Ol Doinyo Eburru is an active complex of

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are ...

es in the

Great Rift Valley, Kenya The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. It is part of the Gregory Rift, the eastern branch of the East African Rift, which starts in Tanzania to the south and continues nor ...

to the northwest of Lake Naivasha. It is being exploited for

geothermal energy Geothermal energy is the thermal energy in the Earth's crust which originates from the formation of the planet and from radioactive decay of materials in currently uncertain but possibly roughly equal proportions. The high temperature and pres ...

. Soysambu Conservancy is located to the north of the massif, between

Lake Elmenteita Lake Elmenteita is a soda lake, in the Great Rift Valley, about 120 km northwest of Nairobi, Kenya. Geography Elmenteita is derived from the Maasai word , meaning "dust place", a reference to the dryness and dustiness of the area, espec ...

to the east and Lake Nakuru to the west.

Geology

Eburru is part of a group of volcanoes in the rift that also includes

Suswa Suswa is a small town along the main road from Nairobi to Narok town and at the foot of Mount Suswa in Narok County. Suswa is also a ward in Narok East sub-county. The Suswa sub-station is located just outside town and electricity that is generate ...

Longonot Mount Longonot is a stratovolcano located southeast of Lake Naivasha in the Great Rift Valley of Kenya, Africa. It is thought to have last erupted in the 1860s. Its name is derived from the Maasai word ''Oloonong'ot'', meaning "mountains of many ...

Olkaria The Olkaria Area is a region located immediately to the south of Lake Naivasha in the Great Rift Valley of Kenya, Africa. It is geothermally active and is being used to generate clean electric power. The region has an estimated potential of 2,000 ...

, Elmenteita and

Menengai Menengai Crater is a massive shield volcano with one of the biggest calderas in the world, in the Great Rift Valley, Kenya. It is the largest volcano caldera in Kenya and the second largest volcano caldera in Africa. Volcanic formed rich loam so ...

. It is separated from Olkaria volcano to the south by the Akira plains. In this part of the rift, the eastern margin is covered by

trachytic Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava enriched with silica and alk ...

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

s, often ignimbritic, and some trachytic

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

s. The western margin is covered by trachytic and

pantelleritic Pantellerite is a type of volcanic rock, specifically a peralkaline rhyolite. It has a higher iron and lower aluminium composition than comendite. It is named after Pantelleria, a volcanic island in the Strait of Sicily and the type location ...

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular vol ...

as well as deposits of

ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...

falls ejected from Eburru. Ol Doinyo Eburru

The Eburru massif rises to above the floor of the rift. It developed in three stages. The products of the first stage, in the west, are now mostly buried apart from small pantelleritic lava outcrops. The second stage formed the Waterloo Ridge on the eastern side of the massif. These rocks came from a series of pyroclastic eruptions originating in a

fault zone In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

. The third stage created craters, small cones, domes and lava flows. The summit has more than fifty craters with diameters from to . The pumice lapilli and ash beds from these centers covers most of the massif as well as the western shoulder of the rift. The youngest formations are no more than a few hundred years old. The Eburru massif today is ridge-shaped and eroded, with an east–west orientation. The volcanic complex has an area of . There are two summits, Eburru hill and West hill. There are young craters on the eastern part of the ridge. The east flank has

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

domes that were probably created in the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

and are still only partly overgrown with vegetation. There are widespread fumaroles in

cinder cone A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions o ...

s and craters along the faults in the massif.

Geothermal development

In October 2009 Geothermal Development Associates announced that they had signed a contract with Kenya Electricity Generating Company Limited to design, supply and commission a wellhead

geothermal power Geothermal power is electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation is currently used in 2 ...

plant at Eburru. The plant would include a 2.5 MW steam turbine generator manufactured by Elliott Turbomachinery in Jeannette, Pennsylvania. It has been estimated that Eburru could support a 20 MW geothermal power station.

References

Sources

* * * * * {{Great Rift Valley, Kenya Volcanoes of Kenya Mountains of Kenya Great Rift Valley Landforms of Rift Valley Province Nakuru County Active volcanoes Quaternary Africa Complex volcanoes