Some of the ideas discussed in this blog are published in my new book called "The Stonehenge Bluestones" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
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Thursday, 17 May 2018

Ramsey Island

This is a fabulous false-colour laser image of Ramsey Island, showing  what incredible detail can now be picked up on the land surface with modern technology.    This was created as part of a survey of archaeological features, but topographical features are also fascinating -- the two hill masses are heavily ice-moulded, and during the Devensian (and earlier glaciations) the island took the brunt of the weight of the Irish Sea Glacier as it came in from the NW.

We have already wondered, on this blog, about the link between the giant erratics at Broad Haven and the island of Ramsey, and we have strong suspicions that at least some of the material on Flat Holm has come from here too.

The northern hill mass is made of microtonalite, and the southern one has a varied geology, with rhyolitic pyroclastic rocks, some sandstones and conglomerates, and in the south, other rhyolites in a complex relationship with Ordovician sedimentary rocks.


chris johnson said...

Today I went to a study day which included a presentation by an eminent Dutch geologist. On his picture of ice coverage during the last ice age it appears that south-west England was well and truly covered, including Stonehenge. The picture was of the entire Northern Europe and I should get a copy soon which I will forward on to you - although you almost certainly have seen all there is to see on the subject.

BRIAN JOHN said...

Thanks Chris -- interesting! It may well be that people are using some of the models of Henry Patton and others, which do show very extensive ice cover. I keep on trying to encourage these guys to take a look at the Anglian Glaciation, now that the picture for the Devensian is reasonably well understood.....