Wednesday 6 March 2013

The Moine Thrust

2 October 2012
 
The A890 south of Achmore apparently traverses the Moine Thrust which is exposed in a cutting through a small hill. The rock is largely made up of Moine Schists which were formed metamorphically from sedimentary rocks when the Iapetus Ocean closed as the continental land masses Laurentia (North America), Avalonia (Europe), and Baltica collided, with Scotland being on the front line of this massive coming together. Following the heat, pressure, and folding, the rocks recrystallized as thin sheets (foliation or schistosity). Schists are said to comprise platy minerals such as mica, chlorite, amphibole, and talc.
 
Here's a section of the exposed rock. If you look closely you will see the fine sheet-like layers.
 
 
Notice too how although the bulk of the rock appears a shiny grey, typical of mica schist, there are also areas in which the predominant colour is pale green which maybe indicates the presence of more chlorite schist. There is also a seam of some quartz-like mineral cutting through the schist.
 
 
 
 
 
A rather interesting bright red mineral seeping through pores in the rock, or a recent murder scene.
 
 
A band of iron mineral-containing rock.
 
 
I wonder if some of this reddish stuff is garnet-mica schist.
 
 
 
 
 
A bunch of local chavs on there way to a hidden dell with their bags of bucky, cheap cider, and various assorted solvents.
 
 
 
 
 
 
 
 
 
 
 
Interesting!
 
 
Looking back south towards Loch Alsh.
 
 
Lunch at Plockton
 
 
All geological assertions in this blog must be taken with half a teaspoon of smoked paprika.