En-echelon quartz veins, Marloes, Pembrokeshire 1

At the western end of Marloes Sands, the Milford Haven Group sandstones (Lower Devonian) are cut by a prominent conjugate set of en-echelon quartz veins.

The two conjugate sets indicate a localised tensional regime during the general Variscan folding of the area. They are arranged more-or-less symmetrically about the strike of the beds. In this photo the bedding is steeply inclined approx 60° to the south (right).

The grey rocks in the distance are Silurian age.