The Ngorongoro Volcanic Highlands (Crater Highlands, Ngorongoro Volcanic Complex) is a group of eight volcanoes creating a volcanic highlands measuring 90 x 80 km.  They were active 3.7 – 1.8 Ma.  Five of the volcanoes are shields.  Three of them are calderas.  Internal walls of the calderas are steep with little erosion.  There are discrete ecosystems on the floors of the calderas.  Some researchers include Ol Doinyo Lengai and Kerimasi at the far NE corner of the highlands as part of the highlands.  We will treat them separately, though certainly related to overall activity along this linear trend. 

Volcanism here is dominated by lavas with abundant pyroclastics.  Layering is exposed in eroded gorges on the flanks.  They show thick beds of lavas, pyroclastics and debris flow deposits.

Ngorongoro is the largest of these, with a base 35 km in diameter.  It is topped with a 22 x 18 km near circular caldera, one of the largest and best-preserved calderas on the Earth.  Caldera rims peak at 2,380 m.  The 370 km2 flat floor is 1,700 m.  The mountain is thought to have been up to 5,000 m before collapse. 

The caldera is an internally drained basin fed by two external streams.  There are several freshwater springs (both hot and cold) that feed a small lake and support wetlands.  A second, larger lake is alkaline, with carbonates and clays.  Biotic CO2 plays an important role in stabilizing the carbonates.  The alkaline lake has large variations in size and alkalinity.  It was highest some 24 ka.  Parts of the caldera floor are covered by lake sediments.  The SW part of the floor is covered by ash erupted by neighboring Ol Doinyo Lengai. 

The Ngorongoro Conservation Area surrounds the volcanic highlands.  It borders the Serengeti National Park and Kenya’s Maasai Mara game reserve.  Maasai Mara is home to the Great Migration, a massive annual migratiojn of wildebeest, zebra, gazelle and other animals.  Human settlement and farming has been restricted in the crater in deference to the wildlife, a population of some 25,000.  This population includes Cape buffalo, hippo, wildebeest, zebra, eland, and gazelle.  They are hunted by a population of cheetah, leopard, lion, and hyena. 

The highlands are surrounded by the Ngorongoro Conservation Area, situated between a pair of lakes in the rift valley.  Lake Natron to the N, Lake Eyasi immediately S.  While there are a lot of smallish towns in the region, the largest cities are Nairobi, Kenya, 275 km NE, Arusha, Tanzania, 132 km E, and Mwanza, on the E shore of Lake Victoria, 184 km W. 

Some 300,000 live in the immediate region, mostly in the depressions and lowlands.  Livestock farming is the most important economic activity, though tourism is growing.  Arusha has an immediate population of nearly 620,000.  Its region has nearly 2.4 million. 

Climate in this portion of Africa varies with altitude, warmer in the lowlands where most of the population lives.  There is a seasonal monsoon Mar – May, with Jun – Oct being the dry season.  Average rainfall is nearly 120 cm / yr.  Average temperatures run 17° – 10° C. 

There are webcams around Ngorongoro that monitor the wildlife in the crater.  The volcano is not actively monitored. 

Oldupai (Olduvai) Gorge

Oldupai Gorge is a 48 km long, 90 m deep pair of erosion features on the W flank of the Ngorongoro Highlands.  They may be the most important paleoanthropological site in the world, containing evidence of over 1.9 Ma of human evolution through fossils and tools.  Initial exploration took place in 1911, with a German geologist finding fossil horse remains.  A return trip in 1913 found hominid remains dated 17 ka.  In 1931 Louis Leakey returned and found hand axes.  His wife joined him on another expedition in 1935.  They made multiple subsequent visits 1941 – 1957.

Ultimately, they found evidence of human evolution, increasing integration of tools into their lives, and increasing socialization (cooperation between individuals) beginning 1.9 Ma.  Remains of over 90 individuals have been unearthed.  Animal bones found before that time had gnaw marks on them.  Afterwards, there were gouges from cutting and scraping tools.  Fossils included multiple ancestral species of humans.

The basement of the Gorge is formed by the 7 m thick Naabi ignimbrite, erupted 2.04 Ma with the formation of the Ngorongoro caldera.  Subsequent rocks were deposited by volcanic activity, erosion runoff from the highlands, and lake sediments.  Erosion and rifting opened the gorge allowing investigation.  The lake dried completely 500 ka.  Over its history, the location supported a rich and varied population of plants and animals that drew the early humans. 

Region

We will start with volcanoes within about 100 km from the center of the Ngorongoro caldera and work our way into the eight volcanoes of the Ngorongoro Volcanic Highlands.  These volcanoes include Ngorongoro, Oldeani, Sadiman, Lemagarut, Olmoti, Loolmalasin, and Embagai.  Kermasi and Ol Doinyo Lengai are on its periphery. 

Published work on these volcanoes concentrate on the petrology of erupted rocks and their inclusions, as the interest appears to be in upwelling magmas due to the ongoing rifting event.  There is not a lot available about basic descriptions of individual volcanoes and their eruptive history outside the layered beds of volcanic materials at the Oldupai and Laetolil paleoanthropological sites. 

For purposes of the rest of the post, I will break known volcanoes into three groups.  The first group of volcanoes are those N of the Ngorongoro Volcanic Highlands, part of a 92 km long trend of activity S – N over time.  Distances are all measured from the center of the Ngorongoro crater (caldera).  The second group of volcanoes are part of a general 145 km W – E trend of activity from Essimingor to Kilimanjaro over time.  The final group of volcanoes will be those making up the Ngorongoro Volcanic Highlands proper.  All distances will be measured from the center of Ngorongoro’s caldera. 

Volcanoes N of Ngorongoro Volcanic Highlands

Kerimasi

Kerimasi is a 2,602 m extinct shield located at the NE corner of the Ngorongoro Volcanic Highlands and the E scarp of the Gregory Rift, 54 km NE from the center of the Ngorongoro crater.  It was active during the last major rifting episode 0.6 – 0.4 Ma.  Kerimasi has been called a neglected carbonatite volcano, unlike its active neighbor Ol Doinyo Lengai.  The volcano is built of nephelinitic pyroclastics with carbonatite tuffs.  There are at least 100 small volcanic features in this part of the Gregory Rift including tuff cones, tuff rings and maar craters.  These are mainly silicate and carbonate pyroclastics with small volumes of lavas. 

Carbonatities are present as both intrusive and extrusive rocks.  A new type of garnet present in carbonatite, Kerimasite, was identified in samples collected from outcrops and explosion craters on its E flank. 

Ol Doino Lengai

Ol Doinyo Lengai is a 2,962 m active volcano located some 59 km NE from Ngorongoro.  It is famous as the only volcano known to erupt carbonatite tephras and lavas in historic times.  The cone-shaped stratovolcano rises from the broad plain S of Lake Natron in the Gregory Rift valley. 

Cone building ended some 15 ka.  Since then, it has ejected tephras and some lava flows in its summit crater and down its upper flanks.  The depth of the summit crater changed significantly in historic times, from a crater floor with steep walls some 60 – 70 years ago, to its current shape of multiple platforms mostly filling the crater.  Lava flows beginning 1983 mostly filled the N crater over the next 20 years.  Lava began overflowing the crater rim in 1998.  

Estimates for the start of volcanic activity here vary wildly from 500 – 22 ka.  The initial stage erupted mainly phonolites, building the cone.  This stopped by 15 ka when the Naisiusiu beds were emplaced at the Oldupai Gorge.  During construction, the cone collapsed at least twice, between 850 – 135 ka and 50 – 10 ka.  There are debris avalanche deposits around the volcano, particularly on the N flank. 

Following the end of cone construction, it started erupting carbonatites.  The oldest of these erupted 1,250 years ago.  An eruption 3.0 – 2.5 ka deposited a tephra W that is being shaped by winds forming dunes, most notably the Shifting Sands of Oldupai Gorge.  Another explosive eruption 1,250 years ago produced the Namorod Ash in the Gorge.  The most recent one 600 years ago deposited the Footprint Tuff.

Today, the volcano is continuously active, though written records only stretch back to the 1880s.  Satellites measure deformation caused by magma intrusion during eruptions.  Ground observations identify movement in neighboring fault systems caused by magma intrusions.  Landslides from the steep slopes are common.  Erosion cut gullies into soft volcanic deposits.  Steam jets have been observed. 

The most recent series of eruptions began 1983.  Ash from that eruption made it tens of kilometers from the vent.  An explosive eruption Sept 2007 created a new crater and a 3 km plume.  Explosions continued into 2008 when it once again became effusive. 

Lavas are typically brown or black when erupted.  Their surface turns white within hours to days.  The carbonatite lavas are cool and highly fluid.  More silicic lavas are erupted from time to time, most recently in 1993. 

Naibor Soito

Naibor Soito is a monogenetic volcanic field located between Ol Doinyo Lengai and Gelai.  This would put it some 60 – 85 km NE from Ngorongoro.  Google Map satellite view of the region puts the majority of the field closer to Gelai, comprising its SW flank.  The 2022 Ho and Wauthier paper suggests the field measures 50 x 50 km and was the source of the Gelai earthquake and dike swarm intrusions Jul – Sept 2007.  The field may be may still be active. 

Gelai

Gelai volcano is a 2,652 m shield located some 85 km NE from Ngorongoro.  Its base measures 40 x 17 km, with the long axis parallel to that of neighboring Lake Natron to the NW.  The volcano was active less than 1.0 Ma.  There were a number of earthquakes in the region summer 2007.  A narrow graben formed on the S flank in 2007 that may be due to intrusion of a narrow dike at the 4,000 m level. 

Mosonik

Mosonik is a 3.25 Ma extensively eroded stratovolcano at the SW corner of Lake Natron, some 72 km NNE from Ngorongoro.  It is one of a group of volcanoes known as the Older Extrusive Series, 5.9 – 3.2 Ma that built massive shields in the region.  There is no summit crater or caldera.  Neighboring Leshuta River gorge exposes debris flows and lahars from the volcano.  The volcano erupted lavas, carbonatites and pyroclastics.  Most of the lavas are some variation of nephelinites. 

Volcanoes SE to E of Ngorongoro between Essimingor and Kilimanjaro

Essimingor

The 2,159 m, heavily eroded Essimingor is one of the oldest volcanoes in the region, active 5.91 – 5.76 Ma.  Due to its age and eroded state, there is no crater or caldera on top of it.   It erupted phonolitic lavas.  Essimingor is located 62 km ESE from Ngorongoro. 

Burko

Burko is a 2,136 m volcano located some 73 km ESE from Ngorongoro.  It is part of an eroded volcanic highlands and does not show a visible crater.  Activity here was dated at 0.97 Ma.  It erupted nephelinites as tuffs, agglomerates and lavas. 

Ketumbeine

Ketumbeine is a 2,850 m shield located some 79 m ENE from Ngorongoro, 32 km S from neighboring Gelai.  It is similar in size to Gelai, though more circular, around 25 km in diameter.  The cone is topped with a 1 – 2 km diameter crater.  The volcano was active 2.20 – 1.94 Ma, mostly erupting trachytes, and 1.28 – 1.23 Ma, mostly erupting phonolites. 

Tarosero

Tarosero is a large, heavily eroded volcano located some 88 km E from Ngorongoro.  It tops out at 2,117 m.  Volcanism here took place 2.4 – 1.9 Ma.  Initial activity built a lava plateau of basalts and trachyandesites.  Later activity built a cone through the plateau. 

Monduli

Located 98 km ESE from Ngorongoro.  It is a heavily eroded volcano rising some 1,300 m above the surrounding rolling plains.  This is one of the driest parts of Tanzania.  The remaining mountain is heavily vegetated. 

Meru

Meru is located some 131 km E from Ngorongoro.  We covered Meru in a May 2021 post. 

Ngorongoro Volcanic Highlands

The N and W part of the highlands and surrounding conservation area are covered by thin ash from recent eruptions of Ol Doinyo Lengai.  Prevailing E winds dispersed the ash.  It also covers part of the SW Ngorongoro caldera floor.  Ash created dunes near the Oldupai Gorge.  The black sand of the dunes are unusual in fields of red or yellow sands.  The dunes are migrating W. 

Paleoanthropological interest in Oldupai and Laetoli helped sort out previously unknown activity from volcanoes in the highlands.  Oldupai consists of lava, ash flow, air fall, water deposited tuffs, and lake sediments.  It has been subdivided into six units:  Bed I, II, III, IV, Maesk, Ndutu and Naisiusiu Beds.  All of these are built on the Naabi rhyolitic ignimbrite from Ngorongoro caldera formation.  While all these volcanoes are listed in the VOGRIPA database, none of the caldera-forming eruptions are.  A 1.8 Ma VEI 4.0 from Olmoti is the only eruption carried in the database. 

Ngorongoro

Ngorongoro is constructed mainly from basaltic trachyandesites.  The caldera walls expose layered basaltic lavas and tephra layers.  Flows of basalts and trachytes erupted from ring fractures near the caldera walls.  There are two rhyolite ignimbrites near the top of the rim.  They are associated with caldera formation some 2.0 Ma.  The ignimbrites erupted from a stratified magma chamber.  Post caldera activity erupted basalts in the caldera forming low hills and small scoria cones.  Lavas and ash from Ngorongoro are found in the Oldupai Gorge on the E Serengeti Plains. 

Ngorongoro is basaltic to rhyolitic in composition.  Activity ranges 2.95 – 2.15 Ma.  Ignimbrites collected on the caldera wall dates 1.98 – 1.83 Ma.  A global polarity change during its time os activity 2.43 Ma helped fix its activity.  While such a large, explosively formed caldera would normally require an eruption in the VEI 6 – 7- range, none is currently listed (that I could find). 

Olmoti

The 3,101 m Olmoti volcano is 30 km in diameter.  The central cone is visible N of the Ngorongoro caldera, 31 km NNE Ngorongoro.  Olmoti is topped with a 6.5 km caldera, 100 – 200 m deep.  The flanks are a thick sequence of lava flows.  There is a small post-caldera plug (130 m high) of trachyte lavas and breccias.  Most of the caldera floor is covered by lake sediments at least 50 m thick.  There is a small lake in the caldera.  The SE flanks of the volcano are cut by the Munge River.  The river flows over a series of waterfalls through a ravine into the Ngorongoro caldera. 

Volcanic activity here was short lived 2.01 – 1.79 Ma.  It may have been active at the same time as neighboring Ngorongoro and Embagai.  The lower part of the volcano is basalt – trachyandesites.  The upper part is tracytes.  Magmas show a mantle source.  It is thought to be the source of Oldupai Bed I lava as well as the majority of Bed I and Bed II tuffs in Oldupai Gorge.  Collected samples include trachyte basalts, ignimbrites and phonolitic tephras. 

The volcano has four small blowholes that emit strong drafts of cold are.  They are thought to be fossilized fumaroles.  The volcano is extinct with no evidence of geothermal heat.

Sadiman (Satiman)

The three volcanoes of Sadiman (Sadiman, Lemagrut and Oldeani) construct the SW portion of the Ngorongoro Highlands.  They are thought to be of similar age, though only Sadiman has been dated at 3.7 Ma.  Sadiman has a thickly forested 2,860 m cone constructed of tuffs, agglomerates and minor lava flows.  Erupted material range from nephelinite to phonolites.

Sadiman is immediately adjacent to Ngorongoro, 17 km E.  Sadiman tops out at 2,879 m, and it is constructed of interlayered phonolitic tuffs, breccias and nephelinite lava flows.  Ol Doinyo Lengai and other sites have similar rock types, connected with carbonatites.  It is some 400 – 500 m above the Malanja depression.  It is believed to be the source of the 3.66 Ma Laetoli Footprint Tuff, where Australopithecus afarensis footprints were discovered in 1979.  There is dispute about this conclusion.  It is also thought to be a source for the Wembere – Manonga sediments 170 km SW Laetoli.

This is the oldest extinct volcano of the Crater Highlands.  Initial dating of lavas suggest it was active 4.8 – 4.0 Ma, with eruptions continuing as recently as 3.3 Ma.  The 1.5 Ma duration of activity here is much longer than other volcanoes of the highlands.  Additional work is necessary to properly date the most recent period of eruptions 4.0 – 3.3 Ma. 

Lemagurut (Lemagrut)

3,130 m Lemagurut was constructed from tuffs and agglomerates topped with minor basalts and trachybasalts. It is located 22 km W from Ngorongoro.  Erosion washed material from this cone into neighboring Oldupai Side Gorge.  W slope of the Ngorongogo Highlands beneath Lemagrut volcano include the 2.41 Ma Ogol lavas, erupted from parasitic cones on the E Serengeti Plains.  Activity here dates 4.3 – 2.4 Ma. 

The Ogol lavas are a series of basalt flows SW of Lemagurut erupted from a series of small, isolated vents and cones.  They lie along a E – W line extending 25 km, and range from 0.5 – 1.5 m in diameter, 50 -150 m high.  Ogol is a Massai work meaning hard.  The Ogol lavas top the 3.5 – 2.4 Ma Ndolanya beds and date 2.31 – 2.27 Ma.  The Ogol lavas and vents may end up being a separate volcanic system or connected to Ngorongoro activity at the time. 

Oldeani

The 3,216 m Oldeani cone is topped with a small summit crater.  It is located some 20 km SW of Ngorongoro.  Basalt lava flows are found on the lower slopes, though they are difficult to find due to heavy forests.  Age and duration of activity here is not yet determined, though thought to be active at the same time as Ngorongoro and Lemagurut. 

Oldeani is built largely of basalt and thought to be the source of basalt cobbles found in the Laetoli basin used by hominids to make stone tools.  While undated, these cobbles are found in beds between 3.5 – 2.4 Ma. 

Engelosin

Engelosin is a volcanic cone about 8 km N of Oldupai Gorge, 35 km NNW from Ngorongoro.  It is 500 m in diameter and 145 m high.  The cone erupted mostly phonolites, and was active 2.68 Ma. 

Loolmalasin

Loolmalasin is a heavily eroded, 25 km diameter shield topping out at 3,648 m, 31 km NE from Ngorongoro.  The E and SE slopes are steep, thickly forested with deep ravines.  The volcano is not yet dated but thought to be of similar age as its neighbors.  It is constructed from basalts and trachytes.  There is no crater or caldera.  The rounded summit is cut by small faults.  The 3,260 m Olosirwa Mountain is considered to be part of the main shield.  There is an unnamed 2,624 m volcano immediately to the E.  Loolmalasin is constructed of basalt and nephelinites. 

Embagai (Empakaai)

Empakaai is the most N of the volcanoes of the Ngorongoro highlands, 41 km NE from Ngorongoro.  It is similar in size to Olmoti, 30 km wide, topping out at 3,225 m.  The highest point is on the N and offers views of the rift valley and Ol Doinyo Lengai.  Activity here took place 1.2 – 0.5 Ma. 

It is topped with a thickly forested 8 x 6 km caldera.  This one is deep at almost 1,000 m.  Post caldera activity built small parasitic cones.  There is also a deep lake in the crater.   Composition of the cone exposed in the caldera walls is trachybasalts topped by nephelinites – phonolites.  It is thought to be the source of upper beds at Oldupai. 

Tectonics

Tectonics in this part of Africa is driven by the propagation of the East African Rift System S from the Afar triple junction.  This particular arm is referred to as the Gregory Rift.  The Ngorongoro Highlands are located in the middle of a 200 km wide structure called the Northern Tanzania Divergence (NTD), a structurally complex section of the rift.  There are three arms identified.  The Eyasi Arm to the W and the Natron – Manyara in the center are defined by half grabens that peter out to the S.  The easternmost Pangani Arm is an active rift that extends into the Indian Ocean and may connect with the mid-ocean ridge.  The Ngorongoro Highlands are located where the Eyasi and Natron – Manyara arms diverge. 

The complex, rifted terrane of the NTD includes plateau-style volcanism in the pre-rift stage.  Few of these older features have been dated.  The deeply eroded Ol Doinyo Dili volcano may be part of the pre-rift stage.  The divergence is thought to have formed in response to S propagating rifting impacting the Central African craton.  Rifting changed direction upon impact, moving E away from the craton. 

Current plate velocity is 15 km/Ma, with 90 km displacement over the last 6 Ma.  Northward progression of volcanism is due to progressive faulting along the rift axis.  Ages of the faulting episodes are not well constrained.  Earliest extension appears on the W flank of the Natron basin 3 Ma, erupting basalts younger than the Ol Donyo Ogol fault scarp.  A second episode of extension 1.6 Ma is visible in the Oldupai area.  The Stage 2 magmatic pulse 2.3 Ma was due to mechanical deformation af the start of the main rifting event.  Later changes in slope 1.2 Ma and 0.4 Ma mark subsequent pulses of magmatic activity and possible rifting. 

Rift associated volcanism in N Tanzania began with Older Volcanism at the eight overlapping volcanoes of the Ngorongoro volcanic complex 4.9 – 1.8 Ma.  Multiple massive volcanic cones are found to the E between Ngorongoro and Kilimanjaro.  These include Tarosero, 2.4 – 1.9 Ma, Monduli, 2.15 – 2.09 Ma, and Ketumbeine, 1.87 – 1.54 Ma.  Essimingor is the oldest of these at 6.0 – 3.2 Ma.  There are several lesser-known large volcanic domes in the area.  Shira, 2.5 – 1.9 Ma is the oldest of these.  Hanang, 1.5 – 0.9 Ma is the youngest of these, overlapping Older and Newer volcanism.

The Younger volcanism in N Tanzania built six massive volcanoes.  Mosonik, 1.28 is the oldest of these.  Gelai, 0.99 – 0.96 Ma, Kerimasi, 0.6 – 0.4 Ma, and Ol Doninyo Lengai are located close to a scarp near Lake Natron.  The two highest peaks of Kilimanjaro and Mawenzi, 1.0 – 0.45 Ma are part of the Younger volcanism, as are Burko, 1.03 – 0.97 and Meru, 0.4 Ma – present.  Some of these are still active (Meru and Ol Doinyo Lengai).  

Conclusions

The Ngorongoro Volcanic Highlands are a spectacular example of rift-related volcanism in Africa.  As the rifting event propagates to the S, volcanic activity moves toward the N end of the highlands, extending it.  Volcanism in the neighboring line of volcanoes is working its way E, along the direction of the rift.  The highlands is unique as it is associated with the first site of hominid fossils and tools known, the Oldupai Gorge.  While activity migrated N, there is still sufficient warmth to power warm springs in the Ngorongoro caldera.

Additional information

Seven Natural Wonders – Ngorongoro Crater

Sedimentation patterns in a plio-Pleistocene volcaniclastic rift-platform basin, Olduvai Gorge, Tanzania, Ashley & Hay, 2002

Chronostratigraphic studies of the Ootun area revealing the late Holocene plume volcanism of the Oldoinyo Lengai, Ngorongoro, Tanzania, Makongoro, et al, Sept 2022

Hydrogeochemistry in the Ngorongoro crater, Tanzania, and the implications for land use in a World Heritage Site, DM Deocampo, Oct 2003

Geology of national parks of central / southern Kenya and northern Tanzania, RN Scoon, Springer Nature, 2018

Geochemical, mineralogical, and geomorphological characterization of ash materials as a tracer for the origin of shifting sands near Oldupai Gorge, Ngorongoro, Tanzania, Makongoro, et al, Oct 2022

Understanding modern and ancient hydrogeologic features:  springs in the Ngorongoro volcanic highland and global wetland facies, MK Norton, Oct 2019

Seismological investigations in the Olduvai Basin and Ngorongoro volcanic highlands (western flank of the North Tanzanian Divergence), Parisi, et al, 2020

Petrogenesis of basalt-trachyte lavas from Olmoti Crater, Tanzania, Mollel, et al, Aug 2009

Rift propagation at cration margin.:  distribution of faulting and volcanism in the North Tanzanian Divergence (East Africa) during Neogene times,  Le Gall, et al, Feb 2008

Radiometric dating of the Ootun palaelosol and its implication for the age of the Shifting Sand in Ngorongoro Lengai Geopark (Arusha, Tanzania), Makongoro, et al, 2022

The Gregory Rift Valley and Neogene-Recent volcanoes of Northern Tanzania, JB Dawson. Geological Society Memoir No. 33, 2008

Petrochemistry and geochronology of Ngorongoro volcanic highland complex (NVHC) and its relationship to Laetoli and Olduvai Gorge, Tanzania, GF Mollel, Oct 2007

The Ngorongoro Volcanic Highland and its relationships to volcanic deposits at OIduvai Gorge and East African Rift volcanism, Mollel & Swisher, Aug 2012

The Ngorongoro Crater as the biggest geotouristic attraction of the Gregory Rift (Northern Tanzania, Africa) – geological heritage, Zaba & Gaidzik, 2011

Geochemical evolution of Ngorongoro Caldera, Northern Tanzania:  Implications for crust-magma interaction, Mollel, et al, Jul 2008

Tectonic development of the northern Tanzania secrot of the East African rift system, Ebinger, et al, Aug 1997

Mineralogy, geochemistry and petrology of the phonolitic to nephelinitic Sadiman volcano, Crater Highlands, Tanzania, Zaitsev, et al, Nov 2012

Kerimasite, Ca3Zr2(Fe3+2Si)O12, a new garnet from carbonatites of Kerimasi volcano and surrounding explosion craters, northern Tanzania, Zaitsev, et al, Oct 2010 

Fractional crystallization history recorded by the lava flows of Ketumbeine volcano, North Tanzania, Pierce & Mana, Mar 2018

Magmatic activity across the East African North Tanzanian Divergence Zone, Mana, et al, May 2015