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Wednesday, 12 March 2014

Classic Pembrokeshire Pleistocene locations (1)

 Ancient till site, Lydstep Headland, South Pembrokeshire. The till (beneath the overhang) is solidly cemented (this is on Carboniferous Limestone) and may be Anglian or older

Raised beach (rock cut) platform cut into a Carbonbiferous Limestone cliff in Broad Haven (South) Bay, South Pembrokeshire

Close-up view of the same platform

Probable pre-glacial shoreline and old marine cliffline, with a spur almost cut off by an arcuate humped channel called Cwm Mawr -- Dinas, North Pembrokeshire

Close-up of the Cwm Mawr Subglacial Meltwater Channel, Dinas.  This feature may be composite in age, dating from the Anglian Glaciation and maybe used again during the Devensian

Rock-cut raised beach platform (age unknown) with probably Ipswichian interglacial beach deposits resting on it, and Devensian periglacial and glacial deposits above.  Poppit, near St Dogmaels in the Teifi estuary.

Apologies for the colours in these pictures -- they are scanned from some very old slides from my collection, and colour rendering is somewhat hit and miss......

2 comments:

TonyH said...

IPSWICHIAN interglacial beach deposits??!!.... [ final image caption]

Gosh, I KNOW glaciers are no respectors of distance in human terms, but Ipswich is an awful long way east of Pembrokeshire. And my Undergraduate knowledge of Glacial Geomorphology is by now quite archaic.

BRIAN JOHN said...

Tony -- Ipswichian is the name conventionally used for the last Interglacial (oxygen isotope Stage 5E). Given that name because the "type locality" which fixed this interglacial in a wider sequence was near Ipswich....