Hostname: page-component-5c6d5d7d68-wtssw Total loading time: 0 Render date: 2024-08-08T03:19:56.908Z Has data issue: false hasContentIssue false
  • English
  • Français

The Glas Eilean lavas: evidence of a Lower Permian volcano-tectonic basin between Islay and Jura, Inner Hebrides

Published online by Cambridge University Press:  03 November 2011

B. G. J. Upton ,
J. G. Fitton  and
R. M. Macintyre
B. G. J. Upton
Affiliation:
Grant Institute of Geology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, Scotland.
J. G. Fitton
Affiliation:
Grant Institute of Geology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, Scotland.
R. M. Macintyre
Affiliation:
S.U.R.R.C, East Kilbride, Glasgow G75 0QU, Scotland.
Get access Rights & Permissions [Opens in a new window]

Abstract

Subaerial lavas and intercalated sediments crop out on the islet of Glas Eilean and the Black Rock skerries in the Sound of Islay between Islay and Jura. The visible succession is c. 120 m thick and is traceable c. 2 km along strike (NNW–SSE). The lavas are alkali olivine-basalts containing olivine ± plagioclase and augite phenocrysts. Decreasing Mg, Cr and Ni upwards, coupled with decreasing average flow thickness and increasing amounts of inter-flow sediment, suggest progressively waning volcanic activity marked by decreasing ascent rates and greater degrees of differentiation. K-Ar dating on one sample gave an early Permian age of 285 ± 5 Ma. It is inferred that the lavas erupted from an isolated basalt volcano situated on a NNW–SSE trending fracture, associated with a narrow developing half-graben within the Dalradian metasediments. The tectonism and magmatism is inferred to be related to the ‘Clyde Belt’ of fault-bounded basins extending from Cheshire to the Little Minch.

Keywords

alkali olivine-basalthalf-grabensub-aerial lavas
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 77 , Issue 4 , 1987 , pp. 289 - 293
Copyright
Copyright © Royal Society of Edinburgh 1987

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

Baxter, A. N. & Mitchell, J. G. 1984. Camptonite-monchiquite dyke swarms of Northern Scotland: age relationships and their implications. SCOTT J GEOL 20, 297–308.CrossRefGoogle Scholar
de Souza, H.A.F. 1979. The Geochronology of Scottish Carboniferous Volcanism. Unpublished Ph.D. thesis, Edinburgh University.Google Scholar
Dixon, J. E., Fitton, J. G. & Frost, R. T. C. 1981. The Tectonic Significance of Post-Carboniferous Igneous Activity in the North Sea Basin. In Illing, L. V. and Hobson, G. D. (eds) Petroleum Geology of the Continental Shelf of North-West Europe, 121–37. London: Institute of Petroleum.Google Scholar
Fitch, F. J., Miller, J. A. & Williams, S. C. 1970. Isotopic ages of British Carboniferous rocks. C R 6e CONGR INT STRATIGR GEOL CARBONIF, Sheffield 1967 2, 771–89.Google Scholar
Fitton, J. G. & James, D. 1986. Basic volcanism associated with intraplate linear features. PHILOS TRANS R SOC LONDON A317, 253–66.Google Scholar
Forster, S. C. & Warrington, G. 1985. Geochronology of the Carboniferous, Permian and Triassic. In Snelling, N. J. (ed.) The Chronology of the Geological Record. MEM GEOL SOC LONDON 10, 99–113.CrossRefGoogle Scholar
Francis, E. H. 1983. Carboniferous-Permian igneous rocks. In Craig, G. Y. (ed.) Geology of Scotland, 297–324. Edinburgh: Scottish Academic Press.Google Scholar
Geikie, A. 1899. In Summary of Progress for 1897. MEM GEOL SURV GB 75.Google Scholar
Leitch, D. 1941. The Upper Carboniferous rocks of Arran. TRANS GEOL SOC GLASGOW 20, 141–54.CrossRefGoogle Scholar
Lorenz, V. & Nicholls, I. A. 1975. The Permocarboniferous basin and range province of Europe. An application of plate tectonics. In Falke, H. (ed.) The Continental Permian in Central, West and South Europe, 3132–42. Dordrecht: D. Reidel.Google Scholar
MacGregor, A. G. 1948. Problems of Carboniferous-Permian volcanicity in Scotland. Q J GEOL SOC LONDON 104, 133–53.CrossRefGoogle Scholar
Macintyre, R. M., Cliff, R. A. & Chapman, N. A. 1981. Geochronological evidence for phased volcanic activity in Fife and Caithness necks, Scotland. TRANS R SOC EDINBURGH: EARTH SCI 72, 1–7.CrossRefGoogle Scholar
McLean, A. C., 1978. Evolution of fault-controlled ensialic basins in north-western Britain. In Bowes, D. R. & Leake, B. E. (eds.) Crustal Evolution in North Western Britain and Adjacent Regions. GEOL J SPEC ISSUE 10, 325–46.Google Scholar
Mykura, W. 1967. The Upper Carboniferous rocks of south-west Ayrshire. BULL GEOL SURV GB 26, 23–98.Google Scholar
Norry, M. J. & Fitton, J. G. 1983. Compositional differences between oceanic and continental basic lavas and their significance. In Hawkesworth, C. J. and Norry, M. J. (eds) Continental Basalts and Mantle Xenoliths, 5–19. Nantwich: Shiva. 5–19.Google Scholar
Peach, B. N. 1907. In The Geology of Islay. MEM GEOL SURV p. 55.Google Scholar
Penn, I. E., Holliday, D. W., Kirby, G. A., Kubala, M., Sobey, R. A., Mitchell, W. I., Harrison, R. K. & Beckinsale, R. D. 1983. The Larne No. 2 Borehole: discovery of a new Permian volcanic centre. SCOTT J GEOL 19, 333–46.CrossRefGoogle Scholar
Pringle, J. 1952. On the occurrence of Permian rocks in Islay and north Kintyre. TRANS GEOL SOC EDINBURGH 14, 297–301.CrossRefGoogle Scholar
Pringle, J. & Bailey, E. B. 1944. The Carboniferous Rocks of Glas Eilean, Sound of Islay, Argyllshire. TRANS GEOL SOC GLASGOW 22, 249–59.Google Scholar
Simpson, J. B. & Richey, J. E., 1936. The geology of the Sanquhar Coalfield and the adjacent basin of Thornhill. MEM GEOL SURV GB.Google Scholar
Smith, D. B., Brunstrom, R. G. W., Manning, P. I., Simpson, S. & Shotton, F. W. 1974. A correlation of Permian Rocks in the British Isles. SPEC REP GEOL SOC LONDON 5.Google Scholar
Steiger, R. H. & Jäger, E. 1977. Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. EARTH PLANET SCI LETT 36, 359–362.CrossRefGoogle Scholar
Sun, S. S. 1980. Lead isotope study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs. PHILOS TRANS R SOC LONDON A297, 409–45.Google Scholar
Tyrrell, G. W. 1928. A further contribution to the petrography of the late-Palaeozoic igneous suite of the west of Scotland. TRANS GEOL SOC GLASGOW 18, 259–94.CrossRefGoogle Scholar
Ziegler, P. A. 1978. North-western Europe: tectonics and basin development. In van Loon, A. J. (ed.) Key-notes of the MEGS-II (Amsterdam, 1978) GEOL MIJNBOUW 57, 589–626.Google Scholar