Drumlins are often associated with smaller, glacially streamlined bedrock forms known as roches moutonnées.
Because the bedrock formed at that spot, it will offer evidence of the site's geological history.
In the right conditions, then, the bottom layers of an ice sheet can melt and pool in depressions in the bedrock, forming large bodies of water.Although researchers have, in the past, detected microbes in samples from the bottom of the ice sheet over the surface of the lake, they are not quite sure that these bacteria were not contaminants taken down with the drillhead.
Acidic rainwater eats away at the limestone bedrock, forming cavities in the subsurface.
The medium size bedrock forms on southern Disko as tors, clefts and roche moutonées have been studied in the field.
Different hypotheses must be investigated in the future, for example, the presence of bedrock formed by granitic rocks (with U, Th, K, Llambias 2008; Rapella and Baldo 2014) that may produce high internal radiogenic heat over long time periods.
Main ice-flow has been from the NE and has resulted in plucking of SW facing lee sides, however the resulting bedrock forms are mainly controlled by structures and orientation of joints.
New multibeam bathymetry data, onshore high-resolution elevation data (NEXTMap) and fieldwork in the Ullapool area of NW Scotland reveal large-scale megagrooves and streamlined bedrock forms in a well-defined ∼ 20 km wide zone.
Based on the strongly convergent bedform distribution, the presence of megagrooves and highly elongate bedrock forms, we interpret the erosional landscape to be the signature of a fast-flowing tributary that once fed the The Minch palaeo-ice stream — a major artery of the last British Irish ice sheet.
The peninsula has been covered by seawater at least seven times since the bedrock formed.
