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Chlorite composition and geothermometry: a comparative HRTEM/AEM-EMPA-XRD study of Cambrian basic lavas from the Ossa Morena Zone, SW Spain

Published online by Cambridge University Press:  09 July 2018

A. López-Munguira ,
F. Nieto  and
D. Morata
A. López-Munguira*
Affiliation:
Área de Cristalografía y Mineralogía, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz, Spain
F. Nieto
Affiliation:
Departamento de Mineralogía y Petrologa y I.A.C.T., Universidad de Granada-CSIC, Avda. Fuentenueva s/n, 18002, GranadaSpain
D. Morata
Affiliation:
Departamento de Geología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago de Chile, Chile
*
*E-mail: [email protected]
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Abstract

Chlorites from Cambrian basaltic vesicular lavas, characterized by relatively high Xc (0.81-0.98), gave temperatures of formation of 285 to 350°C (Cathelineau's empirical geothermometer). Both the Xc and temperature calculations gave results which were too high for the diagenetic conditions indicated by the interbedded shale mineralogy. The HRTEM and XRD studies indicate the absence of smectite layers in these chlorites; i.e. according to lattice images, the actual value of Xc is 1. The chlorite composition in these basaltic lavas must, therefore, be explained in relation to their whole-rock geochemistry, with which a good correlation has been found. The basaltic lavas are characterized by relatively high FeO/M ratios (3.28±1.66) and must be considered as an Fe-rich system, with similar chemical behaviour to pelitic rocks. In these cases, direct chlorite formation, without a previous smectite precursor, is a normal occurrence and the Xc calculation and empirical geothermometric calculations are inadequate.

Keywords

chloritemetabasitesvery low-grade metamorphismchemical compositionthermometry
Type
Research Article
Information
Clay Minerals , Volume 37 , Issue 2 , June 2002 , pp. 267 - 281
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2002

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References

Aagaard, P. & Jahren, J.S. (1992) Diagenetic illitechlorite assemblages in arenites. II. Thermodynamic relations. Clays and Clay Minerals, 40, 547–554.CrossRefGoogle Scholar
Aguirre, L., Robinson, D., Bevins, R., Morata, D., Vergara, M., Fonseca, E. & Carrasco, J. (2000) A low-grade metamorphic model for the Miocene volcanic sequences in the Andes of central Chile. New Zealand Journal of Geology and Geophysics, 43, 83–93.CrossRefGoogle Scholar
Árkai, P., Mata, M.P., Giorgetti, G., Peacor, D.R. & Tóth, M. (2000) Comparison of diagenetic and low-grade metamorphic evolution of chlorite in associated metapelites and metabasites: an integrated TEM and XRD study. Journal of Metamorphic Geology, 18, 531–550.Google Scholar
Bettison, L.A. & Schiffman, P. (1988) Compositional and structural variations of phyllosilicates from the Point Sal ophiolite, California. American Mineralogist, 73, 62–76.Google Scholar
Buseck, P.R. (1992) Principles of transmission electron microscopy. Pp. 1–35 in. Minerals and Reactions at the Atomic Scale: Transmission Electron Microscopy (Buseck, P.R., editor). Reviews in Mineralogy, 27, Mineralogical Society of America, Washington, D.C.Google Scholar
Buseck, P.R., Cowley, J.M. & Eyring, L. (1988) Highresolution Transmission Electron Microscopy and associated Techniques. Oxford University Press, New York, 128 pp.Google Scholar
Cathelineau, M. (1988) Cation site occupancy in chlorites and illites as a function of temperature. Clay Minerals, 23, 471–485.Google Scholar
Cathelineau, M. & Nieva, D. (1985) A chlorite solid solution thermometer. The Los Azufres geothermal system (Me). Contributions to Mineralogy and Petrology, 91, 235–244.Google Scholar
Champness, P.E., Cliff, G. & Lorimer, G.W. (1981) Quantitative analytical electron microscopy. Bulletin of Mineralogy, 104, 236–240.CrossRefGoogle Scholar
Cliff, G. & Lorimer, G.W. (1975) The quantitative analysis of thin specimens. Journal of Microscopy, 103, 203–207.CrossRefGoogle Scholar
De Caritat, P.D., Hutcheon, I. & Walshe, J.L. (1993) Chlorite geothermometry: a review. Clays and Clay Minerals, 41, 219–239.CrossRefGoogle Scholar
Essene, E.J. & Peacor, D.R. (1995) Clay minerals thermometry A critical perspective. Clays and Clay Minerals, 43, 540–553.CrossRefGoogle Scholar
Frimmel, H.E. (1997) Chlorite thermometry in the Witwat ersrand Basin: constr aints on the Paleoproterozoic geotherm in the Kaapvaal Craton, South Africa. Journal of Geology, 105, 601–615.Google Scholar
Hutcheon, I. (1990) Clay-carbonate reactions in the Venture area, Scotia Shelf, Nova Scotia, Canada. Pp. 199–212 in. Fluid-mineral Interactions: A Tribute to H.P. Eugster (Spencer, R.J. & Chou, I.M., editors). Special Publicat ion 2, Geochemical Society, Washington, D.C.Google Scholar
Jiang, W.W. & Peacor, D.R. (1994) Prograde transition of corrensite and chlorite in low-grade pelitic rocks from the Gaspe Peninsula, Quebec. Clays and Clay Minerals, 42, 497–517.Google Scholar
Jiang, W.W., Peacor, D.R. & Buseck, P.R. (1994) Chlorite geothermometry? contamination and apparent octahedral vacancies. Clays and Clay Minerals, 42, 593–605.Google Scholar
Jowett, E.C. (1991) Fitting iron and magnesium into the hydrothermal chlorite geothermometer (abstract). GAC/MAC/SEG Joint Annual Meeting. Program and Abstracts, 16, A62.Google Scholar
Julivert, M., Fontboté, J.M., Ribeiro, A. & Conde, L. (1974) Mapa Tectónico de la Península Ibérica y Baleares. Instituto Geológico y Minero de España, Madrid, Spain, 113 pp.Google Scholar
Kranidiotis, P. & McLean, W.H. (1987) Systematics of chlorite alteration at the Phelps Dodge massive sulfide deposit. Matagami, Quebec. Economic Geology, 82, 1898–1991.Google Scholar
Laird, J. (1988) Chlorites: metamorphic petrology. Pp. 405–453 in: Hydrous Phyllosilicates (Exclusive of Micas) (Bailey, S.W., editor ). Reviews in Mineralogy, 19, Mineralogical Society of America, Washington, D.C.Google Scholar
Liñán, E., Gámez-Vintaned, J.A., Palacios, T., Álvaro, J., Gonzalo, R., Mayoral, E., Moreno-Eiris, E., Perejón, A., Quesada, C. & Sánchez-García, T. (1995) The Cambrian of the Alconera Unit. Neoproterozoic- Cambrian Transet of Sierra Morena and Montes de Toledo. Pre-conference Field Guide. Pp. 9–21 in: Annual IGCP Project 319 Meeting, Regional IGCP Project 320 Meeting and XIII Geological Meeting on the West of Iberia Peninsul a, University of Salamanca, Spain.Google Scholar
López-Munguira, A. & Nieto, F. (2000) Transmission electron microscopy study of very low-grade metamorphic rocks in Cambrian sandstones and shales, Ossa-Morena zone, South-West Spain. Clays and Clay Minerals, 48, 213–223.Google Scholar
López-Munguira, A., Nieto, F. & Sebastian-Pardo, E. (1993) Caracterización de las pizarras cámbricas de la Unidad Alconera (Zona de Ossa-Morena). Su utilidad como indicadores de las condiciones metamórficas. Geogaceta, 13, 69–71.Google Scholar
López-Munguira, A., Morata, D. & Nieto, F. (1996) Geoquímica de los materiales pelíticos cámbricos al noroeste de Zafra (Badajoz). Geogaceta, 22, 149–152.Google Scholar
López-Munguira, A., Nieto, F. & Morata, D. (1998) Metamorphic evolution from diagenesis to epizone in Cambrian formations from NW Zafra (Ossa- Morena zone, SW Spain). Neues Jahrbuch für Mineralogie Abhandlungen, 174, 131–157.Google Scholar
Mata, M.P., Giorgetti, G., Árkai, P. & Peacor, D.R. (2001) Comparison of evolution of trioctahedral chlorite/ berthierine/ smectite in coeval metabasites and metapelites from diagenetic to epizonal grades. Clays and Clay Minerals, 49, 318–332.Google Scholar
Merriman, R.J. & Peacor, D.R. (1999) Very low-grade metapelites. Mineralogy, microfabrics and measuring reaction progress. Pp. 10–58 in: Low-grade Metamorphism. (Frey, M. & Robinson, D., editors). Blackwell Science. Oxford, UK.Google Scholar
Merriman, R.J., Roberts, B., Peacor, D.R. & Hirons, S.R. (1995) Strain-related differences in the crystal growth of white mica and chlorite: a TEM and XRD study of the development of metapelite microfabrics in the Southern Uplands thrust terrene, Scotland. Journal of Metamorphic Geology, 13, 559–576.Google Scholar
Sagredo, J. & Peinado, M. (1992) Vulcanismo Cámbrico de la Zona de Ossa-Morena. Pp. 567–576 in: Paleozo ico Inferior de Iberoamérica. (Gutiérrez-Marco, J.G., Saavedra, J. & Rábano, I., editors). Universidad de Extramadura, Badajoz, Spain.Google Scholar
Schiffman, P. & Day, H.W. (1999) Petrological methods for the study of very-low grade metabasites. Pp. 108–142 in: Low-grade Metamorphism (Frey, M. & Robinson, D., editors). Blackwell Science, Oxford, UK.Google Scholar
Schmidt, D. & Livi, K.J.T. (1999) HRTEM and SAED investigations of polytypism, stacking disorder, crystal-growth, and vacancies in chlorites from subgreenschist facies out cr ops. American Mineralogist, 84, 160–170.Google Scholar
Schmidt, D., Livi, K.J.T. & Frey, M. (1999) Reaction progress in chloritic material an electron microbeam study of the Taveyanne Greywacke, Switzerland. Journal of Metamorphic Geology, 17, 229–241.Google Scholar
Schmidt, S.Th. & Robinson, D. (1997) Metamorphic grade and porosity and permeability controls on mafic phyllosilicate distributions in a regional zeolite to greenschist facies transition of the North Shore Volcanic Group, Minnesota. Geological Society of America Bulletin, 109, 683–697.2.3.CO;2>CrossRefGoogle Scholar
Shau, Y.H., Peacor, D.R. & Essene, E.J. (1990) Corrensite and mixed-layer chlorite/corrensite in metabasalt from northern Taiwan: TEM/AEM, EMPA, XRD, and optical studies. Contributions to Mineralogy and Petrology, 105, 123–142.CrossRefGoogle Scholar
Walker, J.R. (1993) Chlorite polytype geothermometry. Clays and Clay Minerals, 41, 260–267.Google Scholar
Walshe, J.L. (1986) A six-component chlorite solid solution model and the conditions of chlorite formation in hydrothermal and geothermal systems. Economic Geology, 81, 681–703.CrossRefGoogle Scholar
Warren, E.A. & Ransom, B. (1992) The influence of analytical error upon the interpretation of chemical variation in clay minerals. Clay Minerals, 27, 193–209.Google Scholar
Xie, X., Byerly, G.R. & Ferrell, R.E. (1997) IIb trioctahedral chlorite from the Barberton greenstone belt: crystal structure and rock composition constraints with implications for geothermometry. Contributions to Mineralogy and Petrology, 126, 275–291.Google Scholar
Zane, A., Sassi, R. & Guidotti, C.V. (1998) New data on metamorphic chlorite as a petrogenetic indicator mineral, with special regard to greenschist-facies rocks. The Canadian Mineralogist, 36, 713–726.Google Scholar
Zang, W. & Fyfe, W.S. (1995) Chloritization of the hydrothermally altered bedrock at IgarapéBahia gold deposits, Carajás, Brazil. Mineralium Deposita, 30, 30–38.Google Scholar