Ngorongoro Crater

Ngorongoro Crater is among of the nine complex coalescing basaltic shield volcanoes forming Ngorongoro Volcanic Highlands (NVH), which lies at the center of Northern Tanzania Divergence Rift Zone of the Gregory Rift Valley. The volcanoes formed during the period of voluminous volcanism, 4 Ma, associated with the first phase of faulting of the “Eyasi Rift” at 20 Ma. The collapse and formation of calderas at some of the NVH vents were caused by the second phase faulting “Natron-Manyara Rift”, 2 Ma, to the east of NVH. A part of Ngorongoro crater, Olmoti “the cooking pot” and Empakaai are the two craters to the north of Ngorongoro crater; remaining volcanoes form dome shaped features with small craters on top.
The Ngorongoro Crater is the largest deeply eroded volcanic feature of the NVH. It is 22 kilometers in diameter, stands at an elevation of 3,000 meters, and has walls that on average are 610 meters high. Prior to collapse, the volcano may have attained an elevation that exceeded 5,000 meters, thus rivaling Kilimanjaro. The crater is composed largely of lava, ranging from basalt to rhyolite, and it includes ignimbrites and agglomerates. On the crater floor are several small cones, hillrocks, knolls, and a alkaline lake which occupies the lowest area. The crater have an internally-drained basin fed by two external streams. Several freshwater springs support wetlands.