Oldoinyo Lengai Photographs
View of Oldoinyo Lengai volcanoe from a nearby field camp, northern Tanzania. Oldoinyo Lengai is famous as the world's only active carbonatite volcano. It is 9,442 feet to the summit.
View of Oldoinyo Lengai from the base of the mountain, Northern Tanzania. The volcanoe has experience repeated violent eruptions during the past century, the last of which was in 1993. Clouds commonly develop over the mountain as hot equtorial air rises over the high elevation of its summit.
White extrusive carbonatite-capped Oldoinyo Lengai, northern Tanzania. Oldoinyo Lengai means "mountain of the gods" to the Massai, and they interpret the white rock to symbolize the write beard of god. Carbonatite lava is dark brown upon extrusion, but it rapidly reacts with moisture in the air to hydrate to secondary alteration minerals that impart a white color to the rock.
Steeply dipping carbonatite-cemented agglomerate on the slope of Oldoinyo Lengai, northern Tanzania.
Active crater at summit of Oldoinyo Lengai, northern Tanzania. Recent carbonatite flows (dark brownish grey) were deposited on earlier hydrated carbonatite flows (white), both sourced from vents on the floor of the crater. Lake Natron (a saline lake) is present in the distance. Volcanoes and saline lakes are characteristic of the East African Rift. Photo courtesy of Abigail Church.
Close-up of an active vent eruping carbonatite lava, Oldoinyo Lengai crater, northern Tanzania. Photo courtesy of Abigail Church.
Thin section of natrocarbonatite viewed by cathodoluminescence (CL) microscopy (CLM) showing phenocrysts of hexagonal gregorite (Gr; dark brown) and orthorhombic nyerereite (Ny; orange) in a groundmass of acicular (needle-like) nyerereite (orange), fluorite (dark blue), and sylvite (light blue). Gregorite also contains exsolution lamellae of Nyerereite. Ny=(Na,K)2Ca(CO3)2; Gr= (Na0.78K0.05)Ca0.17CO3. Manganese is the element that activates the colors shown by nyerereite and gregorite. CLM is an especially illustrative technique for studying the mineralogy and textures of carbonatites. CL micrograph from Koberski and Keller (1995).
Maasai warriers, a colorful group of peoples common throughout Tanzania and Kenya. Oldoinyo Lengai lies in the heart of Maasailand.