SYN- TO POST-KINEMATIC FIBROLITE-BIOTITE INTERGROWTHS IN THE ARDARA AUREOLE, NW IRELAND

The relations of fibrolite-biotite are discussed by presenting data from the Ardara aureole, NW Ireland. Biotite-fibrolite intergrowths are developed in all three aureole zones including: the outer kyanite-bearing andalusite zone, the middle kyanite-free andalusite zone and the inner prismatic silli...

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Bibliographic Details
Format: Article
Language:English
Published: University of Tehran 2002-12-01
Series:Journal of Sciences, Islamic Republic of Iran
Online Access:https://jsciences.ut.ac.ir/article_31634_336f753598ae2a3a4ab94c79d3455cb9.pdf
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Summary:The relations of fibrolite-biotite are discussed by presenting data from the Ardara aureole, NW Ireland. Biotite-fibrolite intergrowths are developed in all three aureole zones including: the outer kyanite-bearing andalusite zone, the middle kyanite-free andalusite zone and the inner prismatic sillimanite zone. A strain-assisted mechanism is proposed for the fibrolitisation of biotite in the Ardara aureole. The concentration of fibrolite in zones of high non-coaxial strain, which wrap around zones of low co-axial strain, now occupied by minerals such as plagioclase (in the outer kyanite-bearing andalusite zone), andalusite (in the middle kyanite-free andalusite zone) and pods rich in biotite, quartz and plagioclase (in the inner sillimanite zone) provides strong evidence that fibrolite growth was syn-kinematic. Some textural evidence, especially from the inner sillimanite zone is consistent with continuation of fibrolite growth after ductile deformation.
ISSN:1016-1104
2345-6914