The Strangest Rock: Acude Jerimum, Ceara, Brazil
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This page documents a strange metamorphic rock that crops out in the Acude Jerimum. The rock is comprised of kyanite (upto 5cm long), bronze-coloured sillimanite in radial aggregates (upto 15cm in diameter), garnet (upto 2cm in diameter) and biotite. There are patches of fine-grained garnetite, patches 50cm wide of almost pure silimanite, and red garnet with a thin outer greenish grey rim in regions with biotite and kyanite.
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| a) Coarse garnet-biotite-hyanite-sillimnanite rock. | b) Zoom in in (a) showing zoned garnet in biotite-kyanite (sillimanite) coarse matrix. |
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| c) | d) |
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| e) Coarse kyanite in amongst bronze-coloured sillimanite at contact with biotite-kyanite rocks. Note patches of fine-grained garnetite (the more homogeneous, finer patches). | f) Detail of (e). |
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g) Radial sillimanite, bronze-coloured, 15cm in diameter. | h) Radial sillimanite, bronze-coloured, 15cm in diameter.. |