M22. Pelitic Gneiss - Slishwood
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Fact sheet
Description: 

Pelitic gneiss with kyanite replacing sillimanite. This rock is part of the Slishwood Division, a Neoproterozoic metasedimentary sequence deposited after c. 926 Ma. The Slishwood Division structurally underlies adjacent Dalradian rocks and records high pressure granulite- and eclogite-facies metamorphism and later magmatism that are not present within the adjacent Dalradian rocks. This unique rock show that the Slishwood rocks cooled slowly at a high pressure and temperature for kyanite to pseudomorph sillimanite,

Rotation 1 - Sillimanite XPL has second order colours and straight extinction. Kyanite has first order inclined extinction.

Rotation 2 - Lovely quartz strain shadows and kyanite showing two cleavages, extinction straight to dominant cleavage.

In Place
In Time
Location description: 
Slishwood, Northeast Ox Mountains, Co Sligo, Ireland
Accuracy:
Timescale:
Timescale: 
Proterozoic
Ma = Millions of years ago
In Focus
Type:
Type: 
metamorphic
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