The Ngorongoro Lengai UNESCO Global Geopark, received official global geopark status from UNESCO in 2018. This is the second Geopark in Africa after M’Goun Geopark of Morocco, and the first geopark in the eastern Africa and Africa Southern Sahara. The Geopark covers an area of nearly 12,000Km2 (4,634 sq miles) and has a resident population of around 250,000 people, most of whom belong to the Maasai Tribe.
The Geopark name “Ngorongoro-Lengai” reflect the two distinct, unique and famous geological features, Ngorongoro “gift of life” Caldera and the active
carbonatite volcanic lava Mt. Ol Doinyo Lengai.
The Ngorongoro-Lengai Geopark links its geological heritage with its stunning natural heritage, intangible heritage and its local population representing a huge human diversity with ethnic groups such as Masai, Iraqw, Datoga, and Hadzabe.
At Ngorongoro Lengai Geopark, local and regional partnerships have been formed to promote and conserve not only the geological wonders of the geopark, but also the rich cultural, biological and historical identities of the area.
It’s all started long, long ago – a very long time ago, over 500 million years ago (Ma) on the sea floor, in the roots of large mountain ranges which occupied this area, with deposition and accumulation of muds and sands by ancient rivers, and later the formation of ancient crystalline basement rocks, mainly granites, crushed rocks, metamorphic gneisses and schists that once rivalled the Himalayas. After these rocks had become brittle, the earth’s crust was subjected to violent movements. The effect of this movement was to uplift the rocks to form land, and the sea retreated from the region. The newly formed land was immediately attacked by atmospheric agents of the earth and the subsequent erosion was constantly removing the rocks at the earth’s surface and exposing those that lay beneath. In this way the ancient crystalline rocks which had formed deep within the crust, eventually became exposed at the surface to make the features of the present-day topography in the Gol Mountains in the north and in the Lake Eyasi region.
Associated with the rifting was a period of voluminous volcanism that began around 4Ma and created the Ngorongoro Volcanic Highlands. The highlands are a complex of coalescing basaltic shield volcanoes, some of which may at one time have rivalled Mt. Kilimanjaro in both scale and elevation. Many of these shield volcanoes have calderas at their summits, formed by the collapse of large central magma chambers.
The period of voluminous volcanism had radically changed the topography of the eastern part of the geopark and completely buried the corner of the fault to south and the eastern extension of the Ol Doinyo Gol Hills.
The building of Ngorongoro Volcanic Highlands followed by the Second Phase of Rift Faulting “Gregory Rift Valley” (about 2 to 3Ma) trending north-south along the east side of the highlands. Like the first phase, once again the land on the east side subsides.
At this time in the highlands, the momentous events took place, the inward collapse at Ngorongoro, Olmoti and Empakaai to form the world-famous Ngorongoro caldera “Crater”, as well as two lesser known but equally impressive craters Olmoti and Empakaai. The formation of the Gregory Rift Valley also allowed the formation of Lakes Manyara and Natron with basins of Engaruka and Olmkoko.
After the formation of the Gregory Rift Valley and the large calderas, around 1Ma much of the volcanic activity in the Geopark area had declined. However, there is still one active volcano within the region called Ol Doinyo Lengai. It is located just north of the Geopark near Lake Natron and last erupted in 2013. Ol Doinyo Lengai is the only active volcano in the world to produce carbonatite lava which is rich in calcium, sodium and carbon-dioxide, rather than the silica-rich lavas produced by almost all other volcanoes. Some of the ashes from Ol Doinyo Lengai wandered on the Sale and Serengeti Plains form longitudinal sand dunes.
On the Serengeti Plain, the dunes carried by prevailing winds to form a series of moving crescent shaped dunes, which named “The Shifting Sand”.
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