Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-26T05:46:29.364Z Has data issue: false hasContentIssue false

The Nod Glas décollement of the Welsh Basin

Published online by Cambridge University Press:  01 May 2009

W. T. Pratt
Affiliation:
Institute of Earth Studies, University College of Wales, Aberystwyth, Dyfed, SY23 3DB, U.K.

Abstract

Structural, petrographic and metamorphic evidence is presented for localized end-Caledonian (Acadian) décollement within a ‘black shale’ formation in the central Welsh Basin, close to the Caradoc–Ashgill boundary. Similar detachments are probably widespread in other parts of the, paratectonic Caledonides with upright folds and cleavage, particularly in sequences with strong viscosity contrasts.

Type
Rapid Communications
Copyright
Copyright © Cambridge University Press 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allen, P. M. & Jackson, A. A. 1985. Geology of the country around Harlech. Memoir of the British Geological Survey, Sheet 135 with part of Sheet 149 (England and Wales).Google Scholar
Cave, R. 1965. The Nod Glas sediments of Caradoc age in North Wales. Geological Journal 4, 279–98.CrossRefGoogle Scholar
Cave, R. & Haines, B. A. 1986. Geology of the country between Aberystwyth and Machynlleth. Memoir of the British Geological Survey, Sheet 163 (England and Wales).Google Scholar
Cave, R. & Price, D. 1978. The Ashgill Series near Welshpool, North Wales. Geological Magazine 115, 183–94.CrossRefGoogle Scholar
Hossack, J. R. 1979. Use of balanced cross-sections in calculation of orogenic contractions. Journal of the Geological Society of London 136, 705–11.CrossRefGoogle Scholar
Jones, O. T. & Pugh, W. J. 1935. The geology of the district around Machynlleth and Aberystwyth. Proceedings of the Geologists' Association 46, 247300.CrossRefGoogle Scholar
Martin, B. A., Howells, M. F. & Reedman, A. J. 1981. A geological reconnaissance study of the Dyfi Valley region, Gwynedd/Powys, Wales. Environmental Protection Unit (Report ENPU 81–1), Institute of Geological Sciences.Google Scholar
Merriman, R. J. & Roberts, B. 1989. Caledonian strain-related low temperature metatnorphism in the Corris Slate Belt, Central Wales, U.K. Terra Abstracts 1, 310.Google Scholar
Price, D. & Magor, P. 1984. The ecological significance of variation in the genetic composition of Rawtheyan (late Ordovician) trilobite faunas from North Wales, U.K. Geological Journal 19, 187201.CrossRefGoogle Scholar
Pugh, W. J. 1923. The geology of the district around Corris and Aberllefenni (Merionethshire). Quarterly Journal of the Geological Society of London 79, 508–45.CrossRefGoogle Scholar
Wilson, G. 1967. The geometry of cylindrical and conical folds. Proceedings of the Geologists' Association 78, 179210.CrossRefGoogle Scholar
Woodcock, N. H. 1984. Early Palaeozoic sedimentation and tectonics in Wales. Proceedings of the Geologists' Association 95, 323–35.CrossRefGoogle Scholar