the cradle of humankind
Olduvai Gorge, located in north central Tanzania, is often referred to as the cradle of humankind. The walls of the gorge expose sedimentary rocks that span a time period from 2 Ma to the present, a critical time period in the story of human evolution. It is at Olduvai that Louis and Mary Leaky conducted their pioneering anthropological studies into the origin of humans. It is at Olduvai that the Leakeys identified the first species of our own genus Homo (Homo habilis). It is Olduvai where fossilized cranial and postcranial skeletons have provided important evidence for the evolution of Homo habilis to Homo erectus to Archaic Homo sapien and, finally, to modern humans (Homo sapien).
Olduvai is the only site in the world where multiple hominin species (e.g. Zinjanthropus boisei, Austrolopithecus cf. africanus and Homo habilis) have been shown to live together in the same habitats during the Early Pleistocene.
It is at Olduvai where evidence of early stone tool technology and technology evolution was first discovered. This evolution started with simple core-and-flake stone technology, famously known as the Oldowan industry. This was followed by hand axes, picks, and cleavers (the Aechulean Industry) and ultimately gave way to later stone tool industries characterized by stone arrowheads, blades and micro-blades. Olduvai also preserves an unparalleled record of Early Pleistocene to Recent vertebrate fauna.
In short, Olduvai remains the best-dated hominin-bearing geological sequence over the past 2 Ma, and provides a yardstick for rates of evolution of human form and technology. It truly is the cradle of humankind.
Series of maps showing the region in which the Alumni College will take place. (a) Large scale geologic map of East Africa showing the location of the Tanzanian Craton (~2.4 billion years), the surrounding Mozambique Mobile Belt (~ 0.6 billion years) and the very complex East Africa Rift zone.
(b) More detailed map showing the main features of the Kilimanjaro-Olduvai-Serengeti region. The route followed during the Alumni College is shown as a dashed magenta line. The black stars indicate the various lodges where evenings will be spent.
(c) Very detailed map of the region surrounding Olduvai Gorge. To the east of the gorge lie the Ngorongoro Volcanic Highlands. To the west lies the world famous Serengeti Plain.
Click on the map to see a larger version.
Olduvai Gorge is a fairly young geologic feature (˜0.6 my before the present) that is located along the western flanks of the eastern branch of the East African Rift (EAR). It is sandwiched between the imposing Ngorongoro Volcanic Highlands to the east and the world famous Serengeti Plain to the west.
Exposed in the sides of the gorge are volcanic sedimentary rocks that date back as far as 2 million years ago. For the most part, these rocks were formed in and around a long-lived saline lake which collected large amounts of volcanic ash and pumice derived from volcanoes of the nearby Ngorongoro Volcanic Highlands. These sedimentary rocks yield a rich fossil and stone artifact record that indicates a sequence of evolving environments, flora, fauna and prehistoric cultures. These deposits sit on 0.6 billion years old Precambrian basement rocks (Mozambique mobile belt), which wrap around the old, and mechanically strong, Archean Tanzania Craton (2.4 billion years old).
Today, the Olduvai region encompasses a spectacular ecological mosaic of ancient volcanoes and volcanic craters, lush highland forests, woodlands, grasslands, faults, rivers and lakes. The region is so unique in its modern and ancient natural and cultural landscapes that the entire region has been designated as a World Heritage Site and World Biosphere Reserve.
While in the Serengeti, you will travel through some of the oldest rocks in the world (the ˜2.4-2.7 billion-year-old schists and granites of the Tanzanian Craton) and spend two nights deep within one of the many greenstone belts that form the core of the craton.
Through Ngorongoro’s conservation policy of multiple land-use, Olduvai is home to the pastoral Maasai tribe and many wildlife species. This region presents the spectacular Serengeti grass plains, which are the annual host to the world’s highest concentration of migratory wildebeest, zebra and gazelle numbering over two million strong. These vast grass plains are maintained by the alkali-rich volcanic ash erupted from the active Ol Doinyo Lengai ("the Mountain of God" in Maasai language).
There is a new onsite museum at Olduvai that offers informative exhibits, lectures and tours of the hominid sites.
In addition to the exhibits, there is opportunity for shopping as local people sell souvenirs, antiques and ethnographic items of various ethnic groups living today in Tanzania such as the Hadza (the Hunter-Gatherers of Lake Eyasi basin), Datoga (pastoralists of Central Tanzania), Sonjo (pastoralists and fierce warriors of the Rift Valley), and Maasai (pastoralists).
The famous Laetoli site is where Dr. Mary Leakey discovered 3.6 million year-old human footprints preserved in a volcanic ash layer along the southwestern slopes of Lemagrut volcano. Laetoli is located about 30 miles south of Olduvai.
Olduvai, Laetoli and other sites in the Ngorongoro-Serengeti ecosystems (e.g., L. Ndutu, L. Masek and Nasera rock shelter) continues to disclose a rich record of humanity’s past, and is still the best place in the world to investigate the ecology and origin of the earliest species of the genus Homo due to the richness of its fossil and archaeological records, and the great variety of ancient environments exposed by the Gorge’s deposits. Indeed, it is the best place to investigate the environmental pressures that selected for the novel traits in early Homo (first technology, first significant increase in brain size over that seen in the apes, first evidence for meat-eating from larger animals). These traits define the fundamental aspects of human distinctiveness from non-human primates and other animals.
"These traits define the fundamental aspects of human distinctiveness from non-human primates and other animals."
In 2014, a scientific drilling program was carried out at Olduvai by the Olduvai Gorge Coring Project (OGCP). It has yielded about 600 m of continuous core obtained from ancient lakebeds. The core constitutes approximately 30% of all cores from East African paleolake and hominin sites (including Kenya and Ethiopia). OGCP is co-led by Jackson Njau (Indiana University, Earth and Atmospheric Sciences), and Kathy Schick and Nick Toth (Indiana University and The Stone Age Institute). The goal of this project is to understand the relationship between Earth’s dynamics and human evolution. High-quality cores are valuable in this endeavor because they record paleoclimate and paleoenvironmental information at high resolution.
A series of parallel active and passive seismic studies conducted in the area, in collaboration with the King Abdullah University for Science and Technology (KAUST) scientists, has transformed into a strong interdisciplinary research program bridging paleoanthropology and the Earth sciences. OGCP is one of the top drilling projects in Eastern Africa hominin sites. To date, more than two dozen scientists from eight different countries and more than fourteen institutions are focusing on different aspects of the overall research, including: sedimentology, chemical composition (XRF), argon-argon and paleomagnetic age dating, tephrostratigraphy, soil carbonate isotope, phytoliths, pollen, diatoms, ostracods, organic geochemistry, paleontology, archaeology, geophysics, and seismology. This ground-breaking research is providing modern methods that address our species’ humble beginnings, and help us answer questions about our origins.