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Clay mineral associations in the clay cap from the Cerro Pabellón blind geothermal system, Andean Cordillera, Northern Chile

Published online by Cambridge University Press:  14 June 2018

S.N. Maza ,
G. Collo ,
D. Morata ,
C. Lizana ,
E. Camus ,
M. Taussi ,
A. Renzulli ,
M. Mattioli ,
B. Godoy  and
B. Alvear
...Show all authors
S.N. Maza*
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
G. Collo
Affiliation:
Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Córdoba, Argentina. Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Centro de investigaciones en Ciencias de la Tierra, (CICTERRA). Córdoba, Argentina.
D. Morata
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
C. Lizana
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
E. Camus
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
M. Taussi
Affiliation:
Dipartimento di Scienze Pure e Applicate, Università degli Studi di Urbino Carlo Bo, Via Cà le Suore, 2/4 –, 61029 Urbino, Italy.
A. Renzulli
Affiliation:
Dipartimento di Scienze Pure e Applicate, Università degli Studi di Urbino Carlo Bo, Via Cà le Suore, 2/4 –, 61029 Urbino, Italy.
M. Mattioli
Affiliation:
Dipartimento di Scienze Pure e Applicate, Università degli Studi di Urbino Carlo Bo, Via Cà le Suore, 2/4 –, 61029 Urbino, Italy.
B. Godoy
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
B. Alvear
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
M. Pizarro
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile.
C. Ramírez
Affiliation:
ENEL Green Power Chile and Andean countries. Av. Presidente Riesco 5335, 14. Las Condes, Santiago, Chile.
G. Rivera
Affiliation:
Department of Geology and Andean Geothermal Center of Excellence (CEGA), Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile. ENEL Green Power Chile and Andean countries. Av. Presidente Riesco 5335, 14. Las Condes, Santiago, Chile.
*
*E-mail: [email protected]
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Abstract

The occurrence of smectite-illite and smectite-chlorite minerals series was studied along a thick clay cap (~300 m) drilled in the Cerro Pabellón geothermal field (northern Andes, Chile). X-ray diffraction (XRD) and scanning electronic microscopy (SEM) were used to characterize the alteration mineralogy and clay mineral assemblages and their changes with depth. Cerro Pabellón is a high-enthalpy blind geothermal system, with a reservoir zone from ~500 m to 2000 m depth, with temperatures of 200–250°C. Three main hydrothermal alteration zones were identified: (1) argillic; (2) sub-propylitic, and (3) propylitic, with variable amounts of smectite, illite-smectite, chlorite-smectite, mixed-layer chlorite-corrensite, illite and chlorite appearing in the groundmass and filling amygdales and veinlets. Chemical and XRD data of smectites, I-S and illites show, with some exceptions, a progressive illitization with depth. The evolution of I-S with depth, shows a sigmoidal variation in the percentage of illite layers, with the conversion of smectite to R1 I-S at ~180–185°C. These temperatures are greater than those reported for other similar geothermal fields and might indicate, at least in part, the efficiency of the clay cap in terms of restricting the circulation of hydrothermal fluids in low-permeability rocks. Our results highlight the importance of a better understanding of clay-mineral evolution in active geothermal systems, not only as a direct (or indirect) way to control temperature evolution, but also as a control on permeability/porosity efficiency of the clay cap.

Keywords

clay mineralsXRDSEMclay capgeothermicsCerro PabellónAndean CordilleraChile
Type
Article
Information
Clay Minerals , Volume 53 , Issue 2 , June 2018 , pp. 117 - 141
Copyright
Copyright © Mineralogical Society of Great Britain and Ireland 2018 

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Footnotes

This paper was presented during the session: ‘GG01-Clays in faults and fractures + MI-03 Clay mineral reaction progress in very low-grade temperature petrologic studies’ of the International Clay Conference 2017.

Guest Associate Editor: Blanca Bauluz

References

REFERENCES

Abad, I., Nieto, F., Gutierrez-Alonso, G., Do Campo, M., Lopez-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
Ahumada, S. & Mercado, J.L. (2009) Evolución geológica y estructural del complejo volcánico Apacheta-Aguilucho (CVAA), Segunda Región, Chile. Dissertation, Bachelor's Degree Thesis, Universidad Católica del Norte, Antofagasta, Chile.Google Scholar
Aravena, D., Muñoz, M., Morata, D., Lahsen, A., Parada, M.A. & Dobson, P. (2016) Assessment of high enthalpy geotermal resources and promising areas of Chile. Geothermics, 59, 1–13.Google Scholar
Artemieva, I.M., editor (2011) The Lithosphere: An Interdisciplinary Approach. Cambridge University Press, UK, 794 pp.Google Scholar
Bauluz, B., Peacor, D.R. & Ylagan, R.F. (2002) Transmission electron microscopy study of smectite illitization during hydrothermal alteration of a rhyolitic hyaloclastite from Ponza, Italy. Clays and Clay Minerals, 50 (2), 157–173.Google Scholar
Beaufort, D., Patrier, P., Meunier, A. & Ottaviani, M.M. (1992) Chemical variations in assemblages including epidote and/or chlorite in the fossil hydrothermal system of Saint Martin (Lesser Antilles). Journal of Volcanology and Geothermal Research, 51, 95–114.Google Scholar
Beaufort, D., Baronnet, A., Lanson, B. & Meunier, A. (1997) Corrensite: A single phase or a mixed-layer phyllosilicate in the saponite-to-chlorite conversion series? A case study of Sancerre-Couy deep drill hole (France). American Mineralogist, 82, 109–124.Google Scholar
Beaufort, D., Rigault, C., Billon, S., Billault, V., Inoue, A., Inoue, S., Patrier, P. & Ferrage, E. (2015) Chlorite and chloritization processes through mixed-layer mineral series in low-temperature geological systems – a review. Clay Minerals, 50, 497–523.Google Scholar
Bethke, C.M. & Stephen, P.A. (1986) Layer-by-layer mechanism of smectite illitization and application to a new rate law. Clays and Clay Minerals, 34, 136–145.Google Scholar
Brasse, H., Lezaeta, P., Rath, V., Schwalenberg, K., Soyer, W. & Haak, V. (2002) The Bolivian Altiplano conductivity anomaly. Journal of Geophysical Research, 107, 2096.Google Scholar
Charrier, R., Pinto, L. & Rodríguez, M.P. (2007) Tectonostratigraphic evolution of the Andean Orogen in Chile. Pp. 21–114 in: The Geology of Chile (Moreno, T. & Gibbons, W., editors). ‘Geology of Series’, Geological Society London.Google Scholar
Chemtob, S.M., Nickerson, R.D., Morris, R.V., Agresti, D.G. & Catalano, J.G. (2015) Synthesis and structural characterization of ferrous trioctahedral smectites: Implications for clay mineral genesis and detectability on Mars. Journal of Geophysical Research: Planets, 120, 1119–1140.Google Scholar
Corrado, S., Aldega, L., Celano, A.S., de Benedetti, A.A. & Giordano, G. (2014) Cap rock efficiency and fluid circulation of natural hydrothermal systems by means of XRD on clay minerals (Sutri, northern Latium, Italy). Geothermics, 50, 180–188.Google Scholar
Day-Stirrat, R.J., Dutton, S.P., Milliken, K.L., Loucks, R.G., Aplin, A.C., Hillier, S. & van der Pluijm, B.A. (2010) Fabric anisotropy induced by primary depositional variations in the silt: clay ratio in two fine-grained slope fan complexes: Texas Gulf Coast and northern North Sea. Sedimentary Geology, 226, 42–53.Google Scholar
de Silva, S.L. (1989) Altiplano-Puna volcanic complex of the central Andes. Geology, 17, 1102–1106.Google Scholar
de Silva, S.L. & Gosnold, W.D. (2007) Episodic construction of batholiths: Insights from the spatiotemporal development of an ignimbrite flare-up. Journal of Volcanology and Geothermal Research, 167, 320–335.Google Scholar
Farías, M., Charrier, R., Comte, D., Martinod, J. & Hérail, G. (2005) Late Cenozoic deformation and uplift of the western flank of the Altiplano: Evidence from the depositional, tectonic, and geomorphologic evolution and shallow seismic activity (northern Chile at 19 30′ S). Tectonics, 24, 1–27.Google Scholar
Franchini, M., Impiccini, A., Meinert, L., Grathoff, G. & Schalamuk, I.B.A. (2007) Clay mineralogy and zonation in the Campana Mahuida porphyry Cu deposit, Neuquén, Argentina: Implications for porphyry Cu exploration. Economic Geology, 102, 27–54.Google Scholar
Francis, P.W. & Rundle, C.C. (1976) Rates of production of the main magma types in the central Andes. Geological Society of America Bulletin, 87, 474–480.Google Scholar
Gifkins, C., Herrmann, W. & Large, R. (editors) (2005) Altered Volcanic Rocks – A Guide to Description and Interpretation. Centre for Ore Deposit Research, University of Tasmania, Hobart, 288 pp.Google Scholar
Guidotti, C.V., Yates, M.G., Dyar, M.D. & Taylor, M.E. (1994) Petrogenetic implications of the Fe3+ contents of muscovite in pelitic schists. American Mineralogist, 79, 793–795.Google Scholar
Guisseau, D., Patrier-Mas, P., Beaufort, D., Girard, J.P., Inoue, A., Sanjuan, B., Petit, S., Lens, A. & Genter, A. (2007) Significance of the depth-related transition montmorillonite-beidellite in the Bouillante geothermal field (Guadeloupe, Lesser Antilles). American Mineralogist, 92, 1800–1813.Google Scholar
Godoy, B., Rodríguez, I., Pizarro, M. & Rivera, G. (2017) Geomorphology, lithofacies, and block characteristics to determine the origin, and mobility, of a debris avalanche deposit at Apacheta-Aguilucho Volcanic Complex (AAVC), northern Chile. Journal of Volcanology and Geothermal Research, doi: 10.1016/j.jvolgeores.2017.09.008Google Scholar
González, G., Cembrano, J., Carrizo, D., Macci, A. & Schneider, H. (2003) The link between forearc tectonics and Pliocene-Quaternary deformation of the Coastal cordillera, northern Chile. Journal of South American Earth Sciences, 16, 321–342.Google Scholar
Harrison, W.E., Luza, K.V., Prater, M.L. & Chueng, P.K. (1983) Geothermal resource assessment of Oklahoma. Special Publication, Oklahoma Geological Survey, 83–1.Google Scholar
Harvey, C.C. & Browne, P.R.I. (1991) Mixed-layer clay geothermometry in the Wairakei geothermal field, New Zealand. Clay and Clay Minerals, 39, 614–621.Google Scholar
Harvey, C.C. & Browne, P.R.I. (2000) Studies of mixed-layer clays in geothermal systems. A review of the developments and their effectiveness as mineral geothermometers. Proceeding of the World Geothermal Congress, Japan.Google Scholar
Herrera, S., Pinto, L., Deckart, K., Cortés, J. & Valenzuela, I. (2017) Cenozoic tectonostratigraphic evolution and architecture of the Central Andes in northern Chile based on the Aquine region, Western Cordillera (19–19°30’ S). Andean Geology, 44, 87–122.Google Scholar
Huang, W.L., Longo, J.M. & Pevear, D.R. (1993) An experimentally derived kinetic model for smectite-to-illite conversion and its use as a geothermometer. Clays and Clay Minerals, 41, 162–177.Google Scholar
Inoue, A. (1995) Formation of clay minerals in hydrothermal environments. Pp. 268–329 in: Origin and Mineralogy of Clays (Velde, B., editor). Springer, Berlin, Heidelberg.Google Scholar
Inoué, S. & Kogure, T. (2016) High-angle annular dark field scanning transmission electron microscopic (HAADF- STEM) study of Fe-rich 7 Å–14 Å interstratified minerals from a hydrothermal deposit. Clay Minerals, 51, 603–613.Google Scholar
Inoue, A. & Utada, M. (1991) Smectite-to-chlorite transformation in thermally metamorphosed and volcanoclastic rocks in the Kamikita area, northern Honshu, Japan. American Mineralogist, 76, 628–640.Google Scholar
Inoue, A., Meunier, A. & Beaufort, D. (2004) Illite-smectite mixed-layer minerals in felsic voclaniclastic rocks from drill cores, Kakkonda, Japan. Clays and Clay Minerals, 52, 66–84.Google Scholar
Inoue, A., Kurokawa, K. & Hatta, T. (2010) Application of chlorite geothermometry to hydrothermal alteration in Toyoha Geothermal System, southwestern Hokkaido, Japan. Resource Geology, 60, 52–70.Google Scholar
Jahren, J.S. & Aagaard, P. (1989) Compositional variations in diagenetic chlorites and illites, and relationships with formation-water chemistry. Clay Minerals, 24, 157–170.Google Scholar
Ji, J. & Browne, P.R.J. (2000) Relationship between illite crystallinity and temperature in active geothermal systems of New Zealand. Clay and Clay Minerals, 48, 139–144.Google Scholar
Keith, T.E.C. & Bargar, I.C.E. (1988) Petrology and hydrothermal mineralogy of U.S. Geological Survey Newberry 2 drill core from Newberry caldera, Oregon. Journal of Geophysical Research, 93, 10174–10190.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
Kübler, B. (1968) Evaluation quantitative du métamorphisme par la cristallinité d l'illite. Bulletin de la Centre Recherche de Pau – S.N.P.A., 2, 385–397.Google Scholar
Lahsen, A. (1988) Chilean geothermal resources and their possible utilization. Geothermics, 17, 401–410.Google Scholar
Lahsen, A. & Trujillo, P. (1975) El Tatio geothermal field. Proceedings of the Second United Nations Symposium on the Development and Use of Geothermal Resources, pp. 157–178.Google Scholar
Li, X., Wang, C., Mao, J., Hua, R., Liu, Y. & Xu, Q. (2005) Kübler Index and K-Ar ages of illite in the Yinshan Polymetallic Deposit, Jiangxi Province, South China: Analyses and implications. Resource Geology, 55, 397–404.Google Scholar
Maffucci, R., Corrado, S., Aldega, L., Bigi, S., Chiodi, A., Di Paolo, L. & Invernizzi, C. (2016) Cap rock efficiency of geothermal systems in fold-and-thrust belts: Evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina). Journal of Volcanology and Geothermal Research, 328, 84–95.Google Scholar
Marinoviç, N. & Lahsen, A. (1984) Carta geológica de Chile No. 58: Hoja Calama, Región de Antofagasta.Google Scholar
Mas, A., Guisseau, D., Patrier Mas, P., Beaufort, D., Genter, A., Sanjuan, B. & Girard, J.P. (2006) Clay minerals related to the hydrothermal activity of the Bouillante geothermal field (Guadeloupe). Journal of Volcanology and Geothermal Research, 158, 380–400.Google Scholar
Maydagan, L., Franchini, M., Impiccini, A., Lentz, D., Patrier, P. & Beaufort, D. (2018) Chlorite, white mica and clay minerals as proximity indicators to ore in the shallow porphyry environment of Quebrada de la Mina deposit, Argentina. Ore Geology Reviews, 92, 297–317.Google Scholar
McDowell, S.D. & Elders, W.A. (1980) Authigenic layer silicate minerals in borehole Elmore 1, Salton Sea geothermal field, California, USA. Contributions to Mineralogy and Petrology, 74, 293–310.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 Sciences Ltd., Oxford, UK.Google Scholar
Meunier, A. (2005) Hydrothermal process – thermal metamorphism. Pp. 379–415 in: Clays (Meunier, A., editor). Springer Science & Business Media, Berlin.Google Scholar
Meunier, A. & Velde, B. (1989) Solid solution in illite/smectite mixed layer minerals and illite. American Mineralogist, 74, 1106–1112.Google Scholar
Meunier, A., Mas, A., Beaufort, D., Patrier, P. & Dudoignon, P. (2008a) Clay minerals in basalt-hawaiite rocks from Mururoa atoll (French Polynesia). I. Mineralogy. Clays and Clay Minerals, 56, 711–729.Google Scholar
Meunier, A., Mas, A., Beaufort, D., Patrier, P. & Dudoignon, P. (2008b) Clay minerals in basalt- hawaiite rocks from Mururoa atoll (French Polynesia). II. Petrography and geochemistry. Clays and Clay Minerals, 56, 730–750.Google Scholar
Moore, D.M. & Reynolds, R.C. Jr, editors (1997) X-ray Diffraction and the Identification and Analysis of Clay Minerals. 2nd edition. Oxford University Press, New York, 378 pp.Google Scholar
Nieto, F. (1997). Chemical composition of metapelitic chlorites: X-ray diffraction and optical property approach. European Journal of Mineralogy, 9, 829–841.Google Scholar
Piscaglia, F. (2012) The high temperature geothermal field of the Apacheta-Aguilucho Volcanic Complex (northern Chile): Geo-petrographic surface exploration, crustal heat sources and cap-rocks. Plinius, 38, 148–153.Google Scholar
Prasetyo, I., Sardiyanto, , Koestono, H. & Thamrin, M.H. (2015) Clay alteration study from wells of Tompaso Geothermal Field, north Sulawesi, Indonesia. Proceedings World Geothermal Congress 2015, 1–9.Google Scholar
Ramírez, C.F. & Huete, C. (1981) Carta Geológica de Chile, Hoja Ollagüe, Escala 1:250,000. Instituto de Investigaciones Geológicas, Carta No. 40.Google Scholar
Renzulli, A., Menna, M., Tibaldi, A. & Flude, S. (2006) New data of surface geology, petrology and Ar-Ar geochronology of the Altiplano-Puna Volcanic Complex (Northern Chile) in the framework of future geothermal exploration. Congreso Geológico Chileno N°11 Actas, pp. 307–310.Google Scholar
Rivera, G., Morata, D. & Ramírez, C. (2015) Evolución vulcanológica y tectónica del área del Cordón Volcánico Cerro del Azufre – Cerro de Inacaliri y su relación con el Sistema Geotérmico de Pampa Apacheta, II Región de Antofagasta. Congreso Geológico Chileno N°14 Actas, pp. 556–559.Google Scholar
Sánchez-Alfaro, P., Sielfeld, G., van Campen, B., Dobson, P., Fuentes, V., Reed, A., Palma-Behnke, R. & Morata, D. (2015) Geothermal barriers, policies and economics in Chile – Lessons for the Andes. Renewable and Sustainable Energy Reviews, 51, 1390–1401.Google Scholar
Sánchez-Alfaro, P., Reich, M., Arancibia, G., Pérez-Flores, P., Cembrano, J., Driesner, T., Lizama, M., Rowland, J., Morata, D., Heinrich, C.A., Tardani, D. & Campos, D. (2016) Physical, chemical and mineralogical evolution of the Tolhuaca geothermal system, southern Andes, Chile: Insights into the interplay between hydrothermal alteration and brittle deformation. Journal of Volcanology and Geothermal Research, 324, 88–104.Google Scholar
Schmitz, M., Lessel, K., Giese, P., Wigger, P., Araneda, M., Bribach, J., Graeber, F., Grunewald, S., Haberland, C., Lüth, S., Röwer, P., Ryberg, T. & Schulze, A. (1999) The crystal structure beneath the central Andean forearc and magmatic arc as derived from seismic studies – the PISCO 94 experiment in northern Chile (21°–23°S). Journal of South American Earth Sciences, 12, 237–260.Google Scholar
Springer, M. & Förster, A. (1998) Heat-flow density across the Central Andean subduction zone. Tectonophysics, 29, 123–139.Google Scholar
Środoń, J. (1981) X-ray identification of randomly inter-stratified illite–smectite in mixtures with discrete illite. Clay Minerals, 16, 297–304.Google Scholar
Stimac, J., Goff, F. & Goff, C. (2015) Intrusion-related geothermal systems. Pp. 799–822 in: The Encyclopedia of Volcanoes. Elsevier, Amsterdam.Google Scholar
Tassi, F., Aguilera, F., Darrah, T., Vaselli, O., Capaccioni, B., Poreda, R.J. & Delgado-Huertas, A. (2010) Fluid geochemistry of hydrothermal systems in the Arica-Parinacota, Tarapacá and Antofagasta regions (northern Chile). Journal of Volcanology and Geothermal Research, 192, 1–15.Google Scholar
Tibaldi, A., Corazzato, C. & Rovida, A. (2009) Miocene–Quaternary structural evolution of the Uyuni–Atacama region, Andes of Chile and Bolivia. Tectonophysics, 471, 114–135.Google Scholar
Tibaldi, A., Bonali, F.L. & Corazzato, C. (2016) Structural control on volcanoes and magma paths from local- to orogen-scale: The central Andes case. Tectonophysics, 699, 16–41.Google Scholar
Tierney, C.R., Schmitt, A.K., Lovera, O.M. & de Silva, S.L. (2016) Voluminous plutonism during volcanic quiescence revealed by thermochemical modeling of zircon. Geology, 44, 683–686.Google Scholar
Todesco, M. & Giordano, G. (2010) Modelling of CO2 circulation in the Colli Abani area. Pp. 311–330 in: The Colli Albano Volcano (Funiciello, R. & Giordano, G., editors). Special Publication of IAVCEI, 3. The Geological Society, London.Google Scholar
Trumbull, R., Riller, U., Oncken, O., Scheuber, E., Munier, K. & Hongn, F. (2006) The time space distribution of Cenozoic volcanism in the South-Central Andes: a new data compilation and some tectonic implications. Pp. 29–43 in: The Andes Active Subduction Orogeny, Frontiers in Earth Sciences (Oncken, O., Chong, G., Franz, G., Giese, P., Götze, H.J., Ramos, V.A, Strecker, M.R, Wigger, P., editors). Springer, Heidelberg, Berlin.Google Scholar
Urzúa, L., Powell, T., Cumming, W.B. & Dobson, P. (2002) Apacheta, a new geothermal prospect in Northern Chile. Geothermal Resources Council Transactions, 26, 22–25.Google Scholar
Vázquez, M., Nieto, F., Morata, D., Droguett, B., Carrillo-Rosúa, F.J. & Morales, S. (2014) Evolution of clay mineral assemblages in the Tinguiririca geothermal field, Andean Cordillera of central Chile: an XRD and HRTEM-AEM study. Journal of Volcanology and Geothermal Research, 282, 43–59.Google Scholar
Vázquez, M., Bauluz, B., Nieto, F. & Morata, D. (2016) Illitization sequence controlled by temperature in volcanic geothermal systems: The Tinguiririca geothermal field, Andean Cordillera, Central Chile. Applied Clay Science, 134, 221–234.Google Scholar
Velde, B. (1985) Clay Minerals: A Physico-Chemical Explanation of their Occurrence. Elsevier, Amsterdam and New York.Google Scholar
Vidal, O., Lanari, P., Munoz, M., Bourdelle, F. & Andrade, V. (2016) Deciphering temperature, pressure and oxygen-activity conditions of chlorite formation. Clay Minerals, 51, 615–633.Google Scholar
Ward, K.M., Zandt, G., Beck, S.L., Christensen, D.H. & McFarlin, H. (2014) Seismic imaging of the magmatic underpinnings beneath the Altiplano-Puna volcanic complex from the joint inversion of surface wave dispersion and receiver functions. Earth and Planetary Science Letters, 404, 43–53.Google Scholar
Warr, L.N. & Cox, S.C. (2016) Correlating illite (Kübler) and chlorite (Árkai) “crystallinity” indices with metamorphic mineral zones of the South Island, New Zealand. Applied Clay Science, 134, 164–174.Google Scholar
Warr, L.N. (2017) On the availability of clay mineral “crystallinity” index standards. 16th International Clay Conference, Granada, Spain.Google Scholar
Warr, L.N. & Ferreiro, Mahlmann R.F. (2015) Recommendations for Kübler Index standardization. Clay Minerals, 50, 283–286.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
Wohletz, K. & Heiken, G. (1992) Volcanology and Geothermal Energy. University of California Press, Berkeley, California, USA, 432 pp.Google Scholar
Zandt, G., Leidig, M., Chmielowski, J., Baumont, D. & Yuan, X. (2003) Seismic detection and characterization of the Altiplano-Puna magma body, Central Andes. Pure and Applied Geophysics, 160, 789–807.Google Scholar