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Permian K-rich volcanic rocks of Devon: petrogenesis, tectonic setting and geological significance

Published online by Cambridge University Press:  03 November 2011

R. S. Thorpe
R. S. Thorpe
Affiliation:
Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, Buckinghamshire, U.K.
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Abstract

Potassium (K)-rich volcanic rocks occur within Permian sedimentary rocks in SW England and are approximately contemporaneous with the emplacement of the Cornubian granite batholith. The volcanic rocks have chemical characteristics of subduction-related magmas and may have been derived by small amounts of partial melting of heterogeneous large-ion lithophile (LIL) enriched mantle with the assemblage olivine–pyroxene–garnet–phlogopite–titanate. The LIL enrichment may have occurred during shallow or oblique subduction of oceanic lithosphere below SW England during the Devonian and Carboniferous. Such LIL-enriched mantle may have contributed some components to the Cornubian granite batholith.

Keywords

Hercynian orogenyK-rich volcanic rockslamprophyresmantle heterogeneity.
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 77 , Issue 4 , 1987 , pp. 361 - 366
Copyright
Copyright © Royal Society of Edinburgh 1987

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References

Arãna, V. and Vegas, R. 1974. Plate tectonics and volcanism in the Gibraltar arc. TECTONOPHYSICS 24, 197–212.CrossRefGoogle Scholar
Badham, J. P. N. 1982. Strike-slip orogens—an interpretation of the Variscan tectonics of SW Britain. J GEOL SOC LONDON 14, 89–102.Google Scholar
Badham, J. P. N. & Halls, C. 1975. Microplate tectonics, oblique collisions, and evolution of the Hercynian orogenic systems. GEOLOGY 3, 373–376.2.0.CO;2>CrossRefGoogle Scholar
Bailey, D. K. 1982. Mantle metasomatism—continuing chemical change within the Earth. NATURE 296, 525–530.CrossRefGoogle Scholar
Baranzangi, M. & Isacks, B. L. 1976. Spatial distribution of earthquakes and subduction of the Nazca plate beneath South America. GEOLOGY 4, 686–692.2.0.CO;2>CrossRefGoogle Scholar
Baranzangi, M. & Isacks, B. L. 1979. Subduction of the Nazca plate beneath Peru: evidence from spatial distribution of earthquakes. GEOPHYS J R ASTROPHYS SOC 57, 537–555.CrossRefGoogle Scholar
Civetta, L., Innocenti, F., Manetti, P., Peccerillo, A. & Poli, G. 1981. Geochemical characteristics of potassic volcanics from Mts Ernici (Southern Latium, Italy) CONTRIB MINERAL PETROL 78, 37–47.CrossRefGoogle Scholar
Cosgrove, M. E. 1972. The geochemistry of the potassium-rich Permian volcanic rocks of Devonshire. CONTRIB MINERAL PETROL 36, 155–170.CrossRefGoogle Scholar
Cross, T. A. & Pilger, R. H. 1982. Controls of subduction geometry, location of magmatic arcs and tectonics of arc and back-arc regions. BULL GEOL SOC AM 93, 545–562.2.0.CO;2>CrossRefGoogle Scholar
Cundari, A. 1973. Petrology of the leucite-bearing lavas in New South Wales. J GEOL SOC AUSTRALIA 20, 465–492.CrossRefGoogle Scholar
Cundari, A. 1979. Petrogenesis of leucite-bearing lavas in the Roman region, Italy: The Sabatini lavas. CONTRIB MINERAL PETROL 70, 9–21.CrossRefGoogle Scholar
Darbyshire, D. F. F. & Shepherd, T. J. 1985. Chronology of granite magmatism and associated mineralisation, S. W. England. J GEOL SOC LONDON 142, 1159–1177.CrossRefGoogle Scholar
Dewey, J. F., Pitman, W. C., Ryan, W. B. F. & Bonnin, J. 1973. Plate tectonics and the evolution of the Alpine System. BULL GEOL SOC AM 84, 3137–3180.2.0.CO;2>CrossRefGoogle Scholar
Floyd, P. A. 1982. Chemical variations in Hercynian basalts relative to plate tectonics. J GEOL SOC LONDON 139, 505–520.CrossRefGoogle Scholar
Floyd, P. A., Exley, C. S. & Stone, M. 1983. Variscan magmatism in southwest England—discussion and synthesis. In Hancock, P. L. (ed.) The Variscan fold belt of the British Isles, 178–185. Bristol: Adam Hilger Ltd.Google Scholar
Foden, J. D. & Varne, R. 1980. The petrology and tectonic setting of Quaternary-Recent volcanic centres of Lombok and Sumbawa, Sunda arc. CHEM GEOL 30, 201–226.CrossRefGoogle Scholar
Gill, J. B. 1981. Orogenic andesites and plate tectonics. Berlin: Springer-Verlag.CrossRefGoogle Scholar
Green, T. H. & Pearson, N. J. 1986. Ti-rich accessory phase saturation in hydrous mafic-felsic compositions at high P, T. CHEM GEOL 54, 185–201.CrossRefGoogle Scholar
Hancock, P. L. 1983. The Variscan fold belt of the British Isles. Bristol: Adam Hilger Ltd.Google Scholar
Hawkes, J. R. 1981. A tectonic ‘watershed’ of fundamental consequence in the post-Westphalian evolution of Cornubia. PROC USSHER SOC 5, 128–131.Google Scholar
Hawkesworth, C. J., Rogers, N. W., van Calsteren, P. W. C. & Menzies, M. A. 1984. Mantle enrichment processes. NATURE 311, 331–335.CrossRefGoogle Scholar
Helmstaedt, H. & Gurney, J. J. 1984. Kimberlites of southern Africa—are they related to subduction processes? In Kornprobst, J. (ed.) Kimberlites, I: Kimberlites and related rocks, 425–434. Amsterdam: Elsevier.CrossRefGoogle Scholar
Holm, P. M., Lou, S. & Nielsen, A. 1982. The geochemistry and petrogenesis of the lavas of the Vulsinian district, Roman Province, central Italy. CONTRIB MINERAL PETROL 80, 367–378.CrossRefGoogle Scholar
Iddings, J. P. & Morley, E. W. 1915. Contributions to the petrography of Java and Celebes. J GEOL 23, 231–245.CrossRefGoogle Scholar
Jacques, A. L., Lewis, J. D., Smith, C. B., Gregory, G. P., Ferguson, J., Chappel, B. W. & McCulloch, M. T. 1984. The diamond-bearing ultrapotassic (lamproitic) rocks of the west Kimberley region, western Australia. In Kornprobst, J. (ed.) Kimberlites, I: Kimberlites and related rocks, 225–254. Amsterdam: Elsevier.CrossRefGoogle Scholar
Knill, D. C. 1982. Permian volcanism in south-western England. In Sutherland, D. S. (ed.). Igneous rocks of the British Isles, 329–332. Chichester: John Wiley.Google Scholar
Kuehner, S. M., Edgar, A. D. & Arima, M. 1981. Petrogenesis of the ultrapotassic rocks from the leucite Hills, Wyoming. AM MINERAL 66, 663–677.Google Scholar
Leat, P. T., Thompson, R. N., Morrison, M. A., Hendry, G. L. & Trayhorn, S. C. 1987. Geodynamic significance of post-Variscan intrusive and extrusive potassic magmatism in SW England. TRANS R SOC EDINBURGH: EARTH SCI 77, 349–60.CrossRefGoogle Scholar
McKenzie, D. 1985. The extraction of magma from the crust and mantle. EARTH PLANET SCI LETT 74, 81–91.CrossRefGoogle Scholar
Mertes, H. & Schminke, H.-U. 1985. Mafic potassic lavas of the Quaternary west Eifel volcanic field I. Major and trace elements. CONTRIB MINERAL PETROL 89, 330–345.CrossRefGoogle Scholar
Miller, J. A., Shibata, K. & Munro, M. 1961. The potassium-argon age of the lava of Killerton Park, near Exeter. GEOPHYS J 6, 394–396.CrossRefGoogle Scholar
Mitchell, R. H. & Bell, K. 1976. Rare earth element geochemistry of potassic lavas from the Birunga and Toro-Ankole regions of Uganda, Africa. CONTRIB MINERAL PETROL 58, 293–303.CrossRefGoogle Scholar
Odin, G. S., Curry, D., Gale, N. H. & Kennedy, W. J. 1984. The Phanerozoic time scale in 1981. In Odin, G. S. (ed.) Numerical dating in stratigraphy, 957–960. Chichester: John Wiley.Google Scholar
Pearce, J. A. 1982. Trace element characteristics of lavas from destructive plate boundaries. In Thorpe, R. S. (ed.) Andesites: Orogenic andesites and related rocks, 525–548. Chichester: John Wiley.Google Scholar
Rogers, N. W., Hawkesworth, C. J., Parker, R. J. & Marsh, J. S. 1985. The geochemistry of potassic lavas from Vulsini, central Italy and implications for mantle enrichment processes beneath the Roman region. CONTRIB MINERAL PETROL 90, 244–257.CrossRefGoogle Scholar
Selwood, E. B. & Thomas, J. M. 1986. Variscan facies and structure in Central SW England. J GEOL SOC LONDON 143, 199–207.CrossRefGoogle Scholar
Sheraton, J. W. & Cundari, A. 1980. Leucitites from Gaussberg, Antarctica CONTRIB MINERAL PETROL 71, 417–427.CrossRefGoogle Scholar
Simpson, P. R., Brown, G. C., Plant, J. & Ostle, D. 1979. Uranium mineralisation and granite magmatism in the British Isles. PHILOS TRANS R SOC LONDON A291, 385–412.Google Scholar
Stone, M. & Exley, C. S., 1986. High heat production granites of Southwest England and their associated mineralisation: a review. TRANS INST MIN METALL 95, 25–36.Google Scholar
Thompson, R. N., Morrison, M. A., Hendry, G. L. & Parry, S. J. 1984. An assessment of the relative roles of crust and mantle in magmagenesis: an elemental approach. PHILOS TRANS R SOC LONDON A310, 549–590.Google Scholar
Thorpe, R. S. & Francis, P. W. 1979. Variations in Andean andesite compositions and their petrogenetic significance. TECTONOPHYSICS 57, 53–70.CrossRefGoogle Scholar
Thorpe, R. S., Cosgrove, M. E. & van Calsteren, P. W. C. 1986. Rare-earth element, Sr- and Nd-isotope evidence for petrogenesis of Permian basaltic and K-rich volcanic rocks from southwest England. MINERAL MAG 50, 481–490.CrossRefGoogle Scholar
Van Kooten, G. K. 1981. Pb and Sr systematics of ultrapotassic and basaltic rocks from the central Sierra Nevada, California. CONTRIB MINERAL PETROL 76, 378–385.CrossRefGoogle Scholar
Velde, D. 1971. A note on an analcite-bearing lamproite from Devonshire. GEOL MAG 108, 201–204.CrossRefGoogle Scholar
Venturelli, G., Capedri, S., Di Battistini, G., Crawford, A., Kogarko, L. N. & Celestini, S. 1984. The ultrapotassic rocks from southeastern Spain. LITHOS 17, 37–54.CrossRefGoogle Scholar
Watson, J. V., Fowler, M. B., Plant, J. & Simpson, P. R., 1984. Variscan-Caledonian comparisons: late orogenic granites. PROC USSHER SOC 6, 2–12.Google Scholar
Wendlandt, R. F. 1984. An experimental and theoretical analysis of partial melting in the system KAlSiO4-CaO-MgO-SiO2-CO2 and its applications to the genesis of potassic magmas, carbonatites and kimberlites. In Kornprobst, J. (ed.) Kimberlites, I: Kimberlites and related rocks, 359–369. Amsterdam: Elsevier.CrossRefGoogle Scholar
Wood, D. A. 1979. A variably veined suboceanic upper mantle-genetic significance for mid-ocean ridge basalts from geochemical evidence. GEOLOGY 7, 499–503.2.0.CO;2>CrossRefGoogle Scholar