GRITTY GRANITE EARTHCACHE
In Northern Scotland, United Kingdom
Size:  (not chosen)
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A tricky Earthcache at the top of a remote mountain in the Scottish Highlands.
Beinn Dearg is one of the most isolated Munros in Scotland requiring a 14 km walk or rough bike ride in from the nearest road to reach it's 1008 m (3307 ft) summit. It is a lone granite peak surrounded by vast areas of flat land or low, rounded schist hills. The latter are covered in boggy peat and heather and it is a joy to step onto the drier, sparsely-vegetated granite above 850 metres. This Earthcache explores why this should be.
Granite is an igneous rock formed when molten magma rises up into the Earth's crust and slowly cools and crystallises underground.
The 3 main crystalline components of granite are:-
i) quartz (ie a glass-like mineral which is pure silica),
ii) felspar (ie silicates, which are silica combined with oxides of other elements) &
iii) mica. (a lustrous & flexible form of potassium aluminium silicate)
In granite the oxides are acidic and total amount of silica can be 70 - 80% making the rock hard and resistant to erosion. However, the mica is not so hard and when this erodes a shallow gritty soil is produced. Because it retains little moisture and is difficult for vegetation to colonise so the parent granite mass is never far below the surface.
Schists are metamorphic rocks. That is they are igneous or sedimentary rocks that have been altered by being subjected to great heat and / or pressure as a result of burial or folding within the earth's crust. Schists have fracture planes at right angles to the pressures they were subjected to and as a result usually weather more easily than granite, forming smaller particles that hold more moisture. This allows vegetation such as heather and coarse grasses to colonise and a deep peaty soil builds up. This retains water well and often becomes very boggy or waterlogged.
To log this cache e mail to tell me
Question 1:- What is the over-riding colour of the granite rocks at the summit of Beinn Dearg?
Question 2:- What is the letter and number on the bench mark pate on the trig point?
Because you can find the answers to both of these questions on the internet if you are crafty the third and crucial question to prove you've visited this isolated spot is to go 9 paces north of the trig point to NN 85295 77785 (N 56o 52.638' W 003o 53.029') where there is a rock that should project above any snow.
Question 3:- What colour is the lichen patch that is growing on the tip of this rock?
N.B. Although the walk is long and the peak remote it is a fairly safe peak (unless the wind is strong) as there are no cliffs or steep ground.
Vs lbh pna'g qb 28 xz (nebhaq 9 ubhe jnyx) va n qnl gurer ner obguvrf arneol lbh pna fcraq gur avtug va.
Last Updated: on 11/18/2013 1:59:59 AM (UTC-08:00) Pacific Time (US & Canada) (9:59 AM GMT)
Coordinates are in the WGS84 datum