Bob:
Many years ago I observed the following:
Several sub vertical, usually fairly narrow, breccia dykes developed
in metamorphic host rocks south of the Barnesmore granite pluton in Co
Donegal in a fairly well exposed area.
These dykes are sub-parallel to each other and to the granite contact.
They are displaced by significant sub-vertical faults that displace
the granite contact in the same sense. In one exposure the cobbles are
large and rounded. My notes, sketch-map and photos are are in
Ireland, not accessible until next year, if anyone is interested.
Although not confirmed, the 'dykes' appear to emanate from an
extensive shatter zone on the opposite (east) side of the Lowerymore
river.
Malcolm
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