Marginal features of a piedmont glacier.
This piedmont glacier expanding onto a lowland shows various sedimentary features. The dark lines along the glacier are medial moraines, the merged lateral moraines of tributary glaciers. The dark lines arcing parallel to the margin are debris-rich ice layers which have been sheared up from the base of the glacier. The intersecting sharp-crested ridges in front of the ice margin are crevasse fillings, ridges of till or gravel deposited in cracks in the ice. The ridge which borders the ice to the left, especially upstream, is a moraine pushed up when the glacier was thicker and more extensive during the Neoglacial advance a few centuries ago.
(Source: Natural Resources Canada.
Photograph by Ron DiLabio. Copyright Terrain Sciences Division, Geological
Survey of Canada.)
