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Intrusion history of the Portrush Sill, County Antrim, Northern Ireland: evidence for rapid emplacement and high-temperature contact metamorphism

Published online by Cambridge University Press:  19 September 2011

MORGANE LEDEVIN ,
NICHOLAS ARNDT ,
MARK R. COOPER ,
GARTH EARLS ,
PAUL LYLE ,
CHARLES AUBOURG  and
ERIC LEWIN
MORGANE LEDEVIN*
Affiliation:
Institut des Sciences de la Terre (ISTerre), Université de Grenoble, Grenoble 38401, France
NICHOLAS ARNDT
Affiliation:
Institut des Sciences de la Terre (ISTerre), Université de Grenoble, Grenoble 38401, France
MARK R. COOPER
Affiliation:
Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Belfast, Northern Ireland, BT9 5BF, UK
GARTH EARLS
Affiliation:
Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Belfast, Northern Ireland, BT9 5BF, UK
PAUL LYLE
Affiliation:
Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Belfast, Northern Ireland, BT9 5BF, UK
CHARLES AUBOURG
Affiliation:
Université Cergy-Pontoise, 5 mail Gay-Lussac Neuville-sur-Oise, F-95031 Cergy-Pontoise
ERIC LEWIN
Affiliation:
Institut des Sciences de la Terre (ISTerre), Université de Grenoble, Grenoble 38401, France
*
†Author for correspondence: [email protected]
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Abstract

The gabbroic Portrush Sill in Northern Ireland, part of the North Atlantic Igneous Province, intruded Lower Jurassic mudstones and siltstones about 55 Ma ago. We used petrologic observations and geochemical analyses to study how the sill interacted with the sedimentary rocks. Field relationships show that an Upper Sill and numerous associated Minor Intrusions were emplaced in the sedimentary host rocks before intrusion of the Main Sill, some 10 m above its upper contact. Geochemical analyses reveal two magma contamination processes: Nb and Ta anomalies, coupled with incompatible element enrichment, record contamination by deep crustal rocks, whereas Li, Pb and Ba anomalies reveal a superficial contamination through fluid circulation at the contact between magmatic and sedimentary rocks. Analysis of mineral assemblages and geochemical data from the contact aureole demonstrate uniform metamorphic conditions between the two main intrusions and an absence of a thermal gradient. The identification of pyrrhotite by magnetization analyses and of orthopyroxene by microprobe analyses indicates very high temperatures, up to 660°C. Thermal modelling explains these temperatures as the coupled effects of the Main Sill and the earlier intruded Upper Sill and Minor Intrusions. Even though the chemical composition of the Main Sill suggests another type of parental liquid, all three units were emplaced in a very short time, certainly less than five years.

Keywords

Portrush Sillcontact metamorphismmagma contaminationthermal modellingNorthern Ireland
Type
Original Articles
Information
Geological Magazine , Volume 149 , Issue 1 , January 2012 , pp. 67 - 79
Copyright
Copyright © Cambridge University Press 2011

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References

Akella, J. & Winkler, H. G. F. 1966. Orthorhombic amphibole in some metamorphic reactions. Contributions to Mineralogy and Petrology 12, 1–12.CrossRefGoogle Scholar
Barrat, J. A. & Nesbitt, R. W. 1996. Geochemistry of the Tertiary volcanism of Northern Ireland. Chemical Geology 129, 15–38.CrossRefGoogle Scholar
Chauvel, C., Bureau, S. & Poggi, C. 2011. Comprehensive chemical and isotopic analyses of basalt and sediment reference materials. Geostandards and Geoanalytical Research 35, 125–43.CrossRefGoogle Scholar
Coffin, M. F. & Eldholm, O. 1994. Large igneous provinces. Reviews of Geophysics 32, 1–36.CrossRefGoogle Scholar
Coulon, C. 2003. Panaches, magmatisme associé et déchirure continentale. Conférence Université d'Aix Marseille.Google Scholar
Courtillot, V., Jaupart, C., Manighetti, I., Tapponnier, P. & Besse, J. 1999. On causal links between flood basalts and continental breakup. Earth and Planetary Science Letters 166, 177–95.CrossRefGoogle Scholar
Farley, K. A. & Eltgroth, S. F. 2003. An alternative age model for the Paleocene–Eocene thermal maximum using extraterrestrial 3He. Earth and Planetary Science Letters 208, 135–48.CrossRefGoogle Scholar
Fourier, J. 1822. Théorie Analytique de la Chaleur. Paris: Firmin Didot Père et Fils (1822). Réédition Jacques Gabay (1988).Google Scholar
Ganerød, M., Mckenna, C., Smethurst, M., Prestvik, T., Rousse, S., Torsvik, T., Hendriks, B. 2008. The age of the Antrim Lava Group, Northern Ireland, and its correlation to the North Atlantic Igneous Province. American Geophysical Union, Fall Meeting, abstract #V53A-2124.Google Scholar
Govindaraju, K. 1980. Report (1980) on three GIT-IWG rock reference samples: anorthosite from Greenland, AN-G; basalte d'Essey-la-Côte, BE-N; granite de Beauvoir, MA-N. Geostandards Newsletter 4, 49–138.CrossRefGoogle Scholar
Hallam, A 1971. Mesozoic geology and the opening of the North Atlantic. Journal of Geology 79, 129–57.CrossRefGoogle Scholar
Hawkes, H. E. & Wilson, A. H. 1975. The Portrush Sill, County Antrim, Northern Ireland. Bulletin of the Geological Survey of Great Britain 51, 1–19.Google Scholar
Hofmann, A. W. 1988. Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust. Earth and Planetary Science Letters 90, 297–314.CrossRefGoogle Scholar
Holness, M. B. & Humphreys, M. C. S. 2003. The Traigh Bhàn na Sgùrra Sill, Isle of Mull: flow localization in a major magma conduit. Journal of Petrology 44, 1961–76.CrossRefGoogle Scholar
Huppert, H. E. & Sparks, R. S. J. 1989. Chilled margins in igneous rocks. Earth and Planetary Science Letters 92, 397–405.CrossRefGoogle Scholar
Kennett, J. P. & Scott, L. D. 1991. Abrupt deep-sea warming, palaeoceanographic changes and benthic extinctions at the end of the Palaeocene. Nature 353, 225–9.CrossRefGoogle Scholar
Landes, M., Ritter, J. R. R & Readman, P. W. 2007. Proto-Iceland plume caused thinning of Irish lithosphere. Earth and Planetary Science Letters 255, 32–40.CrossRefGoogle Scholar
Lyle, P 2003. The North of Ireland. Classic Geology in Europe 5. Harpenden, UK: Terra Publishing.Google Scholar
McHone, J. G. & Butler, J. R 1984. Mesozoic igneous provinces of New England and the opening of the North Atlantic Ocean. Geological Society of America Bulletin 95, 757–65.2.0.CO;2>CrossRefGoogle Scholar
McKenna, C. 2009. The age and petrogenesis of Palaeogene flood basalt volcanism in NE Ireland. 52nd Annual Irish Geological Research Meeting, February 2009.Google Scholar
Mitchell, W. I. (ed). 2004. The Geology of Northern Ireland – Our Natural Foundation, 2nd ed. Belfast: Geological Survey of Northern Ireland (GSNI).Google Scholar
Norris, R. D. & Röhl, U 1999. Carbon cycling and chronology of climate warming during the Palaeocene/Eocene transition. Nature 401, 775–8.CrossRefGoogle Scholar
Old, R. A 1975. The age and field relationships of the Tardree Tertiary rhyolite complex, County Antrim, N. Ireland. Bulletin of Geological Survey of Great Britain 51, 21–40.Google Scholar
Patterson, E. M 1955. The Tertiary lava succession in the Northern part of the Antrim Plateau. Proceedings of Royal Irish Academy 57B, 79–121.Google Scholar
Pirajno, F. 2004. Hotspots and mantle plumes: global intraplate tectonics, magmatism and ore deposits. Mineralogy and Petrology 82, 183–216.CrossRefGoogle Scholar
Playfair, J 1802. Illustrations of the Huttonian Theory of the Earth. Edinburgh: Neill, 388 pp.Google Scholar
Richardson, W 1803. Inquiry into the consistency of Dr. Hutton's theory of the earth with the arrangement of the strata, and other phenomena on the basaltic coast of Antrim. Transactions of the Royal Irish Academy 9, 429–87.Google Scholar
Rhöl, U., Bralower, T. J., Norris, R. D. & Wefer, G 2000. New chronology for the late Paleocene thermal maximum and its environmental implications. Geology 28, 927–30.2.0.CO;2>CrossRefGoogle Scholar
Scarrow, J. H., Curran, J. M. & Kerr, A. C 2000. Major element records of variable plume involvement in the North Atlantic Province Tertiary flood basalts. Journal of Petrology 41, 1155–76.CrossRefGoogle Scholar
Schmitz, B., Peucker-Ehrenbrink, B., Heilmann-Clausen, C., Aberg, G., Asaro, F. & Lee, C. A 2004. Basaltic explosive volcanism, but no comet impact, at the Paleocene-Eocene boundary: high-resolution chemical and isotopic records from Egypt, Spain and Denmark. Earth and Planetary Science Letters 225, 1–17.CrossRefGoogle Scholar
Schreyer, W. 1965. Synthetische und natürliche Cordierite: II. Die chemischen Zusammensetzungen nattrlicher Cordierite und ihre Abhengigkeit von den PTX-Bedingungen bei der Gesteinsbildung. Neues Jahrbuch für Mineralogie Abhandlungen 103, 35–79.CrossRefGoogle Scholar
Schreyer, W. & Yoder, H. S. 1964. The system Mg-cordierite-H2O and related rocks. Neues Jahrbuch für Mineralogie Abhandlungen 101, 271–342.Google Scholar
Scott, S. D 1974. Sulfide Mineralogy, Short Course Notes. Mineralogical Society of America I, CS21–CS29.Google Scholar
Sigmundsson, F. 2006. Iceland Geodynamics Crustal Deformation and Divergent Plate Tectonics. New York: Springer, pp. 209.Google Scholar
Storey, M., Duncan, R. A. & Swisher, C. C. 2007. Paleocene-Eocene Thermal Maximum and the opening of the northeast Atlantic. Science 316, 587–9.CrossRefGoogle ScholarPubMed
Svensen, H., Planke, S., Chevallier, L., Malthe-Sorenssen, A., Corfu, F. & Jamtveit, B 2007. Hydrothermal venting of greenhouse gases triggering Early Jurassic global warming. Earth and Planetary Science Letters 256, 554–66.CrossRefGoogle Scholar
Svensen, H., Planke, S., Malthe-Sorenssen, A., Jamtveit, B., Myklebust, R., Rasmussen Eidem, T. & Rey, S. S 2004. Release of methane from a volcanic basin as a mechanism for initial Eocene global warming. Nature 429, 542–5.CrossRefGoogle ScholarPubMed
Terashima, S., Ando, A., Okai, T., Kanai, Y., Taniguchi, M., Takizawa, F. & Itoh, S. 1990. Elemental concentrations in nine new GSJ rock reference samples “sedimentary rock series”. Geostandards Newsletter 14, 1–5.CrossRefGoogle Scholar
Thomas, E. & Shackelton, N. J. 1996. The Paleocene–Eocene benthic foraminiferal extinction and stable isotope anomalies. In Correlation of the Early Paleogene in Northwest Europe (eds Knox, R. W. O'B., Corfield, R. M. & Dunay, R. E.), pp. 401–41. Geological Society of London, Special Publication no. 101.Google Scholar
Thompson, P 1985. Dating the British Tertiary Igneous Province in Ireland by the 40Ar–39Ar stepwise degassing method. Published Ph.D. thesis, University of Liverpool.Google Scholar
Tripati, A. & Elderfield, H. 2005. Deep-sea temperature and circulation changes at the Paleocene-Eocene Thermal Maximum. Science 308, 1894–8.CrossRefGoogle ScholarPubMed
White, R. S. 1989. Initiation of the Iceland plume and opening of the North Atlantic. In Extensional Tectonics and Stratigraphy of the North Atlantic Margins (eds Tankard, A. J. & Balkwill, H. R.), pp. 149–54. American Association of Petroleum Geologists Memoir no. 46.Google Scholar
White, R. S. & McKenzie, D, . 1995. Mantle plumes and flood basalts. Journal of Geophysical Research 100, 17543–85.CrossRefGoogle Scholar
Winkler, H. G. F 1965. Petrogenesis of Metamorphic Rocks. New York, Berlin: Springer-Verlag, 220 pp.CrossRefGoogle Scholar
Zachos, J. C., Röhl, U., Schellenberg, S. A., Sluijs, A., Hodell, D. A., Kelly, D. C., Thomas, E., Nicolo, M., Raffi, I., Lourens, L. J., McCarren, H. & Kroon, D. 2005. Rapid acidification of the ocean during the Paleocene-Eocene Thermal Maximum. Science 308, 1611–15.CrossRefGoogle ScholarPubMed