Ngorongoro Lengai Geopark
Volcano, Culture and Geoheritage
Referred to as Africa’s first and the only geopark, the aspiring Geopark derived its name from the iconic features which are ; the Ngorongoro crater (El-Nkoronkoro) meaning Gift of Life in Maa language and the Oldoinyo Lengai" Mountain of God" in the Maa language,
is an active volcano located in the Gregory Rift, south of Lake Natron within the Arusha Region of Tanzania. The Ngorongoro Lengai aspiring Geopark area has some important features, such as the Ngorongoro Crater, which harbors greater diversity of wildlife species that co-exist with human. Apart from the famous Ngorongoro main crater, there are Empakai and Olmoti craters, which are smaller and less famous compared to the former. The Laetoli is another important area where fossils of early human footprints were discovered and preserved. There are also footprints of wildlife species, such as giraffe, elephant, lion and small antelopes in the area. The Olduvai Gorge, the most important paleoanthropological site in the world also features in the aspiring Geopark. The historical and aesthetical feature ‘shifting sand’ is another important attraction in the aspiring boundary limit. The aspiring geopark boundary limit can be accessed from different angles using different means, such as air and roads. There are airstrips in the Ngorongoro Conservation Area, Maswa Game Reserve, Serengeti National Park, as well the Kilimanjaro International Airport and Arusha Airport. The Arusha-Serengeti-Mwanza/Mara main roads pass through the geopark territory. Almost 85% of the area has mobile communication coverage, such as TIGO, VODACOM, HALOTEL, TTCL and AIRTEL. Though the boundary limits of aspiring Geopark are beyond the boundaries of NCA, it will not disrupt the existing designations of the NCA, but rather complement to conservation and protection of natural and geological resources. The main focus for the Ngorongoro Lengai aspiring Geopark Management organ is to integrate community cultures and social activities into the Geotourism activities so that the community benefit socially and economically. This will be done by the following:-
This will be achieved through involvement of different national and international stakeholders in the academic and non-academic institution. So far Ngorongoro Lengai aspiring Geopark is working with Tanzania Wildlife Research Institute, The University of Dar es salaam, National Museum, Geological Association of Tanzania, Allaince Franceise (Tanzania) and Tanzania Tour Operators Association in implementation of its activities.
Location of the aspiring Geopark
The Ngorongoro Lengai Aspiring geopark is located between -1° 40' 43" and -3° 56' 0.3" South to 34° 19' 47" and 36° 36' 34" East. The aspiring area is confined to the North and North-West by Serengeti National Park, Lake Natron G.C.A, to the East, Greater Rift Valley Left arm to the South, and Maswa Game Reserve to the West. The Ngorongoro aspiring Geopark has varied altitude, ranging from the lowest areas, the main Crater (600 m.a.s.l) to the highest altitude, the Oldonyo Lengai (2,962 m.a.s.l).
Economic activity in the aspiring Geopark
According to the 2012 National Census, The main economic activities in the Ngorongoro- Lengai Aspiring Geopark is Pastoralism especially along Maasai and Datoga, Agriculture, Tourism and Trade. Pastoralism for the Maasai and Datoga is embedded in their culture and some very small percentages that do not have cattle engage in other activities like agriculture and trade. Productivity is generally limited due to lack of pasture compared to large number of cattle, goats and sheep owned in the Geopark area. The Ngorongoro Lengai Area is a popular tourist destination area in Tanzania for Tourist who visits the Ngorongoro crater, Lake Natron and Eyasi and also for tourist who pass by to go to other national parks such as Lake Manyara and Serengeti.
The Ngorongoro Lengai aspiring Geopark received fund from the European Union to build infrastructures in Oldupai and reinstate the Leakey Camp. The infrastructures consist of Museum (geological heritage and human origin), dinning, geotrail and community center which will enable community members to sell traditional products (Geopark products) but will also enable visitors to have the glimpse of the Maasai culture Promotional materials (brochure, leaflets and guide books) about the Ngorongoro-Lengai aspiring Geopark are available and general information (guiding services, hotels, restaurants, transportation) available at the gates (Loduare, Naabi, Endoro, Endamagha and Kakesio) in the Ngorongoro-Lengai aspiring Geopark Website and in all Districts Tourism offices. Also Ngorongoro-Lengai is working with members of Tanzania Tour Operators Association (TATO) to include the Geotourism in their packages.
Initially the Ngorongoro Conservation Area Authority and the District Councils through village committee are in-charge of protection and maintenance of the Geosite. However, the Geopark Management body has an authority to advice in the council and steering meetings.
The Ngorongoro Lengai area has been for a long time one of the key area for researchers and it has been studied by specialists from different disciplines from the humanities, social and natural sciences. Because of its complex geological and geomorphological settings, the territory has been of interest for many researchers, both Tanzanian and foreigners. Ngorongoro Lengai website will contain a wide range of scientific publications on various aspects of the territory.
The vision of the Ngorongoro Lengai aspiring Geopark is to be a regional and national model geotourism destination. The Ngorongoro Lengai aspiring Geopark combine a magnificent geological heritage with unique natural, social and cultural element to represent the motto: Volcano, culture and geoheritage. It is the aim of Ngorongoro Lengai aspiring Geopark to promote Geotourism as one of the key activity in the area like wildlife tourism. By so doing, the pressure put by tourist in areas such as the Ngorongoro crater will be reduced and also lengthen stay days in the area, therefore increase income of communities in this area.
Surface area, Physical and Human Geography Characteristics
According to the National Bureau of Statistics NBS (2012) there is a total of 230,586 inhabitants in the four Districts (18 wards) within the aspiring Geopark. The human population is distributed as follows; Karatu 54%, Ngorongoro 27%, Longido 10% and 9% in Monduli District.
The identification and establishment of geosites is the result of the territorial analysis carried out by the team from “Promotion of Earth and Human Heritage of Ngorongoro by valorization of the Oldupai and from reserve Geologique of Haute de France with the support, collaboration and participation of the local population. This analysis resulted in a geosites map and database Laetoli sites, local communities development and creation of the Ngorongoro Geopark” project funded by the European Union and Ngorongoro Conservation Area Authority. The analysis also involved members from the District councils, TAWIRI, National Museum and an Expert including characterization and evaluation. Historical, cultural and archeological sites were also documented in the analysis. New sites of interest are continuously incorporated in the database and existing sites are monitored to evaluate their contribution to education goals.
The Ngorongoro Crater is the largest unbroken caldera in the World, and one of the New Seven Natural Wonders in Africa. This feature lies in the boundary limit.
Geological map Ngorongoro Crater (Source: Google Earth map)
The crater has been formed by collapse of volcano, 25 million years ago when the Rift Valley geology was formed. Its formation resulted into an expansive caldera, surrounded by a ring of hills. The believed remains of the volcano peak ‘Round table’, Ngoitoktok spring, Mwandusi and Gorigor swamps beautify the Crater. Within the crater, there is a lake of molten rock ‘Lake Magadi’ a home to thousands flocks of lesser and greater flamingoes and other bird species. The Munge River which originates from Olmoti crater feeds the saline lake in the main Crater. The crater is inhabited and supports variety of wildlife species, such as elephants, black rhinos, buffaloes, lion, eland, wildebeest, gazelles, and other large carnivores, such as lion and hyena. The crater geosite has a diversity of habitat cover such as; short grasslands, long grasslands, shrublands, woodlands swamps and marshes and thick forests especially on the southern rim.
2: Olduvai Gorge
The famous steep-sided ravine, derived its Maa name from a wild sisal plant “Oldupai”. The Gorge is located at the western flank of the Ngorongoro Volcanic Highlands in the Ngorongoro Conservation Area (NCA), on the plains of the Serengeti ecosystem.
The Gorge is 100-m deep and 46-km long stream-cut valley. It is one of the most famous paleontological site in the world, renowned from tireless investigation by late L. S. B. Leakey and M. D. Leakey. The volcanic beds formed in Pliocene Epoch spanning the last 2 million years before present (bp) have yielded an unsurpassed record of past environments; fossil hominids attributed to Australopithecus (Paranthropus) boisei, Homo habilis, and Homo erectus, Early, Middle and Late Stone Age artifacts; and a wide range of fossilized faunal remains.
Since the area is known for its oldest evidence of mankind’s evolution “Cradle of human kind”, there have been ongoing research work by scientists from abroad and within the country. In addition to that, excavations have been renewed in order to apply new technologies that were not available for the past 50 years of research in the area. These researches have contributed to publication of journals, books, articles and dissertations. The Olduvai Geosite henceforth has both scientific and educational value in understanding our past and present.
Olduvai Gorge Geosite is open to the public and is one of the most visited tourist attractions in Ngorongoro. The significance of the site in understanding the origins of sophisticated hominid behavior, such as foraging strategies, is documented by abundant butchered bones and evidence of repeated transport of portions of at least 48 large mammal carcasses (mostly Bovidae) to this location on the paleolandscape. Despite of some hill terrain and few vegetation covers, most of the site is easily accessible by foot, which facilitates tourist education and enjoyment.
It is one of the most important paleontological and paleoanthropological sites in Africa. Laetoli is located 36-km south of Olduvai Gorge in a rolling, open plains setting of the Serengeti ecosystem. This site may be viewed as contiguous with Olduvai Gorge. Laetoli is famous for two remarkable sets of discoveries by the late M. D. Leakey. First are the fossil remains including fragments of postcranial bones, jaws, and teeth of an ape-like human ancestor known as Australopithecus afarensis. Second, the site is unique for the discovery of remarkable well preserved several trails of footprints of Australopithecus afarensis about 3.8 million before present
Illustration of hominid footprints
The footprints were imprinted on a fine-grained volcanic ash, as a result of volcanic eruption from Lemagrut and Sadiman mountains and they are the world’s only undisputed evidence for the origin of habitual bipedal locomotion in the human lineage In addition, Early and Middle Stone Age artifacts and a wide range of faunal remains have been recovered. Moreover the Upper Ndolanya Beds (2.66 Ma) have produced the only specimen of Paranthropus aethiopicus definitively known from outside of the Turkana Basin in northen Kenya and southern Ethiopia. The Laetoli hominid footprints trails have remained buried since its discovery until recently when the 4th President of United Republic of Tanzania, Hon. Jakaya Mrisho Kikwete directed scientists in the country in collaboration with scientists from abroad to open the closure for the public. Closure by then was necessary because of the fragmentary nature of the hominid footprints. The partial closure was re-opened however it was re-buried again with the aim of reopening following the construction of on-site museum. It is expected the museum would serve as an exhibition and research center for study, enjoyment, and appreciation by people from all over the world. Some distance away from the preserved human footprints there are also conspicuous animal footprints of elephant, giraffe, lion, small gazelles, birds and insects on the volcanic ashes. The same action of volcanic eruption of the Sadiman mountain releasing diagenesis calcite, Fe-nontronite, and philipsite causing very rapid cementation is suggested as the cause of the preservation of these delicate prints.
There is a temporary museum (outside the volcanic tuff areas of hominid/ animal and bird footprints) with documentations of the human footprint trail, posters on the history of the discoveries of the sites and research, which have significant role in educational, awareness and archaeo-tourism.
It is the uplifted metamorphic gneiss inselberg, a monolith that is fully exposed above the plain in the shadow of crater mountain - Oldonyo Lengai. It is 27 km north of Olduvai and, about 350 m in elevation. The site has been internationally known for decades through its archaeological resources that have been excavated since 1930s. Most of the findings at Nasera consist of stone artifacts high in quartz, but low frequencies of chert and obsidian occur throughout the sequence. Also bone fragments and sherds of pottery had been uncovered. The cultural materials of Nasera have absolutely dated to about 30,000 before present. The shelter has some traces of paintings nevertheless the paintings are not visible because of their poor state of preservation. They have faded that only rock art expert can observe traces of pigments.
The gorge is situated under the huge mountains, slicing canyon and spectacular rock that beautifies the area. It is extremely deep and narrow gorge cutting through high fault Mountains.
The gorge could have been formed by tectonic faults that opened the mountains forming a river through the core of the Mountains. The river course is nearly flat with very gentle slopes. The peak of these raised mountains could approach a kilometer. The gorge extends up to 8 km long. The walls of these mountains are vertical 90-100º. It’s unique gorge of its kind in the entire Rift Valley Escarpment. On top of the mountains, there are primary nesting sites of the ruppell’s griffon vultures.
The Empakai Crater is about 6 km wide and a lake covers nearly half of its floor. The lake is about 85 m deep which make it unusually and unique deep compared to many soda lakes in East Africa. The waters being alkaline the lake attracts flamingos as in the case of Manyara and Natron lakes. The walls of the crater are steep, clothed in the forest and rise in some places to almost 300 m above the floor The views along the trail downwards are spectacular at every point. All along one can enjoy the changing views of Empakai itself. In addition to that, from the northern and eastern side you can have dramatic cone view of the still active volcano the Oldonyo Lengai Mountain. If the sky is clearer, you can look beyond Lengai to the Great Rift Valley and Lake Natron as well as snows of Kilimanjaro Mountain far on the eastern side of the Valley. On the trail to the crater floor you might see buffaloes or bushbucks, blue monkeys, many birds (like sunbirds and turacos). At the shore of the lake are often waterbucks and elands.
Olmoti “The cooking pot” in Maasai Language is the crater that is relatively shallow pristine grass dominated caldera. The crater is at an attitude of about 3100 m above sea level. Wildlife species such as bushbuck and eland beautifies the crater. This caldera forms the spectacular waterfall, which feeds the Munge River, which flows to Ngorongoro crater. The depression that is formed where the slopes of Olmot, Empakai, Lolmalasin and Losirua volcanoes join with the outer rim of Ngorongoro can be observed.
8. The Breathing Holes
On slopes of Olmot Mountain there are four holes of 8-10 inches at the opening but narrowing towards inside. These holes are blowing very cold air. The blown air is odorless and light to breath. Some locals residing the areas for many years have known these holes. In one of these holes a blowing sound like wind or flowing water inside can be heard. The original source of this cool air is not known, however, it is speculated that it is blown from Olkarien Gorge. Within the Olkarien Gorge there are narrow walls, which have cold air similarly to what comes from the holes of Olmot Mountain. There could be small channels that face their direction towards Olmot Mountain thus blowing wind, which under pressure and cooling processes underground the outlet air become cold. In meantime, these two natural cold air-fanning holes are used for aesthetic and ritual purposes.
The Eyasi Basin is found in Mbulu and Karatu districts, Northern Tanzania. This Hadza territory is located about 200 km southwest of Arusha town and 50 km southwest of Karatu town. Also, it is located about 50 km south of Olduvai Gorge, 25 km southeast of Laetoli and southern border of Ngorongoro Conservation Area (NCA). The Eyasi Basin lies at the bottom of a branch of the East African Rift Valley System.
This Geosite includes several geo-tourism sites, which altogether forms the Eyasi Basin geosite. This includes the Lake Eyasi itself where there is a good viewpoint of the spectacular landscape of the Lake. The Hadza hunter-foragers of Eyasi Basin are one of Tanzania’s unique communities that have attracted tourists, researchers and many people to learn, observe and study their culture. (The Hadza hunter-foragers demonstrate arrow throwing to visitors. Tourists buy their material culture, such as bead necklaces, earrings, pendants, tobacco pipes, arrows and.
There are Datoga who are typically pastoralist depending entirely on livestock for their livelihoods. Their traditional ways of living have brought a lot of tourists and researchers in Eyasi Basin improving the economy of local community residing the area. Moreover the hot spring natural waters found on the Eyasi Lake are interesting to find and observe. Furthermore, around Ghorofani area, in Mang’ola there is natural spring water (chemchem in Kiswahili) that is the main source of water in Mang’ola village. The Mumba rock shelter where evidences of our cultural history and evolution origin have been uncovered is also the potential site included within the Eyasi Basin Geosite.
10. Lake Eyasi
Lake Eyasi itself is oriented SW-NE and is 80 km long, with a mean width of 14.5 km. It has an area of 1,160 km2 and is located at an altitude of 1030 m above sea level. Lake Eyasi is highly saline and shallow; its seasonal water level fluctuations in the lake are dramatic. During the dry season, the lake may dry almost entirely leaving a thin crust of salt. At the Lake one can explore the trails around the lake, canoe along the shore particularly depending on the time of the year and the amount of rain the local area has had. The wet season starts from November to early May. There are two peaks of rainfall during the wet season; the short rains of December to January and the long rains occurring from March to May. Normally the typical dry season in the area lasts from May to October. At this time the lake is so dry that you could drive completely across it.
The impressive nature of the lake tourists could just sit and enjoy the beautiful lake views especially at sunset on top of the rock.
The Datoga are highland Nilotic pastoralists. They moved into the southern areas of the Eyasi Basin in the last few centuries as they were displaced, first, by the plain Nilotic Maasai pastoralists from the Ngorongoro highlands, and later by the agriculturalist Iraqwi. The Datoga livelihood in the Eyasi Basin depends on livestock. They herd the East African short horn zebu (Bos indicus), some goats, sheep, and donkeys.
Nowadays, Datoga pastoralists interact more with the Hadza than any other ethnic group in the region. They exchange food, meat and other commodities with the Hadza hunter-foragers. Like to the Hadza hunter-foragers, tourists and researchers also visit the Datoga pastoralists to observe their ways of life. People visit Datoga pastoral to see their sacred areas, bomas, and traditional dances and buy traditional souvenirs. Tourists also enjoy watching Datoga blacksmith manufacturing various metal objects. These dances are organized whenever there is a ceremony or traditional activities, and to visitors.
Although cultural tourism in Eyasi Basin is improving the livelihood of the people but is growing at an alarming rate. Tourists come to the Eyasi Basin primarily to observe foragers and pastorals ways of living (culture). The Hadza hunter-foragers for instance in Mang’ola nowadays camp at particular strategic areas to attract tourists and stay at the camp longer than usual. Traditionally, hunter-foragers used to be mobile, staying at a camp for a couple of weeks. Thus, the hunter-forager mobile land-use system is changing towards a semi-permanent land- use pattern due to tourism. Thus proper management and control of visitors should be taken into account.
At Lake Eyasi there are three hot natural springs. One is which is quite hot is found in Jangwani area on a flat surface near the big lovely rock on the lake flat. The hot spring effuses its water in almost one to two square meters area. The other spring is located on the foot edge of a big outcrop of uplifted metamorphic rock. The latter has moderate temperature. These hot springs are produced by the emergency of geothermally ground water from the earth crust.
Drought is persistent in the Eyasi Basin due to uncertainty of rainfall and the nature of the climate of the region being semiarid. Unreliable rains and high temperatures had exacerbated the existence of drought conditions throughout the years in the basin. Most of known springs scattered along Lake Eyasi shore, Barazani and Qangdend/ Ghorofani village have dried up due to drought.
Nonetheless there is one fresh water spring (Chemchem) around Qangdend/ Ghorofani village which has the flow of water and the only remaining depending water source in Mang’ola area. People utilize the waters for domestic use, agriculture and pastoralism. This spring gets water from the evergreen forests on Oldeani and the Ngorongoro crater rim. The fresh water spring source at Qangdend/Ghorofani village is in critical condition and if no immediate actions taken, the risk of perishing is growing. Environmental degradation caused by excessive clearing of trees, bushes, grazing and trampling of water sources by large herds of cattle, goat, donkey and sheep is higher. Underneath the tree covers is completely dry. In addition to that large amount of large trees have all dried. Animals are drinking water up to the outlet of the spring and there is no restriction and control that preserve the five hectares catchment area.
The increasing demands of water for large-scale irrigation using water pumps, particularly for onions as a cash crop, maize and rice in Barazani, Jangwani and Ghorofani where the catchment originates, have reduced water from the Ngorongoro highlands aquifers. Competing demands of water resources between sectors, especially wildlife, livestock, people and irrigation farming have contributed to water shortages in Eyasi Basin. Therefore there is a need to establish management plans to protect and conserve this fresh water spring that not long will disappear if no further intervention from stakeholders and government. And because people are not settled around the catchment area, this might make easier to control the rest of challenges. This may be done through awareness seminars, public meetings and by-law enforcement.
The natural fresh water spring is unique because all the Eyasi Basin area is salty nonetheless the waters produced from the spring at Qangdend/ Ghorofani village is 100% fresh. Another value of this fresh water spring is that it is the only remaining source of water in Mang’ola for human habitation. Both foragers, famers, herders need water alike. Hence the need to protect and conserve it is mandate
The Lake Eyasi basin is situated near the southwestern terminus of the Crater Highlands volcanic area, but volcanic debris is found only in the northernmost portion of the lake and does not reach the rock shelter. The basin is of Pleistocene age and is now filled mostly with sediment. When dry, the lakebed is subject to severe aeolian deflation by strong northerly winds, but the lake level has been high enough at times to submerge Mumba rock shelter. The assemblages of Middle Stone Age (MSA) and Later Stone Age (LSA) artifacts collected from this site constitute the type sequences for these cultural phases in East Africa. The best-known and most notable feature is the presence of geometric microlithic stone artifacts and ostrich eggshell (OES) beads found throughout a large portion of the sequence. Microlithic technologies and the manufacture of personal ornaments play a central role in deliberations about the origins of modern human behaviour, the dispersals of modern humans within and out of Africa, and their responses to factors such as climate change. The abundant occurrence of microlithics and personal ornaments in the archaeological record is often used to differentiate between the LSA and MSA in Africa. Also, Iron Age and biological evidence for the emergence of our own subspecies, Homo sapiens sapiens have been uncovered in Mumba. Three hominid molars of anatomically modern Homo sapiens were recovered from the Mumba Bed VI-B dated to ca. 130,000 bp.
Mumba rock shelter also has rock art.
Shelter dimension were not taken in the field due to the floor surface to stand upon due to severe excavations and removal of surface sediments near the wall. Nonetheless, the shelter is estimated to be more than 20 m long, 15 m wide and 20 m high. The slope of painted surface is steep to about 40-90°. The painted surface is horizontally and vertically not so quite flat and smooth. The size of painted area can reach to about 18-25 m2. A quick field interpretation has shown that these paintings belong into two-rock art traditions. These are Hunter-Foragers, Red-Geometric (H-F, RG) Art tradition and Bantu Language Speaker Art tradition. Although most of the paintings have fed, but H-F, RG are characterized by animals, “stick” human figures painted in monochrome dusky red. Bantu Language Speaker Art are characterized by animals (possibly domesticated animals), human figures etc. These are crudely painted in monochrome dirty-white colour. Painting analysis of this shelter has not been conducted.
Mumba rock shelter and the rock painting sites are not officially open to tourists as no Antiquities guides are posted at the sites. Nevertheless, tour and safari operators from Arusha and some individuals in the Eyasi Basin have been taking tourists to these important sites.
Engaruka is located at the foot of the Manyara–Natron rift scarp at about 1000 m a.s.l, and about 43 km north of Mto wa Mbu and almost the same distance south of Lake Natron, Northern Tanzania. There are several geo-tourism tour packages sites such as Engaruka Juu, Chini, Oldonyo Lengai, and several craters. These geo-tourism sites are potential for aesthetic, scientific and education value
Engaruka Juu has a complex of late Iron Age farming settlement covering an area of about 25 Km. The farming communities at Engaruka depended on an irrigation system. Remains of terraced irrigated fields, stone/lined irrigation furrows, houses, stone circles and probably graves are found at the site, which are unique in size and preservation. The first archaeological investigation of the area started in 1900s. Recent surveys of the habitation platforms indicate that what was thought to be seven villages might in fact have been one continuous settlement, broken only by obstacles such as rivers and gullies.
Reconstructions based on settlements indicate that the past population was much greater than the 7,000-12,000 people.
The ancient land-use system at Engaruka Juu consists of an extensive pattern of terraces, stone-lined fields, cairns, stone circles and irrigation canals. Given the size and elaborated nature of the arable fields it is evident that agriculture was the dominant activity. Regarding crops cultivated, only sorghum has been confirmed, and it is likely that this was the dominant crop, supplemented with a wide variety of other food crops. Some stone circles have been interpreted as cattle pens, and it is highly probable that livestock, being of immense cultural and economic value, was an important, supplementary asset.
Researchers have indicated that the formerly irrigated and now abandoned fields are located on and below alluvial fans deposited where five rivers from Mt Lolmalasin flow over the escarpment. Today, only Engaruka River is permanent, while the other rivers carry water only during heavy rains. However, the extent and configuration of terraces and canals indicate that all rivers once were used for irrigation and it is thus evidencing that the water flow in the now dry rivers was greater some- time in the past. Features built during wetter periods may, of course, have been used also during drier periods, but it is unlikely that much effort would have been invested if the water supply were not more reliable than at present.
According to the most recent archaeological findings the settlements of ancient Engaruka were occupied until the early 1800s. The ancient system then fell into decline, and Engaruka was perhaps even abandoned completely for some time. Although there have been a lot of explanation on the downfall of ancient Engaruka but the more plausible cause might be the extreme drought due to climate change, catastrophic events and change in the livelihood strategies for coping with environmental change, subjected the fall of ancient Engaruka.
Castle wall-like protrusions within the desert; brown-colored irregular-shaped towers protrude on the flat extensive desert like a forest or castle walls. The area is about 500 m in EW by 300 m in NS. The high of the towers is less than 3 meters and the diameter is variable, up to about 10m. The rock surface is porous calcium carbonate colored in brown to light brown due to the impurity, irregular-shaped with rounded corners, chains of droplets, and nearly-vertical flow structure due to precipitation of carbonate possibly from hot spring.
Over tens of young tuff cones and scoria cones are scattered in the area extended southeast and east of the Oldoinyo Lengai Volcano. They represent sporadic intrusion of magma (monogenetic volcanoes), often observed in the extensional tectonic stress field. It seems that they are distributed roughly along N-S, the direction of the rift extension. Ages of those cone formation are considered to be as young as Pleistocene, since one of cones is open on the deposit from the Oldoinyo Lengai volcano (probably after ~150 thousand years ago) on its western flank. Tuff cones have open craters as large as about 1 km across with deep vegetated flat bottoms and low-angle outer slopes of volcanic ash formations. It is considered that heterogeneous distribution of groundwater produced this variety of pyroclastic cones with different sizes of open craters.
In one site (about 12 km SW of Lengai volcano), stratification of volcanic ash formations is well exposed on steep and tall inner walls. Large and thick, shiny black minerals of biotite were sporadically exposed or scattered on the ash formations. They show a very beautiful cube of centimeter-size “book”. They are one of representative minerals that were crystallized in a magma highly enriched in alkalis, characterizing volcanic activity in this rift valley.
According to the Maasai tribe they believe that these tuff cones are the footprints that were left by their god “Ngai” as he was walking to the Oldonyo Lengai.
“Mountain of God” or “Holy Mountain” in Maasai language is the youngest and still active volcano located in the Eastern Africa major Rift Valley, 16 km south of Lake Natron, Arusha region. Oldonyo Lengai is a massive Mountain 2960 m high but is not a rock. The whole area is hard packed dirt with small lose rocks stuck in. It is the first of the volcanic system of the EARV, uniquely and strangest produces natrocarbonatite lava that contains almost no silcon. Magma erupted in the Ngorongoro Volcanic Highland shows large variety from less-alkalic to highly alkalic basalt to andesite or trachyte. The Lengai volcanic rocks are highly alkalic (nephelinitic to pohonolite). Lengai Volcano is well known as only volcano in the world, issuing carbonate lava flows and volcanic ash.
The volcano is considered to start the activity ~150 thousand years ago and the large-scale collapse of the volcanic body (major sector collapse) occurred ~10,000 years ago. The present scarp surrounding the summit cone is the remnant of the collapse. The collapsed materials (debris avalanche) flowed down about 25 km north of the volcano, reaching the southern coast of the Natron Lake. Small isolated hills on the northern floor of the Lengai valley (hummocky surface) are fragments of the collapsed volcanic body that remained within the avalanche deposits.
NB: The summit area of Oldoinyo Lengai Volcano seen from NE (Google Earth Image). A scar surrounding the summit cone is the scar of a large-scale collapse of this volcano during its growth. Present summit cone formed after this large collapse. White is the color of carbonaite volcanic rocks.
Evolution of Oldonyo Lengai Mountain
There were series of faulting activities on the western slopes of Gelai Mountains during lower Pleistocene time (2.58-0.78 ma) accompanied by highly gaseous volcanic activities which gave the rise to explosive craters, tuff rings and tuff cones. The NNW-SSE faulting on the lower northeastern slopes of Kerimasi was accompanied by the formation of Mica-augite tuff rings of explosion craters, such as swallow of Loluni craters and some other craters exposed in the Sinya Landare. The craters in the Sinya Landare were then eroded, the early drainage cutting through them in a W-E direction. It was on this eroded, pitted land surface that the first yellow aggromerates of Oldonyo Lengai ejected blanketing and burying the cones and craters and piling up against the Rift escarpment to its west. The faults were probably formed 1.2 ma (Dawson, 2008) and volcanic activities in the area occurred both before and after this faulting. Among the older volcanoes in the area include Ngorongoro, Ketumbeine, Gelai, Shombole, Mosonik and Kerimasi. Oldoinyo Lengai is less than 370, 000 years old and is the strangest and youngest big volcano in this part of the Rift Valley. It was formed by complex sequence of events including explosive eruptions of tuffs and aggromerates and effusive eruption of lava. It has a steep conical volcano built up by many layers of hardened lava, tephra, pumice and volcanic ashes.
Local products of Ngorongoro Lengai aspiring Geopark vary from farm produce, handcrafts to local foods and clothing. These vary also from one ethnic group to another. The most famous product in the area includes Maasai beads commonly known as Maasai shanga. These are colorful beads made into bracelets, earrings, necklaces and rings. The Datoga clothes is another famous product in the territory, these clothing are normally made of animal skin decorated by beads. Bow and arrows made by Datoga black smith is another iconic local product sold within and outside the territory. Other geopark products are local honey, coffee and leather products.
THE GEOLOGICAL TRAILS
Visitors get the opportunity to walk along the nature trails and gather medicinal plants and insects, an ancestral diet in this region that are still consumed by contemporary population.
A JOURNEY TO THE CRADDLE OF HUMANKIND
There are two main proposals for the trail:
1) the SHORTDUVAI TRAIL, visiting the “must-see” sites for people with
limited time for the visit. The short trail includes the STOP 1, 2 and 3 (and
back to the museum following the same path), and it takes some 1.5-2
hours (2 km).
STOP 1: WHY OLDUVAI GORGE IS UNIQUE?
STOP 2: WHOSE WERE OUR ANCESTORS?
STOP 3: WHY HOMININS LIVED HERE?
2) the FULLDUVAI TRAIL, a 5 km walk for those interested in spending
morning or an afternoon in the Gorge.
STOP 1: WHY OLDUVAI GORGE IS UNIQUE?
STOP 2: WHO WERE OUR ANCESTORS?
STOP 3: WHY DID HOMININS LIVE HERE?
STOP 4: WHO PIONEERED THE DISCOVERIES?
STOP 5: A RESEARCHERS´ HEADQUARTER
STOP 6: THE 21st CENTURY “ZINJ-SITE”
STOP 7: LIVING TOGETHER