Der Große Salzsee Nordamerikas

Abstract

The Great Salt Lake of Utah is a remnant of the pluvial Lake Bonneville. It is situated in the northeastern corner of the semiarid Great Basin. Three rivers which have their origin in the humid Wasatch Range and Uinta Mts. bring water to the lake. The Great Salt Lake shows fluctuations in its level and its area in relation to the changes in climate. Precipitation in the mountains and evaporation from the lake are the main factors that influence the water budget of the lake. The long term fluctuations in the lake level are overlapped by annual fluctuations. Regularly in May and June the lake is at its highest level and in November and December the lake is at its lowest level. It is extremely difficult to find out the amount of groundwater which flows to the lake from the rainy Wasatch Range. The author tried by considering the water budget to find out the amount of groundwater which flows to the lake in two specific years. An evaporation rate of 1077 mm and 1290 mm respectively was used. The groundwater which flows to the lake varies between 300 million and 1 billion m³. The salinity of the lake is about 25 %. The chief constituent of this salt is sodium chloride (77 %). The origin of the salt is not yet definitely known. The relative chemical composition of the Salt Lake brine is very similar to that of seawater. Some authors therefore think that the winds which come from the Pacific Ocean have through the ages carried the salt into the Great Salt Lake basin. The sediments of the Great Salt Lake are: 1. Calcareous clays and silts, 2. Oolite sands, 3. Algal reefs, 4. Saline precipitates. In spite of its high salinity there is some life in the brine. Two kinds of algae are food for the Brine Shrimp and the salt fly. Since pioneer days sodium chloride has been recovered from the brine of the Salt Lake. Today about 300.000 t of common salt are produced by divers operations. One company is preparing to recover lithium from the brine. There are plans to devide the lake by several dikes into three basins. The result would be a brackish lake, a salt lake and a dry lake. Only when there is surplus salt water would this water flow into the dry lake which usually will be dry.