Environmental Engineering Reference
In-Depth Information
FIG
19.
Minchin Hole, a nationally important site for studies of the Pleistocene. (Harold Grenfell)
The limit of this last glaciation in South Wales has been the subject of much debate. By about 22,000
years ago, much of Wales had been overrun by ice, and large glaciers occupied Carmarthen and Swansea
bays. Much of south Gower, however, lay beyond the limits of the ice sheet and the deposits found above
the raised beach sediments at Worms Head record these cold conditions. These 'head' deposits consist of
angular limestone fragments prised from the slopes and cliffs above by the action of frost. During this
coldperiodmuchofthegroundwouldhavebeenpermanentlyfrozen(permafrost)-onlytheupperlayers
would have thawed out, and during such thaws, soil and other loose materials would have slipped down
the slope (solifluction) to lie with the broken limestone fragments above the raised beach deposits. These
different types of sediment make Worms Head an outstanding site for scientists studying the ice ages and
thewayclimaticchangesoccurthroughtime.TheevidencefromWormsHeadcomplementsthatobtained
from Rhossili Bay, where there is more direct evidence for glacial activity during this period.
TABLE
4.
The development of the Gower landform. (Adapted from Bridges, 1997)
