how to recognise …a roche moutonnée honnister pass in the lake district n.g. ref ny 212148
TRANSCRIPT
How to recognise …a Roche Moutonnée
Honnister Pass in the Lake District N.G. Ref
NY 212148
Ask some questions…
Was the area once under ice?
Of what is the feature composed?
What shape is the feature?
What would the direction of ice flow have been?
Now for some answers…
Here is the view down valley of the feature
CorrieArête
‘U’ Shaped profile
So – the area has been glaciated
Some more answers…
Up valley
Down valley
So the ice went this way
Rock not sediment
Gently sloping smooth side
Steep and rugged side
Have a closer look
here
Is there evidence of abrasion?
…and here
Is there evidence of plucking?
The up-valley (up-ice) side
Smoothed rock with striations parallel to direction of ice flow
Plucked face
The down-valley (down-ice) side
Steep face
Now look closer!
The lee end
Much evidence of plucking
It all adds up to …
Ice smoothed (abraded) ‘stoss’ end
Plucked ‘lee’ end
Formed of bed rock
Asymmetrical profile
A Roche Moutonnée