01 May 2021

Second last fieldtrip of the year

 Our fieldwork module was coming to an end! We were about to do the second last of our day trips. And this one went to Rhosneigr. We would do two loops there; one around the small local lake, and then one over the beach. By the lake we could see granite intrusions, and the contact metamorphism that resulted from it. These granites are more then 600 million years old! Not at all the oldest rocks we had stood on; that had been about 800 million years old. But still quite respectable. Wales was still part of a continent on the south pole when that was formed.

On the other side of the lake we saw Ordovician sandstones. These are some 125 million years younger. Life had changed by then! We had almost crossed an Ocean by then. And the bit further on they turned into beautiful conglomerates, where Jaco did an impromptu lecture about transport of gravel by seawater. And we decided to have lunch there.

After lunch we went to the beach to look at the beautifully deformed muds and sands. If you want to see textbook examples of folding and cleavage, then go there!

When we were done on the beach we were done altogether. And then only the trip to Lligwy beach was still to come. That would be the week after. And that would be it for this year with regards to fieldtrips. Last year, we hadn't got past this trip, as by then the lockdown happened. I suppose that given the pandemic has by no means gone away, we had managed quite well this year with these trips!

Llyn Maelog

Lovely Ordovician conglomerate

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