Geology - Pembrokeshire
Dolerite - Cooling Joints- Pen Anglas
The inclined rock face at Pen Anglas shows the Cooling Joints of the Dolerite columns.
Dolerite is a Subvolcanic rock with larger crystals than a similar in composition rock - Volcanic Basalt.
The joints arise when a pattern of tensional forces is set up in a layer of Lava as it contracts on cooling.
In Gallery 4.5
Ref: 4937
Date: 07/05/2009
Location: SM 949.405
