Alluvium, the silt, clay, sand, and other material transported and deposited by running water. The term excludes lake and ocean deposits and is usually restricted to geologically recent sediments. Alluvium is laid down in many places but occurs most extensively on flood plains (areas along streams that are subjected to flooding); in river deltas; and in alluvial fans, cones, and plains at the base of steep mountains. Some of the world's richest agricultural land consists of alluvial soil. Such regions are also among the most heavily populated on earth. Examples include the Nile River valley and the deltas of eastern and southeastern Asia.
You Might Also Like
Folks in Montana usually expect snow or rain to fall from the sky, not ash. But the 1980 eruption of Mount St. Helens in Washington flung ash across state lines. What is this gritty, gray stuff?
The Smithsonian Institution began with an unexpected donation and has now grown to a massive collection of American artifacts. The Smithsonian is world renowned for its museum and for scientific endeavors. Take this quiz and learn more about the famous Smithsonian Institution.