Castle Rock (Edinburgh)
| Castle Rock | |
|---|---|
| File:Castle from Princes Street, Edinburgh.JPG
Castle Rock as seen from Princes Street
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| Highest point | |
| Elevation | Lua error in Module:Convert at line 1851: attempt to index local 'en_value' (a nil value). [1] |
| Prominence | c. 80 m (260 ft) |
| Listing | Tump |
| Coordinates | Lua error in package.lua at line 80: module 'strict' not found. |
| Geography | |
| Location | Edinburgh, Scotland |
| Topo map | OS Landranger 66 |
| Geology | |
| Age of rock | ~350 million years |
| Mountain type | Crag and tail, volcanic plug |
| Climbing | |
| First ascent | Unknown |
Castle Rock is a volcanic plug in the middle of Edinburgh upon which Edinburgh Castle sits. The rock is estimated to have risen some 350 million years ago during the lower Carboniferous period. It is the remains of a volcanic pipe which cut through the surrounding sedimentary rock before cooling to form very hard dolerite, a type of basalt. Subsequent glacial erosion was resisted by the dolerite, which protected the softer rock to the east, leaving a crag and tail formation.[2]
The summit of the castle rock is 130 metres (430 ft) above sea level, with rocky cliffs to the south, west and north, rearing up to 80 metres (260 ft) from the surrounding landscape.[1] This means that the only readily accessible route to the castle lies to the east, where the ridge slopes more gently. The defensive advantage of such a site is clear, but the geology of the rock also presents difficulties, since basalt is an extremely poor aquifer. Providing water to the Upper Ward of the castle was problematic, and despite the sinking of a 28-metre (92 ft) deep well, the water supply often ran out during drought or siege,[3] for example during the Lang Siege of 1573.[4]
