Lower Palaeozoic soft-sediment deformation structures in the western end of the Longford-Down inlier, Ireland

Summary Two types of interrelated soft-sediment deformation (D 0 ) structures are described, disturbed bedding and folds. Disturbed bedding varies from pinch-and-swell bed(s) to lenticular boudins. Folds are variable in style and scale; one fold is associated with a welded contact, two with décollement zones. All structures are stratabound. The structures are considered to be the product of dewatering of channel infill deposits combined with slope instabilities caused by channeling and/or penecontemporaneous volcanism. Packages of beds of alternating, opposed younging direction are also present and predate tectonic folds and cleavage. These structures may correlate with either D 0 or represent an intermediate stage between D 0 and post-lithification D 1 tectonic structures.