CYNGOR CEFN GWLAD CYMRU

COUNTRYSIDE COUNCIL FOR WALES

SITE OF SPECIAL SCIENTIFIC INTEREST: CITATION

ANGLESEY CARMEL HEAD

National Grid Reference: SH293928

Site Area: 8.3 ha

Description:

A great variety of geological features along this stretch of coastline make the Carmel Head area one of the most interesting sections in North Wales. The ancient rocks of the Mona Complex have been pushed over younger rocks to form the famous "Carmel Head Thrust" ‑ a subject which generated much argument in the 19th century until the important work of Charles Matley was published around 1900. Although the Carmel Head Thrust has been mapped right across Northern Anglesey, this site is the classic locality for viewing the thrust and as a result of this it is extremely popular with teaching parties. In addition the rocks further south show unusually complicated contortions ("folds") produced by the movement of the nearby thrust. Further south still, beyond Porth y Dyfn, an important fault (containing quartz veins once mined for copper) has moved up more Monian rocks which are well exposed along the cliffline. These exposures are of the coarse, crystalline rock‑type known as 'gneiss' and are something of a rarity in North Wales, being only found in central Anglesey, NE Anglesey and here at Carmel Head. This locality provides the best exposures of these Precambrian gneisses, which are almost certainly the oldest rocks in Wales.