Erratic resting on a bergy bit in a vast glacier meltwater lagoon in Iceland. Nothing to do with the sea or the coast, but deemed by TD to have something to do with coastal boulder emplacement........
I don't usually waste valuable space on this blog to considering the contents of other blogs -- but our friend Tim Daw, over on Sarsen.org, has just demonstrated that when it comes to matters glacial he really is out with the fairies.In a post entitled "erratic castaway" he argues that "any Glacial erratic found on the edge of a body of water is probably a boulder that hitched a ride on an iceberg rather than evidence of actual glaciers." He has done a nice little image search on Google and has come up with a couple of pictures of glacial erratic boulders resting on bits of floating glacier ice -- and he assumes that these photos prove his hypothesis.
Oh dear -- how best to put this in the kindest possible way? Tim has clearly never heard of eustatic and isostatic sea-level effects, and is clearly blissfully unaware that at a time when ice rafting of the type he now demonstrates was occurring around the British Isles, relative sea level was more than 100m lower than it is today, and the coastline of the Bristol Channel coasts was more than 100 km to the west. The whole of the Celtic Sea arena was dry land. During the Quaternary interglacials, when sea-level was more or less where it is today, with the coast in more or less its present position, there is no way that the ice rafting of large erratic boulders can have occurred in southern Britain.
This blog has a very good search facility, and there are abundant articles on glacial isostasy and palaeo-coastal positions. I recommend to Tim that he does a little research.......
Tim should stick to what he knows. As I have said before to those who purport to be bluestone experts, with friends like him, who needs enemies?
1 comment:
Perhaps the Stonehenge sarsens were brought there by Saracens captured during the Crusades, Tim?
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