Image: Wave-cut platform below Allt Wen - geograph.org.uk - 1751658

Description: Wave-cut platform below Allt Wen This view along the wave-cut platform shows the vertical alignment of the strata. The rock in the foreground shows how the strata are bent due to the presence of nearby micro-fold axes. Aberystwyth with its castle, South Beach and harbour can be seen in the background. Allt Wen, the northern end of the coastal cliff south of Aberystwyth, is a remarkable geological site. A number of micro-folds only a few metres across with nearly parallel vertical limbs have been exposed on a wave-cut platform at the base of the cliff. The exact sequence of events that have taken place here is still debated, but it is thought that during the Caledonian orogeny 400Ma ago, freshly deposited layers of sediment became pressurised and folded before they were fully lithified and thus more deformable. There are also quartz veins parallel with the bedding in some places. It is thought that they were pressed into the fresh sediment before the folding took place. For more details, see the Geological Conservation Review's site report http://www.thegcr.org.uk/Sites/GCR_v03_C04_Site2318.htm .
Title: Wave-cut platform below Allt Wen - geograph.org.uk - 1751658
Credit: From geograph.org.uk
Author: Rudi Winter
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