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2011-03-01 05:44:10   •   ID: 1018

Obsidian during the Stone Age of East Africa and the Levant

Figure 1
This is a pyramidal core from a late neolithic site in Anatolia.

Obsidian, a volcanic glass, is formed when volcanic lava is coming in contact with water. Iron and magnesium usually give the obsidian a dark green to black color but dark green, red, or even clear variants are also known.

Obsidian is an excellent raw material for the production of sharp stone tools. Other trace elements, such as rare-earth elements, scandium, rubidium, cesium, tantalum, thorium and uranium can be used for geochemical analysis.

Indeed, Obsidian from each volcano has a unique chemical fingerprint, which can be used for securely provenancing the raw material source of an Obsidian artifact.

Non-destructive X-ray fluorescence analytical methods are often used successfully for this purpose.

Obsidian is therefore an optimal material for the assessment of the size of exploited territories, the evaluation of spatial networks among groups and the identification of particular mobility patterns.

The Rift valley in East Africa is one of the few African areas with abundant obsidian sources. Sources of high quality volcanic glass are present in Ethiopia, in Kenya, close to the Lake Naivasha basin and Mount Eburru.

Minor sources of are found in the east of the Lake Turkana and in the southern in the Suguta Valley Melka Konture, located 50 km south of Addis Abeba is the only known example of obsidian use during the Oldowan. The raw material came from a source, about 7 km away from the archaeological site.

During the Acheulean, the intense use of obsidian has only been documented at Melka Kunture and at Kariandusi (Kenia; 0.7 –1.0myr BP). A few pieces of worked obsidian have been recorded at the Kenyan Acheulean sites of Kilombe, (0.7 myr BP) and at Olorgesailie (0.9 myr PB).

At Olorgesailie the nearest source of volcanic glass is 26 km away from the main site. At Gadeb 8E (Ethiopia; 0.7-1.48 myr BP) only 4/222 bifaces were made from obsidian. The nearest source of obsidian is located 100 km to the West.

Beginning with the MSA, Obsidian was frequently used in East African sites, mostly within a 50-km radius of the sources. Occasional very long distances have been documented between the source and the site of Obsidian knapping.

For example some stone tools from the Nasera Rock Shelter, Tanzania have been sourced to an obsidian outcrop 240 km away. Porc- Epic Cave, Ethiopia yields artifacts exhibiting a distance of 250 km from site to source.

Some authors claim, that these large distances are unique for the MSA compared with the Middle Paleolithic in Europe, but maybe the data are biased by the secure provenancing and high “visibility” of Obsidian compared to other raw-materials.

It has to be remembered, that such long distances have been also occasionally observed in Europe (Micoquian of the Kulna Cave in the Moravian Karsts).

Recently new 40Ar/39Ar geochronological data revealed that the advanced MSA at Gademotta dates back at least 276,000 years. These dates are much older than technologically comparable MSA ensembles from elsewhere. I

It has therefore been suggested that MSA technology evolved diachroneous in different places in Africa. One reason for the sophisticated technique used at Gademotta could be the abundance of high quality Obsidian near this site.

During Late Stone Age lithic assemblages in East Africa, Obsidian is generally the dominant raw material for the production of stone tools.

While volcanic glass is not important during the Middle and early upper Paleolithic in the Levant, it becomes gradually more important during the Geometric Kebaran with ever increasing frequency.

An excellent page about the Obsidian “Trade” in the Near East can be found as external link