Also known as volcanic rocks. . A fan-shaped sedimentary deposit that forms where rapidly flowing water enters a relatively open, flat area. As water slows down, it deposits sediment and gradually builds a fan. See alluvial fan . Sudden movements on faults cause earthquakes . .
Potassium feldspars contain considerable potassium.
Plagioclase feldspars contain considerable sodium and calcium. Feldspar crystals are stubby prisms, generally white, gray, or pink. . Microscopic tunnels made in crystals by escaping nuclear particles emitted by radioactive elements. Most commonly studied are fission tracks in zircon crystals made by the radioactive decay of uranium, present as an impurity. A lake, stream, or other body of water that flows over its natural confining boundaries.