Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Beranek, L. P. Articles by Fanning, C. M. Search for Related Content GeoRef GeoRef Citation

Miocene to Holocene landscape evolution of the western Snake River Plain region, Idaho: Using the SHRIMP detrital zircon provenance record to track eastward migration of the Yellowstone hotspot

Luke P. Beranek^,1, Paul Karl Link^,1 and C. Mark Fanning^,2

¹ Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA
² Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia

We report new U-Pb detrital zircon sensitive high-resolution ion microprobe (SHRIMP) age data (702 grains) from 13 samples collected from Miocene to Holocene sedimentary deposits in the western Snake River Plain region. These samples effectively show that modern stream sediments of the Snake River system reliably and repeatedly record the detrital zircon age populations that are present as sources in their drainage basins across the Cordilleran thrust belt and Basin and Range Province. We use this framework and the provenance of Neogene sedimentary rocks in the region to test the effect of the migrating Yellowstone hotspot on regional drainage patterns in southern Idaho since the middle Miocene. Our results indicate that Neogene paleodrainages were first directed radially away from the tumescent Yellow-stone highland, then subsequently reversed their flow toward the subsiding Snake River Plain basin. This occurred in east-progressing time-constrained intervals starting at 16 Ma. In northern Nevada, the drainage divide is represented by a northeast-trending, southeast-migrating crest of high topography.

Specifically, middle to late Miocene (16–10 Ma) sedimentary deposits of the western Snake River Plain and Oregon-Idaho graben contain early to middle Eocene (52–42 Ma) detrital zircon populations sourced in Challis magmatic rocks north of the Snake River Plain. Middle Jurassic (160 Ma) and middle to late Eocene (42–35 Ma) detrital zircons, sourced from rocks in northern Nevada, are not present. Late Eocene detrital zircons from Nevada are present in two younger than 7 Ma sedimentary units of the Idaho Group along the Oregon-Idaho border. This indicates that by the late Miocene, southeastward headward erosion of the paleo–Owyhee River into the Owyhee Plateau had captured drainage from north-central Nevada and directed it northwestward toward the subsiding western Snake River Plain. The modern Owyhee Plateau is still a topographic high, in contrast to the modern Snake River Plain, suggesting that lowering of the regional Snake River Plain base level, rather than crustal subsidence, drove stream capture. By the late Pliocene (3 Ma), Middle Jurassic detrital zircons are recorded in the Glenns Ferry Formation and Tuana Gravel of the central Snake River Plain, suggesting that surface subsidence reversed the flow direction of paleo–Salmon Falls Creek from southward into Nevada to northward toward Idaho.

Miocene strata of the western Snake River Plain lack recycled Proterozoic detrital zircons that are ubiquitous in sedimentary rocks of the central and southeast Idaho thrust belts. Such detrital zircons appear on the central and western Snake River Plain in early Pliocene to Holocene (4–0 Ma) deposits. This records capture of drainage from the eastern Snake River Plain. The Yellowstone hotspot controlled the east-migrating continental divide, in the wake of which formed the western-draining, and progressively eastward-collecting, Snake River system.

Key Words: Snake River Plain • Yellowstone hot-spot • Neogene • SHRIMP detrital zircon • Idaho • Nevada

This article has been cited by other articles:

				R. Hershler, H.-P. Liu, and D. L. Gustafson A second species of Pyrgulopsis (Hydrobiidae) from the Missouri River basin, with molecular evidence supporting faunal origin through Pliocene stream capture across the northern continental divide J. Mollus. Stud., November 1, 2008; 74(4): 403 - 413. [Abstract] [Full Text] [PDF]

				A. R. Wallace, M. E. Perkins, and R. J. Fleck Late Cenozoic paleogeographic evolution of northeastern Nevada: Evidence from the sedimentary basins Geosphere, February 1, 2008; 4(1): 36 - 74. [Abstract] [Full Text] [PDF]

				J. E. Spencer, G. R. Smith, and T. E. Dowling Middle to late Cenozoic geology, hydrography, and fish evolution in the American Southwest Geological Society of America Special Papers, January 1, 2008; 439(0): 279 - 299. [Abstract] [Full Text] [PDF]

				K. W. Wegmann, B. D. Zurek, C. A. Regalla, D. Bilardello, J. L. Wollenberg, S. E. Kopczynski, J. M. Ziemann, S. L. Haight, J. D. Apgar, C. Zhao, et al. Position of the Snake River watershed divide as an indicator of geodynamic processes in the greater Yellowstone region, western North America Geosphere, August 1, 2007; 3(4): 272 - 281. [Abstract] [Full Text] [PDF]