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Tectonic position of the Dalradian rocks of Connemara and its bearing on the evolution of the Midland Valley of Scotland

Published online by Cambridge University Press:  03 November 2011

Bernard E. Leake ,
P. W. Geoff Tanner ,
R. M. Macintyre  and
E. Elias
Bernard E. Leake
Affiliation:
Department of Geology, University of Glasgow, Glasgow G12 8QQ, Scotland.
P. W. Geoff Tanner
Affiliation:
Department of Geology, University of Glasgow, Glasgow G12 8QQ, Scotland.
R. M. Macintyre
Affiliation:
Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 OQU, Scotland.
E. Elias
Affiliation:
Department of Geology, University of Glasgow, Glasgow G12 8QQ, Scotland.
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Abstract

The Dalradian terrane of Connemara was thrust southsoutheastwards about 460 Ma ago (Rb–Sr and K–Ar ages). It rides on a major thrust of post-D age over mylonitised acidic volcanic rocks of putative lower Ordovician age and contains a number of thrusts of similar age. Several major S- to SE-directed thrusts also limit the southeastern margin of the Dalradian rocks in Mayo and Tyrone. It is suggested by analogy with Ireland that during mid-Ordovician times the Highland Boundary fault in Scotland could have been a thrust zone which carried the Scottish Dalradian rocks over a lower Ordovician basement now represented only as fragments in the Highland Border Complex.

Keywords

basicConnemaraHighland Boundary faulthornblendeIrelandK–Ar datingmyloniteOrdovicianrhyolitethrustingultrabasic
Type
Highland Border and Dalradian terranes
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 75 , Issue 2: Deep Geology of the Midland Valley of Scotland and Adjacent Regions. Bicentenary Symposium , 1984 , pp. 165 - 171
Copyright
Copyright © Royal Society of Edinburgh 1984

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References

Andreasson, P. G. & Lagerblad, B. 1980. Occurrence and significance of inverted metamorphic gradients in the western Scandinavian Caledonides. J GEOL SOC LONDON 137, 219–30.CrossRefGoogle Scholar
Bailey, E. B. & Holtedahl, O. 1938. Northwestern Europe—Caledonides Handbook of Regional Geology. Leipzig: Akademie Verlag.Google Scholar
Bluck, B. J. 1984. Pre-Carboniferous history of the Midland Valley of Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 275–95.CrossRefGoogle Scholar
Brown, R. L. 1981. Metamorphic complex of SE Canadian Cordillera and relationship to foreland thrusting. In McClay, K. R. and Price, N. J. (eds) Thrust and nappe tectonics. SPEC PUBL GEOL SOC LONDON 9, 463–73.Google Scholar
Cobbing, E. J. 1964. The Highland Boundary Fault in East Tyrone. GEOL MAG 101, 496–501.CrossRefGoogle Scholar
Cobbing, E. J., Manning, P. I. & Griffith, A. E. 1965. Ordovician–Dalradian unconformity in Tyrone. NATURE 206, 1132–5.CrossRefGoogle Scholar
Cruse, M. J. B. & Leake, B. E. 1968. The geology of Renvyle, Inishbofin and Inishshark, NW Connemara, Co. Galway. PROC R IR ACAD 67, 1–36.Google Scholar
Curry, G. B., Ingham, J. K., Bluck, B. J. & Williams, A. 1982. The significance of a reliable Ordovician age for some Highland Border rocks in Central Scotland. J. GEOL SOC LONDON 139, 451–4.CrossRefGoogle Scholar
Curry, G. B., Bluck, B. J., Burton, C. J., Ingham, J. K.. Siveter, D. J. & Williams, A. 1984. Age, evolution and tectonic history of the Highland Border complex, Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 113–33.CrossRefGoogle Scholar
Dempster, T. J. 1984. Localized uplift in the Scottish Dalradian. NATURE 307, 156–9.CrossRefGoogle Scholar
Evans, B. W. 1964. Fractionation of elements in the pelitic hornfelses of the Cashel-Lough Wheelaun intrusion, Connemara, Eire. GEOCHIM COSMOCHIM ACTA 28, 127–56.CrossRefGoogle Scholar
George, T. N. 1960. The stratigraphical evolution of the Midland Valley. TRANS GEOL SOC GLASGOW 24, 32–107.CrossRefGoogle Scholar
Halliday, A. N. 1984. Coupled Sm–Nd and U–Pb systematics in the late Caledonian granites and the basement under northern Britain. NATURE 307, 299–33.CrossRefGoogle Scholar
Harland, W. G., Cox, A. V., Llewellyn, P. G., Pickton, C. A. G., Smith, A. G. & Walters, R. 1982. A geologic timescale. Cambridge University Press.Google Scholar
Harris, A. L. & Pitcher, W. S. 1975. The Dalradian Supergroup. In Harris, A. L. et al. (eds) A correlation of Precambrian rocks in the British Isles, 52–75. GEOL SOC LONDON SPEC REP 6.Google Scholar
Hutton, D. H. W. 1982. A possible Tay Nappe correlative in the Dalradian rocks of mid-Ulster. Tectonic Studies Group (Geological Society of London), Annual General Meeting, Cardiff 1982, Abstr.Google Scholar
Hutton, D. H. W. 1983. Deformational history of an area with well-developed tectonic slides: Dalradian rocks of Horn Head, NW Irish Caledonides. TRANS R SOC EDINBURGH EARTH SCI 73, 151–71.CrossRefGoogle Scholar
Kilburn, C., Pitcher, W. S. & Shackleton, R. M. 1965. The stratigraphy and origin of the Port Askaig Boulder Bed Series (Dalradian). GEOL J 4, 343–60.CrossRefGoogle Scholar
Leake, B. E. 1963a. The location of the Southern Uplands Fault in Central Ireland. GEOL MAG 100, 420–3.CrossRefGoogle Scholar
Leake, B. E. 1963b. A possible fossil in a graphitic marble in the Connemara Schist, Cornamona, Co. Galway, Ireland. GEOL MAG 100, 44–6.CrossRefGoogle Scholar
Leake, B. E. 1970. The fragmentation of the Connemara basic and ultrabasic intrusions. In Newall, G. and Rast, N. (eds) Mechanism of igneous intrusion, 103–22. GEOL J SPEC ISSUE 2.Google Scholar
Leake, B. E. 1980. Some metasomatic calc-magnesium silicate rocks from Connemara, western Ireland: mineralogical control of rock composition. AM MINERAL 65, 26–36.Google Scholar
Leake, B. E. & Skirrow, G. 1960. The pelitic hornfelses of the Cashel-Lough Wheelaun intrusion, County Galway, Eire. J GEOL 68, 23–40.CrossRefGoogle Scholar
Leake, B. E., Tanner, P. W. G., Singh, D. & Halliday, A. N. 1983. Major southward thrusting of the Dalradian rocks of Connemara, western Ireland. NATURE 305, 210–3.CrossRefGoogle Scholar
Max, M. D. & Inamdar, D. D. 1983. Detailed compilation magnetic map of Ireland and a summary of its deep geology. GEOL SURV IR REP SER R5 29.Google Scholar
Max, M. D. & Riddihough, R. P. 1975. Continuation of the Highland Boundary Fault in Ireland. GEOLOGY 3, 206–10.2.0.CO;2>CrossRefGoogle Scholar
Max, M. D. & Ryan, P. 1975. The Southern Uplands Fault and its relation to the metamorphic rocks of Connemara. GEOL MAG 112, 610–2.CrossRefGoogle Scholar
Phillips, A. 1981. The orthotectonic Caledonides. In Holland, C. H. (ed.) A geology of Ireland, 17–39. Edinburgh: Scottish Academic Press.Google Scholar
Phillips, W. E. A., Graham, J. R. & Simon, J. B. 1983. Pre-Carboniferous evolution of the western continuation, in Ireland, of the Midland Valley of Scotland (abstract). TRANS R SOC EDINBURGH EARTH SCI 75, 299.Google Scholar
Pitcher, W. S., Shackleton, R. M. & Wood, R. S. R. 1971. The Ballybofey anticline: a solution of the general structure of parts of Donegal and Tyrone. GEOL J 7, 321–8.CrossRefGoogle Scholar
Pidgeon, R. T. 1969. Zircon U–Pb ages from the Galway Granite and the Dalradian, Connemara, Ireland. SCOTT J GEOL 5, 375–92.CrossRefGoogle Scholar
Ryan, P. D., Sawal, V. K. & Rowlands, A. S. 1983. Ophiolitic mélange separates ortho- and para-tectonic Caledonides in western Ireland. NATURE 302, 50–2.CrossRefGoogle Scholar
Tanner, P. W. G. & Shackleton, R. M. 1979. Structure and stratigraphy of the Dalradian rocks of the Bennabeola area, Connemara, Eire. In Harris, A. L., Holland, C. H. & Leake, B. E. (eds) The Caledonides of the British Isles—reviewed, 243–56. SPEC PUBL GEOL SOC LONDON 8.Google Scholar
Thirlwall, M. F. & Fitton, J. G. 1983. Sm–Nd garnet age for the Ordovician Borrowdale Volcanic Group, English Lake District. J GEOL SOC LONDON 140, 511–8.CrossRefGoogle Scholar
Treloar, P. J. 1981. Garnet-biotite-cordierite thermometry and barometry in the Cashel thermal aureole, Connemara, Ireland. MINERAL MAG 44, 183–9.CrossRefGoogle Scholar
Yardley, B. W. D., Leake, B. E. & Farrow, C. M. 1980. The metamorphism of Fe-rich pelites from Connemara, Ireland. J PETROL 21, 365–99.CrossRefGoogle Scholar
Yardley, B. W. D., Vine, F. J. & Baldwin, G. T. 1982. The plate tectonic setting of NW Britain and Ireland in late Cambrian and early Ordovician times. J GEOL SOC LONDON 139, 457–66.CrossRefGoogle Scholar