at Bennan Head, south coast of Arran, Buteshire
Distant views of the Bennan Head composite dolerite - quartz porphyry
sill intrusive in Triassic sandstone. Dolerite dykes on foreshore
and raised beach in foreground.
The upper part of the cliff is formed of quartz porphyry, with dolerite
near the base of the sill, which becomes lower westwards and reaches
sea level near the point. At the right edge of the photo, horizontally-bedded
sandstone is visible under the dolerite. North-south dolerite dykes
occur on the foreshore. Note the apparent absence of dykes cutting
the sill, which must post-date the dykes. The raised beach at the
foot of the cliffs was formed during a period of high sea level
shortly after the end of the latest glaciation.
SCRAN ID: 000-000-146-236-C; British Geological Survey