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A new, high precision U–Pb date from the oldest known rocks in southern Britain

  • D. I. SCHOFIELD (a1), I. L. MILLAR (a2), P. R. WILBY (a1) and J. A. EVANS (a2)

Abstract

A new high precision U–Pb zircon age of 710.8 ± 1.5 Ma for granophyric granitic rock from the Stanner Hanter Complex of the Welsh Borderland lies just within error of an older Rb–Sr isochron age. ϵNd values of −0.3 and −1.2 combined with TDM of 1394 Ma and 1468 Ma indicate that the magma incorporated an older crustal source component. The Nd data highlight differences with western Avalonia, the widely considered Late Neoproterozoic north American counterpart to southern Britain, and point toward a closer similarity with other Peri-Gondwanan terranes that incorporate older, cratonic source material.

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Corresponding author

Author for correspondence: dis@bgs.ac.uk

References

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Allen, P. M. & Jackson, A. A. 1978. Bryn-Teg Borehole, North Wales. Bulletin of the Geological Survey of Great Britain 61, 51 pp.
Barclay, W. J., Ambrose, K., Chadwick, R. A. & Pharaoh, T. C. 1997. Geology of the country around Worcester. Memoir of the British Geological Survey, Sheet 199 (England and Wales). Keyworth, Nottingham: British Geological Survey, 156 pp.
Bevier, M. L., Barr, S. M., White, C. E. & Macdonald, A. S. 1993. U–Pb geochronologic constraints on the volcanic evolution of the Mira (Avalon) terrane, southeastern Cape Breton Island, Nova Scotia. Canadian Journal of Earth Sciences 30, 110.
Brasier, M. D. 1989. Sections in England and their correlation. In The Precambrian–Cambrian Boundary (eds Cowie, J. W. & Brasier, M. D.), pp. 82104. Oxford University Press.
British Geological Survey. 1996. Tectonic map of Britain, Ireland and adjacent areas. 1:1 500 000 scale. Keyworth, Nottingham: British Geological Survey.
Callaway, C. 1879. The Precambrian Rocks of Shropshire – Part 1. Quarterly Journal of the Geological Society of London 35, 643–62.
Compston, W., Wright, A. E. & Toghill, P. 2002. Dating the Late Precambrian volcanicity of England and Wales. Journal of the Geological Society, London 159, 323–39.
Cope, J. C. W. & Gibbons, W. 1987. New evidence for the relative age of the Ercall Granophyre and its bearing on the Precambrian–Cambrian boundary in southern Britain. Geological Journal 22, 5360.
D'Lemos, R. S. & Brown, M. 1993. Sm–Nd isotope characteristics of late cadomian granite magmatism in northern France and the Channel Islands. Geological Magazine 130, 797804.
Doig, R., Murphy, J. B. & Nance, R. D. 1993. Tectonic significance of the Late Proterozoic Economy River Gneiss, Cobequid Highlands, Avalon composite terrane, Nova Scotia. Canadian Journal of Earth Sciences 30, 474–9.
Dunning, G. R. & O'Brien, S. J. 1989. Late Proterozoic–Early Palaeozoic crust in the Hermitage flexure, Newfoundland Appalachians: U–Pb ages and tectonic significance. Geology 17, 548–51.
Egal, E., Guerrot, C., Le Goff, D., Thieblemont, D. & Chantraine, J. 1996. The Cadomian orogeny revisited in northern France. In Avalonian and Related Peri-Gondwanan Terranes of the Circum North Atlantic (eds Nance, R. D. & Thompson, M. D.), pp. 281318. Geological Society of America, Special Paper no. 304.
Gibbons, W. & Horák, J. M. 1996. The evolution of the Neoproterozoic Avalonian subduction system: evidence from the British Isles, In Avalonian and Related Peri-Gondwanan Terranes of the Circum North Atlantic (eds Nance, R. D. & Thompson, M. D.), pp. 269–80. Geological Society of America, Special Paper no. 304.
Greig, D. C., Wright, J. E., Hains, B. A. & Mitchell, G. H. 1968. Geology of the Country around Church Stretton, Craven Arms, Wenlock Edge and Brown Clee. Memoir of the Geological Survey of Great Britain, England and Wales Sheet 166. London: HMSO.
Holgate, N. 1977. Tourmaline from amphibolized gabbro at Hanter Hill, Radnorshire. Mineralogical Magazine 41, 124–7.
Holgate, N. & Hallowes, K. A. K. 1941. The igneous rocks of the Stanner-Hanter district, Radnorshire. Geological Magazine 78, 241–67.
Jaffey, A. H., Flynn, G. K. F., Glendenin, L. E., Bentley, W. C. & Essling, A. M. 1971. Precision measurements of half-lives and specific activities of 235U and 238U. Physical Reviews C 4, 18891906.
James, J. H. 1952. Notes on the Relationship of the Uriconian and Longmyndian rocks near Linley, Shropshire. Proceedings of the Geologist's Association 63, 198200.
James, J. H. 1956. The structure and stratigraphy of part of the Pre-Cambrian outcrop between Church Stretton and Linley, Shropshire. Quarterly Journal of the Geological Society, London 112, 315–37.
Jones, K. A. 2000. Hanter Hill. In Precambrian Rocks of England and Wales (eds Carney, J. N., Horák, J. M., Pharaoh, T. C., Gibbons, W., Wilson, D., Barclay, W. J. & Bevins, R. E.), pp. 118–22. Geological Conservation Review Series 20. Peterborough: Joint Nature Conservation Committee.
Kawai, T., Windley, B. F., Terabayashi, M., Yamamoto, H., Maruyama, S., Omori, S., Shibuya, T., Sawaki, Y. & Isozaki, Y. 2007. Geotectonic framework of the Blueschist Unit on Anglesey-Lleyn, UK, and its role in the development of a Neoproterozoic accretionary orogen. Precambrian Research 153, 1128.
Keppie, J. D. & Dostal, J. 1998. Birth of the Avalonian arc in Nova Scotia, Canada: geochemical evidence for 700–630 Ma back-arc rift volcanism off Gondwana. Geological Magazine 135, 171–81.
Keppie, J. D., Nance, R. D., Murphy, J. B. & Dostal, J. 1991. The Avalon Terrane. In The West African Orogens and Circum-Atlantic Correlatives (eds Dallmayer, R. D. & Lecorché, J. P.), pp. 315–33. New York: Springer.
Keppie, J. D., Nance, R. D., Murphy, J. B. & Dostal, J. 2003. Tethyan, Mediterranean, and Pacific analogues for the Neoproterozoic–Palaeozoic birth and development of peri-Gondwanan terranes and their transfer to Laurentia and Laurussia. Tectonophysics 365, 195219.
Ludwig, K. R. 1993. PBDAT. A computer program for processing Pb–U–Th isotope data, version 1.24. U.S. Geological Survey Open-file Report 88-542.
Ludwig, K. R. 2003. Isoplot 3.00. A geochronological toolkit for Microsoft Excel. Berkley Geochronological Centre, Special Publication no. 4, 71 pp.
Mattinson, J. M. 2005. U–Pb inter-laboratory calibrations using zircon samples: Application of the new CA-TIMS technique. Geochimica et Cosmochimica Acta 69, A319.
Murphy, J. B. 2002. Geochemistry of the Neoproterozoic metasedimentary Gamble Brook Formation, Avalon Terrane, Nova Scotia: evidence for a rifted arc environment along the West Gondwanan margin of Rodinia. Journal of Geology 110, 407–20.
Murphy, J. B., McCausland, P. J. A., O'Brien, S. J., Pisarevsky, S. & Hamilton, M. A. 2008. Age, geochemistry and Sm–Nd isotopic signature of the 0.76 Ga Burin Group: compositional equivalent of Avalonian basement? Precambrian Research 165, 3748.
Murphy, J. B., Pisarevsky, S. A., Nance, R. D. & Keppie, J. D. 2004. Neoproterozoic–Early Palaeozoic evolution of peri-Gondwanan terranes: implications for Laurentia–Gondwana connections. International Journal of Earth Sciences 93, 659–82.
Murphy, J. B., Strachan, R. A., Nance, R. D., Parker, K. D. & Fowler, M. B. 2000. Proto-Avalonia: a 1.2–1.0 Ga tectonothermal event and constraints for the evolution of Rodinia. Geology 28, 1071–4.
Nance, R. D. & Murphy, J. B. 1994. Contrasting basement isotopic signatures and the palinspastic restoration of peripheral orogens: Example from the Neoproterozoic Avalonian–Cadomian belt. Geology 22, 617–20.
Nance, R. D., Murphy, J. B. & Keppie, J. D. 2002. Cordilleran model for the evolution of Avalonia. Tectonophysics 352, 1132.
Nance, R. D., Murphy, J. B., Strachan, R. A., Keppie, J. D., Gutiérrez-Alonso, G., Fernández-Suárez, , Quesade, C., Linnemann, U., D'Lemos, R. & Pisarevsky, S. A. 2008. Neoproterozoic-early Palaeozoic tectonostratigraphy and palaeogeography of the per-Gondwanan terranes: Amazonian v. West African connections. In The Boundaries of the West African Craton (eds Ennih, N. & Liégeois, J.-P.), pp. 345–83. Geological Society of London, Special Publication no. 297.
Noble, S. R., Tucker, R. D. & Pharaoh, T. C. 1993. Lower Palaeozoic and Precambrian igneous rocks from eastern England, and their bearing on late Ordovician closure of the Tornquist Sea: constraints from U–Pb and Nd isotopes. Geological Magazine 130, 835–46.
O'Brien, S. J., Dunning, G. R., Dubé, B., O'Driscoll, C. F., Sparkes, B., Israel, S. & Ketchum, J. 2001. New insights into the Neoproterozoic geology of the central Avalon Peninsula (parts of map areas 1N/6 and 1N/3), Eastern Newfoundland. Current Research (2001), Newfoundland Department of Mines and Energy, Geological Survey Report 2001–1, 169–89.
O'Brien, S. J., O'Driscoll, C. F., Greene, B. A. & Tucker, R. D. 1995. Pre-Carboniferous geology of the Connaigre Peninsula and the adjacent coast of fortune bay, Southern Newfoundland. Current Research (1995), Newfoundland Department of Natural Resources, Geological Survey Report 1995–1, 267–98.
Patchett, P. J., Gale, N. H., Goodwin, R. & Humm, M. J. 1980. Rb–Sr whole-rock isochron ages of late Precambrian to Cambrian igneous rocks from southern Britain. Journal of the Geological Society, London 137, 649–56.
Pauley, J. C. 1991. A revision of the stratigraphy of the Longmyndian Supergroup, Welsh Borderland, and its relationship to the Uriconian volcanic complex. Geological Journal 26, 167–83.
Pharaoh, T. C. & Carney, J. N. 2000. Introduction to the Precambrian rocks of England and Wales. In Precambrian Rocks of England and Wales (eds Carney, J. N., Horák, J. M., Pharaoh, T. C., Gibbons, W., Wilson, D., Barclay, W. J. & Bevins, R. E.), pp. 118. Geological Conservation Review Series 20. Peterborough: Joint Nature Conservation Committee.
Pharaoh, T. C., Merriman, R. J., Evans, J. A., Brewer, T. S., Webb, P. C. & Smith, N. J. P. 1991. Early Palaeozoic arc-related volcanism in the concealed Caledonides of southern Britain. Annales de la Société Géoloqique de Belgique 114, 6391.
Pharaoh, T. C., Webb, P. C., Thorpe, R. S. & Beckinsale, R. D. 1987. Geochemical evidence for the tectonic setting of late Proterozoic volcanic suites in central England. In Geochemistry and Mineralization of Proterozoic Volcanic Suites (eds Pharaoh, T. C., Beckinsale, R. D. & Rickard, D.), pp. 541–52. Geological Society of London, Special Publication no. 33.
Pocock, R. W. & Whitehead, T. H. 1935. British Regional Geology: The Welsh Borderland. London: H. M. Geological Survey and Museum, 84 pp.
Rushton, A. W. A., Hamblin, R. J. O. & Strong, G. E. 1988. The Croft borehole in the Lilleshall inlier of north Shropshire. Report of the British Geological Survey no. 19.
Samson, S. D. & D'Lemos, R. S. 1998. U–Pb geochemistry and Sm–Nd isotopic composition of Proterozoic gneisses, Channel Islands, U.K. Journal of the Geological Society, London 156, 4754.
Samson, S. D., D'Lemos, R. S., Miller, B. V. & Hamilton, M. A. 2005. Neoproterozoic palaeogeography of the Cadomia and Avalon terranes: constraints from detrital zircon U–Pb ages. Journal of the Geological Society, London 162, 6571.
Schofield, D. I., Evans, J. A., Millar, I. L., Wilby, P. R. & Aspden, J. A. 2008. New U–Pb and Rb–Sr constraints on pre-Acadian tectonism in North Wales. Journal of the Geological Society, London 165, 891–4.
Stacey, J. S. & Kramers, J. D. 1975. Approximation of terrestrial lead isotope evolution by a two stage model. Earth and Planetary Science Letters 26, 207–21.
Strachan, R. A., Collins, A. S., Buchan, C., Nance, R. D., Murphy, J. B. & D'Lemos, R. S. 2007. Terrane analysis along a Neoproterozoic active margin of Gondwana: insights from U–Pb zircon geochronology. Journal of the Geological Society, London 164, 5760.
Strachan, R. A., Nance, R. D., Dallmeyer, R. D., D'Lemos, R. S., Murphy, J. B. & Watt, G. R. 1996. Late Precambrian tectonothermal evolution of the Malverns Complex. Journal of the Geological Society, London 153, 589600.
Swinden, S. & Hunt, P. A. 1991. A U–Pb age from the Connaigre Bay Group, Southwestern Newfoundland: Implications for regional correlations and metallogenesis. Radiometric and isotopic studies, Report 4. Geological Survey of Canada Special Paper 90–2, 310.
Tassinari, C. C. G. & Macambira, M. J. B. 1999. Geochronological provinces of the Amazonian Craton. Episodes 22, 174–82.
Thorpe, R. S., Beckinsale, R. D., Patchett, P. J., Piper, A., Davies, G. R. & Evans, J. A. 1984. Crustal growth and late Precambrian-early Palaeozoic plate tectonic evolution of England and Wales. Journal of the Geological Society, London 141, 521–36.
Tucker, R. D. & Pharoah, T. C. 1991. U–Pb zircon ages for Late Precambrian rocks in southern Britain. Journal of the Geological Society, London 148, 435–43.
Valverde-Vaquero, P., Dunning, G. R. & O'Brien, S. J. 2006. Polycyclic evolution of Late Neoproterozoic basement in the Hermitage Flexure region (southwest Newfoundland Appalachians): New evidence from the Cinq-Cerf gneiss. Precambrian Research 148, 118.
Wendt, J. I., Kröner, A., Fiala, J. & Todt, W. 1993. Evidence from zircon dating for existence of approximately 2.1 Ga old crystalline basement in southern Bohemia, Czech Republic. Geologische Rundschau 82, 4250.
Woodcock, N. H. 1988. Strike-slip faulting along the Church Stretton Lineament, Old Radnor Inlier, Wales. Journal of the Geological Society, London 145, 925–33.
Woodcock, N. H. & Gibbons, W. 1988. Is the Welsh Borderland Fault System a terrane boundary? Journal of the Geological Society, London 145, 915–33.
Wright, A. E., Fairchild, I. J., Moseley, F. & Downey, C. 1993. The lower Cambrian Wrekin Quartzite and the age of its unconformity on the Ercall Granophyre. Geological Magazine 130, 257–64.

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