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GEOREF RECORD

Carboniferous glacigenic deposits of the proto-Precordillera of west-central Argentina

Lindsey C. Henry, John L. Isbell and Carlos O. Limarino
Carboniferous glacigenic deposits of the proto-Precordillera of west-central Argentina (in Resolving the late Paleozoic ice age in time and space, Christopher R. Fielding (editor), Tracy D. Frank (editor) and John L. Isbell (editor))
Special Paper - Geological Society of America (2008) 441: 131-142

Abstract

Glacigenic strata associated with the proto-Precordillera were deposited in the Calingasta-Uspallata and Rio Blanco back-arc basins and the Paganzo foreland basin in west-central Argentina during the early Pennsylvanian (upper Namurian; Bashkirian). These basins were formed due to tectonic loading and later postcollisional extension in a convergent-margin setting along the western margin of Gondwana during the Chanic and Rio Blanco tectonic events. Uplift of the proto-Precordillera fold-and-thrust belt during the latest Visean-earliest Namurian (Serpukhovian) resulted in the development of a widespread unconformity that formed the pregiacial basin floors. During the Namurian, alpine glaciers carved deep valleys into the upland, and ice drained radially away from the proto-Precordillera. Valley glaciers or an ice cap also occupied basement uplifts in the Sierras Pampeanas to the east. Ice was grounded below sea level in the Calingasta-Uspallata and Rio Blanco Basins, where thick glaciomarine successions were deposited. In the Paganzo Basin, a thin glacial succession was deposited in both terrestrial and glaciomarine settings. Throughout the proto-Precordilleran region, deposition is interpreted to have occurred (1) subglacially, (2) in morainal banks, (3) as a result of settling from suspension out of meltwater plumes, (4) as rain-out from melting icebergs, and/or (5) from mass movement and sediment gravity flows. An abrupt upward transition from diamictites to marl-bearing, dropstone-free mudrocks marks glacial retreat and establishment of sediment-starved marine conditions. Above this, coarsening-upward successions and truncation surfaces signal either postglacial deltaic progradation during a forced regression or fluvial incision associated with a base-level fall. Although much is known about these strata, many questions remain, including the age of the deposits, environments of deposition, and the mechanisms responsible for the observed stratigraphic architecture.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 441
Title: Carboniferous glacigenic deposits of the proto-Precordillera of west-central Argentina
Title: Resolving the late Paleozoic ice age in time and space
Author(s): Henry, Lindsey C.Isbell, John L.Limarino, Carlos O.
Author(s): Fielding, Christopher R.editor
Author(s): Frank, Tracy D.editor
Author(s): Isbell, John L.editor
Affiliation: University of Wisconsin Milwaukee, Department of Geosciences, Milwaukee, WI, United States
Affiliation: University of Nebraska Lincoln, Department of Geosciences, Lincoln, NE, United States
Pages: 131-142
Published: 2008
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 978-0-8137-2441-6
Meeting name: Late Paleozoic ice age; toward a more refined understanding of timing, duration, and character
Meeting location: Salt Lake City, UT, USA, United States
Meeting date: 20050821Oct. 21, 2005
References: 46
Accession Number: 2008-123127
Categories: Stratigraphy
Document Type: Serial Conference document
Bibliographic Level: Analytic
Annotation: NSF Grant ANT-0440919. IGCP Project No. 471
Illustration Description: illus. incl. sect., strat. cols., geol. sketch maps
S32°30'00" - S30°00'00", W69°30'00" - W68°00'00"
Secondary Affiliation: University of Wisconsin Milwaukee, USA, United StatesUniversidad de Buenos Aires, ARG, Argentina
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200847
Program Name: IGCPInternational Geological Correlation Programme
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