Quarrying began at Dalkey Hill between 1815 and 1817, in order to supply granite for the construction of a new pier in Dun Laoghaire and also for the South Bull Wall in Dublin Harbour. The granite from this quarry was also used as flagstone for many streets in Dublin.
The granite was also used in the construction of the Basilica of St John the Baptist in Newfoundland, USA, following its export in the 1840s.
The quarry was connected to Dun Laoghaire by means of a light railway. The remaining part of this route is now a public path known as The Metals. Much of the original granite paving survives here. Quarrying continued at Dalkey Quarry until 1917.
The quarry is now extensively used by climbers, and over the years, clearing of vegetation and loose rock has uncovered even more quality climbs for climbers.
The quarry has four main sections. Above Ardbrugh Road are three valleys: The Far East Valley (which is private property), the East Valley and the West Valley. Between the East and West valleys is a broad ridge along which the quarry railway used to run; this is used to gain access to the Upper Tier, which contains the quarry's highest cliffs. The Upper Tier is passed through by a tarmac path leading to the Killiney Hill car park at one end, and a set of steps leading to the top of the hill at the other end.
Granite
Granite is a light coloured igneous rock with large visible grains. Granite is formed from the slow crystallisation of magma below the earth’s surface. Granite always consists of the minerals quartz and feldspar, usually with a variety of other accessory minerals, but sometimes without.
Quartz and feldspar generally give granite a light ‘base’ colour, ranging from pink to white. The accessory minerals are darker specks, giving the granite a ‘salt and pepper’ look.
Granite begins as a molten liquid state (magma) that solidifies as it cools. The texture will be determined by the rate of cooling. Large mineral crystals in granite provide evidence that it cooled slowly from molten rock. The slow cooling occurred under the earth's surface over a long period of time. Granite that cools closer to the surface cools more rapidly and the resultant granite will have smaller crystals.
To log this earthcache as a find:
1. Examine the granite located here. Based on your observations, do you think that the granite cooled at a rapid or a slow rate? Why?
2.What is the main colour of the granite here?
3. At the given coordinates, you are standing at a sheer rock face - how high do you estimate the rock to be here?
4.Why do you think granite is a good rock for climbers?
Please send me your answers via my profile/the message centre, then log the cache. If there is a problem with your answers, I will contact you.
Happy earthcaching!
While you're here....
You might want to check out two great nearby caches The Metals and THE QUARRY