Cenozoic landscape evolution of a post-compressional orogenic wedge: intermontane basin development and sediment dispersal patterns, Renova Formation, southwest Montana

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dc.contributor Robinson, D. M.
dc.contributor Schwartz, Joshua
dc.contributor Schwartz, Robert K.
dc.contributor.advisor Weislogel, Amy L.
dc.contributor.author Rothfuss, Jennifer L.
dc.date.accessioned 2017-03-01T14:36:13Z
dc.date.available 2017-03-01T14:36:13Z
dc.date.issued 2010
dc.identifier.other u0015_0000001_0000396
dc.identifier.other Rothfuss_alatus_0004M_10491
dc.identifier.uri https://ir.ua.edu/handle/123456789/902
dc.description Electronic Thesis or Dissertation
dc.description.abstract Sediment pathways and landscape evolution are useful proxies for refining the current understanding of crustal and surficial processes that initiated Paleogene post-compressional demise of the Cordilleran orogenic wedge in southwest Montana. Basin-fill deposits of Cenozoic intermontane basins that lie along the leading edge of the Sevier fold thrust belt provide a relatively complete sedimentary record by which to evaluate surficial and crustal processes that regulate landscape evolution of a deconstructional orogen. The Paleogene Renova Formation records initial post-Laramide sediment accumulation in the intermontane basins, marking the transition from fluvial incision to sediment backfilling. Facies assemblages reflect dominance by high-energy fluvial systems and alluvial fans that record radiating dispersal from basin-bounding uplifts including as the Boulder batholith-Highland Range and Pioneer Mountains. Paleogene fluvial systems were marked by rapid fluvial aggradation, and coeval basin margin deposits preserve rapid alluvial fan progradation. Progradational and aggradational stacking patterns reflect a rapidly subsiding environment in which the rate of accommodation space generation either outpaced or was equal to the rate of sediment influx. Syndepositional volcanism coupled with rapid denudation of Sevier-Laramide highlands, some of which were bounded by normally-reactivated reverse faults, provided abundant detritus into the depositional systems during the Paleogene. Paleogene paleodrainage reconstructions are strikingly similar to Cretaceous paleodrainage reconstructions for the Kootenai, Blackleaf, and Frontier Formations (Schwartz and DeCelles, 1988), and the Beaverhead Group (Sears and Ryan, 2003), suggesting that relict Late Cretaceous paleotopography coupled with regional Sevier-Laramide structural grain, exhibited strong infrastructural control on post-Laramide drainage evolution. Two distinct Paleogene paleodrainage networks have been identified in the study area based on detrital zircon age populations and paleoflow indicators, and likely reveal the presence of two distinct and separate Paleogene fluvial systems. Altogether, data presented suggest that rugged paleotopography characterized the Southwest Montana Re-entrant of the Sevier fold thrust belt during the Paleogene. Normal-sense reactivation of Sevier thrust faults coupled with erosion by high energy fluvial and alluvial systems rapidly dissected the Cordilleran orogenic wedge.
dc.format.extent 165 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Geology
dc.title Cenozoic landscape evolution of a post-compressional orogenic wedge: intermontane basin development and sediment dispersal patterns, Renova Formation, southwest Montana
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Dept. of Geological Sciencess
etdms.degree.discipline Geology
etdms.degree.grantor The University of Alabama
etdms.degree.level master's
etdms.degree.name M.S.

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