FINGAL'S CAVE
STAFFA, SCOTLAND

It
is formed entirely from hexagonally jointed basalt columns
within a Paleocene lava flow, similar in
structure to the Giant Causeway in Northern Ireland and those of
nearby Ulva.
In all these cases, cooling
on the upper and lower surfaces of the solidified lava resulted in contraction
and fracturing, starting in a blocky tetragonal pattern and transitioning to a
regular hexagonal fracture pattern with fractures perpendicular to the cooling
surfaces. As cooling continued these cracks gradually extended
toward the centre of the flow, forming the long hexagonal columns we see in the
wave-eroded cross-section today. Similar hexagonal fracture patterns are found
in desiccation cracks in mud where contraction is due to loss of water instead
of cooling.
ACTIVITIES AT FINGAL'S CAVE
- Cave exploration
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