Photograph courtesy of John Anderson, Rice University. A large glacial erratic . Ice is capable of carrying all sizes of material if it is available. Photograph courtesy of John Anderson, Rice University. As the ice flows over the bedrock , it picks up particles.
Bedrock is made up of different components in different areas.
In another area, the glaciers may flow over granitic rocks and acquire a granite signature. A glacial geologist can tell where the ice came from by the minerals and rocks in the subglacial till. In Alaska, geologists trace gold by finding it in glacial deposits. They then follow the trail of ice to where the gold originated. Based on that broad definition, there are several different types of moraines.