Abermawr -- the base of the Irish Sea Till

A fresh exposure of Quaternary deposits at the northern end of Abermawr bay.  Above the broken bedrock we can see a coarse rockfall breccia grading upwards into finer brecciated slope deposits.  Then above a coarser layer of broken bedrock slabs is the base of the Irish Sea Till -- weathered to a foxy red colour.  Above that is the unmodified blue-grey clay-rich Irish Sea till with its weathered upper surface -- and then the "rubble drift" ow interpreted as a modified and maybe remobilised meltout till capped by some blown sand and modern soil.  The till wedges out from right to left.

The severe storms during the month of February 2020 have not come from the north, but nonetheless there has been severe damage to the northern drift cliff at Abermawr, with cliff retreat in places, and a complete rearrangement of the storm beach at the base of the Quaternary exposures.  Pebbles have been piled up high against the face, and a number of fresh features have been exposed.

At the moment the basal contact between the Irish Sea Till and the brecciated slope deposits is particularly easy to examine.  The contact is very sharp, indicative of a sudden arrival of the ice front on a surface frozen solid by permafrost.  There are signs that this is an erosional contact, meaning that the overriding ice has removed some of the brecciated slope materials;  there is some evidence of shearing, and of the incorporation of rock debris into the glacier base.  Others have studied the glacier tectonics here in the past.  As we see elsewhere, the lowest 10 cm or so of the Irish Sea till have been weathered by water percolating upwards from within the slope deposits.  But this is pure clay-rich Irish Sea till right down to the base of the glacial layer.

The contact between the brecciated slope deposits (below) and the Irish Sea Till.  The massive clay-rich till with scattered erratics is weathered and stained to a foxy red colour in the 

lowest 15 cm - 20 cm -- from the trowel handle to the tip of the blade.

Evidence of glacitectonic features on the glacier bed