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Saturday, 26 March 2011

More on Lake Brynberian

Thanks to Neil Glasser for a copy of the paper by Etienne et al 2006, concerning the sequence of pro-glacial lakes thought tom have been formed along the North Pembrokeshire coast during the advance of the Irish Sea Glacier at the time of the LGM.  On the map the purple tint shows Irish Sea till and related deposits, the yellow shows lake deposits, and the red tint shows the deposits of the Teifi Glacier, down as far as Llandysul.

It's a great map.  Click to enlarge.  The ice margin shown on the western part of the map is clearly wrong, but we'll let that pass...

Note that the supposed Lake Brynberian, impounded against the north face of Preseli. is thought to have overflowed via a col into the Rhosddu channel, at an altitude of c 220m.  That means that shoreline deposits, if they are present, should be along the 220m contour........

Next time I go for a walk along in that direction, I'll take a look.

2 comments:

Constantinos Ragazas said...

Brian,

Once again, what do we have?

Glacier ice, ice sheets, glacier lake formation, lakes freezing, lakes slowly melting and draining, and perched big boulders supported by little rocks! Interesting … keep up the good work!

Kostas

BRIAN JOHN said...

Kostas, I fear that none of this evidence gives you the transport mechanism that you want. Anyway, make what you will of the posts!