674
Print ISSN: 0016-7606
© 2023 Geological Society of America
GSA Bulletin (2023)
Article history
Received:
22 Mar 2022
Revision Received:
09 Oct 2022
Accepted:
26 Nov 2022
First Online:
16 Mar 2023
Citation
Nate Mitchell, Brian Yanites, Alison Duvall, Eugene Humphreys, Jonathan Perry-Houts, Philip Schoettle-Greene, Seth Williams; Late Miocene or older canyon incision in the northern U.S. Cordillera shown by erosion rates, incision models, and basalt flow ages. GSA Bulletin 2023; doi: https://doi.org/10.1130/B36524.1
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