Rothiemurchus eskers

eskers Nova Scotia

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

An exposed esker ridge in lower Glen Shee.

The gravel is horizontally- and cross-bedded. Imbrication indicates the former flow of water towards the camera. The sediment on the flanks of the esker has been disturbed by post-depositional slumping.

Esker sediments

This classic sketch by Mannerfelt (1945) shows the form, internal structure and sediments in a model esker.

Note the sinuous form of the ridge. The cross section shows that the esker is composed mainly of bedded sand and gravel, with the beds conforming in a general way to the shape of the ridge. The bedding, together with the rounded nature of the gravel, demonstrates movement by water. The presence of both large blocks and sand shows that meltwater discharge in the former ice tunnel must have varied markedly. The sediments are locally faulted, perhaps due to ice-push or simply to the withdrawal of lateral support as the ice melted. This esker has a till cover, representing glacial material let down on the esker surface as the overlying ice finally melted.