Discovery of Silurian sponge spicules from the Argentine Precordillera

Autores
Beresi, Matilde Sylvia
Año de publicación
2011
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
An association of silicified spicules of hexactinellid sponges was collected from Silurian sandstones at the top of the La Chilca Formation, cropping out at Cerro del Fuerte, 20 km east of Jáchal, in the San Juan Precordillera of west-central Argentina. This is the first occurrence of a Silurian spicule fauna recorded at higher palaeolatitudes from Argentina and the entire South American part of Gondwana. The spicules were extracted by means of formic acid treatment from sandstones of the uppermost part of the La Chilca Formation, which ranges in age from the late Hirnantian to Llandovery, based on graptolites, brachiopods and conodonts. The spicule association is composed only of scarce siliceous hexactine-based spicules which cannot be attributed to any specific hexactinellid taxon. The fragmentary preservation of this allochthonous sponge assemblage points toward preburial transport. These spicules represent the only microfauna found in the uppermost sandstones. Macrofossils are absent. No conodonts have been recovered in these levels. Two interpretations on the spicules of the Precordillera can be argued: (a) that those early Silurian hexactinellids could have occurred in quartz sandstones of the shore-facies to off-shore transitional associations, in the upper La Chilca Formation, or (b) that these sponges flourished in mainly calcareous shales in quiet deep-water conditions, and that their fragile spicules were removed and deposited by oceanic currents, on the top of the outer-shelf sand bars. Both hypotheses on the palaeoenvironmental origin of these spicules are substantially different, but the scarcity of spicules does not allow a more precise interpretation. The discovery of these hexactinellid spicules provides a new perspective on Silurian sponge occurrence and distribution for the Argentine Precordillera.
Fil: Beresi, Matilde Sylvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina
Materia
Silurian
Spicules
Precordillera
San Juan
Hexactinellid Sponge Spicules
Central Precordillera
San Juan Province
Argentina
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/4850

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spelling Discovery of Silurian sponge spicules from the Argentine PrecordilleraBeresi, Matilde SylviaSilurianSpiculesPrecordilleraSan JuanHexactinellid Sponge SpiculesCentral PrecordilleraSan Juan ProvinceArgentinahttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1An association of silicified spicules of hexactinellid sponges was collected from Silurian sandstones at the top of the La Chilca Formation, cropping out at Cerro del Fuerte, 20 km east of Jáchal, in the San Juan Precordillera of west-central Argentina. This is the first occurrence of a Silurian spicule fauna recorded at higher palaeolatitudes from Argentina and the entire South American part of Gondwana. The spicules were extracted by means of formic acid treatment from sandstones of the uppermost part of the La Chilca Formation, which ranges in age from the late Hirnantian to Llandovery, based on graptolites, brachiopods and conodonts. The spicule association is composed only of scarce siliceous hexactine-based spicules which cannot be attributed to any specific hexactinellid taxon. The fragmentary preservation of this allochthonous sponge assemblage points toward preburial transport. These spicules represent the only microfauna found in the uppermost sandstones. Macrofossils are absent. No conodonts have been recovered in these levels. Two interpretations on the spicules of the Precordillera can be argued: (a) that those early Silurian hexactinellids could have occurred in quartz sandstones of the shore-facies to off-shore transitional associations, in the upper La Chilca Formation, or (b) that these sponges flourished in mainly calcareous shales in quiet deep-water conditions, and that their fragile spicules were removed and deposited by oceanic currents, on the top of the outer-shelf sand bars. Both hypotheses on the palaeoenvironmental origin of these spicules are substantially different, but the scarcity of spicules does not allow a more precise interpretation. The discovery of these hexactinellid spicules provides a new perspective on Silurian sponge occurrence and distribution for the Argentine Precordillera.Fil: Beresi, Matilde Sylvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaWiley2011-12-06info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/4850Beresi, Matilde Sylvia; Discovery of Silurian sponge spicules from the Argentine Precordillera; Wiley; Geological Journal; 48; 2-3; 6-12-2011; 248-2550072-1050enginfo:eu-repo/semantics/altIdentifier/url/http://onlinelibrary.wiley.com/doi/10.1002/gj.1334/abstractinfo:eu-repo/semantics/altIdentifier/doi/10.1002/gj.1334info:eu-repo/semantics/altIdentifier/doi/info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T10:11:47Zoai:ri.conicet.gov.ar:11336/4850instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 10:11:48.065CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Discovery of Silurian sponge spicules from the Argentine Precordillera
title Discovery of Silurian sponge spicules from the Argentine Precordillera
spellingShingle Discovery of Silurian sponge spicules from the Argentine Precordillera
Beresi, Matilde Sylvia
Silurian
Spicules
Precordillera
San Juan
Hexactinellid Sponge Spicules
Central Precordillera
San Juan Province
Argentina
title_short Discovery of Silurian sponge spicules from the Argentine Precordillera
title_full Discovery of Silurian sponge spicules from the Argentine Precordillera
title_fullStr Discovery of Silurian sponge spicules from the Argentine Precordillera
title_full_unstemmed Discovery of Silurian sponge spicules from the Argentine Precordillera
title_sort Discovery of Silurian sponge spicules from the Argentine Precordillera
dc.creator.none.fl_str_mv Beresi, Matilde Sylvia
author Beresi, Matilde Sylvia
author_facet Beresi, Matilde Sylvia
author_role author
dc.subject.none.fl_str_mv Silurian
Spicules
Precordillera
San Juan
Hexactinellid Sponge Spicules
Central Precordillera
San Juan Province
Argentina
topic Silurian
Spicules
Precordillera
San Juan
Hexactinellid Sponge Spicules
Central Precordillera
San Juan Province
Argentina
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv An association of silicified spicules of hexactinellid sponges was collected from Silurian sandstones at the top of the La Chilca Formation, cropping out at Cerro del Fuerte, 20 km east of Jáchal, in the San Juan Precordillera of west-central Argentina. This is the first occurrence of a Silurian spicule fauna recorded at higher palaeolatitudes from Argentina and the entire South American part of Gondwana. The spicules were extracted by means of formic acid treatment from sandstones of the uppermost part of the La Chilca Formation, which ranges in age from the late Hirnantian to Llandovery, based on graptolites, brachiopods and conodonts. The spicule association is composed only of scarce siliceous hexactine-based spicules which cannot be attributed to any specific hexactinellid taxon. The fragmentary preservation of this allochthonous sponge assemblage points toward preburial transport. These spicules represent the only microfauna found in the uppermost sandstones. Macrofossils are absent. No conodonts have been recovered in these levels. Two interpretations on the spicules of the Precordillera can be argued: (a) that those early Silurian hexactinellids could have occurred in quartz sandstones of the shore-facies to off-shore transitional associations, in the upper La Chilca Formation, or (b) that these sponges flourished in mainly calcareous shales in quiet deep-water conditions, and that their fragile spicules were removed and deposited by oceanic currents, on the top of the outer-shelf sand bars. Both hypotheses on the palaeoenvironmental origin of these spicules are substantially different, but the scarcity of spicules does not allow a more precise interpretation. The discovery of these hexactinellid spicules provides a new perspective on Silurian sponge occurrence and distribution for the Argentine Precordillera.
Fil: Beresi, Matilde Sylvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina
description An association of silicified spicules of hexactinellid sponges was collected from Silurian sandstones at the top of the La Chilca Formation, cropping out at Cerro del Fuerte, 20 km east of Jáchal, in the San Juan Precordillera of west-central Argentina. This is the first occurrence of a Silurian spicule fauna recorded at higher palaeolatitudes from Argentina and the entire South American part of Gondwana. The spicules were extracted by means of formic acid treatment from sandstones of the uppermost part of the La Chilca Formation, which ranges in age from the late Hirnantian to Llandovery, based on graptolites, brachiopods and conodonts. The spicule association is composed only of scarce siliceous hexactine-based spicules which cannot be attributed to any specific hexactinellid taxon. The fragmentary preservation of this allochthonous sponge assemblage points toward preburial transport. These spicules represent the only microfauna found in the uppermost sandstones. Macrofossils are absent. No conodonts have been recovered in these levels. Two interpretations on the spicules of the Precordillera can be argued: (a) that those early Silurian hexactinellids could have occurred in quartz sandstones of the shore-facies to off-shore transitional associations, in the upper La Chilca Formation, or (b) that these sponges flourished in mainly calcareous shales in quiet deep-water conditions, and that their fragile spicules were removed and deposited by oceanic currents, on the top of the outer-shelf sand bars. Both hypotheses on the palaeoenvironmental origin of these spicules are substantially different, but the scarcity of spicules does not allow a more precise interpretation. The discovery of these hexactinellid spicules provides a new perspective on Silurian sponge occurrence and distribution for the Argentine Precordillera.
publishDate 2011
dc.date.none.fl_str_mv 2011-12-06
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/4850
Beresi, Matilde Sylvia; Discovery of Silurian sponge spicules from the Argentine Precordillera; Wiley; Geological Journal; 48; 2-3; 6-12-2011; 248-255
0072-1050
url http://hdl.handle.net/11336/4850
identifier_str_mv Beresi, Matilde Sylvia; Discovery of Silurian sponge spicules from the Argentine Precordillera; Wiley; Geological Journal; 48; 2-3; 6-12-2011; 248-255
0072-1050
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/http://onlinelibrary.wiley.com/doi/10.1002/gj.1334/abstract
info:eu-repo/semantics/altIdentifier/doi/10.1002/gj.1334
info:eu-repo/semantics/altIdentifier/doi/
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Wiley
publisher.none.fl_str_mv Wiley
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instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
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repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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