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Oligocene-Miocene basin evolution in the northern Altiplano, Bolivia: Implications for evolution of the central Andean backthrust belt and high plateau

2010; Geological Society of America; Volume: 122; Issue: 9-10 Linguagem: Inglês

10.1130/b30129.1

1943-2674

Bryan P. Murray, Brian K. Horton, Renato M. Darros de Matos, M. T. Heizler,

Geochemistry and Geologic Mapping

Research Article| September 01, 2010 Oligocene–Miocene basin evolution in the northern Altiplano, Bolivia: Implications for evolution of the central Andean backthrust belt and high plateau Bryan P. Murray; Bryan P. Murray † 1Department of Earth Science, University of California, Santa Barbara, Webb Hall, Santa Barbara, California 93106-9630, USA †E-mail: bmurray@umail.ucsb.edu Search for other works by this author on: GSW Google Scholar Brian K. Horton; Brian K. Horton 2Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78712, USA Search for other works by this author on: GSW Google Scholar Ramiro Matos; Ramiro Matos 3Instituto de Investigaciones Geológicas y Medio Ambiente, Universidad Mayor de San Andrés, Casilla Postal 4787, La Paz, Bolivia Search for other works by this author on: GSW Google Scholar Matthew T. Heizler Matthew T. Heizler 4New Mexico Bureau of Geology and Mineral Resources, Socorro, New Mexico 87801, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Bryan P. Murray † 1Department of Earth Science, University of California, Santa Barbara, Webb Hall, Santa Barbara, California 93106-9630, USA Brian K. Horton 2Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78712, USA Ramiro Matos 3Instituto de Investigaciones Geológicas y Medio Ambiente, Universidad Mayor de San Andrés, Casilla Postal 4787, La Paz, Bolivia Matthew T. Heizler 4New Mexico Bureau of Geology and Mineral Resources, Socorro, New Mexico 87801, USA †E-mail: bmurray@umail.ucsb.edu Publisher: Geological Society of America Received: 13 Jul 2009 Revision Received: 16 Oct 2009 Accepted: 23 Oct 2009 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2010 Geological Society of America GSA Bulletin (2010) 122 (9-10): 1443–1462. https://doi.org/10.1130/B30129.1 Article history Received: 13 Jul 2009 Revision Received: 16 Oct 2009 Accepted: 23 Oct 2009 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Bryan P. Murray, Brian K. Horton, Ramiro Matos, Matthew T. Heizler; Oligocene–Miocene basin evolution in the northern Altiplano, Bolivia: Implications for evolution of the central Andean backthrust belt and high plateau. GSA Bulletin 2010;; 122 (9-10): 1443–1462. doi: https://doi.org/10.1130/B30129.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The upper Oligocene to lower Miocene Peñas and Aranjuez formations are exposed in north-northwest–trending outcrop belts of the central Andean backthrust belt situated within the central Andean plateau along the boundary between the northern Altiplano and the Eastern Cordillera of Bolivia. Sedimentary lithofacies analyses indicate that these coarse-grained siliciclastic formations were deposited primarily in alluvial fan to braided fluvial environments. An upsection change from principally fine-grained sandstone to cobble conglomerate is consistent with increased proximity to the sediment source with time. Paleocurrent analyses reveal that flow was predominantly directed toward the west-southwest away from Cordillera Real, the elevated core of the Eastern Cordillera. Provenance data from conglomerate clast compositions and sandstone petrofacies suggest derivation from recycled quartz-rich metasedimentary and sedimentary rocks from the Paleozoic section in the Eastern Cordillera. The paleoflow orientations, sediment provenance, and increased proximity of the sediment source suggest that deposition of the Peñas and Aranjuez formations was related to surface uplift of the Eastern Cordillera relative to the Altiplano. Growth strata observed in the Aranjuez Formation further indicate that shortening was synchronous with deposition, probably in a hinterland basin. New 40Ar/39Ar ages from a lowermost exposed igneous unit and interbedded ash-fall tuff beds in the Aranjuez and Peñas formations show that synorogenic sedimentation and fold-thrust deformation in the frontal (west-southwestern) zone of the central Andean backthrust belt was concentrated during late Oligocene–early Miocene time. These age results are consistent with previous studies of east-derived sedimentation in the Altiplano and indicate regional uplift of the Eastern Cordillera at this time. Upsection trends in provenance data further suggest a progressively greater contribution from younger Paleozoic strata, possibly due to activation of new thrust faults during west-southwestward propagation of the backthrust belt toward the Altiplano. Such a progression of late Oligocene–early Miocene shortening along the Altiplano–Eastern Cordillera boundary likely reflects significant crustal thickening, potential isostatic uplift, and initial topographic expression of the eastern margin of the central Andean plateau. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.