3 - Aberdaron to Porth Oer
Gwna Melange
The West side of Trwyn Maen Melyn shows huge Quartzite Clasts.
The Melange formed in large debris-flows at a plate margin being subducted under North Wales
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The Gwna Group are a chaotic collection of sedimentary and igneous rocks some 610 million years old.
Since deposition the group as a whole has been subject to low grade metamorphism producing rocks of many colours.
Ref: NW 236
Date: 10/10/2021
Location: SH 1363 2549
