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Lewisian Gneiss, Torridian and Cambro-Ordovician sediments |
Rocks from the Lower Devonian to Tertiary Period |
Moine Thrust Zone |
Caledonides |
Major granitic intrusions |
The rocks of the Highlands and Western Isles of Scotland are a Geologists dream which probably accounts for the fact the basis of the science was "discovered" here. Even to the amateur, a glance at the simplified map above indicates that the geology of the area is extraordinarily complex.
Millions of years ago (supposedly) the landmass of the earth was made up of one continent. This then split up into three bits. The two bits of interest "Laurentia" moved away as a result of plate tectonics from "Gondwanaland". Some time later the two lumps collided together again but they lined up in different places from where they started off. Hence the PINK area above has more in common with Greenland or North America whilst the BLUE bit has more in common with South America and Africa.
Of course when you start moving great lumps of planet about and then banging it together again all sorts of mess happens. First of all where the bump happens, the ORANGE bit, the rocks there need serious attention from the body shop, this is the Moine Thrust Zone and all that grinding together of rock creates some serious heat and as a consequence there was a great deal of volcanic activity in the form of volcanic extrusion and intrusion (believe me, the two are different!). This process did not happen overnight in fact took over 100,000,000 years sometime around 520-400 million years ago and today is known as the Caledonian Orogeny.
Of course this is a very vague explanation for what took place but for most of us what is has left is more important, the diverse geology has created a diverse ecology and put together a scenery that can only be Scotland. If you're into collecting rocks and crystals a visit to the West Coast or even the Outer Isles will not disappoint.
External Information Links
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