Hostname: page-component-7479d7b7d-jwnkl Total loading time: 0 Render date: 2024-07-10T22:59:54.705Z Has data issue: false hasContentIssue false

The Garnedd-wen Formation (Ashgillian) of the Towyn-Abergynolwyn district, Merionethshire

Published online by Cambridge University Press:  01 May 2009

D. M. D. James
Affiliation:
c/o Brunei Shell Petroleum Company Limited, Seria, State of Brunei, Borneo

Summary

A lithostratigraphy is described and related to that in the adjacent Corris-Machynlleth district. Thickness of the Formation is estimated to be c. 500 m near Towyn rather than c. 1000 m as generally accepted, although poor exposure precludes accurate determination. Palaeocurrent data are given for a prominent interval of turbidite arenites, here termed the Llyn Barfog Member. Sedimentary facies are interpreted as slope-base and deep basinal deposits and are consistent with control of sedimentation by the Bala and Corris ‘basement faults’.

Type
Articles
Copyright
Copyright © Cambridge University Press 1973

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

Bassett, D. A., Whittington, H. B. & Williams, A. 1966. The stratigraphy of the Bala district, Merionethshire. Q. Jl geol. Soc. Lond. 122, 219–71.CrossRefGoogle Scholar
Beavis, F. C. 1970. Cleavages and Linear Structures in Ordovician Sandstones, Victoria. Geol. Mag. 107, 429–38.CrossRefGoogle Scholar
Field, M. E. & Pilkey, O. H. 1971. Deposition of Deep-Sea Sands: Comparison of two areas of the Carolina Continental Rise. J. sedim. Petrol. 41, 526–36.Google Scholar
James, D. M. D. 1971. Petrography of the Plynlimon Group, west central Wales. Sediment. Geol. 6, 255–70.CrossRefGoogle Scholar
James, D. M. D. 1972. Sedimentation across an intra-basinal slope: the Oarnedd-wen Formation (Ashgillian), west central Wales. Sediment. Geol. 7, 291307.CrossRefGoogle Scholar
James, D. M. D. & James, J. 1969. The influence of deep fractures on some areas of Ashgillian—Llandoverian sedimentation in Wales. Geol. Mag. 106, 562–82.CrossRefGoogle Scholar
Jehu, R. M. 1926. The geology of the district around Towyn and Abergynolwyn. Q. Jl geol. Soc. Lond. 82, 465–89.CrossRefGoogle Scholar
Jones, O. T. & Pugh, W. J. 1935. The geology of the districts around Machynlleth and Aberystwyth. Proc. Geol. Ass. 46, 247300.CrossRefGoogle Scholar
Lynas, B. T. D. 1970. Clarification of the Polyphase Deformations of North Wales Palaeozoic Rocks. Geol. Mag. 107, 505–10.CrossRefGoogle Scholar
Pugh, W. J. 1923. The geology of the district around Corris and Aberllefenni (Merionethshire). Q. Jlgeol. Soc. Lond. 79, 508–41.CrossRefGoogle Scholar
Pugh, W. J. 1928. The geology of the district around Dinas Mawddwy (Merionethshire). Q. Jl geol. Soc. Lond. 84, 345–90.CrossRefGoogle Scholar
Smith, B. & George, T. N. 1961. North Wales. Brit. reg. Geol. H.M.S.O. London 96p.Google Scholar
Sorauf, J. E. 1965. Flow rolls of Upper Devonian rocks of southcentral New York State. J. sedim. Petrol. 35, 553–63.CrossRefGoogle Scholar