- Ribbed moraines
A ribbed moraine (also called a Rogen moraine) is a type of
moraine formed subglacially (i.e., belowglacier s or ice sheets) looking similar to giant current ripples. Ribbed moraines occur in groups or "fields" and are oriented transverse to former ice flow. They are often associated withdrumlins , the latter being oriented parallel to ice flow.Their exact origin is a matter of debate. The main theories are:
* differential subglacialerosion by catastrophic release of meltwater
* ductile deformation of unfrozen sediments, either subglacial or proglacial
* brittle deformation of frozen sediments, either subglacial or proglacialee also
*
Drumlin External links
* [http://www.nr.gov.nl.ca/mines&en/geosurvey/publications/cr2005/marich.pdf Scientific paper about ribbed moraines (Marich et al., 2005)]
* [http://www.d.umn.edu/~meye0787/research.html More information about ribbed moraines]
* [http://www.sentex.net/~tcc/moraine.html Ribbed moraines formed by catastrophic subglacial meltwater floods]
Wikimedia Foundation. 2010.