M07. Garnet-Kyanite Gneiss - Slishwood
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Fact sheet
Description: 

This sample comes from the narrow northeast end of the Ox Mountains inlier, the same region as the metabasite garnet amphibolite P5218 in this collection. These rocks record a history of intense metamorphism within the high-pressure granulite facies, but the age of the protoliths and the age of metamorphism are uncertain. It is possible that the rocks are Dalradian, and that metamorphism occurred early in the Grampian orogenic event, but conventionally the extreme grade of metamorphism, and the clear signs of Grampian retrogression, has led to the view that the rocks are basement to the Dalradian Supergroup. Millimetre-sized garnet, kyanite and opaques are associated with ribbons of optically continuous quartz. K-feldspar, plagioclase and biotite are also present. The last three are mostly fine-grained and appear to have partially recrystallized after having been severely strained (the rock may once have been mylonite).

Rotation 1 - Nice kyanite with both cleavage traces sharp. Kyanite has straight extinction to the elongation. Rotation 2 - Strain shadowing and twinning in kyanite

In Place
In Time
Location description: 
Ballygawley, near 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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