Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)

Autores
Campodonico, Verena A.; Pasquini, Andrea I.; Lecomte, Karina L.; García, M. Gabriela; Depetris, Pedro J.
Año de publicación
2019
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Fil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Lecomte, Karina L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Lecomte, Karina L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: García, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: García, M. Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Depetris, Pedro J. Academia Nacional de Ciencias; Argentina.
Subtropical laterites are partially found in the Argentinian province of Misiones, covering the JurassicCretaceous Serra Geral flood basalts (known as Posadas Formation in Argentina). Two hypotheses have been proposed to explain the origin of these laterites. The autochthonous theory attributes the origin of these deposits to the chemical weathering of the underlying tholeiitic basalts. However, during the last decade, an allochthonous “tropical loess” model was proposed. Several mineralogical/geochemical characteristics of a lateritic profile (~2 m thick, 26°9′58″S–54°35′3″W) are analyzed in this paper in order to constrain the nature of weathering processes in this region and the provenance of the lateritic layer. The basaltic bedrock at the sampling site exhibits intergranular texture and is mainly composed of clinopyroxene, plagioclase and opaque minerals (likely titanomagnetite and ilmenite). Altered glass and apatite were also identified in lower proportions. The X-ray diffraction of the clay-size fraction shows prevailing kaolinite and hematite in the most altered samples, complemented by amorphous Fe-Al (hydr)oxides. Serra Geral basalts-normalized spidergrams and mass balance calculations confirmed almost complete losses of all major oxides (i.e., ~50 g of material was removed by weathering from each 100 g of the original basalt) and depletions of some trace elements (e.g., Sc, V, Sr, Cr,Ni, Rb and U) in the uppermost and intermediate layers of the lateritic profile, reflecting the weathering of feldspars, clinopyroxenes, volcanic glass and apatite. In contrast, some elements are enriched in the topmost and intermediate layers, due to intrinsic immobility during weathering (e.g., Zr, Hf, Ta, Th) or adsorption onto clays (e.g., Cs). Rare earth elements (REEs) are depleted in the top layers and enriched in the middle section of the profile. The preferential leaching of REEs from the uppermost levels during weathering and its accumulation in the middle section can be caused by a pH increase in this level, the decomposition of organic matter and the consequent precipitation of REEs which exhibit an affinity to form aqueous organic complexes, or the presence of Fe and Mn (hydr)oxides in the intermediate level. Weathering intensity was appraised by means of different alteration indices, which showed the extreme leaching endured by the basaltic bedrock. The index of lateritization (IOL), which ranges between 35 and 55, and the accompanying SAF ternary plot (SiO2-Al2O3-Fe2O3), indicate an increasing weathering trend towards the profiles' top, reflecting the modest loss of SiO2 (relative to Al2O3 and Fe2O3) during kaolinitization. The geochemical approach used to constrain the origin of the lateritic mantle that partially covers Misiones province, clearly relates the analyzed laterites to the underlying tholeiitic basalts, supporting the autochthonous origin theory.
publishedVersion
Fil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Lecomte, Karina L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Lecomte, Karina L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: García, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: García, M. Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Depetris, Pedro J. Academia Nacional de Ciencias; Argentina.
Geoquímica y Geofísica
Materia
Tropical weathering
Subtropical weathering
Posadas Fm
Serra Geral Fm
REE
Weathering indices
Nivel de accesibilidad
acceso abierto
Condiciones de uso
Repositorio
Repositorio Digital Universitario (UNC)
Institución
Universidad Nacional de Córdoba
OAI Identificador
oai:rdu.unc.edu.ar:11086/562202
Acceder
id RDUUNC_e078fdc7e4f4b9a5bb3520b3246b4288
oai_identifier_str oai:rdu.unc.edu.ar:11086/562202
network_acronym_str RDUUNC
repository_id_str 2572
network_name_str Repositorio Digital Universitario (UNC)
spelling Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)Campodonico, Verena A.Pasquini, Andrea I.Lecomte, Karina L.García, M. GabrielaDepetris, Pedro J.Tropical weatheringSubtropical weatheringPosadas FmSerra Geral FmREEWeathering indicesFil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Pasquini, Andrea I. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Pasquini, Andrea I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Lecomte, Karina L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Lecomte, Karina L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: García, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: García, M. Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Depetris, Pedro J. Academia Nacional de Ciencias; Argentina.Subtropical laterites are partially found in the Argentinian province of Misiones, covering the JurassicCretaceous Serra Geral flood basalts (known as Posadas Formation in Argentina). Two hypotheses have been proposed to explain the origin of these laterites. The autochthonous theory attributes the origin of these deposits to the chemical weathering of the underlying tholeiitic basalts. However, during the last decade, an allochthonous “tropical loess” model was proposed. Several mineralogical/geochemical characteristics of a lateritic profile (~2 m thick, 26°9′58″S–54°35′3″W) are analyzed in this paper in order to constrain the nature of weathering processes in this region and the provenance of the lateritic layer. The basaltic bedrock at the sampling site exhibits intergranular texture and is mainly composed of clinopyroxene, plagioclase and opaque minerals (likely titanomagnetite and ilmenite). Altered glass and apatite were also identified in lower proportions. The X-ray diffraction of the clay-size fraction shows prevailing kaolinite and hematite in the most altered samples, complemented by amorphous Fe-Al (hydr)oxides. Serra Geral basalts-normalized spidergrams and mass balance calculations confirmed almost complete losses of all major oxides (i.e., ~50 g of material was removed by weathering from each 100 g of the original basalt) and depletions of some trace elements (e.g., Sc, V, Sr, Cr,Ni, Rb and U) in the uppermost and intermediate layers of the lateritic profile, reflecting the weathering of feldspars, clinopyroxenes, volcanic glass and apatite. In contrast, some elements are enriched in the topmost and intermediate layers, due to intrinsic immobility during weathering (e.g., Zr, Hf, Ta, Th) or adsorption onto clays (e.g., Cs). Rare earth elements (REEs) are depleted in the top layers and enriched in the middle section of the profile. The preferential leaching of REEs from the uppermost levels during weathering and its accumulation in the middle section can be caused by a pH increase in this level, the decomposition of organic matter and the consequent precipitation of REEs which exhibit an affinity to form aqueous organic complexes, or the presence of Fe and Mn (hydr)oxides in the intermediate level. Weathering intensity was appraised by means of different alteration indices, which showed the extreme leaching endured by the basaltic bedrock. The index of lateritization (IOL), which ranges between 35 and 55, and the accompanying SAF ternary plot (SiO2-Al2O3-Fe2O3), indicate an increasing weathering trend towards the profiles' top, reflecting the modest loss of SiO2 (relative to Al2O3 and Fe2O3) during kaolinitization. The geochemical approach used to constrain the origin of the lateritic mantle that partially covers Misiones province, clearly relates the analyzed laterites to the underlying tholeiitic basalts, supporting the autochthonous origin theory.publishedVersionFil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Pasquini, Andrea I. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Pasquini, Andrea I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Lecomte, Karina L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: Lecomte, Karina L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: García, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.Fil: García, M. Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Depetris, Pedro J. Academia Nacional de Ciencias; Argentina.Geoquímica y Geofísica2019info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf0341-8162http://hdl.handle.net/11086/562202enginfo:eu-repo/semantics/openAccessreponame:Repositorio Digital Universitario (UNC)instname:Universidad Nacional de Córdobainstacron:UNC2026-09-24T11:43:30Zoai:rdu.unc.edu.ar:11086/562202Institucionalhttps://rdu.unc.edu.ar/Universidad públicaNo correspondehttp://rdu.unc.edu.ar/oai/snrdoca.unc@gmail.comArgentinaNo correspondeNo correspondeNo correspondeopendoar:25722026-09-24 11:43:31.174Repositorio Digital Universitario (UNC) - Universidad Nacional de Córdobafalse
dc.title.none.fl_str_mv Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
title Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
spellingShingle Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
Campodonico, Verena A.
Tropical weathering
Subtropical weathering
Posadas Fm
Serra Geral Fm
REE
Weathering indices
title_short Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
title_full Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
title_fullStr Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
title_full_unstemmed Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
title_sort Chemical weathering in subtropical basalt-derived laterites: A mass balance interpretation (Misiones, NE Argentina)
dc.creator.none.fl_str_mv Campodonico, Verena A.
Pasquini, Andrea I.
Lecomte, Karina L.
García, M. Gabriela
Depetris, Pedro J.
author Campodonico, Verena A.
author_facet Campodonico, Verena A.
Pasquini, Andrea I.
Lecomte, Karina L.
García, M. Gabriela
Depetris, Pedro J.
author_role author
author2 Pasquini, Andrea I.
Lecomte, Karina L.
García, M. Gabriela
Depetris, Pedro J.
author2_role author
author
author
author
dc.subject.none.fl_str_mv Tropical weathering
Subtropical weathering
Posadas Fm
Serra Geral Fm
REE
Weathering indices
topic Tropical weathering
Subtropical weathering
Posadas Fm
Serra Geral Fm
REE
Weathering indices
dc.description.none.fl_txt_mv Fil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Lecomte, Karina L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Lecomte, Karina L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: García, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: García, M. Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Depetris, Pedro J. Academia Nacional de Ciencias; Argentina.
Subtropical laterites are partially found in the Argentinian province of Misiones, covering the JurassicCretaceous Serra Geral flood basalts (known as Posadas Formation in Argentina). Two hypotheses have been proposed to explain the origin of these laterites. The autochthonous theory attributes the origin of these deposits to the chemical weathering of the underlying tholeiitic basalts. However, during the last decade, an allochthonous “tropical loess” model was proposed. Several mineralogical/geochemical characteristics of a lateritic profile (~2 m thick, 26°9′58″S–54°35′3″W) are analyzed in this paper in order to constrain the nature of weathering processes in this region and the provenance of the lateritic layer. The basaltic bedrock at the sampling site exhibits intergranular texture and is mainly composed of clinopyroxene, plagioclase and opaque minerals (likely titanomagnetite and ilmenite). Altered glass and apatite were also identified in lower proportions. The X-ray diffraction of the clay-size fraction shows prevailing kaolinite and hematite in the most altered samples, complemented by amorphous Fe-Al (hydr)oxides. Serra Geral basalts-normalized spidergrams and mass balance calculations confirmed almost complete losses of all major oxides (i.e., ~50 g of material was removed by weathering from each 100 g of the original basalt) and depletions of some trace elements (e.g., Sc, V, Sr, Cr,Ni, Rb and U) in the uppermost and intermediate layers of the lateritic profile, reflecting the weathering of feldspars, clinopyroxenes, volcanic glass and apatite. In contrast, some elements are enriched in the topmost and intermediate layers, due to intrinsic immobility during weathering (e.g., Zr, Hf, Ta, Th) or adsorption onto clays (e.g., Cs). Rare earth elements (REEs) are depleted in the top layers and enriched in the middle section of the profile. The preferential leaching of REEs from the uppermost levels during weathering and its accumulation in the middle section can be caused by a pH increase in this level, the decomposition of organic matter and the consequent precipitation of REEs which exhibit an affinity to form aqueous organic complexes, or the presence of Fe and Mn (hydr)oxides in the intermediate level. Weathering intensity was appraised by means of different alteration indices, which showed the extreme leaching endured by the basaltic bedrock. The index of lateritization (IOL), which ranges between 35 and 55, and the accompanying SAF ternary plot (SiO2-Al2O3-Fe2O3), indicate an increasing weathering trend towards the profiles' top, reflecting the modest loss of SiO2 (relative to Al2O3 and Fe2O3) during kaolinitization. The geochemical approach used to constrain the origin of the lateritic mantle that partially covers Misiones province, clearly relates the analyzed laterites to the underlying tholeiitic basalts, supporting the autochthonous origin theory.
publishedVersion
Fil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Pasquini, Andrea I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Lecomte, Karina L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: Lecomte, Karina L. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: García, M. Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
Fil: García, M. Gabriela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.
Fil: Depetris, Pedro J. Academia Nacional de Ciencias; Argentina.
Geoquímica y Geofísica
description Fil: Campodonico, Verena A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Ciencias de la Tierra; Argentina.
publishDate 2019
dc.date.none.fl_str_mv 2019
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dc.identifier.none.fl_str_mv 0341-8162
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instname_str Universidad Nacional de Córdoba
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