7 October 2016

Friday folds: Dalradian schists at St. Ninian’s Isle

Posted by Callan

Remember St. Ninian’s Isle?

It is connected to Mainland Shetland by a tombolo. But it has rocks there, too. Here are some outcrops on the beach:

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If you visit these schisty fins, you’ll find they are populated by a cavalcade of small folds.

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Some of the folds are crisp things known as kink bands:

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Annotated version:
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And finally, as a lagniappe, here’s a bit of boudinage. This quartz vein has broken into segments, and the segments have separated from one another along the plane of foliation. Note how the foliation deflects into the boudin neck from each side:

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Annotated version:
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