Environmental Engineering Reference
In-Depth Information
emergence produces a similar effect but entire
raised platforms
and abandoned cliffs
become stranded above contemporary sea level if emergence occurs faster than erosion
(Plate 17.5). Incomplete erosion or locally more resistant rock leaves remnant and
transient
arches
and
stacks
. Their shapes attest to progressive exploitation of rock
structures and decay of rock strength during retreat.
THE GLOBAL COASTLINE
Whatever the nature and controlling mechanisms of individual coastal landforms and
landsystems, four universal influences are recognized in coastline patterns at the global
scale. The youth and vigour of sea-floor spreading and continental margin orogenic
activity impart morphotectonic control. Global tide and atmospheric circulation establish
tidal range and wave energy patterns, complicated by continental coastlines. Tectonic and
climatic causes of sea-level change, varying temporally and spatially, create patterns of
emergent and submergent coastlines.
Plate 17.5
The 61 m raised platform at Rhossili and Worm's
Head, Gower, South Wales.
Photo: Ken Addison.
