Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-23T15:13:57.590Z Has data issue: false hasContentIssue false
  • English
  • Français

The Rhinns Complex: Proterozoic basement on Islay and Colonsay, Inner Hebrides, Scotland, and on Inishtrahull, NW Ireland

Published online by Cambridge University Press:  03 November 2011

R. J. Muir ,
W. R. Fitches  and
A. J. Maltman
R. J. Muir
Affiliation:
Institute of Earth Studies, University of Wales, Aberystwyth, Dyfed, Wales, SY23 3DB, UK
W. R. Fitches
Affiliation:
Institute of Earth Studies, University of Wales, Aberystwyth, Dyfed, Wales, SY23 3DB, UK
A. J. Maltman
Affiliation:
Institute of Earth Studies, University of Wales, Aberystwyth, Dyfed, Wales, SY23 3DB, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

The Precambrian basement on the islands of Islay, Colonsay and Inishtrahull comprises a deformed igneous association of mainly syenite and gabbro, with minor mafic and felsic intrusions. This association is collectively referred to as the Rhinns Complex. Isotopic data indicate that the complex represents new addition of material to the crust at c. 1·8 Ga. The igneous protolith was juvenile mantle-derived material, not reworked Archaean crust. Overall, the complex has an alkalic composition, with major and trace element patterns similar to igneous rocks generated in a subduction-related setting: high LILE/HFSE and LREE/HREE ratios, together with negative Nb, P and Ti anomalies.

The formation of the Rhinns Complex was contemporaneous with the Laxfordian tectonothermal cycle in the Lewisian Complex. These Proterozoic events are most likely associated with an extensive 1·9–1·7 Ga mobile belt around the southern margin of Laurentia-Baltica. As part of this belt, the Rhinns Complex forms a link between the Ketilidian province of South Greenland and the Svecofennian of Scandinavia.

Inherited isotopic signatures in the Caledonian granites on the north side of the Highland Boundary Fault may reflect the presence of a large area of Proterozoic basement (?Rhinns Complex) beneath Scotland and NW Ireland. Alternatively, the Proterozoic signature could be derived from the incorporation of Moine or Dalradian sediment into the granitic magmas.

Keywords

alkalic igneous provincesyenitegabbrogeochemistryNd isotopesLewisian ComplexLaxfordian
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 85 , Issue 1 , 1994 , pp. 77 - 90
Copyright
Copyright © Royal Society of Edinburgh 1994

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

Aftalion, M. & Max, M. D. 1987. U-Pb zircon geochronology from the Precambrian Annagh Division gneisses and the Termon Granite, NW County Mayo, Ireland. J GEOL SOC LONDON 144, 401–6.CrossRefGoogle Scholar
Arndt, N. T. & Goldstein, S. L. 1987. Use and abuse of crustformation ages. GEOLOGY 15, 893–5.2.0.CO;2>CrossRefGoogle Scholar
Blaxland, A. B., Aftalion, M. & van Breemen, O. 1979. Pb isotopic composition of feldspars from Scottish Caledonian granites and the nature of the underlying crust. SCOTT J GEOL 15, 139–54.CrossRefGoogle Scholar
Bentley, M. R. 1986. The tectonics of Colonsay, Scotland. Unpublished Ph.D. Thesis, Aberystwyth, University of Wales.Google Scholar
Bentley, M. R. 1988. The Colonsay Group In Winchester, J. A. (ed.)Late Proterozoic Stratigraphy of the North Atlantic Regions, 119–30. Glasgow: Blackie.Google Scholar
Bentley, M. R., Maltman, A. J. & Fitches, W. R. 1988. Colonsay and Islay: A suspect terrane within the Scottish Caledonides. GEOLOGY 16, 26–8.2.3.CO;2>CrossRefGoogle Scholar
Bowes, D. R. & Hopgood, A. M. 1975. Structure of the gneiss complex of Inishtrahull, Co. Donegal. PROC R IRISH ACAD 75B, 369–90.Google Scholar
Brown, G. C. 1982. Calc-alkaline intrusive rocks; Their diversity,evolution and relation to volcanic arcs. In Thorpe, R. S. (ed.) Andesites, 437–61. London: John Wiley.Google Scholar
Cliff, R. A., Gray, C. M. & Hahma, H. 1983. A Sm-Nd isotopic study of the South Harris Igneous Complex, the Outer Hebrides. CONTRIB MINERAL PETROL 82, 91–8.Google Scholar
Clayburn, J. A. P. 1988. The crustal evolution of Central Scotland and the nature of the lower crust: Pb, Nd, and Sr isotope evidence from Caledonian granites. EARTH PLANET SCI LETT 90, 41–51.CrossRefGoogle Scholar
Corriveau, L. 1990. Proterozoic subduction and terrane amalgamation in the southwestern Grenville province, Canada: evidence from ultrapotassic to shoshonitic plutonism. GEOLOGY 18, 614–17.Google Scholar
Cunningham-Craig, E. M., Wright, W. B. & Bailey, E. B. 1911. The geology of Colonsay and Oronsay, with part of the Ross of Mull. MEM GEOL SURV SCOTLAND.Google Scholar
Daly, J. S. & Menuge, J. F. 1989. Nd isotopic evidence for the provenance of the Dalradian Supergroup sediments in Ireland. TERRA ABST 1, 12.Google Scholar
Daly, J. S., Muir, R. J. & Cliff, R. A. 1991. A precise U-Pb zircon age for the Inishtrahull syenitic gneiss, County Donegal, Ireland. J GEOL SOC LONDON 148, 639–42.Google Scholar
De Paolo, D. J. 1981. Neodymium isotopes in the Colorado Front Range and crust-mantle evolution in the Proterozoic. NATURE 291, 193–6.Google Scholar
Dickin, A. P. 1992. Evidence for an Early Proterozoic crustal province in the North Atlantic region. J GEOL SOC LONDON 149, 483–6.Google Scholar
Dickin, A. P. & Bowes, D. R. 1991. Isotopic evidence for the extent of early Proterozoic basement in Scotland and northwest Ireland. GEOL MAG 128, 385–8.CrossRefGoogle Scholar
Evans, D., Kenolty, N., Dobson, M. R. & Whittington, R. J. 1979. Geology of the Malin Sea. REP INST GEOL SCI 79/15.Google Scholar
Fettes, D. J. & Mendum, J. R. 1987. The evolution of the Lewisian complex in the Outer Hebrides. In Park, R. G. & Tarney, J. (eds) Evolution of the Lewisian and Comparable Precambrian High Grade Terrains, 27–44. SPEC PUBL GEOL SOC LONDON 27.Google Scholar
Fitches, W. R. & Maltman, A. J. 1984. Tectonic development and stratigraphy at the western margin of the Caledonides: Islay and Colonsay, Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 365–82.Google Scholar
Fitches, W. R., Muir, R. J., Maltman, A. J. & Bentley, M. R. 1990. Is the Colonsay-west Islay block of SW Scotland an allochthonous terrane? Evidence from Dalradian tillite clasts. J GEOL SOC LONDON 147, 417–20.CrossRefGoogle Scholar
Fitton, J. G. & Upton, B. G. J. (eds) 1987. Alkaline Igneous Rocks. SPEC PUBL GEOL SOC LONDON 30.Google Scholar
Frost, C. D. & O'Nions, R. K. 1985. Caledonian magma genesis and crustal recycling. J PETROL 26, 515–44.CrossRefGoogle Scholar
Gaal, G. & Gorbatschev, R. 1987. An outline of the Precambrian Evolution of the Baltic Shield. PRECAMB RES 35, 15–52.CrossRefGoogle Scholar
Hall, J., Brewer, J. A.Matthew, D. H. & Warner, M. R. 1984. Crustal structure across the Caledonides from ‘WINCH’ seismic reflection profile: Influences on the evolution of the Midland valley of Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 97–109.CrossRefGoogle Scholar
Halliday, A. N. 1984. Coupled Sm-Nd and U-Pb systematics in late Caledonian granites and the basement under northern Britain. NATURE 307, 229–33.CrossRefGoogle Scholar
Halliday, A. N., Stephens, W. E., Hunter, R. H., Menzies, M. A., Dickin, A. P. & Hamilton, P. J. 1985. Isotopic and chemical constraints on the building of the deep Scottish lithosphere. SCOTT J GEOL 21, 465–91.Google Scholar
Halliday, A. N.Aftalion, M., van Breemen, O. & Jocelyn, J. 1979. Petrogenetic significance of Rb-Sr and U-Pb isotopic systems in the 400 Ma old British Isles granitoids and their hosts In Harris, A. L., Holland, C. M. & Leake, B. E. (eds) The Caledonides of the British Isles–Reviewed, 653–61. SPEC PUBL GEOL SOC LONDON 8.Google Scholar
Hamilton, P. J., Evensen, N. M., O'Nions, R. K. & Tarney, J. 1979. Sm-Nd systematics of Lewisian gneisses: implications for the origin of granulites. NATURE 277, 25–8.CrossRefGoogle Scholar
Heaman, L. M. & Tarney, J. 1989. U-Pb baddeleyite ages for the Scourie dyke swarm, Scotland: evidence for two distinct intrusion events. NATURE 340, 705–8.Google Scholar
Hoffman, P. F. 1988. United plates of America, the birth of a craton: Early Proterozoic assembly and growth of Proto-Laurentia. ANN REV EARTH PLANET SCI 16, 543–603.Google Scholar
Hutton, D. H. W. 1992. Granite sheeted complexes: evidence for the dyking ascent mechanism. TRANS R SOC EDINBURGH EARTH SCI 83, 377–82.Google Scholar
Irvine, T. N. & Baragar, W. R. A. 1971. A guide to the chemical classification of the common volcanic rocks. CAN J EARTH SCI 8, 523–48.CrossRefGoogle Scholar
Johnson, Y., Park, R. G. & Winchester, J. 1987. Geochemistry, petrogenesis and tectonic significance of the Early Proterozoic Loch Maree amphibolites. In Paroah, T. C, Beckinsale, R. D. & Rickard, D. T. (eds) Geochemistry and Mineralization of Proterozoic Volcanic Suites, 255–69. SPEC PUBL GEOL SOC LONDON 33.Google Scholar
Lambert, R. St. J. & Holland, J. G. 1972. A geochronological study of the Lewisian from Loch Laxford to Durness, Sutherland, NW Scotland. SCOTT J GEOL 6, 214–20.CrossRefGoogle Scholar
Le Maitre, R. W. 1989. A Classification of Igneous Rocks and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. Oxford: Blackwell Scientific Publications.Google Scholar
Lyon, T. B. D., Pidgeon, R. T., Bowes, D. R. & Hopgood, A. R. 1973. Geochronological investigation of the quartzofeldspathic rocks of the Lewisian of Rona, Inner Hebrides. J GEOL SOC LONDON 129, 389–402.Google Scholar
MacCallien, W. J. 1930. The gneiss of Inishtrahull, Co. Donegal. GEOL MAG 67, 542–49.CrossRefGoogle Scholar
Maclntyre, R. M., van Breemen, O., Bowes, D. R. & Hopgood, A. M. 1975. Isotopic study of the gneiss complex, Inishtrahull, Co. Donegal. SCI PROC R DUBLIN SOC 5A, 301–9.Google Scholar
Marcantonio, F., Dickin, A. P., McNutt, R. H. & Heaman, L. M. 1988. A 1800-million-year-old Proterozoic gneiss terrane in Islay with implications for the crustal structure and evolution of Britain. NATURE 335, 62–4.Google Scholar
Max, M. D. & Long, C. B. 1985. Pre-Caledonian basement in Ireland and its cover relationships. GEOL J 20, 341–66.Google Scholar
Menuge, J. F. & Daly, J. S. 1991. Proterozoic evolution of the Erris Complex, NW Mayo, Ireland: Neodymium isotope evidence. In Gower, C. F., River, T. & Ryan, B.Mid-Proterozoic Laurentia-Baltica, 41–52. SPEC PAP GEOL ASSOC CANADA 38.Google Scholar
Morton, A. C. & Taylor, P. N. 1991. Geochemical and isotopic constraints on the nature and age of basement rocks from the Rockall Bank, NE Atlantic. J GEOL SOC LONDON 148, 631–34.CrossRefGoogle Scholar
Muir, R. J. 1990. The Precambrian basement and related rocks of the southern Inner Hebrides, Scotland. Unpublished Ph.D. Thesis, Aberystwyth, University of Wales.Google Scholar
Muir, R. J., Fitches, W. R. & Maltman, A. J. 1992. Rhinns complex: a missing link in the Proterozoic basement of the North Atlantic region. GEOLOGY 20, 1043–46.2.3.CO;2>CrossRefGoogle Scholar
Nakamura, N. 1974. Determination of REE, Ba, Fe, Mg, Na and K in carbonaceouos and ordinary chondrites. GEOCHIM COSMOCHIM ACTA 38, 757–73.Google Scholar
Park, A. F. 1991. Continental growth by accretion: a tectonostratigraphic terrane analysis of the evolution of the western and central Baltic Shield, 2·50 to 1·75 Ga. BULL GEOL SOC AM 103, 522–37.Google Scholar
Park, R. G. 1991. The Lewisian Complex. In Craig, G. Y. (ed.) Geology of Scotland, 25–58. 3rd edn. London: Geological Society.Google Scholar
Park, R. G. & Tarney, J. 1987. The Lewisian Complex: a typical Precambrian high-grade terrane? In Park, R. G. & Tarney, J. (eds) Evolution of the Lewisian and Related High Grade Terrains, 13–25. SPEC PUBL GEOL SOC LONDON 27.Google Scholar
Patchett, P. J. & Arndt, N. T. 1986. Nd isotopes and tectonics of 1·9—1·7 Ga crustal genesis. EARTH PLANET SCI LETT 78, 329–38.Google Scholar
Patchett, P. J. & Bridgwater, D. 1984. Origin of continental crust of 1·9—1·7 Ga age defined by Nd isotopes in the Ketilidian terrain of South Greenland. CONTRIB MINERAL PETROL 87, 311–18.Google Scholar
Pidgeon, R. T. & Aftalion, M. 1978. Cogenetic and inherited U-Pb systems in Palaeozoic granites of Scotland and Ireland. In Bowes, D. R. & Leake, B. E. (eds) Crustal Evolution of North-Western Britain and Adjacent Regions, 183–220. GEOL J SPEC ISSUE 10.Google Scholar
Pidgeon, R. T. & Compston, W. 1992. A SHRIMP ion microprobe study of inherited and magmatic zircons from four Scottish Caledonian granites. TRANS R SOC EDINBURGH EARTH SCI 83, 473–83.Google Scholar
Roddick, J. C. & Max, M. D. 1983. A Laxfordian age from the Inishtrahull Platform, Co. Donegal, Ireland. SCOTT J GEOL 19, 97–102.Google Scholar
Saunders, A. D., Tarney, J. & Weaver, S. D. 1980. Transverse geochemical variations across the Antarctic Peninsula: implications for the genesis of calc-alkaline magmas. EARTH PLANET SCI LETT 86, 225–39.Google Scholar
Saunders, A. D., Norry, M. J. & Tarney, J. 1991. Trace element compositions of subduction zone magmas. PHIL TRANS R SOC LONDON A335, 377–92.Google Scholar
Sun, S. S. & McDonough, W. F. 1989. Chemical and isotopic systematics of oceanic basalts: Implications for mantle composition and processes. In Saunders, A. D. & Norry, J. J. (eds). Magmatism in the Ocean Basins. SPEC PUBL GEOL SOC LONDON 42, 313–45.Google Scholar
Taylor, P. N., Jones, N. W. & Moorbath, S. 1984. Isotopic assessment of relative contributions from crust and mantle sources to the magma genesis of Precambrian granitoid rocks. PHIL TRANS R SOC LONDON A310, 605–25.Google Scholar
Waters, F. G., Cohen, A. S., O'Nions, R. K, & O'Hara, M. J. 1990. Development of Archaean Lithosphere deduced from chronology and isotope chemistry of Scourie Dykes. EARTH PLANET SCI LETT 97, 241–55.CrossRefGoogle Scholar
Weaver, B. L. & Tarney, J. 1981. Chemical changes during dyke metamorphism in high-grade basement terrains. NATURE 289, 47–9.Google Scholar
Weaver, B. L. & Tarney, J. 1980. Rare-earth element geochemistry of Lewisian granulite-facies gneisses, northwest Scotland: implications for the petrogenesis of the Archaean lower continental crust. EARTH PLANET SCI LETT 51, 279–96.CrossRefGoogle Scholar
Westbrook, G. K. & Borradaile, G. J. 1978. The geological significance of magnetic anomalies in the region of Islay. SCOTT J GEOL 14, 213–24.Google Scholar
Whitehouse, M. J. 1990. An early-Proterozoic age for the Ness anorthosite, Lewis, Outer Hebrides. SCOTT J GEOL 26, 131–36.CrossRefGoogle Scholar
Wilkinson, S. B. 1907. The geology of Islay, including Oronsay and portions of Colonsay and Jura. MEM GEOL SURV SCOTLAND.Google Scholar
Wilson, M. 1989. Igneous Petrogenesis. London: Unwin Hyman.CrossRefGoogle Scholar
Winchester, J. A. & Max, M. D. 1984. Geochemistry and origins of the Annagh Division of the Precambrian Erris Complex, NW Co. Mayo, Ireland. PRECAMB RES 25, 397–414.Google Scholar
van Breemen, O., Aftalion, M. A. & Pidgeon, R. T. 1971. The age of the granite injection-complex of Harris, Outer Hebrides. SCOTT J GEOL 5, 269–85.Google Scholar