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Monday, 1 April 2013

Glacial Lake Brynberian


Further to our discussions about the likelihood of there having been a Glacial Lake Brynberian during the Devensian Glaciation, the light was perfect the other day when I passed by.  So here is a pic of that extensive flattish area where the lake might have been located.

By the way, Rhosyfelin is about half a mile off the picture, to the left.  Whatever might have happened during the Devensian, my conclusion from looking at the glaciology of the Anglian Glaciation is that c 450,000 years ago, the ice passed right across this landscape, moving approx from bottom left to top right, covering the mountain with at least 500m of ice.  As the ice moved upslope, conditions were at one stage perfect for the entrainment of blocks and debris from the ground surface and from rocky protruberances (as at Rhosyfelin) and for movement of this accumulated debris along shear planes up into the body of the Irish Sea Glacier.

1 comment:

Constantinos Ragazas said...

Brian,

From the topography of this landscape, would you say such hypothetical Glacial Lake Brynberian would have engulfed Craig Rhosyfelin? Or better yet, to what highpoint on the landscape (as marked in your photo) the Lake had to reach in order to have engulfed the Craig?

Kostas