Major folds affecting the Lower Old Red Sandstone Group at Lligwy, Anglesey, North Wales, and their regional significance

Treagus, Jack E. and Treagus, Susan H. and Woodcock, Nigel H. (2011) Major folds affecting the Lower Old Red Sandstone Group at Lligwy, Anglesey, North Wales, and their regional significance. Geological Magazine, 148 (4). pp. 644-654. DOI https://doi.org/10.1017/S0016756811000021

PDF Woodcock_GEO_S0016756811000021a.pdf Restricted to Registered users only Download (3MB)

Abstract

The Old Red Sandstone on Anglesey, North Wales, presumed Lower Devonian in age, is folded and locally cleaved, but the intensity of this deformation has previously been understated. We describe two S-verging anticline–syncline pairs, one with a strongly overturned middle limb, their associated minor folds and an axial-planar cleavage. The intensity of the deformation calls into question a proposed link to Variscan fault displacements, and the angular unconformity below the Old Red Sandstone precludes the deformation being part of a continuous ‘late Caledonian’ phase. We consider this deformation of the Old Red Sandstone to be mid-Devonian, correlating with the Acadian phase in mainland Wales. It is predated by a Silurian shortening deformation on Anglesey that is possibly related to the closure of the Iapetus Ocean, absent in mainland Wales and the Lake District, but perhaps preserved also on the Isle of Man.

Item Type:	Article
Uncontrolled Keywords:	2011AREP; IA62;
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title:	Geological Magazine
Volume:	148
Page Range:	pp. 644-654
Identification Number:	https://doi.org/10.1017/S0016756811000021
Depositing User:	Sarah Humbert
Date Deposited:	26 Feb 2011 12:03
Last Modified:	23 Jul 2013 10:01
URI:	http://eprints.esc.cam.ac.uk/id/eprint/2019

Actions (login required)

View Item