M24. Two Pyroxene Granulite - Lewisian Complex, Scotland
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Fact sheet
Description: 

Pyroxene granulite is a water-poor metabasite composed of ortho- and clinopyroxene and plagioclase, and it forms only under the highest range of metamorphic temperatures (at higher temperatures one would be beyond metamorphism and in the realm of magmatism).  This rock comes from the Lewisian Complex, which is part of the ancient Laurentian craton (most of which in now on the far side of the Atlantic Ocean).  Metamorphism occurred about 2400 Ma in an event that has been called the Scourian orogeny. Most of the granulite facies gneisses of the Lewisian Complex were thoroughly recrystallized about 1700 Ma under amphibolite facies conditions (the Laxfordian orogeny), and it was at this time, perhaps, that the narrow border of hornblende developed on pyroxene grain boundaries in this rock.

In Place
In Time
Location description: 
Lewisian Complex, Badcall, Scourie, Sutherland, Scotland
Accuracy:
Timescale:
Timescale: 
Archean
Ma = Millions of years ago
In Focus
Type:
Type: 
metamorphic
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