Image Caption:
STS045-84-036: Great Salt Lake This oblique southwest-looking
view shows the Great Salt Lake and the enormous, light- colored
Bonneville Salt Flats (above), the floor of a once larger lake
that included the Great Salt Lake. Water circulation in the
Great Salt Lake has been stopped almost completely by a rockfill
railroad causeway, which now clearly separates the two halves of
the lake with a stark straight line. The chemistry of the lake
has changed as a result: Fresh water enters from the south, mak-
ing the southern half a darker blue. The lighter blue water of
the northern half is enriched with salts, as a result of strong
evaporation and the lack of fresh water input. The Bonneville
Salt Flats, to the southwest, are so flat that several land speed
records have been established on that surface. During the ice
ages, the Great Salt Lake filled to a depth of more than 1000
feet (its depth now fluctuates between 47 and 27 feet), on
several occasions expanding to cover the entire Bonneville Flats.
Known as Lake Bonneville, this great lake once burst its shore-
line on the north and flooded into the Columbia River drainage
basin. The discharge of this great flood was nearly four times
the average yearly discharge of the Amazon River.




This is a view of the Great Salt Lake and nearby Bonneville Salt Flats, UT, (41.0N, 112.5W). A railroad causeway divides the lake with a stark straight line changing the water level and chemistry of the lake as a result. Fresh water runoff enters from the south adding to the depth and reducing the salinity. The north half receives little frsh water and is more saline and shallow. The Bonnieville Salt Flats is the lakebed of a onetime larger lake.