Monday, 7 September 2020

Raised sediments of Allonby (II)

With some heavy rainfall in the last few days we re-visited Allonby to see what had happened to the newly cut channel of Crookhurst Beck.  The beck has recently re-aligned itself exposing a range of Holocene sediments Click here for a detailed description . The beck had really pushed itself further along and there were some dramatic new exposures. Next time we really must think about taking photographs from the same spot, but the pictures below show, on the left, what it was like on our last visit and the picture on the right as it is now ....although it will have changed again by now! 

Changes...








A newly exposed exposure showing a new section of the sequence between the wind blown sand and top of the first raised beach unit.


The outflow of the beck forming a large fan.


The dark clay is surprisingly resistant to erosion, and this unit alongside the concreted raised beach provides substantial barrier to the beck, creating several knickpoints.

I also spent some time looking for aquatic snails as I suspected the margined ramshorn snails that I had found ontop of the dark grey clay were not in situ and modern in origin. This is a great pondsnail, but a few other species were found, inluding margined ramshorn- although this is a new site for the Solway. 


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