This has allowed the lake to concentrate into a caustic alkaline brine. The lavas have significant amounts of carbonate but very low calcium and magnesium levels. The surrounding bedrock is composed of alkaline, sodium-dominated trachyte lavas that were laid down during the Pleistocene period. The alkalinity of the lake can reach a pH of greater than 12. High levels of evaporation have left behind natron ( sodium carbonate decahydrate) and trona (sodium sesquicarbonate dihydrate). Temperatures at the lake are frequently above 40 ☌ (104 ☏). The surrounding area receives irregular seasonal rainfall, mainly between December and May totalling 800 millimetres (31 in) per year. The lake is a maximum of 57 kilometres (35 mi) long and 22 kilometres (14 mi) wide.

It is quite shallow, less than three metres (9.8 ft) deep, and varies in width depending on its water level. The lake is fed principally by the Southern Ewaso Ng'iro River, which rises in central Kenya, and by mineral-rich hot springs. It is the only regular breeding area for Africa's lesser flamingoes, although this habitat is not protected and is under threat from planned development projects. The lake is within the Lake Natron Basin, a Ramsar Site wetland of international significance. It is in the Gregory Rift, which is the eastern branch of the East African Rift. Lake Natron is a salt or alkaline lake located in north Ngorongoro District of Arusha Region in Tanzania. Numerous near-white salt-crust 'rafts' pepper the shallowest parts of the lake (inset). Fault scarps and the Gelai Volcano can also be seen.

Lake natron tanzania calcified animals