Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero

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In this paper new basaltic outcrops from Ramírez de Velasco ranger (Santiago del Estero province) are described. They are basaltic dikes that vary from few meters to two kilometers long across the igneous basement. All these rocks show dark colors with aphyric (S9 sample) to porphyritic (S17 and S20...

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Autores principales: Leal, P.R., Miró, R.
Formato: Artículo publishedVersion
Publicado: 2010
Materias:
Basalts
Pampean ranges
Ramírez de velasco
augite
basalt
basement rock
chemical composition
dike
emplacement
geochemistry
igneous rock
labradorite
magmatism
mineral alteration
mineralogy
outcrop
petrography
phenocryst
plagioclase
texture
trace element
volcanism
Argentina
Santiago del Estero [Argentina]
Sierras de Cordoba
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00044822_v67_n1_p65_Leal
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v67_n1_p65_Leal_oai
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Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires
id I28-R145-paper_00044822_v67_n1_p65_Leal_oai
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spelling I28-R145-paper_00044822_v67_n1_p65_Leal_oai2024-08-16 Leal, P.R. Miró, R. 2010 In this paper new basaltic outcrops from Ramírez de Velasco ranger (Santiago del Estero province) are described. They are basaltic dikes that vary from few meters to two kilometers long across the igneous basement. All these rocks show dark colors with aphyric (S9 sample) to porphyritic (S17 and S20 samples) textures. When these basalts present phenocrysts, they are composed of lagioclase within a groundmass of subophitic texture. The low alteration of the groundmass allows to recognise microliths of labradorite, augite and opaque minerals of about 0.2 and 0.5 mm. These sizes suggest a hypabisal emplacement of the biggest dikes. Sericite, chlorite, epidote, sphene and opaque minerals compose the alteration assemblage on these rocks. Quartz and carbonates mainly fill small cavities. The geochemical compositions of all analyzed samples support the petrographic classification. They have negative slopes of their trace elements and evidence affiliation with calc-alkaline basalts from magmatic arcs. Their similar textures, mineralogy and chemical compositions suggest that all these basalts where crystallized from the same source and due to the same magmatic process. On the basis of all these data and the features of the basalts that crops out in the surrounding of the study area, this volcanism is attributed to the post-orogenic stage of the Pampean orogeny and therefore it is correlated with the Balbuena Formation (Sierra Norte of Córdoba). Fil:Leal, P.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Miró, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_00044822_v67_n1_p65_Leal info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Rev. Asoc. Geol. Argent. 2010;67(1):65-76 Basalts Pampean ranges Ramírez de velasco augite basalt basement rock chemical composition dike emplacement geochemistry igneous rock labradorite magmatism mineral alteration mineralogy outcrop petrography phenocryst plagioclase texture trace element volcanism Argentina Santiago del Estero [Argentina] Sierras de Cordoba Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v67_n1_p65_Leal_oai
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-145
collection Repositorio Digital de la Universidad de Buenos Aires (UBA)
topic Basalts
Pampean ranges
Ramírez de velasco
augite
basalt
basement rock
chemical composition
dike
emplacement
geochemistry
igneous rock
labradorite
magmatism
mineral alteration
mineralogy
outcrop
petrography
phenocryst
plagioclase
texture
trace element
volcanism
Argentina
Santiago del Estero [Argentina]
Sierras de Cordoba
spellingShingle Basalts
Pampean ranges
Ramírez de velasco
augite
basalt
basement rock
chemical composition
dike
emplacement
geochemistry
igneous rock
labradorite
magmatism
mineral alteration
mineralogy
outcrop
petrography
phenocryst
plagioclase
texture
trace element
volcanism
Argentina
Santiago del Estero [Argentina]
Sierras de Cordoba
Leal, P.R.
Miró, R.
Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero
topic_facet Basalts
Pampean ranges
Ramírez de velasco
augite
basalt
basement rock
chemical composition
dike
emplacement
geochemistry
igneous rock
labradorite
magmatism
mineral alteration
mineralogy
outcrop
petrography
phenocryst
plagioclase
texture
trace element
volcanism
Argentina
Santiago del Estero [Argentina]
Sierras de Cordoba
description In this paper new basaltic outcrops from Ramírez de Velasco ranger (Santiago del Estero province) are described. They are basaltic dikes that vary from few meters to two kilometers long across the igneous basement. All these rocks show dark colors with aphyric (S9 sample) to porphyritic (S17 and S20 samples) textures. When these basalts present phenocrysts, they are composed of lagioclase within a groundmass of subophitic texture. The low alteration of the groundmass allows to recognise microliths of labradorite, augite and opaque minerals of about 0.2 and 0.5 mm. These sizes suggest a hypabisal emplacement of the biggest dikes. Sericite, chlorite, epidote, sphene and opaque minerals compose the alteration assemblage on these rocks. Quartz and carbonates mainly fill small cavities. The geochemical compositions of all analyzed samples support the petrographic classification. They have negative slopes of their trace elements and evidence affiliation with calc-alkaline basalts from magmatic arcs. Their similar textures, mineralogy and chemical compositions suggest that all these basalts where crystallized from the same source and due to the same magmatic process. On the basis of all these data and the features of the basalts that crops out in the surrounding of the study area, this volcanism is attributed to the post-orogenic stage of the Pampean orogeny and therefore it is correlated with the Balbuena Formation (Sierra Norte of Córdoba).
format Artículo
Artículo
publishedVersion
author Leal, P.R.
Miró, R.
author_facet Leal, P.R.
Miró, R.
author_sort Leal, P.R.
title Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero
title_short Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero
title_full Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero
title_fullStr Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero
title_full_unstemmed Ramírez de Velasco basalts: New outcrops of basic rocks in the homonymous range, Santiago del Estero
title_sort ramírez de velasco basalts: new outcrops of basic rocks in the homonymous range, santiago del estero
publishDate 2010
url http://hdl.handle.net/20.500.12110/paper_00044822_v67_n1_p65_Leal
https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v67_n1_p65_Leal_oai
work_keys_str_mv AT lealpr ramirezdevelascobasaltsnewoutcropsofbasicrocksinthehomonymousrangesantiagodelestero
AT miror ramirezdevelascobasaltsnewoutcropsofbasicrocksinthehomonymousrangesantiagodelestero
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