The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional histo...

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Autores principales: López Gamundi, Oscar Raúl, Rossello, Eduardo Antonio
Publicado: 1995
Materias:
foreland basin
Permian
sandstone
syntectonic sedimentation
tuff
Tunas Formation
Argentina, Sierras Australes Foldbelt
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v8_n2_p129_LopezGamundi
http://hdl.handle.net/20.500.12110/paper_08959811_v8_n2_p129_LopezGamundi
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_08959811_v8_n2_p129_LopezGamundi
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spelling paper:paper_08959811_v8_n2_p129_LopezGamundi2023-06-08T15:49:09Z The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin López Gamundi, Oscar Raúl Rossello, Eduardo Antonio foreland basin Permian sandstone syntectonic sedimentation tuff Tunas Formation Argentina, Sierras Australes Foldbelt The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m - thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early - early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana. © 1995. Fil:Lopez-Gamundi, O.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Rossello, E.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1995 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v8_n2_p129_LopezGamundi http://hdl.handle.net/20.500.12110/paper_08959811_v8_n2_p129_LopezGamundi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic foreland basin
Permian
sandstone
syntectonic sedimentation
tuff
Tunas Formation
Argentina, Sierras Australes Foldbelt
spellingShingle foreland basin
Permian
sandstone
syntectonic sedimentation
tuff
Tunas Formation
Argentina, Sierras Australes Foldbelt
López Gamundi, Oscar Raúl
Rossello, Eduardo Antonio
The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin
topic_facet foreland basin
Permian
sandstone
syntectonic sedimentation
tuff
Tunas Formation
Argentina, Sierras Australes Foldbelt
description The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m - thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early - early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana. © 1995.
author López Gamundi, Oscar Raúl
Rossello, Eduardo Antonio
author_facet López Gamundi, Oscar Raúl
Rossello, Eduardo Antonio
author_sort López Gamundi, Oscar Raúl
title The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin
title_short The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin
title_full The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin
title_fullStr The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin
title_full_unstemmed The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin
title_sort tunas formation (permian) in the sierras australes foldbelt, east central argentina: evidence for syntectonic sedimentation in a foreland basin
publishDate 1995
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v8_n2_p129_LopezGamundi
http://hdl.handle.net/20.500.12110/paper_08959811_v8_n2_p129_LopezGamundi
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