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Prograde epizonal clay mineral assemblages and retrograde alteration in tectonic basins controlled by major strike-slip zones (W Iberian Variscan chain)

Published online by Cambridge University Press:  09 July 2018

M. Vázquez ,
I. Abad ,
J. Jiménez-Millán ,
F. T. Rocha ,
P. E. Fonseca  and
H. I. Chaminé
M. Vázquez
Affiliation:
Centro de Minerais Industriais e Argilas (MIA), Departamento de Geociências, Universidade de Aveiro, 3810-193 Aveiro, Portugal
I. Abad*
Affiliation:
Departamento de Geología, Universidad de Jaén, Campus Universitario, Edificio B-3, 23071 Jaén, Spain
J. Jiménez-Millán
Affiliation:
Departamento de Geología, Universidad de Jaén, Campus Universitario, Edificio B-3, 23071 Jaén, Spain
F. T. Rocha
Affiliation:
Centro de Minerais Industriais e Argilas (MIA), Departamento de Geociências, Universidade de Aveiro, 3810-193 Aveiro, Portugal
P. E. Fonseca
Affiliation:
Departamento de Geologia, Faculdade de Ciências da Universidade de Lisboa and LATTEX, Portugal
H. I. Chaminé
Affiliation:
Centro de Minerais Industriais e Argilas (MIA), Departamento de Geociências, Universidade de Aveiro, 3810-193 Aveiro, Portugal Departamento de Engenharia Geotécnica, Instituto Superior de Engenharia do Porto (ISEP), Portugal
*
*E-mail: [email protected]
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Abstract

We have carried out optical microscopy, X-ray diffraction (XRD) and scanning and transmission electron microscopy (SEM and TEM) studies of phyllosilicates from black slates of very low to low-grade metamorphism. Such slates belong to a Middle/Late Devonian basin and an Early Carboniferous basin associated with the Porto–Tomar–Ferreira do Alentejo strike-slip shear zone (Ossa-Morena Zone, Portuguese Iberian Variscan Massif). These black slates are imbricated in an Upper Proterozoic substratum of higher metamorphic grade. Kübler Index values of white micas and mineral assemblages deduced from the XRD, SEM and TEM data (muscovite, chlorite and pyrophyllite) indicate high anchizonal and epizonal metamorphic conditions for slates from these basins. The b parameter and the phengitic contents of mica suggest the occurrence of low pressures (1–2 kbar) related to an extensional geotectonic setting. The dense fracture network shown by SEM images and the high density of crystal defects revealed by the TEM study in the eastern basin, adjacent to faults produced by shearing, suggest that their epizonal phyllosilicates were more affected during deformation than those belonging to the western basin, favouring the development of a retrograde association (siderite, kaolin group minerals and Al-smectite) on the epizonal paragenesis. Microcavities formed along phyllosilicate cleavage acted as channels for fluid transport favouring alteration under low-temperature conditions.

Keywords

TEMSEMshear deformationIberian Massifmuscovitechloritedickitekaoliniteretrograde alterationlow-T metamorphism
Type
Research Article
Information
Clay Minerals , Volume 42 , Issue 1 , March 2007 , pp. 109 - 128
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2007

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References

Abad, I., Nieto, F., Gutiérrez-Alonso, G., Do Campo, M., López-Munguira, A. & Velilla, N. (2006) Illitic substitution in micas of very low-grade metamorphic clastic rocks. European Journal of Mineralogy, 18, 59–69.Google Scholar
Arkai, P., Mahlmann, R.F., Suchy, V., Balogh, K., Sykorova, I. & Frey, M. (2002) Possible effects of tectonic shear strain on phyllosilicates: a case study from the Kandersteg area, Helvetic domain, Central Alps, Switzerland. Schweizerische Mineralogische und Petrographische Mitteilungen, 82, 273–290.Google Scholar
Bailey, S.W. (1980) Structures of layer silicates. Pp. 1–123 in: Crystal Structures of Clay Minerals and their X-ray Identification (Brindley, G.E. & Brown, G., editors). Monograph, 5, Mineralogical Society London, UK.Google Scholar
Beetsma, J.J. (1995) The late Proterozoic/Paleozoic and Hercynian crustal evolution of the Iberian Massif N Portugal, as traced by geochemistry and Sr-Nd-Pb isotope systematics of pre-Hercynian terrigenous sediments and Hercynian granitoids. PhD thesis, Vrije Universiteit, Amsterdam, Holland.Google Scholar
Bevins, R.E., Robinson, D. & Rowbotham, G. (1991) Compositional variations in mafic phyllosilicates from regional low-grade metabasites and application of the chlorite geothermometer. Journal of Metamorphic Geology, 9, 711–721.Google Scholar
Caillère, S., Henin, S. & Rautureau, M. (1982) Minéralogie des argiles. Acte Scientifique Agricol de L’I.N.R.A 8. Masson, Paris.Google Scholar
Cathelineau, M. & Nieva, D. (1985) A chlorite solid solution geothermometer: the Los Azufres (Mexico) geothermal system. Contributions to Mineralogy and Petrology, 91, 235–244.Google Scholar
Chaminé, H.I. (2000) Estratigrafia e estrutura da faixa metamórfica de Espinho-Albergaria-a-Velha (Zona de Ossa-Morena): implicações geodinâmicas. PhD thesis, Universidade do Porto, Portugal.Google Scholar
Chaminé, H.I., Gama Pereira, L.C., Fonseca, P.E., Noronha, F. & Lemos de Sousa, M.J. (2003a) Tectonoestratigrafia da faixa de cisalhamento de Porto—Albergaria-a-Velha—Coimbra—Tomar, entre as Zonas Centro-Ibérica e de Ossa-Morena (Maciço Ibérico, W de Portugal). Cadernos do Laboratorio Xeolóxico de Laxe, A Coruna, 28, 37–78.Google Scholar
Chaminé, H.I., Gama Pereira, L.C., Fonseca, P.E., Moço, L.P., Fernandes, J.P., Rocha, F.T., Flores, D., Pinto de Jesus, A., Gomes, C., Soares de Andrade, A. & Araújo, A. (2003b) Tectonostratigraphy of middle and Upper Palaeozoic black shales from the Porto-Tomar-Ferreira do Alentejo shear zone (W Portugal): new perspectives on the Iberian Massif. Geobios, 36, 649–663.Google Scholar
Chaminé, H.I., Fonseca, P.E., Pinto de Jesus, A., Gama Pereira, L.C., Fernandes, J.P., Flores, D., Moço, L.P., Castro, R.D., Gomes, A., Teixeira, J., Araújo, M.A., Soares de Andrade, A.A., Gomes, C. & Rocha, F.T. (2006) Tectonostratigraphic imbrications along strike-slip major shear zones: an example from the early Carboniferous of SW European Variscides (Ossa-Morena Zone, Portugal). In: Proceedings of the XVth International Congress on Carboniferous and Permian Stratigraphy (Utrecht, 2003) (Wong, T.E., editor). Special Volume of the Royal Netherlands Academy of Arts and Sciences (in press), Netherlands.Google Scholar
Dempster, T.J. & Bluck, B.J. (1995) Regional metamorphism in transform zones during super continent breakup-Late proterozoic events of the Scottish highlands. Geology, 23, 991–994.2.3.CO;2>CrossRefGoogle Scholar
Dias, R. & Ribeiro, A. (1993) Porto-Tomar shear zone, a major structure since the beginning of the Variscan orogeny. Comunicações Instituto Geologico Mineiro, Lisboa, 79, 31–40.Google Scholar
Dias, R. & Ribeiro, A. (1995) The Ibero-Armorican arc: a collision effect against an irregular continent. Tectonophysics, 246, 113–128.CrossRefGoogle Scholar
Do Campo, M. & Nieto, F. (2003) Transmission electron microscopy study of very low-grade metamorphic evolution in Neoproterozoic pelites of the Puncoviscana formation (Cordillera Oriental, NW Argentina). Clay Minerals, 38, 459–481.Google Scholar
Farmer, V.C. (1974) The layer silicates. Pp. 331–365 in: The Infrared Spectra of Minerals (Farmer, V.C., editor). Mineralogical Society of London, UK.Google Scholar
Fernandes, J.P., Flores, D., Rocha, F.T., Gomes, C., Gama Pereira, L.C., Fonseca, P.E. & Chaminé, H.I. (2001) Devonian and Carboniferous palynomorph assemblages of black shales from the Ovar—Albergaria-a-Velha—Coimbra—Tomar (W Portugal): tectonostra-tigraphic implications for the Iberian Terrane. Geociências, Revue de la Universiade de Aveiro, 15, 1–23.Google Scholar
Fernandez, F.J., Chaminé, H.I., Fonseca, P.E., Munhá, J.M., Ribeiro, A., Aller, J., Fuertes-Fuentes, M. & Borges, F.S. (2003) HT-fabrics in a garnet-bearing quartzite from Western Portugal: geodynamic implications for the Iberian Variscan Belt. Terra Nova, 15, 96–103.Google Scholar
Gama Pereira, L.C. (1987) Tipologia e evolução da sutura entre a Zona Centro Ibérica e a Zona Ossa Morena no sector entre Alvaiázere e Figueiró dos Vinhos (Portugal Central). PhD Thesis, Universidade de Coimbra, Portugal.Google Scholar
Gomes, A., Chaminé, H.I., Teixeira, J., Fonseca, P.E., Gama Pereira, L.C., Pinto de Jesus, A., Pérez Albertí, A., Araújo, M.A., Coelho, A., Soares de Andrade, A. & Rocha, F.T. (2007) Late Cenozoic basin opening in relation to major strike-slip faulting along the Porto-Coimbra-Tomar fault zone (Northern Portugal). In: Sedimentary Processes, Equivalents and Basins: a tribute to Peter Friend (Paola, C., Nichols, G. and Williams, E., editors). IAS Special Publication (in press).Google Scholar
Guidotti, C.V. & Sassi, F.P. (1986) Classification and correlation of metamorphic facies series by means of muscovite b data from low-grade metapelites. Neues Jahrbuch fur Mineralogie Abhandlungen, 153, 363–380.Google Scholar
Guidotti, C.V., Yates, M.G., Dyar, M.D. & Taylor, M.E. (1994) Petrogenetic implications of the Fe3+ content of muscovite in pelitic schists. American Mineralogist, 79, 793–795.Google Scholar
Gutiérrez-Alonso, G., Fernandez-Suárez, J. & Weil, A.B. (2004) Orocline triggered lithospheric delamination. Pp. 121–130 in: Orogenic Curvature, Integrating Paleomagnetic and Structural Analyses (Sussman, A.J. & Weil, A.B., editors). Special Paper, 383, Geological Society of America, Boulder, Colorado.Google Scholar
Inoue, A., Meunier, A. & Beaufort, D. (2004) Illitesmectite mixed-layer minerals in felsic volcaniclastic rocks from drill cores in Kakkonda Japan. Clays and Clay Minerals, 52, 66–84.Google Scholar
Julivert, M., Fontboté, J.M., Ribeiro, A. & Conde, L.E.N. (1974) Mapa Tectónico de la Península Ibérica y Baleares, Escala 1:1000.000. Memoria Explicativa, Instituto Geologico y Minero de España, Madrid. 113 pp.Google Scholar
Keller, W.D. (1988) Authigenic kaolinite and dickite associated with metal sulfides. Clays and Clay Minerals, 36, 153–158.Google Scholar
Kemp, S.J., Merriman, R.J. & Bouch, J.E. (2005) Clay mineral reaction progress — the maturity and burial history of the Lias Group of England and Wales. Clay Minerals, 40, 43–61.Google Scholar
Kisch, H.J. (1991) Illite crystallinity: recommendations on sample preparation, X-ray diffraction settings, and interlaboratory samples. Journal of Metamorphic Geology, 9, 665–670.Google Scholar
Kisch, H.J., Arkai, P. & Brime, C. (2004) On the calibration of the illite Kübler index (illite ‘crystal-linity’). Schweizerische Mineralogische un . Petrographische Mitteilungen, 84, 323–331.Google Scholar
Kretz, R. (1983) Symbols for rock-forming minerals. American Mineralogist, 68, 277–279.Google Scholar
López-Munguira, A., Nieto, F. & Morata, D. (2002) Chlorite composition controlled by whole-rock geochemistry. An HRTEM/AEM-EMPA-XRD study in Cambrian basic volcanic rocks from the Ossa Morena Zone, SW Spain. Clay Minerals, 37, 267–281.Google Scholar
Lotze, F. (1945) Zur Gliederung der Varisziden der Iberischen Meseta. Geotektonische Forschungen, Berlin, 6, 78–92.Google Scholar
Mateus, A., Figueiras, J., Gonçalves, M. & Fonseca, P.E. (1999) Evolving fluid circulation within the Beja- Acebuches Variscan Ophiolite Complex (SE, Portugal). Ofioliti, 24, 269–282.Google Scholar
Merriman, R.J. & Frey, M. (1999) Patterns of very low-grade metamorphism in metapelitic rocks. Pp. 61–107 in: Low Grade-Metamorphism (Frey, M. & Robinson, D., editors). Blackwell Science, Oxford, UK.Google Scholar
Merriman, R.J. & Peacor, D.R. (1999) Very low-grade metapelites: mineralogy, microfabrics and measuring reaction progress. Pp. 10–60 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 metapelitic microfabrics in the Southern Uplands thrust terrain, Scotland. Journal of Metamorphic Geology, 13, 559–576.Google Scholar
Moço, L.P., Chaminé, H.I., Fernandes, J.P., Lemos de Sousa, M.J., Fonseca, P.E. & Ribeiro, A. (2001) Organic metamorphism level of Devonian black shale from Albergaria-a-Velha region (NW Portugal): Tectonostratigraphic implications. Gaia (Revue Museo Historia Naturelle, Lisboa), 16, 195–197.Google Scholar
Nieto, F. (2002) Characterization of coexisting NH4- and K-micas in very low-grade metapelites. American Mineralogist, 87, 205–216.Google Scholar
Nieto, F., Velilla, N., Peacor, D.R. & Ortega-Huertas, M. (1994) Regional retrograde alteration of sub-greenschist facies chlorite to smectite. Contributions to Mineralogy and Petrology, 115, 243–252.Google Scholar
Nieto, F., Mata, P., Bauluz, B., Giorgetti, G., Arkai, P. & Peacor, D.R. (2005) Retrograde diagenesis, a widespread process on a regional scale. Clay Minerals, 40, 93–104.CrossRefGoogle Scholar
Oliveira, A., Rocha, F.T., Rodrigues, A., Jouanneau, J., Dias, J.A., Weber, O. & Gomes, C. (2002) Clay minerals of the sedimentary cover from the Northwestern Iberian shelf. Progress in Oceanography, 52, 233–247.Google Scholar
Ribeiro, A., Quesada, C. & Dallmeyer, R.D. (1990) Geodynamic evolution of the Iberian Massif. Pp. 397–410 in: Pre-Mesozoic Geology of Iberia (Dallmeyer, R.D. & Martínez-García, E., editors). Springer Verlag, Berlin.Google Scholar
Ribeiro, A., Marcos, A., Pereira, E., Llana-Fúnez, S., Farías, P., Fernandez, F.J., Fonseca, P.E., Chaminé, H.I. & Rosas, F. (2003) 3-D strain distribution in the Ibero-Armorican Arc: a review. Ciências da Terra, UNL, Lisboa, N° Esp. 5 (CD-Rom), D62—D63.Google Scholar
Robinson, D., Schmidt, S.T. & de Zamora, A.S. (2002) Reaction pathways and reaction progress for the smectite-to-chlorite transformation: evidence from hydrothermally altered metabasites. Journal of Metamorphic Geology, 20, 167–174.Google Scholar
Schleicher, A.M., Warr, L.N. & van der Pluijm, B.A. (2006) Fluid focusing and back-reactions in the uplifted shoulder of the Rhine rift system: a clay mineral study along the Schauenburg Fault zone (Heidelberg, Germany). International Journal of Earth Sciences, 95, 19–33.Google Scholar
Taylor, S.R. & McLennan, S.M. (1985) The Continental Crust: its Composition and Evolution. Blackwell, Oxford, UK, 312 pp.Google Scholar
Warr, L.N. & Rice, H.N. (1994) Interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data. Journal of Metamorphic Geology, 12, 141–152.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