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Possible Late Pleistocene faulting in Iar (West) Connacht, Ireland

Published online by Cambridge University Press:  01 May 2009

P. Mohr
Affiliation:
Department of Geology, University College Galway, Ireland

Abstract

Caledonian and Hercynian faults in Iar Connacht have been examined for evidence of Quaternary movements. Dip–slip displacements are detected, both through preservation of scarps and, in areas of greater denudation, through morphological offsets. The principle sites of this phenomenon are the Maum, Clifden and Gabhla-Shannaveara faults. Tectonic scarps are distinguished from those due to differential erosion and glacial scour. Earthquake risk in Iar Connacht, though slight, is not non-existent.

Type
Articles
Copyright
Copyright © Cambridge University Press 1986

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References

Allen, C. R. 1975. Geological criteria for evaluating seismicity. Bulletin of the Geological Society of America 86, 1041–57.2.0.CO;2>CrossRefGoogle Scholar
Brown, C. & Williams, B. S. 1985. A gravity and magnetic interpretation of the structure of the Irish Midlands. Journal of the Geological Society of London 142, 1059–75.CrossRefGoogle Scholar
Bucknam, R. C. & Anderson, R. E. 1979. Estimation of fault-scarp ages from a scarp height–slope angle relationship. Geology 7, 1114.2.0.CO;2>CrossRefGoogle Scholar
Cobbing, E. J. 1969. The geology of the district north-west of Clifden, Co. Galway. Proceedings of the Royal Irish Academy 67B, 303–25.Google Scholar
Coller, D. W. 1984. Variscan structures in the Upper Palaeozoic rocks of west central Ireland. In Variscan Tectonics of the North Atlantic Region. (ed. Hutton, D. H. Sanderson, D. J.), pp. 185–94. Geological Society of London Special Publication no. 14.Google Scholar
Davies, G. L. H. 1983. Sheets of Many Colours: the Mapping of Ireland's Rocks, 1750 to 1890. Royal Dublin Society, Scientific Publications 4, 242 pp.Google Scholar
Dewey, J. F. & Mckerrow, W. S. 1963. An outline of the geomorphology of Murrisk and north-west Galway. Geological Magazine 100, 260–75.CrossRefGoogle Scholar
Graham, J. R., Leake, B. E. & Ryan, P. D. 1985. Geological map of SW Mayo (1:63 360). Glasgow: University of Glasgow.Google Scholar
Kinahan, G. H. 1874. Geology of West Galway and S. W. Mayo, Ireland. Geological Magazine 1, 453–62.Google Scholar
Kinahan, G. H., Leonard, H. & Cruise, R. J. 1870. Geological map, sheet 104 (1:63360). Geological Survey of Ireland.Google Scholar
Kinahan, G. H., Nolan, J., Leonard, H. & Cruise, R. J. 1878. Memoir to accompany sheets 93 and 94, with the adjoining portions of sheets 83, 84 and 103; illustrating the geological structure of the district around Clifden, Connemara. Memoir of the Geological Survey of Ireland, 177 pp.Google Scholar
Kinahan, G. H., Symes, R. G., Warren, J. L., Wilkinson, S. B., Nolan, J. & Leonard, H. 1874. Geological map, sheet 84 (1:63360). Geological Survey of Ireland.Google Scholar
Kinahan, G. H., Symes, R. G., Wilkinson, S. B., Nolan, J. & Leonard, H. 1876 a. Memoir to accompany sheets 73, 74 (part), 83, 84 (Westport, Eriff Valley, Killary Harbour, West L. Mask). Geological Survey of Ireland, 84 pp.Google Scholar
Kinahan, G. H., Warren, J. L., Leonard, H., Cruise, R. J. & Nolan, J. 1876 b. Geological map, sheet 93 (1:63360). Geological Survey of Ireland.Google Scholar
Kinahan, G. H., Warren, J. L., Nolan, J. & Leonard, H. 1877. Geological map, sheet 94 (1:63360). Geological Survey of Ireland.Google Scholar
Kujansuu, R. 1964. Recent faults in Lapland (in Finnish). Geologi 16, 30–6.Google Scholar
Lagerback, R. 1979. Neotectonic structures in northern Sweden. Geologiska Foreningens i Stockholm Forhandlingar 100, 263–9.CrossRefGoogle Scholar
Leake, B. L., Tanner, P. W. G. & Senior, A. 1981. Fold traces (F3 to F5) and regional metamorphism in the Dalradian rocks of Connemara. Map (1:63360). Glasgow: University of Glasgow.Google Scholar
Lilwall, R. C. 1976. Seismicity and seismic hazard in Britain. Seismological Bulletin of the Institute of Geological Sciences, London 4, 19.Google Scholar
Lundquist, J. & Lagerback, R. 1976. The Parve Fault: a late-glacial fault in the Precambrian of Swedish Lapland. Geologiska Foreningens i Stockholm Forhandlingar 98, 4551.CrossRefGoogle Scholar
Mitchell, G. F. 1976. The Irish Landscape. London: Collins, 240 pp.Google Scholar
Mitchell, J. G. & Mohr, P. 1986. Upper Paleozoic dikes in West Connacht, Ireland. Transactions of the Royal Society of Edinburgh (submitted).CrossRefGoogle Scholar
Nash, D. B. 1980. Morphological dating of degraded normal fault scarps. Journal of Geology (Chicago) 88, 353–60.CrossRefGoogle Scholar
Oliver, J., Johnson, T. & Dorman, J. 1970. Postglacial faulting and seismicity in New York and Quebec. Canadian Journal of Earth Science 7, 579–90.Google Scholar
Pitcher, W. S. 1969. Northeast-trending faults of Scotland and Ireland, and chronology of displacements. In North Atlantic – Geology and Continental Drift (ed. Kay, M.), pp. 724–33. Memoir of the American Association of Petroleum Geologists 12.Google Scholar
Pitcher, W. S., Elwell, R. W. D., Tozer, C. F. & Cambray, F. W. 1964. The Leannan fault. Quarterly Journal of the Geological Society of London 120, 241–73.CrossRefGoogle Scholar
Pudsey, C. J. 1984. Ordovician stratigraphy and sedimentology of the South Mayo inlier. Irish Journal of Earth Sciences 6, 1545.Google Scholar
Robinson, T. 1985. Mapping South Connemara. ‘Reprint’. Dublin: Folding Landscapes, 60 pp.Google Scholar
Ryan, P. D. & Archer, J. B. 1977. The South Mayo Trough: a possible Ordovician Gulf of California-type marginal basin in the west of Ireland. Canadian Journal of Earth Sciences 14, 2453–61.CrossRefGoogle Scholar
Sanderson, D. J. 1984. Structural variation across the northern margin of the Variscides in NW Europe. In Variscan Tectonics of the North Atlantic Region (ed. Hutton, D. H. and Sanderson, D. J.), pp. 149–65. Special Publication of the Geological Society of London no. 14.Google Scholar
Stanton, W. I. 1960. The Lower Palaeozoic rocks of south-west Murrisk, Ireland. Quarterly Journal of the Geological Society of London 116, 269–96.CrossRefGoogle Scholar
Sykes, L. R. 1973. Intraplate earthquakes, lithospheric stresses and the driving mechanism of plate tectonics. Nature 245, 298302.CrossRefGoogle Scholar
Tanner, P. W. G. & Shackleton, R. M. 1979. Structure and stratigraphy of the Dalradian rocks of the Bennabeola area, Connemara, Eire. In The Caledonides of the British Isles – Reviewed (ed. Harris, A. L. Holland, C. H. & Leake, B. E.), pp. 243–56. Special Publication of the Geological Society of London no. 8.Google Scholar
Thompson, W. B. 1981. Postglacial faulting in the vicinity of the Norumbega Fault Zone, eastern Maine. United States Geological Survey, Open File Report 81–1039, 22 pp.CrossRefGoogle Scholar
Us Geological Survey. 1984. Preliminary determination of epicentres. Monthly listing for July 1984. Washington.Google Scholar
Wager, L. R. 1932. The geology of the Roundstone district, County Galway. Proceedings of the Royal Irish Academy 41B, 4672.Google Scholar
Wallace, R. E. 1977. Profiles and ages of young fault scarps, north-central Nevada. Geological Society of America Bulletin 88, 1267–81.2.0.CO;2>CrossRefGoogle Scholar