Aber Mawr

Site of Special Scientific Interest · 51.9695, -5.0844

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Coastal

Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.

Geology & landscape

Geological Period: Quaternary

Landscape processes: Coastal, Glacial, Periglacial

Description

Description Aber Mawr has one of the most extensively exposed successions of surface deposits in northern Pembrokeshire and has provided vital information concerning changing environmental conditions during the Late Pleistocene. The exposures reveal a sequence of glacial and periglacial deposits comprising (1) a series of lower head deposits, (2) Irish Sea till, (3) fluvioglacial sands and gravels, (4) upper head. The succession provides clear evidence for the incursion of an ice sheet from the Irish Sea Basin into northern ‘Pembrokeshire’ and, further, demonstrates that severe periglacial conditions occurred both before and after the Irish Sea glaciation of the area. The sands and gravels are thought to represent outwash from the melting of the Irish Sea ice sheet. The glacial deposits at Aber Mawr contain a variety of organic materials which have been dated using radiocarbon and amino acid techniques. The latter indicate a Late Devensian age. Remarks: The site lies with the Pembrokeshire Coast National Park.