The Olduvai Gorge lies in a semi arid area on the edge of the Great East African rift valley bounded to the east by Ngorongoro highlands and Serengeti plains to the west along the northern circuit safari in Tanzania. The area constitutes of a steep sided valley covering 48 km long and 90 meters deep. The gorge was formed due to tectonic forces associated with formation of Ngorongoro volcanic highlands during the late Pleistocene about 2.3 million years ago. The tectonic rift caused the earth’s crust to tilt eastwards which altered the course of Olduvai River to flow through the basin. As such, the gorge was formed due to a process of erosion that occured over many years and exposed the fossils. Lake Olduvai occupied the center of the basin about 2-1.5 million years ago and later dried up due to Milankovitch cycles that are associated with the collective effects of changes in the Earth’s movements and climate over a period of 20,000 years. The basin was very wide stretching for 3,500 sq. km and 100 meters deep when it was formed with underlying crystalline metamorphic basement rocks. However, the basin’s size reduced over time due erosion and sedimentation of volcanic tuffs, lava and pyroclastic deposits into the basin. The soil in the basin constitutes of quartzo-feldspathic volcanic and clay, black and red soils including Aridisols, Andisols, and Vertisols.
The first person to visit the Olduvai Gorge was a Germany archeologist Wilhelm Kattiwinkel who inspired among other archeologists including Hans Reck who collaborated with Dr. Louis and Mary Leakey family and made the most extensive excavation work for over 30 years. The excavations were categorized into 7 beds from the oldest and lowest in sequence. Mary Leakey and his team unearthed parts of a skull of a new species of hominin called Zinjanthropus boisei that was dated 1.8 million years old. The fossil was nicknamed ‘Nutcracker Man’ due to larger jaws and teeth, making scientists believe that they ate nuts and seeds. The fossil was later reclassified as Paranthropus boisei. Leakey’s son, Jonathan, discovered a jaw bone of Homo habilis and nicknamed it the handy man given that the hominin species were thought to be makers of stone tools and lived between 2.4 million to 1.4 million years ago. Some of the stone records found include stone and bone tools such as burin; artworks of bas relief and cave paintings.
The discoveries made at Olduvai Gorge along with those in South Africa by Raymond Dart in 1924 and by Robert Broom in 1936 established evidence that Africa is the Cradle of Mankind. There are similarities and differences pertaining both discoveries. For instance, Zinjanthropus boisei was the put into the same genus as the southern African species. However, the Leakey family classified theirs as new category of hominin. As such, Olduvai Gorge is one of the world’s most important paleoanthropological sites and was inscribed on the UNESCO world heritage list in 1970s. Olduvai Gorge museum was built to preserve the precious archeological records along with a viewing platform, Olduvai Gorge monument and a restaurant that offers food and refreshments for visitors. A guided tour of Olduvai gorge is available for booking through for booking through a tour operator. Visitors can tour the museum exhibits and also hike through the excavation beds. Oldvai gorge can be visited during your northern Tanzania safari including wildebeest migration and Big Five. The site can be reached when traveling between Ngorongoro crater and Serengeti national park.
Laetoli footprint trail
In addition to Olduvai Gorge, there’s another archeological site located 25 km south of the gorge. Laetoli footprint trail is 88 feet long and consists of a total of 70 prints of extinct mammal and hominid species which walked on a fresh layer of volcanic ash leaving footprints behind. The hominin prints belonged to Australopithecus afarensis, a group of small-bodied and small-brained early hominin species (human relatives) that were capable of upright walking but not well adapted for travelling long distances on the ground. They lived about 3.9–2.9 million years ago during the Pliocene Epoch, making for the earliest known human footprints in the world. These prints are relatively older than those found at the gorge. Among the faunal prints at Laetoli include a three-toed horse, elephants, rhinos, giraffes, guineal fowl, and smaller unrecognized species of carnivores. Mary Leakey found them in 1976, but they were identified by fellow archeologist Paul Abell in 1978. A partial skeleton named ‘Lucy’ of Australopithecus afarensis was first discovered in Afar region of Ethiopia in 1973. The scientists who found it repeatedly played the song “Lucy in the Sky with Diamonds” in celebration and nicknamed it Lucy. The genus name, “Australopithecus”, comes from the Latin word ‘australis’ which refers to southern and the Greek word ‘pithekos’ which means ape.