GeologyRocks

• Location: Blaen Onneu Quarry, South Wales
• Date Taken (dd-mm-yy): 18th March, 2010

This picture shows a cliff of Carboniferous Oolitic Limestone in a disused quarry. The upper surface was kartsified in the Carboniferous with a thick soil on top. The dissolution of the carbonate has left a thick wedge of regolith on top. Note the castellated boundary between the dark grey oolite and the yellow-coloured regolith.

• Location: Antigua, Caribbean
• Date Taken (dd-mm-yy): 14/01/2008

This is Hell's Gate on the North-East side of Antigua. This is a natural arch formed by weathering and erosion of Oligocene limestone. The sea at the front is the Caribbean. On the other side of the arch is the Atlantic ocean. The arch itself is well weathered, showing great (and very sharp!) karstification. It is possible to climb up the left side (through a cave), walk over the arch and back down on the right-hand side.