Capeshore Formation

 Glacial Prehistory 

Capeshore Formation 

  

 

  

Around Shetland a deposit called the Capeshore Formation was laid approximately from MIS 5 to MIS 3.  The Capeshore Formation material is described as "Soft to firm, highly to moderately silty clay with sporadic shell fragments and pebbles." (BGS)

It overlies Ferder Formation and older layers that have been cropped by the rise of sealevel into the North Sea region. If the drawing is correct this may have been the first significant incursion of the Atlantic Ocean into the area.

Diatoms in the sediments are identified as:- "The foraminiferal assemblage is dominated by E. clavatum, Cassidulina reniforme Norvang and Protelphidium orbiculare . " (Johnson) , and the the conditions in which this organism developed are:- "The Cassidulina reniforme–Elphidium clavatum, Textularia spp. assemblage dominates the foraminifera fauna near the glacier proximal that indicates increased sedimentation and meltwater runoff." (Chatterjee)

The presence of this species suggests that meltwater was running away from Shetland probably through MIS 5, 4, and 3.

The small size of the Shetland Isles, and their closeness to the Atlantic Ocean caused an ice sheet sitting on them in MIS 5 to collapse, effectively rendering the area ice-free through MIS 3, 2, and 1.

Sources  

(Johnson) The geology of the northern North Sea. United Kingdom Offshore Regional Report By H Johnson, 

Jeffery Nicholls 

South Ronaldsay 

Orkney 

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