The Pembrokeshire Coast National Park displays a greater variety of geological features and associated landforms than any equivalent area of the same size in the British Isles. The coastal scenery was the prime reason for the National Park's designation.
Pembrokeshire has 50 Geological Conservation Review (GCR) sites, of a total of only c.400 in the whole of Wales. These sites are, at least, of national significance and some are of international importance. T
The cache coordinates are located on the coast at Newgale. Here you will see three cave entrances which are only accessible at low tide.
The primary rock type on St Davids Head is gabbro; an igneous rock (meaning the rock has been formed from prehistoric lava flows) Gabbro is an intrusive and mafic igneous rock. This basically means it is high in magnesium and iron compounds. Mafic igneous formations are created in lava flows which weren't very thick (low viscosity)
The gabbro is formed in distinct layers or planes as they are known geologically.
The cliffs here are layered of mudstones and sandstones; sedimentary rocks. Here at this earthcache, coastal erosion has become an artwork. Within the cave are the exposed layers of the rocks in the cliffs. The caves would have been formed through the eroding power of the waves. The main types of coastal erosion are summed up in the image below:
In order to claim a find on this earthcache please answer the following questions:
1) Describe the texture of the eroded rock within the sea cave and why is it this texture?
2) Estimate the width of one of the cave entrances and why is it the shape it is?
3) What type of rock is sandstone?
Pictures aren't compulsory but are appreciated.
Please send your answers through my geocaching profile. You don't need confirmation from me before logging the find.
Thanks to the NT for permission for this cache.