Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-26T07:15:36.507Z Has data issue: false hasContentIssue false
  • English
  • Français

A vein occurrence of co-existing talc, saponite, and corrensite, Builth Wells, Wales

Published online by Cambridge University Press:  09 July 2018

L. A. J. Garvie  and
R. Metcalfe
L. A. J. Garvie
Affiliation:
Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
R. Metcalfe
Affiliation:
Fluid Processes Group, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

Unique phyllosilicate assemblages occur in quartz-calcite veins cutting altered andesite at Builth Wells, UK. These veins show: (1) a central talc-dominated assemblage, grading into a saponite/corrensite/chlorite-dominated assemblage near their walls; (2) talc replacing calcite and quartz; and (3) closely associated blocky and fibrous saponite. Fibrous saponite occurs in narrow (<1 cm) fractures that extend for up to 1 m from major (⩽ 50 cm wide) talc-bearing veins. A thin halo (<5 mm) of wall-rock alteration, containing blocky saponite and minor corrensite, borders the fibrous saponite. These minerals may have originated when cooling, low-pH, quartz-saturated, Mg-rich fluid invaded pre-existing quartz/calcite veins. Quartz is replaced by talc where calcite dissolution caused the pH to increase. Wallrock alteration liberated Fe and Al to the fluid causing blocky saponite and corrensite to form. Fibrous saponite formed where lithostatic pressures were directed across hydraulic fractures.

Type
Research Article
Information
Clay Minerals , Volume 32 , Issue 2 , June 1997 , pp. 223 - 240
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

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

April, R.H. (1981) Trioctahedral smectite and interstratiffed chlorite/smectite in Jurassic strata of the Connecticut Valley. Clays Clay Miner. 29, 31–39.Google Scholar
April, R.H. & Keller, D.M. (1992) Saponite and vermiculite in amygdales of the Granby basaltic tuff, Connecticut Valley. Clays Clay Miner. 40, 22–31.CrossRefGoogle Scholar
Bailey, S.W. (1982) Nomenclature for regular interstratifications. Clay Miner. 17, 243–248.Google Scholar
Barker, A.J. (1990) Introduction to Metamorphic Textures and Micro structures. Blackie, London.Google Scholar
Beaufort, D. & Meunier, A. (1994) Saponite, corrensite and chlorite-saponite mixed-layers in the Sancerre- Couy deep drill-hole (France). Clay Miner. 29, 47–61.Google Scholar
Bevins, R.E. (1985) Pumpellyite-dominated metadomain alteration at Builth Wells, Wales-–-evidence for a fossil hydrothermal system. Mineral. Mag. 49, 451–456.Google Scholar
Bevins, R.E. & Rowbotham, G. (1983) Low-grade metamorphism within the Welsh sector of the paratectonic Caledonides. Geol. J. 18, 141–167.CrossRefGoogle Scholar
Cahoon, H.P. (1954) Saponite from Milford, Utah. Am. Miner. 39, 222–230.Google Scholar
Caillere, S. & Henin, S. (1951) The properties and identification of saponite (bowlingite). Clay Miner. Bull. 1, 138–144.Google Scholar
de Caritat, P., Hutcheon, I. & Walshe, J.L. (1993) Chlorite geothermometry: a review. Clays Clay Miner. 41, 219–239.CrossRefGoogle Scholar
Cathelineau, M. (1988) Cation site occupancy in chlorites and illites as a function of temperature. Clay Miner. 23, 471–485.Google Scholar
Cowking, A., Wilson M, J., Tait, J.M. & Robertson, R.H.S. (1983) Structure and swelling of fibrous and granular saponitic clay from Orrock quarry, Fife, Scotland. Clay Miner. 18, 49–64.Google Scholar
Curtis, C.D. (1976) ‘Unmixed’ Ca2+/Mg2§ saponite at Carlton Hill, Derbyshire. Clay Miner. 11, 85–89.CrossRefGoogle Scholar
Dubinska, E., Bylina, P. & Sakharov, B.A. (1995) Corrensite from Naslawice (Lower Silesia, Poland): Some problems of minerals identification and origin. Clay Clay Miner. 43, 630–636.Google Scholar
Evans, B.W. & Guggenheim, S. (1988) Talc, pyrophyllite and related minerals. Pp. 225–294 in: Hydrous Phyllosilicates (exclusive of micas) (Bailey, S.W., editor). Reviews in Mineralogy, vol. 19, Mineralogical Society of America, Washington DC.Google Scholar
Evans, J.A. (1991) Resetting of Rb-Sr whole-rock ages during Acadian low-grade metamorphism in North Wales. J. Geol. Soc. London 148, 703–711.CrossRefGoogle Scholar
Fontanive, A., Gragnani, R., Mignuzzi, C. & Spat, G. (1993) Chemical composition of porewaters in Italian Plio-Pleistocene clayey formations. Pp. 389-411 in: Geochemistry of Clay-Pore Fluid Interactions (Manning, D.A.C., Hall, P.L. & Hughes, C.R., editors). Chapman and Hall, London.Google Scholar
Fournier, R.O. (1985) The behaviour of silica in hydrothermal solutions. Pp. 45–61 in: Reviews in Economic Geology, 2: Geology and Geochemistry of Epithermal Systems (Berger, B.R. & Bethke, P.M., editors). Society of Economic Geologists.Google Scholar
Fujishima, K.Y. & Fan P-F. (1977) Hydrothermal mineralogy of the Keolu Hills, Oahu, Hawaii. Am. Miner. 62, 594–582.Google Scholar
Furbish, W.J. (1975) Corrensite of deuteric origin. Am. Miner. 60, 928–930.Google Scholar
Garvie, L.A.J. (1992) Diagenetic tosudite from the lowermost St. Maughan's Group, Lydney Harbour, Forest of Dean. Clay Miner. 27, 507–513.Google Scholar
Garvie, L.A.J., Craven, A.J. & Brydson, R. (1994) Use of electron-loss near-edge fine structure in the study of minerals. Am. Miner. 79, 411–425.Google Scholar
Güven, N. (1988) Smectites. Pp. 497-559 in: Hydrous Phyllosilicates (exclusive of micas) (Bailey, S.W., editor). Reviews in Mineralogy, vol. 19, Mineralogical Society of America, Washington DC.Google Scholar
Ichikawa, A. & Schimoda, S. (1976) Tosudite from the Hokuno mine, Hokuno, Gifu Prefecture, Japan. Clays Clay Miner. 24, 142–148.CrossRefGoogle Scholar
Inoue, A. (1987) Conversion of smectite to chlorite by hydrothermal and diagenetic alterations, Kokuroku Kuroko mineralisation area, northeast Japan. Proc. Int. Clay Conf., Denver, 158-164.Google Scholar
Jiang, W-T., Peacor, D.R. & Buseck, P.R. (1994) Chlorite geothermometry? – Contamination and apparent octahedral vacancies. Clays Clay Miner. 42, 593–605.CrossRefGoogle Scholar
Johnson, J.W., Oelkers, E.H. & Helgeson, H.C. (1991) SUPCRT92: a software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0°C to 1000°C. Department of Geology and Geophysics, Berkeley.Google Scholar
Kawano, M. & Tomita, K. (1991) Dehydration and rehydration of saponite and vermiculite. Clays Clay Miner. 39, 174–183.Google Scholar
de Kimpe, C.R. & Miles, N.M. (1988) Geographic distribution of corrensite and associated minerals in southeastern Ontario. Can. Miner. 26, 957–964.Google Scholar
Kokelaar, B.P., Howells, M.F., Bevins, R.E., Roach, R.A. & Dunkley, P.N. (1984) The Ordovician marginal basin of Wales. Pp. 591–613 in: Marginal Basin Geology (Kokelaar, B.P. & Howells, M.F., editors). Geological Society of London, Special Publication, 16.Google Scholar
Kristmannsdottir, H. (1979) Alteration of basaltic rocks by hydrothermal activity at 100-300° Proc. Int. Clay Conf Oxford, 359-367.Google Scholar
Kuchta, L'. & Fajnor, V.S. (1988) Optimal conditions for hydrothermal synthesis of saponite. Chem. Papers 42, 339–345.Google Scholar
Lundegard, P.D. & Kharaka, Y.K. (1990) Geochemistry of organic acids in subsurface waters. Pp. 169–189 in: Chemical Modeling of Aqueous Systems II (Melchior, D. C. & Bassett, R. L., editors). ACS symposium series 416, American Chemical Society, Washington.Google Scholar
MacEwan, D.M.C. & Wilson, M.J. (1984) Interlayer and intercalation complexes of clay minerals. Pp. 197-248 in: Crystal Structures of Clay Minerals and their X-ray Identification (Brindley, G.W. & Brown, G., editors). Mineralogical Society, London.Google Scholar
Mackenzie, R.C. (1957) Saponite from Allt Ribhein, Fiskavaig Bay, Skye. Mineral. Mag. 31, 672–680.Google Scholar
Metcalfe, R. (1989) Metadomains as indicators of fluidrock interaction in the Welsh Marginal Basin. Proc. 6th Int. Symp. Water-Rock Interaction, 479-482.Google Scholar
Metcalfe, R. (1990) Fluid/rock interaction and metadomain .formation during low-grade metamorphism in the Welsh Marginal Basin. PhD thesis, Univ. Bristol, UK.Google Scholar
Metcalfe, R., Banks, D. & Bottrell, S.H. (1993) An association between organic matter and localized prehnite-pumpellyite alteration at Builth Wells, Wales, U.K. Chem. Geol. 102, 1–21.Google Scholar
Metcalfe, R., Bevins, R.E. & Robinson, D. (1997) Fluid fluxes during low-temperature alteration: implicatons of multi-style alteration assemblages from the Welsh Borderland, U.K. Geol. J. 31 (in press)Google Scholar
Mexias, A., Milton, F., Meunier, A. & Beaufort, D. (1990) Composition and crystallization of corrensite in volcanic and pyroclastic rocks of Hilario Formation (RS) Brazil. Proc. 9th Int. Clay Conf Strasbourg, 4, 135–143.Google Scholar
Newman, A.C.D. & Brown, G. (1987) The chemical constitution of clays. Pp. 1 – 128 in: Chemistry of Clays and Clay Minerals (Newman, A.C.D., editor), Monograph 6, Mineralogical Society, London.Google Scholar
Post, J.L. (1984) Saponite from near Ballarat, California. Clays Clay Miner. 32, 147–153.Google Scholar
Quakernaat, J. (1970) A new occurrence of a macrocrystalline form of saponite. Clay Miner. 8, 491–493.Google Scholar
Reynolds, R.C. Jr. (1988) Mixed-layer chlorite minerals. Pp. 601–629 in: Hydrous Phyllosilicates (exclusive of micas) (Bailey, S.W., editor). Reviews in Mineralogy, vol. 19, Mineralogical Society of America, Washington DC.Google Scholar
Robinson, D. & Bevins, R.E. (1986) Incipient metamorphism in the Lower Palaeozoic marginal basin of Wales. J. Met. Geol. 4, 101–113.Google Scholar
Shau, Y.-H. & Peacor, D.R. (1992) Phyllosilicates in hydrothermally altered basalts from DSDP Hole 504B, Leg 83 - a TEM and AEM study. Contrib. Mineral. Petrol. 112, 119–125.Google 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. Contrib. Mineral. Petrol. 105, 123–142.Google Scholar
Shearman, D.J., Mossop, G., Dunsmore, H. & Martin, M. (1972) Origin of gypsum veins by hydraulic fracture. Trans. Inst. Mining Metal. B 81, 149–155.Google Scholar
Singer, A. & Stoffers, P. (1987) Mineralogy of a hydrothermal sequence in a core from the Atlantis II Deep, Red Sea. Clay Miner. 22, 251–267.CrossRefGoogle Scholar
Stakes, D.S. & O'Niel, J.R. (1982) Mineralogy and stable isotope geochemistry of hydrothermally altered oceanic rocks. Earth Planet. Sci. Lett. 57, 285–304.CrossRefGoogle Scholar
Stoneley, R. (1983) Fibrous calcite veins, overpressures, and primary oil migration. Am. Assoc. Petrol. Geol. Bull. 67, 1427–1428.Google Scholar
Suquet, H., de la Calle, C. & Pezerat, H. (1975) Swelling and structural organization of saponite. Clays Clay Miner. 23, 1–9.Google Scholar
Suquet, H. & Pezerat, H. (1988) Comments on the classification of trioctahedral 2:1 phyllosilicates. Clays Clay Miner. 36, 184–186.Google Scholar
Velde, B. (1985) Clay Minerals– a Physico-Chemical Explanation of their Occurrence. Developments in Sedimentology, 40, Elsevier, Oxford.Google Scholar
Woodcock, N.H. (1987) Kinematics of strikeslip faulting, Builth Inlier, Mid-Wales. J. StrucL Geol. 9, 353–363.Google Scholar
Wright, V.P., Sloan, R.J., Garvie, L.A.J. & Rae, J.E. (1992) A polygenetic palaeosol from the Silurian (Wenlock) of southwest Ireland. J. Geol. Soc. Lond. 148, 849–859.Google Scholar
Zierenberg, R.A. & Shanks, W.C. III (1983) Mineralogy and geochemistry of epigenetic features in metalliferous sediment, Atlanits II Deep, Red Sea. Econ. Geol. 78, 57–72.Google Scholar