Lake Magadi, in southern Kenya; October 1978.

In the upper photo, the line of hills on the horizon is the Nguruman Escarpment, the western wall of the rift valley – one of the lines along which the eastern side of the African continent is fragmenting.  The vast quantities of volcanic rocks produced during the formation of the rift valley are very rich in sodium, which weathers out of these rocks in solution as sodium bicarbonate.  Lake Magadi, looking like its covered in slightly pinkish snow here, is situated at a low altitude in an area of the rift that is one of the hottest and driest parts of Kenya, and it lacks an outflow.

Sodium bicarbonate weathers out from the surrounding volcanic rocks and is transported into the lake in solution via streams and groundwater.  The concentration of sodium bicarbonate in the lake increases as more and more water containing bicarbonate enters the lake – while more and more of the lake’s water evaporates in the ferociously hot climate.

When the lake’s waters become saturated with the bicarbonate,  sodium carbonate is precipitated as a solid mineral. This carbonate forms a white crust on the lake’s surface, which is tinged pink by red algae which proliferate in the highly alkaline water.  Hot springs around the lake are sufficiently alkaline to feel soapy to the touch, i.e. as they immediately start dissolving your skin!  The whole place reeks with the soda’s rank, sulphury smell, and the soda is extracted here commercially.

The lower photo shows the lake’s soda crust.  The jagged soda ridge in the foreground is about six inches high where it casts a very black shadow near the center of the shot.  I purposely made this ridge emanate from the picture’s lower right corner so that it would act as a leading line, drawing the viewer’s eyes ever more deeply into the picture and on out towards the horizon.  On the horizon, very slightly to the left of this “six inch cliff”, is the distinctive outline of the Shompole volcano, which is on the border with Tanzania.

Venturing out onto Lake Magadi’s crust is extremely hazardous, because it can give way at any moment, plunging the unwary into a warm and highly caustic mixture of sodium carbonate and bicarbonate that will cause serious burns.

OM-1 with 28mm Zuiko and polarising filter; Agfa CT18 slides rated at 64 ISO.


    • Yes >>> otherworldly! I can remember getting down to that “lake” edge and seeing that great expanse of hot, stinking, pink soda – I was stunned.

      But I had the Olympus, the 28mm and a polariser and went for it – I especially remember taking the lower picture, looking through the OM-1’s vast and bright viewfinder at that scene – Kenya really used to through up picture opportunities!


    • Thank you, my friend – well, writing can flow pretty freely with me – although that was anything but the case when I started trying to write research papers 40+ years ago! – and anyway I’m a geologist, aren’t I, and this post has a lot of geological context.

      I’m glad you like the post – thanks again! Adrian


  1. What an otherworldly and unforgettable environment! I’m glad to know that you were not one of the unwary and that you shared the knowledge of how the caustic liquid forms and why it feels soapy. I’ll wager that not many folks are aware of this. Great post!


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