Swallowtree Bay anticline-syncline couplet: detail 4

Saundersfoot to Swallowtree Bay geological structures

Detail view no.4 of the asymmetric anticline-syncline couplet in Lower Coal Measures sandstones and siltstones, just south of Swallowtree Bay.

This is a view of the siltstones and sandstones in the fold axis of the anticline below the small thrust which disrupts the fold axis.

The sandstone beds show thickness variation due to channelling and erosive bases into the underlying laminated sandy siltstone beds. Apparent low-angle cross bedding in the central, darker laminated sandy siltstone bed may be partly due to dislocation and bedding plane slip at its junction with the next underlying sandstone.

I took this photo for the shapes, textures and colours as well as the geological interest, hence I omitted a scale object. The section shown is about 1.6 metres in height.

The photo of the entire structure is here: