Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia

Ca-dachiardite is present in Cretaceous volcanic breccias affected by very low grade metamorphism. The cement of the breccia shows quartz, Ca-dachiardite, mordenite, cristobalite, calcite and siderite, while in the clasts there are pectolite, prehnite, yugawaralite, Ca-dachiardite, albite, adularia,...

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Autores principales: Vattuone, M.E., Latorre, C.O., Lea, P.R.
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_07160208_v33_n1_p161_Vattuone
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spelling todo:paper_07160208_v33_n1_p161_Vattuone2023-10-03T15:36:11Z Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia Vattuone, M.E. Latorre, C.O. Lea, P.R. Ca dachiardite Cretaceous Esquel Patagonia argentina Very low grade metamorphism Crystallization Geology Mineral resources Mineralogy Quartz deposits Volcanic rocks crystal property crystallization crystallography metamorphism mineralogy nonsilicate mineral paragenesis silicate mineral volcanic rock Argentina Chubut Esquel Patagonia South America Ca-dachiardite is present in Cretaceous volcanic breccias affected by very low grade metamorphism. The cement of the breccia shows quartz, Ca-dachiardite, mordenite, cristobalite, calcite and siderite, while in the clasts there are pectolite, prehnite, yugawaralite, Ca-dachiardite, albite, adularia, interestratified smectite/chlorite (S/C), quartz and cristobalite. Most Ca-dachiardites are found in the cement of the breccia. It occurs principally as fibrous tubes of parallel or lightly divergent bladed and tabular crystals, arranged in concentrical layers with length along 'b' and the fibers; the crystals are flattened on {001} and rarely on {100}. It shows cyclic twins in cross section normal to the length and multiple twins parallel to {001}, but single crystals are also present. The optical character shows: a=b; g:c=43°; 2Va=55°/60°; strong dispersion r>v. The structural formulae is: Ca1.54-1.72 K0.82-0.98 Na0 (Al3.65-3.98 Si19.95-20.25 O48) 13H2O; TSi=0.83-0.85; R2+/ (R+ + R2+)=0.61/0.68; DEC=Ca and K. The strong diffraction lines are: 3.460 Å 3.190 Å and 1.870 Å a0 =18.679 Å b0=7.488 Å; c0 10.267 Å; b=107°86′. The secondary mineralogical succession deposited according with the decrease in temperature and Xco2, could be: calcite (step I); pectolite, prehnite, quartz, yugawaralite, Ca-dachiardite, S/C, adularia, albite (step II, zeolite facies); mordenite and cristobalite (step III) and then, siderite and calcite (step IV). The metamorphic assemblages suggests that the crystallization conditions of Ca-dachiardite would be 200-220°C at pressures smaller than 0.5 kb, from high aSi and aCa fluids. © 2006 Servicio Nacional de Geologí y Minería. Fil:Vattuone, M.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Latorre, C.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_07160208_v33_n1_p161_Vattuone
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Ca dachiardite
Cretaceous
Esquel
Patagonia argentina
Very low grade metamorphism
Crystallization
Geology
Mineral resources
Mineralogy
Quartz deposits
Volcanic rocks
crystal property
crystallization
crystallography
metamorphism
mineralogy
nonsilicate mineral
paragenesis
silicate mineral
volcanic rock
Argentina
Chubut
Esquel
Patagonia
South America
spellingShingle Ca dachiardite
Cretaceous
Esquel
Patagonia argentina
Very low grade metamorphism
Crystallization
Geology
Mineral resources
Mineralogy
Quartz deposits
Volcanic rocks
crystal property
crystallization
crystallography
metamorphism
mineralogy
nonsilicate mineral
paragenesis
silicate mineral
volcanic rock
Argentina
Chubut
Esquel
Patagonia
South America
Vattuone, M.E.
Latorre, C.O.
Lea, P.R.
Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia
topic_facet Ca dachiardite
Cretaceous
Esquel
Patagonia argentina
Very low grade metamorphism
Crystallization
Geology
Mineral resources
Mineralogy
Quartz deposits
Volcanic rocks
crystal property
crystallization
crystallography
metamorphism
mineralogy
nonsilicate mineral
paragenesis
silicate mineral
volcanic rock
Argentina
Chubut
Esquel
Patagonia
South America
description Ca-dachiardite is present in Cretaceous volcanic breccias affected by very low grade metamorphism. The cement of the breccia shows quartz, Ca-dachiardite, mordenite, cristobalite, calcite and siderite, while in the clasts there are pectolite, prehnite, yugawaralite, Ca-dachiardite, albite, adularia, interestratified smectite/chlorite (S/C), quartz and cristobalite. Most Ca-dachiardites are found in the cement of the breccia. It occurs principally as fibrous tubes of parallel or lightly divergent bladed and tabular crystals, arranged in concentrical layers with length along 'b' and the fibers; the crystals are flattened on {001} and rarely on {100}. It shows cyclic twins in cross section normal to the length and multiple twins parallel to {001}, but single crystals are also present. The optical character shows: a=b; g:c=43°; 2Va=55°/60°; strong dispersion r>v. The structural formulae is: Ca1.54-1.72 K0.82-0.98 Na0 (Al3.65-3.98 Si19.95-20.25 O48) 13H2O; TSi=0.83-0.85; R2+/ (R+ + R2+)=0.61/0.68; DEC=Ca and K. The strong diffraction lines are: 3.460 Å 3.190 Å and 1.870 Å a0 =18.679 Å b0=7.488 Å; c0 10.267 Å; b=107°86′. The secondary mineralogical succession deposited according with the decrease in temperature and Xco2, could be: calcite (step I); pectolite, prehnite, quartz, yugawaralite, Ca-dachiardite, S/C, adularia, albite (step II, zeolite facies); mordenite and cristobalite (step III) and then, siderite and calcite (step IV). The metamorphic assemblages suggests that the crystallization conditions of Ca-dachiardite would be 200-220°C at pressures smaller than 0.5 kb, from high aSi and aCa fluids. © 2006 Servicio Nacional de Geologí y Minería.
format JOUR
author Vattuone, M.E.
Latorre, C.O.
Lea, P.R.
author_facet Vattuone, M.E.
Latorre, C.O.
Lea, P.R.
author_sort Vattuone, M.E.
title Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia
title_short Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia
title_full Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia
title_fullStr Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia
title_full_unstemmed Mineralogy and paragenesis of Ca-dachiardite in Cretaceous zeolitized volcanic rocks, Esquel, Chubut, Argentinian Patagonia
title_sort mineralogy and paragenesis of ca-dachiardite in cretaceous zeolitized volcanic rocks, esquel, chubut, argentinian patagonia
url http://hdl.handle.net/20.500.12110/paper_07160208_v33_n1_p161_Vattuone
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AT leapr mineralogyandparagenesisofcadachiarditeincretaceouszeolitizedvolcanicrocksesquelchubutargentinianpatagonia
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