How Are Rivers Formed. Earth processes. All of the earth's rivers contain only about 0.0001% of the earth's water .
That doesn't sound like very much, but rivers can do some amazing things. The water in rivers comes from many different sources. Rivers can begin in lakes or as springs that bubble up from underground. Earth processes. Glaciers are made up of more than just ice and snow.
They contain water, rocks and sediments. This can make the ice look very dirty. Ice shelves form when glaciers reach the sea and begin to float. The Ross Ice Shelf in Antarctica is a famous ice shelf. National Snow and Ice Data Center. Agpat Glacier is one of many outlet glaciers draining the Greenland Ice Sheet.
—Credit: U.S. Coast Guard. 1969. Agpat Glacier: From the Glacier Photograph Collection. Boulder, Colorado USA: National Snow and Ice Data Center.