Olduvai Gorge

Coordinates: 2°59′37″S 35°21′04″E / 2.993613°S 35.35115°E / -2.993613; 35.35115
Source: Wikipedia, the free encyclopedia.
Olduvai Gorge
Ngorongoro District,
Arusha Region,
 Tanzania
RegionEastern Africa
Coordinates2°59′37″S 35°21′04″E / 2.993613°S 35.35115°E / -2.993613; 35.35115
TypeArchaeological
Length48km
Site notes
Excavation dates1913, 1935, 1941,
1953, 1955, 1958 & 1960
ArchaeologistsWilhelm Kattwinkel, Louis Leakey,
Mary Leakey, Percy Edward Kent & Jonathan Leakey
ConditionExcavated
OwnershipTanzanian Government
ManagementAntiquities Division, Ministry of Natural Resources and Tourism[1]
Public accessYes
Official nameOldupai Gorge
TypePre-historic

The Olduvai Gorge or Oldupai Gorge in

Ngorongoro District of Arusha Region, about 45 kilometres (28 miles) from Laetoli, another important archaeological locality of early human occupation. The British/Kenyan paleoanthropologist-archeologist team of Mary and Louis Leakey established excavation and research programs at Olduvai Gorge that achieved great advances in human knowledge and are world-renowned. The site is registered as one of the National Historic Sites of Tanzania.[2]

The gorge takes its name from the

lake bed. A side gorge, originating from Lemagrut Mountain, joins the main gorge 8 km from the mouth. This side gorge follows the shoreline of a prehistoric lake, rich in fossils and early hominin sites. Periodic flows of volcanic ash from Olmoti and Kerimasi helped to ensure preservation of the fossils in the gorge.[3]

The locality is significant in showing the increasing developmental and social complexities in the earliest

hominids transitioning to homininina—that is, to human clade
.

Homo sapiens
, which is estimated to have emerged roughly 300,000 years ago, is thought to have occupied sites in the gorge 17,000 years ago.

History

Discovery and research

Olduvai Gorge from space
Topography map of the Olduvai Gorge

While travelling in

paleontologist Donald McInnes accompanied Louis Leakey in his 1931 expedition, where Louis found a number of hand axes close to camp soon after their arrival. Mary Leakey first visited the area in 1935, joining Louis and Percy Edward Kent. Subsequent visits were made by the Leakeys in 1941, 1953, 1955 and 1957.[3]

Louis and Mary Leakey are responsible for most of the

type specimen for Homo habilis.[3]
: 17–18, 54, 56–57, 73–77, 87 

Archaeology and geology

Hans Reck and Richard Hay

While Hans Reck was the first geologist to attempt to understand the geology of the gorge, current understanding of the geology of the stratigraphic sequence of Olduvai Gorge was made possible in large part by the efforts of geologist Richard Hay. Hay spent twelve years studying the geology at Olduvai, much of it working along with Mary Leakey, finally formulating a detailed picture of the geologic history of the area. Hay's seminal work The Geology of the Olduvai Gorge was published in 1976.[5]

Reck identified five main layers of deposition in the gorge, which were labelled Beds I through V, with Bed I being the oldest and lowest in the sequence. Hay and other geologists working at the gorge since Reck's time have utilized Reck's original Bed outline, adding clarity, detail, and corrections to achieve a more thorough understanding of gorge history. Reck's original Bed IV interval was later distinguished as consisting of Bed IV and the Masek Beds, while Bed V has been reclassified as the Ndutu Bed and the Naisiuiu Bed.[5]

Gorge Stratigraphy

The stratigraphic sequence in the gorge is up to 90 m thick, with a

Carbon-14 dating were used to date the bones. Hominid fossils and stone tools are found continuously throughout the entire exposed sequence in the gorge. Faulting between 100 and 30 kya, formed the Olbalbal Depression northwest of Ngorongoro.[3]
: 41–43 

Close-up of monolith made of red sediments from Bed III

Bed I

The 20–46 m thick

claystone.[5] Four well-preserved living sites of note are located within Bed I, the FLK and FLK North-North sites mentioned above, plus DK and FLK North. The DK site (Donald McInnes' first initial plus k for korongo) has what Leakey considers to be a stone circle, and also many tools and fossil bones ranging in age from 1.75 mya to 1.9 mya.[3]
: 45, 50–58 

Bed II

Bed II consists of 21–35 m of

: 58–63 


Olduvai Gorge from the air looking south, eastern portion including view of museum (left), and western portion (right)

Bed III

The distinctly red Bed III consists of 6–10 m of clays, sandstones and conglomerates signifying variable lake depths. Few fossils are present and only isolated stone tools, indicating a sparse early man presence.[3]: 63–66 

Bed IV

Bed IV is a distinctly different unit from Bed II in the eastern portion of the gorge. There, it is 5–8 m thick and composed of clays, and stream deposited sandstones and conglomerates. Four distinct tool-bearing levels are evident, including 500 handaxes and

cleavers at the HK (Hopwood's Korongo) site, while phonolite handaxes and an elephant bone handaxe were found at the HEB (Heberer's Gully) site. The WK (Wayland's Korongo) site contained a Homo erectus pelvis and femur.[3]
: 66–70 

Masek beds

The Masek Beds are composed of two episodes of

Oldonyo Lengai tuffs make up the upper portion of the Ndutu Beds, but yield few fossils. Oldonyo Lengai tuffs also make up the Naisiusiu Beds.[3]
: 70–72 

Associated fossil species

The few Australopithecus boisei remains, which include the skull, a thigh bone fragment, and several teeth, were found distributed throughout Beds I and II, which dates them in the range 1.1 to 2 mya. The more common remains of Homo habilis were found in Bed I and the lower portion of Bed II, which makes them contemporaries of Australopithecus boisei. Homo erectus remains were found in the upper portions of Bed II, making them contemporaries of Australopithecus boisei, but not of Homo habilis.[3]: 74 

The stone tools and their makers

Louis Leakey first described the Oldowan stone tool industry in 1951. The Leakeys determined that choppers were the most common stone tool found at the gorge, amounting to over half of the total number, and identified 11 Oldowan sites in the gorge, 9 in Bed I, and 2 in Bed II. They also identified the Developed Oldowan as the subsequent diverse tool-kit found in Beds II, III, and IV, with small tools made mostly from chert rather than quartzite. These tools are mostly spheroids and sub-spheroids, followed by choppers.[3]: 88, 90, 95, 98 

Besides the chert quarry in Bed II, the Leakeys were able to identify the other source locations of the principal rocks used to make the stone tools. The most common material was quartzite, which originated from the Naibor Soit Inselberg just north of the gorges. The phonolite originated from the Engelosen volcano 5 km to the north. The gneiss came from the Kelogi inselborg 9 km to the southwest.[3]: 83–86 

The first species found by the Leakeys, Zinjanthropus boisei or Australopithecus boisei (renamed and still debated as Paranthropus boisei), featured a

sedges.[6]

Conversely, the Leakeys' 1960s finds presented different characteristics. The skull lacked a sagittal crest and the

braincase
was much more rounded, suggesting it was not australopithecine. The larger braincase suggested a larger brain capacity than that of Australopithecus boisei. These important differences indicated a different species, which eventually was named Homo habilis. Its larger brain capacity and decreased teeth size pointed to Homo as the probable toolmaker.

The oldest tools at Olduvai, found at the lowest layer and classified as Oldowan, consist of pebbles chipped on one edge.

Chellean and the Acheulean. Higher still (and later still) are located Levallois artifacts, and finally the Stillbay implements.[7] Oldowan tools in general are called "pebble tools" because the blanks chosen by the stone knapper already resembled, in pebble form, the final product.[8] Mary Leakey classified the Oldowan tools according to usage; she developed Oldowan A, B, and C categories, linking them to Modes 1, 2, and 3 assemblages classified according to mode of manufacture. Her work remains a foundation for assessing local, regional, and continental changes in stone tool-making during the early Pleistocene, and aids in assessing which hominins were responsible for the several changes in stone tool technology over time.[9]

It is not known for sure which hominin species was first to create Oldowan tools. The emergence of tool culture has also been associated with the pre-Homo species Australopithecus garhi,[10] and its flourishing is associated with the early species Homo habilis and Homo ergaster. Beginning 1.7 million years ago, early Homo erectus apparently inherited Oldowan technology and refined it into the Acheulean industry.[11]

Oldowan tools occur in Beds I–IV at Olduvai Gorge. Bed I, dated 1.85 to 1.7 mya, contains Oldowan tools and fossils of Paranthropus boisei and Homo habilis, as does Bed II, 1.7 to 1.2 mya. H. habilis gave way to Homo erectus at about 1.6 mya, but P. boisei persisted. Oldowan tools continue to Bed IV at 800,000 to 600,000 before present (BP). A significant change took place between Beds I and II at about 1.5 mya. Flake size increased, bifacial edges (as opposed to single-face edges) occurred more frequently and their length increased, and signs of battering on other artifacts increased. Some likely implications of these factors, among others, are that after this pivotal time hominins used tools more frequently, became better at making tools, and transported tools more often.[12]

Hunters or scavengers?

Worked lithic flake

Though substantial evidence of hunting and

calories in both groups' diets came from plant sources. Thus, it can be assumed that early hominins had similar diet proportions, (see the middle-range theory or bridging arguments—bridging arguments are used by archaeologists to explain past behaviors, and they include an underlying assumption of uniformitarianism
.)

Much of the information about early hominins comes from tools and debris piles of

lithic flakes from such sites as FLK-Zinjanthropus in Olduvai Gorge. Early hominins selected specific types of rocks that would break in a predictable manner when "worked", and carried these rocks from deposits several kilometres away. Archaeologists such as Fiona Marshall fitted rock fragments back together like a puzzle. She states in her article "Life in Olduvai Gorge" that early hominins, "knew the right angle to hit the cobble, or core, in order to successfully produce sharp-edged flakes ...". She noted that selected flakes then were used to cut meat from animal carcasses, and shaped cobbles (called choppers) were used to extract marrow
and to chop tough plant material.

Bone fragments of birds, fish,

carnivores having gnawed the bones. Since several kinds of marks are present together, some archaeologists including Lewis Binford think that hominins scavenged the meat or marrow left over from carnivore kills. Others like Henry Bunn believe the hominins hunted and killed these animals, and carnivores later chewed the bones.[13] This issue is still debated today, but archaeologist Pat Shipman provided evidence that scavenging was probably the more common practice; she published that the majority of carnivore teeth marks came before the cut marks. Another finding by Shipman at FLK-Zinj is that many of the wildebeest bones found there are over-represented by adult and male bones; and this may indicate that hominins were systematically hunting these animals as well as scavenging them. The question of whether hunting or scavenging was more important at Olduvai Gorge is still a controversial one.[14]

Hominid fossils found at Olduvai Gorge

Panoramic view

Olduvai Gorge monument and museum

In July 2019, the Olduvai Gorge Monument was erected at the turnoff to Olduvai Gorge from the road which connects Ngorongoro Conservation Area and Serengeti National Park (a route traveled by safari-goers). Eng. Joshua Mwankunda conceived the idea of erecting a monument to commemorate this significant site while also serving as a signpost and attracting visitors to the Olduvai Gorge and museum; paleoanthropologists Nicholas Toth, Kathy Schick, and Jackson Njau planned and provided life-size fossil casts at the request of the Tanzanian government, which were used by the celebrated Tanzanian artist Festo Kijo to create the two large concrete skulls. The monument consists of two large-scale models of fossil skulls which sit atop a large pedestal with an informative plaque mounted on the side of the pedestal. The fossil skulls depicted are Paranthropus boisei and Homo habilis, two contemporary species which were first discovered at Olduvai Gorge. The large-scale models created by Kijo are each 6 feet tall and weigh 5,000 pounds. The monument project was funded by the Stone Age Institute and the John Templeton Foundation, in partnership with the Ngorongoro Conservation Area Authority (NCAA).[15]

The Olduvai Gorge Museum, located 5 km beyond the monument, is situated on the rim of the gorge at the junction of the main gorge and the side gorge. As one of the largest onsite museums in Africa, the museum provides educational exhibits related to the gorge and its long history.

IUGS geological heritage site

In respect of the presence of 'palaeoanthropological sites indicating early hominin development and activities', the International Union of Geological Sciences (IUGS) included the 'Palaeoanthropological Sites of Human Evolution of Laetoli – Olduvai Gorge' in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an IUGS Geological Heritage Site as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.'[16]

Gallery

  • The oldest human-made object in the British Museum[17]
    The oldest human-made object in the British Museum[17]
  • The spot where the first P. boisei was discovered in Tanzania
    The spot where the first P. boisei was discovered in Tanzania
  • Oldowan stone chopper
    Oldowan stone chopper
  • About 1.8 million years old
    About 1.8 million years old

See also

References

  1. ^ "Antiquities Division". Retrieved 21 Jul 2022.
  2. ^ "Antiquities Sites" (PDF). Retrieved 21 Jul 2022.
  3. ^ a b c d e f g h i j k l Leakey, Mary (1979). Olduvai Gorge. London: Book Club Associates. pp. 11–17, 40.
  4. ^
    OCLC 2391581.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link
    )
  5. .
  6. ^ .
  7. ^ Napier, John. 1960. "Fossil Hand Bones from Olduvai Gorge." in Nature", December 17th edition.
  8. ^ Barham, Lawrence; Mitchell, Peter (2008). The First Aftricans. Cambridge University Press. p. 126.
  9. PMID 10213682
    .
  10. . .
  11. .
  12. .
  13. .
  14. ^ "Zinj Tower launch: Jubilant PM sees all humans as Tanzanians". www.ippmedia.com. Retrieved 2020-01-23.
  15. ^ "The First 100 IUGS Geological Heritage Sites" (PDF). IUGS International Commission on Geoheritage. IUGS. Retrieved 13 November 2022.
  16. ^ "A History of the World in 100 Objects". The British Museum. Retrieved 18 May 2016.

Further reading

External links