HR: 1340h
AN: T23D-1655    [Abstracts]
TI: Climate and Tectonic Controls on Sedimentation and Incision in the Fiambalá Basin, Northwest Argentina
AU: * McPherson, H M
EM: mcpherson.84@osu.edu
AF: School of Earth Sciences, The Ohio State University, 275 Mendenhall Laboratory, 125 South Oval Mall, Columbus, OH 43210, United States
AU: Schoenbohm, L M
EM: lschoenbohm@gmail.com
AF: School of Earth Sciences, The Ohio State University, 275 Mendenhall Laboratory, 125 South Oval Mall, Columbus, OH 43210, United States
AU: Schmitt, A K
EM: axel@argon.ess.ucla.edu
AF: Department of Earth and Space Sciences and IGPP, University of California, 595 Charles Young Drive East, Box 951567, Los Angeles, CA 90095, United States
AU: Carrapa, B
EM: bcarrapa@uwyo.edu
AF: Department of Geology and Geophysics, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, United States
AU: Bohon, W M
EM: bohon.5@osu.edu
AF: School of Earth Sciences, The Ohio State University, 275 Mendenhall Laboratory, 125 South Oval Mall, Columbus, OH 43210, United States
AB: Global climate change during the Late Pliocene has been credited for a worldwide increase in erosion and sedimentation rate, and a coarsening of clastic sedimentation. This may be a result of lowered sea levels, increased glacial erosion at high altitudes and latitudes, or large climatic fluctuations. However, local structural deformation and regional tectonic uplift may also explain increased sedimentation rates. Clastic sediments preserved within intermontane basins adjacent to plateaus offers a unique record of the timing and pattern of orogenic evolution and its relationship to tectonics and climate. The Pliocene Punaschotter conglomerates of the Fiambalá Basin along the southern margin of the Puna Plateau in Northwest Argentina constitute a classic example of such deposits. These conglomerates may record global climate change, regional or local tectonic uplift, or a combination of those. Here we date 10 ashes collected from within and stratigraphically below the Punaschotter conglomerates using zircon U-Pb geochronology to constrain the timing of conglomerate deposition and sedimentation rates. Structural mapping along transects on the western region of the Fiambalá Basin will constrain the relative timing of deformation in relation to sedimentation. If climate change is the dominant force, the timing of deposition and increased sedimentation rates should correlate along strike in different basins and it should correlate with worldwide climate events. Alternatively, if local structural deformation and tectonic uplift control are dominant factors, sedimentation, and eventually erosion, will correlate poorly or not at all with global climate change and deposition will be syn-tectonic. We expect to find that both tectonics and climate exert control, but that each factor can be evaluated individually. From this study, further insight is gained into the effect that climate and tectonics exert on orogenic growth in a marginal basin setting.
DE: 8175 Tectonics and landscape evolution
DE: 8177 Tectonics and climatic interactions
SC: Tectonophysics [T]
MN: 2007 Fall Meeting