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A silica deposit of possible Tertiary age in the Carboniferous Limestone near Birr, County Offaly, Ireland

Published online by Cambridge University Press:  01 May 2009

A. P. Beese
Affiliation:
Department of Geology, University of Geology, Cork, Ireland
P. M. Brück
Affiliation:
Department of Geology, University of Geology, Cork, Ireland
J. Feehan
Affiliation:
Department of Geology, Trinity College, Dublin 2, Ireland
T. Murphy
Affiliation:
School of Cosmic Physics, Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin 2, Ireland

Abstract

Summary. Stony clays, comprising weathered bryzoan-rich chert and silica clay, are found adjacent to Carboniferous Limestone on the west and a weathered dolomitized zone on the east near Birr, County Offaly, Ireland. A gravity survey together with a stratigraphy obtained from boreholes and other test borings suggests a depth of about 40 m and a surface width or diameter of approximately 60 m for the deposit. Indirect evidence points to a possible Tertiary age. The interpreted origin of the stony clays is by silification of Carboniferous Limestone and preservation by solution subsidence along a possible fault zone.

Type
Articles
Copyright
Copyright © Cambridge University Press 1983

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References

REFERENCES

Brück, P. M. 1982. The regional lithostratigraphical setting of the Silvermines zinc-lead and the Ballynoe barite deposits, Co. Tipperary. In Mineral Exploration in Ireland - Progress and Developments, 1971–81 (ed. Brown, A. G.), pp. 162170. Dublin: Irish Association of Economic Geology.Google Scholar
Brunsden, D., Doornkamp, J. C., Green, C. P. & Jones, D. K. C. 1976. Tertiary and Cretaceous sediments in solution pipes in the Devonian Limestone of South Devon, England. Geol. Mag. 113, 441–7.CrossRefGoogle Scholar
Coote, C. 1801. Statistical Survey of the King's County, Royal Dublin Soc.Google Scholar
Fairie, J. 1901. Notes on Pottery Clays. London: Scott, Greenwood.Google Scholar
Ford, T. D. 1977. Limestone and Clays of the Peak District. University of E. Anglia, Norwich: Geo. Abstracts.Google Scholar
Hudson, R. G. S. & Philcox, M. E. 1965. The Lower Carboniferous Stratigraphy of the Buttevant area, Co. Cork. Proc. R. Ir. Acad. 64 B, 6579.Google Scholar
Maw, G. 1867. On the distribution beyond the Tertiary districts of white clays and sands subjacent to the boulder-clay drifts (Part II). Geol. Mag. 4, 299307.CrossRefGoogle Scholar
Mitchell, G. F. 1980. The search for Tertiary Ireland. J. Earth Sci. R. Dubl. Soc. 3, 1333.Google Scholar
Murphy, T. 1962. Some unusual low Bouguer anomalies of small extent in central Ireland and their connection with geological structure. Geophys. Prospect. 10, 258–70.CrossRefGoogle Scholar
Murphy, T. 1966. Deep alteration of Carboniferous strata in the Midleton, Co. Cork district as detected by gravity surveying. Proc. R. Ir. Acad. 64 B, 323–34.Google Scholar
Pitty, A. F. 1968. The scale and significance of solutional loss from the limestone tract of the Southern Pennines. Proc. Geol. Assoc. 79, 153–77.CrossRefGoogle Scholar
Thomas, T. M. 1954. Solution subsidence outliers of Millstone Grit on the Carboniferous Limestone of the North Crop of the South Wales Coalfield. Geol. Mag. 91, 220–6.CrossRefGoogle Scholar
Walsh, P. T. & Brown, E. H. 1971. Solution subsidence outliers containing probable Tertiary sediment in north-east Wales. Geol. J. 1, 299320.CrossRefGoogle Scholar
Walsh, P. T., Boulter, C. J., Ijtaba, M. & Urbani, D. M. 1972. The preservation of the Neogene Brassington Formation of the southern Pennines and its bearing on the evolution of upland Britain. J. geol. Soc. Lond. 128, 519–59.CrossRefGoogle Scholar
Watts, W. A. 1957. A Tertiary deposit in County Tipperary. Sci. Proc. R. Dubl. Soc. 27, 309–11.Google Scholar
Watts, W. A. 1962. Early Tertiary pollen deposits in Ireland. Nature, Lond. 193, 600.CrossRefGoogle Scholar
Wynne, A. B. 1862. Explanation to accompany Sheet 126 of the maps of the Geological Survey of Ireland. Mem. Geol. Surv., Ireland.Google Scholar