Age of raised beach deposits of South-Western Britain

Raised beach localities in SW Wales

The recent discussions about the Courtmacsherry and Fethard raised beaches, and the suggestion that they might be of early or Mid Devensian age, should not blind us to the fact that over many years evidence has been assembled to indicate that the bulk of raised beaches around the Celtic Sea and Bristol Channel coasts are are truly interglacial -- and probably largely of Ipswichian age. I assembled some of the evidence in my "Nature" article of 1968:

John, BS.  1968. Age of the raised beach deposits of south-western Britain.  Nature, 218 (5142), pp 665-667.

Here is the link:

 https://www.researchgate.net/publication/232783499_Age_of_Raised_Beach_Deposits_of_Southwestern_Britain

The evidence assembled from West Angle and elsewhere still stands -- and of course the evidence relating to the temperate climate of "Patella Beach" times goes back much further, to Strahan (1908) and others.  

Patella and other shell fragments in the cemented Patella raised beach, Gower.  Photo:  Jessica Winder

That having been said, attempts to date the "Patella Beach" exposures on the Gower coasts have been beset by difficulties, and as reported by Jenkins and others in 1985, amino acid dates for Patella shells suggested that they were over 200,000 years old........... Jenkins et al also reminded us that TN George, whose opinions were somewhat mobile, argued at one time that the presence of Lundy granite erratics in the raised beach indicated that it was formed at a time of cold climate, with glacier ice in the vicinity.  Quote: 

"The first modern work on the Quaternary beaches of Gower was by T. N. George (1932) who argued that this Patella beach was deposited in glacial conditions as evidenced by its erratic pebbles which he believed had been rafted on ice-floes. He argued that it predated both Older and Newer Drift Glaciations of Gower....."

It can also be argued that the close proximity of periglacial (?) head or slope breccia to the cemented raised beach exposures might also point to the presence of permafrost or at least a cold climate at the time of beach formation.  As pointed out by Kokelaar (2021) the Patella Beach exposures frequently contain sharp edged and angular rock fragments derived from the immediate vicinity.  But in my view these are most likely to be cliff face rockfall materials which have not been present in the beach for long enough for clast smoothing or rounding processes to have been effective.  (For comparison, many of the present day beaches of Pembrokeshire incorporate recent rockfall materials.)

A cone or fan of rockfall debris dropped onto the pebble beach at Newport in 2019.  Most of this material has now (2024) been dispersed by wave action and incorporated into the beach.

McCarroll (2015) argued that the amino acid dates that have bedevilled the Patella raised beach debate are mostly incorrect, and that the raised beaches date (with rare exceptions) from the Ipswichian Interglacial.

We must keep an open mind and see where the evidence takes us......