Disharmonic recumbent fold

Disharmonic recumbent fold at Broad Haven - general view.

On the north headland of Broad Haven, Pembrokeshire, is this spectacular fold structure in Coal Measures strata. The fold is essentially an anticline strongly overturned northwards (to the left) so that its fold axis is near to horizontal.

The fold is disharmonic - individual beds in the fold have become detached and are no longer concentric with each other, as can be seen above and to left of centre. This has been achieved by considerable slip along individual bedding planes and softer, incompetent, material has been squeezed into the hinge zones from the fold limbs.