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The Miocene Arizaro Basin, Central Andean hinterland; response to partial lithosphere removal?

Peter G. DeCelles, Barbara Carrapa, B. K. Horton, J. McNabb, George E. Gehrels and J. Boyd
The Miocene Arizaro Basin, Central Andean hinterland; response to partial lithosphere removal?
Memoir - Geological Society of America (2015) 212: 359-386

Abstract

The Arizaro Basin in northwestern Argentina sits today in the western Puna Plateau at elevations of 3800-4200 m along the eastern flank of the Miocene to modern magmatic arc. The basin is roughly circular in plan view and approximately 100 km in diameter, and it was filled during Miocene time (ca. 21-9 Ma) by >3.5 km of eolian, alluvial, fluvial, and lacustrine sediment in addition to ash-fall tuffs from the Andean magmatic arc. The basin fill was subsequently shortened in its central part, and it has been uplifted and topographically inverted. The Arizaro Basin is not obviously related to known faults, nor does it exhibit a peripheral belt of coarse-grained sedimentary rocks derived from flanking topographically higher regions. Sandstone modal framework compositions are arkosic, but not as rich in volcanic lithic fragments as typical intra-arc basins. Detrital zircon U-Pb age spectra implicate source terranes in locally exposed Ordovician granitoid rocks, more distal Upper Paleozoic-Mesozoic arc terranes in western Argentina and possibly northern Chile, and the local Miocene magmatic arc. Depositional-age zircons are present in most of the sandstones analyzed for detrital zircon U-Pb geochronology, and zircon U-Pb ages from volcanic tuff layers provide independent chronological control. The tectonic component of subsidence initiated at low rates, accelerated to approximately 0.6 mm/yr during the medial stage of basin development, and tapered off to zero as the basin began to shorten internally and experience topographic inversion after ca. 10 Ma. Together, the data presented here suggest that the Arizaro Basin could have developed in response to the formation and gravitational foundering of a dense Rayleigh-Taylor-type instability in the lower crust and/or mantle lithosphere. Insofar as hinterland basins of uncertain tectonic affinity are widespread in the high central Andes, the model developed here may be relevant for other regions of enigmatic subsidence and sediment accumulation in the Andes and other cordilleran hinterland settings.


ISSN: 0072-1069
Coden: GSAMAQ
Serial Title: Memoir - Geological Society of America
Serial Volume: 212
Title: The Miocene Arizaro Basin, Central Andean hinterland; response to partial lithosphere removal?
Affiliation: University of Arizona, Department of Geosciences, Tucson, AZ, United States
Pages: 359-386
Published: 2015
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 145
Accession Number: 2015-036126
Categories: StratigraphyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
S26°00'00" - S22°00'00", W68°00'00" - W64°00'00"
Secondary Affiliation: University of Texas, Austin, USA, United StatesUniversity of Oregon, USA, United StatesUniversity of Wyoming, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201517
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