Nepheline syenite - Borralan
 >View Microscope
Fact sheet
Description: 

This Nepheline Syenite sample comes from East of Ledbeg, Sutherland, Scotland, and is part of the Borralan intrusion which lies in the SW corner of the Assynt region bordered by the Moine Thrust zone. This intrusive complex is the only plutonic complex composed largely of silica-undersaturated (i.e. feldspathoid-bearing) igneous rocks in the British Isles. Several members of the Borralan suite of intrusion are exceptionally alkaline. It provides Britain's only example of truly ultra-potassic magmatism.

In thin section this rock contains orthoclase feldspar laths which exhibit simple twinning, slightly higher relief and dusty grains of nepheline, phlogopite mica which is pleochroic in dark brown to straw yellow, and rare melanite garnet.          

In Place
In Time
infoImage: 
Location description: 
Borralan Complex, Sutherland, Scotland
Accuracy:
Location precision: 
Good
Timescale:
Timescale: 
Silurian
Ma = Millions of years ago
In Focus
Theme:

Theme:

What\
Type:
Type: 
igneous
What\
Category:

Category:

What\
Rock-forming minerals:

Rock forming mineral:

What\