Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study

Detalhes bibliográficos
Autor(a) principal: Klein, Evandro Luiz
Data de Publicação: 2000
Outros Autores: Fuzikawa, Kazuo, Koppe, Jair Carlos, Dantas, Maria Sylvia Silva
Tipo de documento: Artigo
Idioma: por
Título da fonte: Repositório Institucional da UFRGS
Texto Completo: http://hdl.handle.net/10183/210110
Resumo: The Caxias deposit is situated in the Gurupi Auriferous Province of the Paleoproterozoic São Luís Craton, northern Brazil. It is a lode-type gold mineralization associated with a narrow, steeply dipping, NE-trending, shear zone crosscutting a hydrothermalized microtonalite (northern sector) and schists (southern sector). Fluid inclusion studies on vein quartz crosscutting the microtonalite (northern sector) have identified early carbonic and aqueous-carbonic inclusions and late aqueous inclusions, unrelated to the mineralizing event. The CO2/H2O ratio and the other microthermometric properties show a wide range of values, which are interpreted as product of heterogeneous trapping of two (partially) immiscible fluids and to deformation-related post-formational processes. The resulting mineralizing fluid has XCO2- 6-45 mol %; XN2: <2.5 mol %; XH2O: 55-95 mol %; mean salinity of 4.5 wt % NaCl equiv., and moderate density (0.7-1.0 g/cm3). Bulk isochores coupled with chlorite geothermometry constrained the P-T entrapment conditions between 262-307ºC and 1.6-3.7 kb. Log ¦O2 for this P-T-X range was estimated between –29.8 and –34.2. Geological characteristics and fluid properties found in the northern sector of Caxias gold mineralization are similar to those described for metamorphic fluids of mesothermal gold deposits.
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spelling Klein, Evandro LuizFuzikawa, KazuoKoppe, Jair CarlosDantas, Maria Sylvia Silva2020-06-05T03:48:10Z20000375-7536http://hdl.handle.net/10183/210110000296052The Caxias deposit is situated in the Gurupi Auriferous Province of the Paleoproterozoic São Luís Craton, northern Brazil. It is a lode-type gold mineralization associated with a narrow, steeply dipping, NE-trending, shear zone crosscutting a hydrothermalized microtonalite (northern sector) and schists (southern sector). Fluid inclusion studies on vein quartz crosscutting the microtonalite (northern sector) have identified early carbonic and aqueous-carbonic inclusions and late aqueous inclusions, unrelated to the mineralizing event. The CO2/H2O ratio and the other microthermometric properties show a wide range of values, which are interpreted as product of heterogeneous trapping of two (partially) immiscible fluids and to deformation-related post-formational processes. The resulting mineralizing fluid has XCO2- 6-45 mol %; XN2: <2.5 mol %; XH2O: 55-95 mol %; mean salinity of 4.5 wt % NaCl equiv., and moderate density (0.7-1.0 g/cm3). Bulk isochores coupled with chlorite geothermometry constrained the P-T entrapment conditions between 262-307ºC and 1.6-3.7 kb. Log ¦O2 for this P-T-X range was estimated between –29.8 and –34.2. Geological characteristics and fluid properties found in the northern sector of Caxias gold mineralization are similar to those described for metamorphic fluids of mesothermal gold deposits.application/pdfporRevista brasileira de geociências. São Paulo. Vol. 30, n. 2 (jun. 2000), p. 322-326GeoquímicaGeotectônicaMineraçãoOuroGoldAqueous-carbonic fluidsMesothermalPaleoproterozoicFluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion studyinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/otherinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT000296052.pdf.txt000296052.pdf.txtExtracted Texttext/plain22724http://www.lume.ufrgs.br/bitstream/10183/210110/2/000296052.pdf.txtd58cdc7949c1e621ecc9b8ea554f8e73MD52ORIGINAL000296052.pdfTexto completo (inglês)application/pdf212037http://www.lume.ufrgs.br/bitstream/10183/210110/1/000296052.pdf72cafb4963440e1788a7dc354ea9a55bMD5110183/2101102023-08-09 03:47:30.844463oai:www.lume.ufrgs.br:10183/210110Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-08-09T06:47:30Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false
dc.title.pt_BR.fl_str_mv Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
title Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
spellingShingle Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
Klein, Evandro Luiz
Geoquímica
Geotectônica
Mineração
Ouro
Gold
Aqueous-carbonic fluids
Mesothermal
Paleoproterozoic
title_short Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
title_full Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
title_fullStr Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
title_full_unstemmed Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
title_sort Fluids associated with the Caxias mesothermal gold mineralization, São Luis Craton, northern Brazil: a fluid inclusion study
author Klein, Evandro Luiz
author_facet Klein, Evandro Luiz
Fuzikawa, Kazuo
Koppe, Jair Carlos
Dantas, Maria Sylvia Silva
author_role author
author2 Fuzikawa, Kazuo
Koppe, Jair Carlos
Dantas, Maria Sylvia Silva
author2_role author
author
author
dc.contributor.author.fl_str_mv Klein, Evandro Luiz
Fuzikawa, Kazuo
Koppe, Jair Carlos
Dantas, Maria Sylvia Silva
dc.subject.por.fl_str_mv Geoquímica
Geotectônica
Mineração
Ouro
topic Geoquímica
Geotectônica
Mineração
Ouro
Gold
Aqueous-carbonic fluids
Mesothermal
Paleoproterozoic
dc.subject.eng.fl_str_mv Gold
Aqueous-carbonic fluids
Mesothermal
Paleoproterozoic
description The Caxias deposit is situated in the Gurupi Auriferous Province of the Paleoproterozoic São Luís Craton, northern Brazil. It is a lode-type gold mineralization associated with a narrow, steeply dipping, NE-trending, shear zone crosscutting a hydrothermalized microtonalite (northern sector) and schists (southern sector). Fluid inclusion studies on vein quartz crosscutting the microtonalite (northern sector) have identified early carbonic and aqueous-carbonic inclusions and late aqueous inclusions, unrelated to the mineralizing event. The CO2/H2O ratio and the other microthermometric properties show a wide range of values, which are interpreted as product of heterogeneous trapping of two (partially) immiscible fluids and to deformation-related post-formational processes. The resulting mineralizing fluid has XCO2- 6-45 mol %; XN2: <2.5 mol %; XH2O: 55-95 mol %; mean salinity of 4.5 wt % NaCl equiv., and moderate density (0.7-1.0 g/cm3). Bulk isochores coupled with chlorite geothermometry constrained the P-T entrapment conditions between 262-307ºC and 1.6-3.7 kb. Log ¦O2 for this P-T-X range was estimated between –29.8 and –34.2. Geological characteristics and fluid properties found in the northern sector of Caxias gold mineralization are similar to those described for metamorphic fluids of mesothermal gold deposits.
publishDate 2000
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dc.relation.ispartof.pt_BR.fl_str_mv Revista brasileira de geociências. São Paulo. Vol. 30, n. 2 (jun. 2000), p. 322-326
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