Upper Klamath Lake, a high desert lake, is located in the southern most part of the state of Oregon, at an elevation of 4100 feet above sea level. The lake is protected to the northwest by the Cascade Mountains with an arid sagebrush steppe to the east and south. Klamath Lake has a surface area of about 140 square miles and has an average depth of 8 feet. The lake is fed by 17 mineral-rich rivers that deposit an average of 50,000 tons of mineral-rich silt from the surrounding 4000 square mile volcanic basin, making Upper Klamath Lake one of the richest nutrient traps in the world, impossible to artificially duplicate. The lake waters and its sediments have an astonishingly high mineral and trace element concentration due to a massive volcanic eruption that occurred from Mount Mazama over 7700 years ago. The event covered the area with millions of tons of mineral ash as far as the Canadian border. Crater Lake, to the north, is what is left of this eruption. The region's volcanic legacy is associated with "The Pacific Ring of Fire," a geologically active region that experiences large-scale volcanic, tectonic, and glacial events. The volcanoes, earthquakes, and crumpled mountain chains that border the Pacific are the result of buckling edges of the great plates of the Earth's crust under compression.
