Marble skarn - Antrim
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Fact sheet
Description: 

The sample of rare minerals comes from the boundary between a pure Cretaceous limestone with flint nodules and a Paleocene dolerite plug rising above the Antrim plateau lavas. Metamorphic and metasomatic changes induced by the intrusion led to recrystallisation close to the margin. The rock contains several unusual and rare minerals including larnite a mineral named after the town of Larne where the calcium orthosilicate was first recorded, and spurrite a calcium silicate mineral found exclusively in contact metamorphic boundaries between carbonate and basic magmas.

The thin section is dominated by large grains of spurrite which are clear in plain polarised light but exhibits strong second order colour between crossed polars. The left hand side of the thin section contains large areas of fine grained larnite, a fine grained colourless mineral, generally less than 100 microns in size in this rock, but which also exhibits strong second order birefringence colours.

In Place
In Time
infoImage: 
Location description: 
Scawt Hill, Country Antrim, Northern Ireland
Accuracy:
Location precision: 
Moderate
Timescale:
Timescale: 
Paleogene
Ma = Millions of years ago
In Focus
Theme:

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Type:
Type: 
metamorphic
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Category:

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