Margaret’s favourite
Margaret’s favourite rock is the Precambrian Stromatolitic limestone which I discovered back in 1972 whilst assisting on a field trip of Manchester University students led by Dr Geoff Nichols. He announced that they were looking at oolitic textures in the limestone plus Precambrian melange when I said no, it doesn’t look like an oolite. He told me to apologise and withdraw my comment or prove it, which I did on making a thin section which clearly showed a cell structure. I had discovered stromatolic structures of uniceluar algae dating back to 860 million years ago and published the results in Nature.
Margaret’s favourite place is naturally the Cemaes Bay area as it has these very special rocks embedded in the melange, a rock type discovered and named by Greenly over a century ago. The International Commission on Geoheritage (IUGS) have designated their “First 100 IUGS-Geological Heritage Sites.” We are proud that the Gwna Melange at Ynys Llanddwyn has been included. Their book can be viewed / downloaded free of charge from https://iugs–geoheritage.org/videos–pdfs/iugs_first_100_book_v2.pdf
Margaret’s favourite walk is around Llanddwyn Island where there is an even more impressive multi-coloured melange than at Cemaes. Walking the length of Llanddwyn takes us through pillow lavas, hyaloclastite, red chert (deep ocean sediment), terrigenous sedimentary rocks and finally to the melange.
