Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-22T20:35:51.479Z Has data issue: false hasContentIssue false

Zussmanite in ferruginous metasediments from Southern Central Chile

Published online by Cambridge University Press:  05 July 2018

H.-J. Massonne
Affiliation:
Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Azenbergstr. 18, D-70174 Stuttgart, Germany
F. Hervé
Affiliation:
Departamento de Geologia, Universidad de Chile, Casilla 13518, Correo 21, Santiago de Chile, Chile
O. Medenbach
Affiliation:
Institut für Mineralogie, Ruhr-Universität, D-44780 Bochum, Germany
V. Muñoz
Affiliation:
Departamento de Geologia, Universidad de Chile, Casilla 13518, Correo 21, Santiago de Chile, Chile
A. P. Willner
Affiliation:
Institut für Mineralogie, Ruhr-Universität, D-44780 Bochum, Germany

Abstract

Zussmanite KFe13[AlSi17O42](OH)14, a modulated 2:1 layer silicate, has so far been found only in iron-rich metasediments from Laytonville, California (Agrell et al.), 1965). A new occurrence is reported here from Punta Nihue north of Valdivia, Chile, in banded stilpnomelane-schists. These are intercalated in the ‘Western Series’, a complex of low-grade metamorphic rocks with local high-pressure, low-temperature overprint (e.g. blueschists).

The rock contains conspicuous porphyroblasts of zussmanite of mm size and is composed of chemically distinct bands with the subsequent assemblages: (1) zussmanite-stilpnomelane-quartz, (2) siderite-quartz±stilpnomelane (3) apatite-stilpnomelane-quartz±siderite. The chemical composition of zussmanite, (K0.80Na0.05Ba0.01)(Fe11.292+Mg1.11Mn0.25Fe0.143+Cr0.01Al0.19Ti0.01)[Al1.23Si16.77O42](OH)14, its optical properties and X-ray data correlate well with the Californian occurrence. Additionally, we present new IR data. In type (2) bands of fine-grained crystals of a K,Al poor mineral formed from siderite and quartz. Its chemical composition is close to that of zussmanite. A similar phase was also reported from Laytonville, California (Muir Wood, 1980).

The rarity of rock-forming zussmanite can be explained by its occurrence in strongly Fe-rich and reduced rocks, as well as, by a possibly narrow P-T stability field.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Agrell, S.O., Bown, M.G. and McKie, D. (1965) Deerite, howieite and zussmanite, three new minerals from the Franciscan of the Laytonville district, Mendocino Co., California. Amer. Mineral., 50, 278.Google Scholar
Aguirre, L., Hervé, F. and Godoy, E. (1972) Distribution of metamorphic facies in Chile: an outline. Krystallinikum, 9, 719.Google Scholar
Bernhardt, H.J. , Massonne, H.-J. , Reinecke, T., Reinhardt, J. and Willner, A. (1995) Digital element distribution maps, an aid for petrological investigations. Ber. Deutsch. Mineral. Ges. Beih. Eur. J. Mineral., 7(1), 28.Google Scholar
Collao, S., Kojima, S. and Oyarzun, R. (1986) Geotermobarometria en los sulfuros macizos de la franja metamórfica de esquistos verdes, Chile Central-Sur. Rev. Geol. Chile, 28, 316.Google Scholar
Eggleton, R.A. (1972) The crystal structure of stilpnomelane. Part II. The full cell. Mineral. Mag., 38, 693711.CrossRefGoogle Scholar
Förtsch, E., Uhr, W. and Wondraschek, H. (1992) A novel application of the spindle stage. Microscope, 40, 31–6.Google Scholar
Gonzalez Bonorino, F. and Aguirre, L. (1970) Metamorphism of the crystalline basement of Central Chile. J. Petrol., 12, 149–75.CrossRefGoogle Scholar
Guggenheim, S. and Eggleton, R.A. (1987) Modulated 2:1 layer silicates: Review, systematics, and predictions. Amer. Mineral., 72, 724–38.Google Scholar
Hervé, F. (1988) Late Paleozoic subduction and accretion in Southern Chile. Episodes, 11, 183–8CrossRefGoogle Scholar
Hervé, F., Pankhurst, R.J., Brook, M., Alfaro, G., Frutos, J., Miller, H., Schira, W. and Amstutz, G.C. (1990) Rb-Sr and Sm-Nd data from some massive sulfide occurrences in the metamorphic basement of south-central Chile. In Stratabound Ore Deposits in the Andes (Fontbote, L. Amstutz, G.C. Cardozo, M. Cedillo, E. and Frutos, J., eds.) 221–8, Springer-Verlag, Berlin, Heidelberg.CrossRefGoogle Scholar
Jefferson, D.A. (1976) Stacking disorder and polytypism in zussmanite. Amer. Mineral., 61, 470-83.Google Scholar
Klein, C. (1974) Greenalite, stilpnomelane, minnesotaite, crocidolite and carbonates in a very low-grade metamorphic Precambrian iron-formation. Canad. Mineral., 12, 475–98.Google Scholar
Lattard, D. and Schreyer, W. (1981) Experimental results bearing on the stability of the blueschistfacies minerals deerite, howieite, and zussmanite, and their petrological significance. Bull. Mineral., 104, 431–40.Google Scholar
Lopes-Vieira, A. and Zussman, J. (1969) Further detail on the crystal structure of zussmanite. Mineral. Mag., 37, 4960.CrossRefGoogle Scholar
Mandarino, J.A. (1981) The Gladstone-Dale relationship: Part IV. The compatibility concept and its application. Canad. Mineral., 19, 441–50.Google Scholar
Massonne, H.-J., Willner, A.P., Hervé, F. and Muñoz, V. (1996 a) Zussmanit und ein Zussmanit-ähnliches Mineral in Fe-reichen Metasedimenten aus dem südlichen Zentralchile. Ber. Deutsch. Mineral. Ges., Beih. Eur. J. Mineral., 8(7), 183.Google Scholar
Massonne, H.-J., Hervé, F., Muñoz, V. and Willner, A.P. (1996 b) New petrological results on high-pressure, low-temperature metamorphism of the Upper Palaeozoic basement of Central Chile. Troisième Symp. Int. sur la Géodynamique Andine, Saint-Malo (France), Ext. Abstr., 783–5.Google Scholar
Medenbach, O. (1985) A new microrefractometer spindle-stage and its application. Fortschr. Mineral., 63, 111–33.Google Scholar
Miyano, T. and Klein, C. (1989) Phase equilibria in the system K2O-FeO-MgO-Al2O3-SiO2-H2O-CO2 and the stability limit of stilpnomelane in metamorphosed Precambrian iron-formations. Contrib. Mineral. Petrol., 102, 478–91.CrossRefGoogle Scholar
Muir Wood, R. (1980) The iron-rich blueschist-facies minerals: 3. Zussmanite and related minerals. Mineral. Mag., 43, 605–14.CrossRefGoogle Scholar
Muñoz, V., Hervé, F., Massonne, H.-J., Medenbach, O. and Willner, A.P. (1997) Primer hallazgo de zussmanita en Chile, indicador de facies metamorficas de alta presion–baja temperatura. Actas VIII Congr. Geol. Chileno Antofagasta, 237–41.Google Scholar
Sameshima, T. and Kawachi, Y. (1991) Coombsite, Mn analogue of zussmanite, and associated Mn-silicates, parsettensite and caryopilite, from southeast Otago, New Zealand. N. Z. J. Geol. Geophys., 34, 329–35.CrossRefGoogle Scholar
Willner, A.P., Massonne, H.-J. and Hervé, F. (1997) Wide-spread high pressure/ low temperature-metamorphism of the Upper Palaeozoic basement of Central and Southern Chile. Abstr. suppl. 1, Terra Nova 9, EUG 9, 327.Google Scholar
Yvon, K., Jeitschko, W. and Parthe, E. (1977) LAZY PULVERIX, a computer program, for calculating Xray and neutron diffraction powder patterns. J. Appl. Crystallogr., 10, 73–4.CrossRefGoogle Scholar