Environmental Engineering Reference
In-Depth Information
… all these beloved and enduring things, which combine to make the real Gower which we have
inherited, and which our children's children will enjoy until the time when the glaciers flow south
again, perhaps to envelop and disfigure our peninsula …
Horatio Tucker,
Gower Gleanings
D
ESPITE THE
apparently unchanging nature of the earth, the continents are in constant motion, travel-
lingenormousdistancesovergreatperiodsofgeologicaltime.ThecontinentalplateofwhichGowerispart
has been situated on, and even to the south of, the equator and has drifted slowly northwards over the past
425 million years. The rocks that make up the peninsula today have therefore been deposited under widely
varying conditions, such as subtropical seas rich in corals, arid deserts and coastal swamps. The distinctive
landscape, with its rocky coastal cliffs, sandy bays and rolling hills, is a direct result of the exposed solid
rocks and the processes that have affected them during this long and complex history. Some of the rocks
contain large numbers of fossil plants and these provide not only evidence of past plant communities, but
alsoimportantinformationaboutplantevolution.Ingeologicaltermsthepresent-dayfloraisonlyapassing
phase in the area's long history.
Gower is formed from very ancient rocks (Fig. 15, Table 1), and rocks younger than 290 million years
ago are hardly represented. All were deposited as sediments, as sands, gravels and other fine-grained de-
posits in horizontal layers known as beds or strata, and were themselves the result of existing rocks being
eroded, or of accumulations of organic remains. Small breaks in the deposition, or changes in the sediment
type,cancause thebedstobevisibly separated fromeach other.Thisinterface between onebedandanoth-
erisknownasthe'beddingplane'andshowsclearlywhenrockshavebeenfoldedduetoearthmovements.
Folds where the bedding planes have been bent into an arch are known as 'anticlines' and downward folds
are known as 'synclines'. When erosion cuts across these folds anticlines show the oldest rocks at their
axis, whereas younger rocks are present at the centre of synclines.
