Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-28T10:02:24.390Z Has data issue: false hasContentIssue false

Hydrothermal alteration processes of the Tertiary lavas of Northern Ireland

Published online by Cambridge University Press:  05 July 2018

Ch. Robert*
Affiliation:
Laboratoire de Géologie, UMR CNRS 8538, Ecole Normale Supérieure, 24, rue Lhomond, F75231 Paris cedex 05, France
*

Abstract

The alteration mineralogy of two outcrops of basaltic lavas in northeast Ireland is studied with respect to the hydrothermal alteration history of basalts. Evidence for contact between basaltic flows and palaeorivers or palaeolakes is reported in both outcrops, which belong to two different formations: the Lower Basaltic Formation (LBF) and the Inter Basaltic Formation (Causeway Tholeiite Member, CTM). The secondary minerals consist of layer silicates (chlorite-smectite, C-S, di- and trioctahedral smectites), zeolites, calcite and silica minerals and there is a repetition of the sequence of alteration mineralogy in each formation. The mineralogy of phyllosilicates from the LBF (C-S) corresponds to hotter conditions of alteration than those of CTM (di/trioctahedral smectites), while the zeolite mineralogy is controlled by the fluid composition. In consequence, the mineralogy and the distribution of alteration minerals suggest that the crystallization of phyllosilicates and zeolites did not develop during burial of lavas a long time after the eruption, but reflects thermal gradients driven by lava heat flow and marked by local perturbation caused by regional water flow through the aquifer zone in the lava during the last cooling of each lava sequence.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2001

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

Alt, J.C., Honnorez, J., Laverne, C. and Emmermann, R. (1986) Hydrothermal alteration of a 1 km section through the upper oceanic crust, deep sea drilling project hole 504B: mineralogy, chemistry, and evolution of seawater-baslt interactions. J. Geophys. Res., 91, 10309–35.CrossRefGoogle Scholar
Berman, R.G. (1988) Internally-consistent thermodynamic data for minerals in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-TiO2-H2O-CO2 . J. Petrol., 29, 445522.CrossRefGoogle Scholar
Bettison, L.A. and Schiffman, P. (1988) Compositional and structural variations of phyllosilicates from the Point Sal Ophiolite, California. Amer. Mineral., 73, 6276.Google Scholar
Bevins, R.E., Rowbotham, G. and Robinson, D. (1991) Zeolite to prehnite-pumpellyite facies metamorphism of the late Proterozoic Zig-Zag Dal Basalt Formation, eastern North Greenland. Lithos, 27, 155–65.CrossRefGoogle Scholar
Boles, J.R. (1972) Composition, optical properties, cell dimensions, and thermal stability of some heulandite group zeolites. Amer. Mineral., 57, 1463–93.Google Scholar
Coombs, D.S., Alberti, A., Armbruster, T., Artioli, G., Colella, C., Galli, E., Grice, J.D., Liebau, F., Mandarino, J.A., Minato, H., Nickel, E.H., Passaglia, E., Peacor, D.R., Quartieri, S., Rinaldi, R., Ross, M., Sheppard, R.A., Tillmanns, E. and Vezzalini, G. (1998) Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names. Min. Mag., 62, 533–71.CrossRefGoogle Scholar
Dickin, A.P. (1988) The North Atlantic Tertiary Province. Pp. 111–49 in: Continental Flood Basalts., (MacDougall, J.D., editor ). Kluwer, Dordrecht, The Netherlands.CrossRefGoogle Scholar
Gottardi, G. and Galli, E. (1985) Natural Zeolites., Springer-Verlag, Berlin.CrossRefGoogle Scholar
Hawkins, D.B., Sheppard, R.A. and Gude, A.J. III (1978) Hydrothermal synthesis of clinoptilolite and comments on the assemblage phillipsite-clinoptilolite-mordenite. Pp. 331–44 in: Natural Zeolite Occurrence, Properties and Use., (Sand, L.B. and Mumpton, F.M., editors). Pergamon Press, Oxford.Google Scholar
Honnorez, J., Laverne, C., Hubberten, H.W., Emmermann, R. and Muehlenbachs, K. (1983) Alteration process of layer 2 basalts from DSDP Hole 504B, Costa Rica Rift. DSDP Initial Reports, 70, 509–46.Google Scholar
Kristmannsdóttir, H. and Tómasson, J. (1978) Zeolite zones in geothermal areas in Iceland. Pp. 277–84 in: Natural Zeolite Occurrence, Properties and Use., (Sand, L.B. andMumpton, F.M., editors). Pergamon Press, Oxford.Google Scholar
Liou, J.G., De Capitani, C. and Frey, M. (1991) Zeolite equilibria in the system CaAl2Si2O8-NaAlSi3O8-SiO2-H2O. New Zealand J. Geol. Geophys., 34, 293301.CrossRefGoogle Scholar
Lyle, P. (1980) A petrological and geochemical study of the Tertiary basaltic rocks of Northeast Ireland. J. Earth Sci. R. Dubl. Soc., 2, 137–52.Google Scholar
Lyle, P. and Preston, J. (1993) Geochemistry and volcanology of the Tertiary basalts of the Giant's Causeway area, Northern Ireland. J. Geol. Soc., 150, 109–20.CrossRefGoogle Scholar
Mumpton, F.A. (1960) Clinoptilolite redefined. Amer. Mineral., 45, 351–69.Google Scholar
Nawaz, R. (1980) Morphology, twinning and optical orientation of gismondine. Mineral. Mag., 43, 841–4.CrossRefGoogle Scholar
Nawaz, R. (1982) A chemical classification scheme for the gismondine group zeolites. Ir. Nat. J., 20, 480–3.Google Scholar
Nawaz, R. and Foy, H.J. (1982) A chemical classification scheme of the chabazite group zeolites. Ir. Nat. J., 20, 435–40.Google Scholar
Nawaz, R. and Malone, J.F. (1982) Gobbinsite, a new zeolite mineral from Co. Antrim N. Ireland. Mineral. Mag., 46, 365–9.CrossRefGoogle Scholar
Neuhoff, P.S., Watt, W.S., Bird, D.K. and Pedersen, A.K. (1997) Timing and structural relations of regional zeolite zones in basalts of the East Greenland continental margin. Geology, 25, 803–6.2.3.CO;2>CrossRefGoogle Scholar
Old, R.A. (1975) The age and Field relationships of the Tardree Tertiary rhyolite complex, County Antrim, N. Ireland. Bull. Geol. Surv. Great Britain, 51, 21–40.Google Scholar
Patterson, E.M. (1955) The Tertiary lava succession in the northern part of the Antrim plateau. Proc. Royal Ir. Acad., 57B, 79122.Google Scholar
Philpotts, A.R. (1982) Compositions of immiscible liquids in volcanic rocks. Contrib. Mineral. Petrol., 80, 201–18.CrossRefGoogle Scholar
Preston, J. (1982) Eruptive volcanism. Pp. 351–68 in: Igneous Rocks of the British Isles., (Sutherland, D.S., editor). Wiley, New York.Google Scholar
Robert, Ch. and Goffé, B. (1989) Transport de Si, Al, Ca en conditions hydrothermales de basse température: Etude expérimentale préliminaire de la zéolitisation en eau douce. CR Acad. Sci. Paris., 309(II), 1803–9.Google Scholar
Robert, Ch. and Goffé, B. (1993) Zeolitization of basalts in subaqueous freshwater settings: Field observations and experimental study. Geochim. Cosmochim. Acta, 57, 3597–612.CrossRefGoogle Scholar
Robert, Ch., Goffé, B. and Saliot, P. (1988) Zeolitisation of a basaltic flow in a continental environment: An example of mass transfer under thermal control. Bull. Minéral., 111, 671–7.CrossRefGoogle Scholar
Robinson, D., Bevins, R.E. and Rowbotham, G. (1993) The characterization of mafic phyllosilicates in lowgrade metabasalts from eastern North Greenland. Amer. Mineral., 78, 377–90.Google Scholar
Schiffman, P. and Fridleifsson, G.O. (1991) The smectite to chlorite transition in drillhole NJ-15, Nesjavellir geothermal Field, Iceland: XRD, BSE and electron microprobe investigations. J. Metam. Geol., 9, 679–96.CrossRefGoogle Scholar
Schmidt, S.T. (1993) Regional and local patterns of low grade metamorphism in the North Shore Volcanic Group, Minnesota, USA. J. Metam. Geol., 11, 401–14.CrossRefGoogle Scholar
Tomkeieff, S.I. (1934) Differentiation in basalt lavas, Island Magee, Co. Antrim. Geol. Mag., 71, 501–12.CrossRefGoogle Scholar
Tomkeieff, S.I. (1940) The basalt lavas of the Giant's Causeway district, Northern Ireland. Bull. Volcanol., 6, 89–143.CrossRefGoogle Scholar
Walker, G.P.L. (1951) The amygdale minerals in the Tertiary basalts of Ireland I. The distribution of chabazite habits and zeolites in the Garron plateau area, County Antrim. Mineral. Mag., 29, 773–91.Google Scholar
Walker, G.P.L. (1959) The amygdale minerals in the Tertiary basalts of Ireland, II. The distribution of gmelinite. Mineral. Mag., 32, 202–17.Google Scholar
Walker, G.P.L. (1960 a) The amygdale minerals in the Tertiary basalts of Ireland, III. Regional distribution. Mineral. Mag., 32, 503–27.Google Scholar
Walker, G.P.L. (1960 b) The amygdale minerals in the Tertiary basalts of Ireland, IV. The crystal habit of calcite. Mineral. Mag., 32, 609–18.Google Scholar
Walker, G.P.L. (1979) The environment of Tertiary igneous activity in the British Isles. Bull. Geol. Surv. Great Britain, 70, 5–6.Google Scholar
White, R.S. (1988) A hot-spot model for early Tertiary volcanism in the North-Atlantic. Pp. 685729 in: Early Tertiary Volcanism and the opening of the NE Atlantic., (Morton, A.C. and Parson, L.M., editors). Spec. Publ., 39. Geological Society, London.Google Scholar
Wilson, H.E. and Manning, P.I. (1978) Geology of the Causeway Coast. Mem. Geol. Surv. Northern Ireland. Google Scholar