 Their flatness is due to coastal erosion, such as waves and winds.Other submarine volcanoes offshore of Eastern Canada include the poorly studied Newfoundland Seamounts.The Flin Flon greenstone belt in central Manitoba and east-central Saskatchewan is a collage of deformed volcanic arc rocks ranging in age from 1,904 to 1,864 million years old during the Paleoproterozoic sub-division of the Precambrian eon.