How did the Great Salt Lake originate?

It is all that remains of Lake Bonneville today

by Lorenzo Ciotti
How did the Great Salt Lake originate?
© Justin Sullivan / Staff Getty Images News

The Great Salt Lake is what remains of Lake Bonneville today, a vast prehistoric basin that has largely dried up. The waters of the Great Salt Lake have a chemical composition very similar to that of ocean waters. Due to the high salinity, few living species are able to inhabit it.

The most representative species is made up of the small crustaceans of the Artemia salina species. In 1902 the Southern Pacific Transportation Company built a new elevated track which still exists which divides the lake in two, highlighting a markedly different color in the two sections.

In summer the lake attracts tourists and local people, who go there to swim, similarly to what happens in the Dead Sea, to the point that the place is also known as the American Dead Sea. The lake is located at an average altitude of 1,280 m.

It has a length of approximately 120 km and a width that varies between 48 km and 80 km. The average surface area of the lake is 4,400 km², and is subject to strong seasonal variations. The lake is on average shallow.

Lake Bonneville, the origin of the Great Salt Lake

Lake Bonneville was a Pleistocene lake, which occupied over 50,000 km2 in the Great Basin region of North America: it was mostly included in today's Utah, as well as in Idaho and Nevada.

Formed about 32,000 years ago, it existed until about 14,000 years ago; following climate changes, the lake began to dry up, leaving behind the Great Salt Lake, Utah Lake, Sevier Lake, Rush Lake, the Little Salt Lake and the Bonneville Salt Desert.

It was over 300 meters deep. Around 15,000 years ago, the Bear River began to carry its waters into the lake, raising its level above Red Rock Pass; consequently the lake overflowed beyond this, destroying a natural dam and decreasing its level by over 100 metres, during an overflow which according to some estimates lasted more than a year.

It is named after Benjamin Louis Eulalie de Bonneville, a French-born officer in the United States Army who explored the region.