Geological Structure

Strata-a layer of sedimentary rock or soil, or igneous rock that were formed at the Earth's surface, each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural processes.

Joint-a break of natural origin in the continuity of either a layer or body of rock.

Dip- the angle of tilt measured from the horizontal.

Strike- the direction of a level line on the tilted surface (perpendicular to the direction of the dip)

Fault- a planar fracture where there has been significant displacement as a result of rock-mass movement.

Fold-when strata are bent into a permanent deformation, usually at a convergent plate boundary.

The Glamorgan Heritage Coast is a 14-mile (23 km) stretch of coastline in the Vale of Glamorgan, South Wales, UK.

The coast includes the Southerndown CoastSite of Special Scientific Interest at its heart, a 3.1-mile (5.0 km) section from Ogmore-by-Sea, particularly interesting for its exposed Triassic alluvial fan deposits of carboniferous limestone. There is an Iron Age promontory fort (as well as a 19th-century lighthouse) at Nash Point and an ancient cairn or cromlech at Cwm Marcross.

The concordant coast may take one of two landform types. The Dalmatian type, named from Dalmatia on the Adriatic Sea, features long offshore islands and coastal inlets that are parallel to the coastline. The Adriatic Sea itself is a concordant landform, consisting of a body of water between parallel ranges. The second landform is the Haff type as in the Haffs, or lagoons, of the southern shore of the Baltic Sea, which are enclosed by long spits of sand parallel to the low coast

(Concordant and Discordant landforms have been covered in a seperate resource titled "Costal Features and Landscapes (Litoral Zone)").

Joints and Faults permit sea water to enter them, keading to freeze-thaw weathering and Hydraulic Action, this eventually creates a gap in the cliff face which evolves into a cave. Eventually this cave will be eroded through to form an arch.  Whilst it is still a cave, waves that enter it will be forced upwards and erode the roof, forming a blowhole. This will seperate and turn the arch into a stack, which willthen collapse into a stump.

Resistant Geology will result in tall, steep cliffs with caves, arches, stacks and stumps.

Less Resistant Geology will result in small, sloping cliffs prone to landslides.