The Miocene Arizaro Basin, central Andean hinterland: Response to partial lithosphere removal?

P. G. DeCelles, B. Carrapa, B. K. Horton, J. McNabb, G. E. Gehrels, J. Boyd

Research output: Chapter in Book/Report/Conference proceedingChapter

28 Scopus citations

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 ∼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 ∼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.

Original languageEnglish (US)
Title of host publicationGeodynamics of a Cordilleran Orogenic System
Subtitle of host publicationThe Central Andes of Argentina and Northern Chile
EditorsMihai N. Ducea, Mihai N. Ducea, Peter G. DeCelles, Paul A. Kapp, Barbara Carrapa
PublisherGeological Society of America
Pages359-386
Number of pages28
ISBN (Electronic)9780813712123
DOIs
StatePublished - Jan 1 2015

Publication series

NameMemoir of the Geological Society of America
Volume212
ISSN (Print)0072-1069

ASJC Scopus subject areas

  • Geology

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    DeCelles, P. G., Carrapa, B., Horton, B. K., McNabb, J., Gehrels, G. E., & Boyd, J. (2015). The Miocene Arizaro Basin, central Andean hinterland: Response to partial lithosphere removal? In M. N. Ducea, M. N. Ducea, P. G. DeCelles, P. A. Kapp, & B. Carrapa (Eds.), Geodynamics of a Cordilleran Orogenic System: The Central Andes of Argentina and Northern Chile (pp. 359-386). (Memoir of the Geological Society of America; Vol. 212). Geological Society of America. https://doi.org/10.1130/2015.1212(18)