Lake Magadi, Kenya’s Pink Lake

Lake Magadi is located in the Great Rift Valley, in southern Kenya, in a vast depression whose bed is made almost entirely of solid or semisolid soda. This saline, alkaline lake of approximately 100 square kilometers in size, is composed of a dense sodium carbonate brine which precipitates vast quantities of the mineral trona (sodium sesquicarbonate), the raw material for soda ash or simply sodium carbonate. In places, the salt is up to 40 meters thick. This trona is collected and purified by the Magadi Soda Company and the resulting soda ash is sold for a variety of uses including glass manufacturing, fabric dyeing and paper production. Lake Magadi is among the few places in the world where trona forms naturally, and is the largest source of natural soda ash in Africa.

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Photo credit: Lynne/Flickr

The mineral is formed by chemicals such as sodium carbonate leeched by igneous rocks in this volcanic valley and washed down the valley’s walls and carried into the lake’s trough by the hot springs on the edges of the lake. When they come in contact with carbon dioxide, they precipitate as sodium carbonate brine.

The lake is located at the lowest point of the Rift Valley in a catchment area of faulted volcanic rocks. It has no permanent rivers entering the lake, and is fed only by surface runoff, usually from the short and long rains experienced in this area. The hot and arid condition heats up the surface runoff to as high as 80°C, giving rise to hot springs along the perimeter of the lake that feed the perennial lagoons on the lake’s margins. During the rainy season, about a meter deep layer of brine covers much of the saline pan, but this evaporates rapidly leaving a vast expanse of white salt that cracks to produce large polygons.

The Magadi township lies on the lake's east shore, and is home to the Magadi Soda factory. About a thousand people live here. Recently, the town has developed accommodation for tourists as well as providing visitors with air conditioned canvas tents to stay.

About the lake’s ancient history, I wish to quote Wikipedia:

Lake Magadi was not always so saline. Several thousand years ago (during the late Pleistocene to mid-Holocene), the Magadi basin held a freshwater lake with many fish, whose remains are preserved in the High Magadi Beds, a series of lacustrine and volcaniclastic sediments preserved in various locations around the present shoreline. Evidence also exists for several older Pleistocene precursor lakes that were much larger than present Lake Magadi. At times, Lake Magadi and Lake Natron were united as a single larger lake.

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