Final Assessment : Salar de Uyuni

Landscape Salar de Uyuni Present Year

The Salar de Uyuni is found in an arid region. We know this because that’s how the salt flat was formed. It used to be a giant prehistoric lake called Lake Minchin (ThoughtCo.). 

However, due to the arid climate and having an uneven moisture deficit, the lake evaporated over thousands of years. This is also due to the Salar being a drainage basin that provides a permanent inflow from the Rio Grande de Lipez to the southeast (Orris). The water of the lake was filled with minerals and salt. Meaning when the water evaporated, the salt was left behind. The Salar de Uyuni is a solonetz, or a salt playa due to this (Lecture 23: Arid Landscapes). 

Landscape Salar de Uyuni 10,000 Years from Now

Under the Salar de Uyuni there is “estimated 50% of the world’s lithium” (Los Angeles Times). Humans will have mined the Salar as much as they could, mining for the lithium underneath the surface and the salt on the top. 

Mining for lithium under the surface of the Salar de Uyuni (BBC).

With this depletion of minerals and brine from the soil this would make the rainy summer months create a wet muddy surface. This is because with humans taking more salt than can be replenished by the rainy season, the surface loses mass and is now more permeable. Water is now able to percolate, eluviate, and translocate materials (Lecture 23: Arid Lanscapes).

This diagram shows an example of percolation (imgarcade.com).

Proof of this happening before can be found in Utah. Utah’s Bonneville Salt Flat has been struck with this occurrence the past two years. With mining depleting the salt from the soil faster than it can form, when the rain comes the salt pan turns to “gray, gritty soup” (Scientific American). 

 

Landscape Salar de Uyuni 1,000,000 Years from Now

Tunupa Volcano (Morgan J Salisbury).

Surrounding the Salar de Uyuni are old composite volcanoes. Most of them have last erupted in the Holocene (Orris). However, in the middle of Salar de Uyuni and Salar de Coipasa sits one of the youngest volcanoes.

Tunupa Volcano is a composite volcano with a peak at around 5,000 meters high (researchgate.net). The volcano will have a massive and violent eruption. There is much debate as to why this volcano formed and how the mantle melted to form its magma (Salisbury, Wired). Tephra will coat the Salars neighboring the volcano. There will be pyroclastic flow that runs down the side of Tunupa and into into the Salar de Uyuni (Lecture 13: Volcanic Processes). There will not be any lahars because there is not much snow on Tunupa.

Landscape Salar de Uyuni 10,000,000 Years from Now

The Andes mountains are surrounding the Salar de Uyuni. They are created by the Nazca and South American Plate (Salisbury, Wired). Over millions of years the plates will have been forced together and pushed apart from continental drift and plate tectonics. The massive mountains of the Andes will have become smaller.  This is due the Earth trying to reach isostatic balance. The plates try to adjust themselves so that they are both 5/6^th’s submerged (Lesson 11: Plate Tectonics). With the mountains no longer an obstacle, water is able to reach the Salar de Uyuni regularly. The evaporated water from the ocean is pushed by the Southeast Trade winds and over the Salar de Uyuni. With this increase in moisture and water the moisture deficit is not imbalanced anymore. The lake begins to form again and with each rainy season becomes bigger and bigger.

References

Thought Co., https://www.thoughtco.com/salt-flats-geography-1435836.

Morgan J. Salisbury, Wired. https://www.wired.com/2011/07/guest-post-unusual-volcanism-in-the-central-andes/.

LA Times, http://www.latimes.com/travel/la-tr-d-bolivia-salt-flat-20151213-story.html.

Scientific American, https://www.scientificamerican.com/article/the-race-to-save-the-bonneville-salt-flats-from-a-slushy-demise-slide-show1/.

Orris, G.J. BIBLIOGRAPHY AND SUMMARY OF DATA AVAILABLE FOR THE SALAR DE UYUNI, BOLIVIA. U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY.

Researchgate.net, https://www.researchgate.net/publication/258467738_Age_and_chemical_constraints_of_Volcan_Tunupa_Implications_for_behind_arc_volcanism_in_the_Bolivian_central_Andes.