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2017-05-16 04:01:27   •   ID: 1602

Trihedrals in the Acheulian of Africa and Europe

Figure 1
This is an African trihedral quartzite pick hand-axe (16 cm long) exhibiting wind gloss and desert varnish, found in 1976 in the Grand Erg Oriental in Algeria by a Friend who has already passed away.

In Africa Acheulian stone tool assemblages are defined by the presence of the handaxe (or biface) and/or other large cutting tools (LCTs) such as cleavers, unifaces, or picks/trihedrals.

In the absence other diagnostic markers, an assemblage may still be identified as Acheulean by the presence of particular stone working techniques intended to produce large flake-blanks which are further knapped into LCTs. Among these techniques are the Victoria West, Kombewa, Talbalbal-Tachengit techniques.

Trihedrals in Africa seem to be more numerous during the older and early middle Pleistocene.  Many of these ensembles could be called either younger Oldowan or older Acheulian.

The assemblages in Konso Gardula , Ethiopia were dated to 1.75 million years. The Nachukui Formation is a geological deposit located on the western shore of Lake Turkana, northern Kenya, that includes archaeological sites dated to the earliest stone tool production in the world. The KS4 ensemble, dated to 1.5 million years is characterized by the presence of pick-like tools with a trihedral or quadrangular section, unifacially or bifacially shaped crude hand-axes, and a few cores and flakes.

At 1,5 million years ago, Trihedrals were also present in the Levant at Ubeidiya (Israel), situated on the edge of the western escarpment of the Jordan Rift Valley.

Figure 2
Sidi Abderrahmane near Casablanca Thomas I quarry unit L exhibits classical Trihedrals dated geochronologically  and by OSL to about 1  million years. Trihedrals were  still present during OIS 16 at the STIC Quarry (see a Trihedral from STIC from the classic Biberson Publication 1961 on Figure II).

Here Handaxes were manufactured mainly on various quartzites available close to the site as pebbles of small to medium size and some blocks as well as a few flint nodules collected in a secondary position from beach deposits.

The site of Arkin 8, on the West margin of the Nile at the Sudanese-Egyptian border is undated. However, the character of the stone-tool industry, dominated by heavy duty tools, cordiform, ovate and lanceolate handaxes, as well as Trihedrals; tentatively aligns it with this early Middle Pleistocene group of sites.

Similarly undated, early bifaces and trihedral pieces have recently been recorded for the Fezzan, Libya. Sites of younger Middle Pleistocene age in Noth Africa and Egypt usually have no Trihedrals.

This hold true for the  younger localities at Sidi Abderrahman – Cap Chatelier, Grotte d’Ours, and Grotte des Littorines and sites in the Fayum depression (associated with the 40 m lake), the Wadi Midauwara in the Kharga depression, at Bir Tarfawi and Bir Sahara East. Geochronometric dating of the Acheulean deposits in the oases of the western desert suggest a minimum age of 350 k.a. while recent work on the geochronology of the fossil-spring tufas of the Kharga Oasis have provided U-series minimum ages of 300 k.a.

Figure 3
In Europe the presence / absence of Trihedrals seem to be not of much chronical value. For example an Acheulian with some Trihedrals is known all along the middle and lower Guadalquivir basin along the main river and several of its tributaries (Figure 3 shows a typical example).

The geostratigraphic sequence of the Guadalquivir depression is composed of 14 terraces, dated recently by U/Th and paleomagnetic determinations. Acheulian remains are especially concentrated on the middle terraces, dated not earlier than MIS 11.

Recently a late S- European Acheulean site characterized by an unusual abundance of large cutting tools (LCT) and Dihedrals was described from Porto Maior (As Neves, Pontevedra; c 200 k.a. BP). Such ensembles are known from Africa and the Near east. Therefore, this special ensemble are suggested to point to an African origin.

Overall there are striking similarities between the Acheulean of North Africa and the Iberian Peninsula:

  • Broad similarities in lithic technology

  • presence of cleavers

  • the use of non-flint rocks, such as quartzite, as raw material for bifaces

Gonen Sharon draw attention to a special technique, called entame core method in the chaine operatoire of biface production in Northern Africa and Spain. He notes that:  “It is suggested that the frequent use of the entame core method common to both North Africa and the Iberian Peninsula indicates similarity in lithic tradition during the Acheulean. This may support the view of North African origin for the Iberian Acheulean during the Middle Pleistocene” (Afr Archaeol Rev 2011)

Trihedrals are part of the classic ensemble at La Micoque, layer N. The age of Layer N will possibly remain unknown. After the lower strata have been consistently  dated to a glacial circle at 250-300 k.a. BP, there is a possibility that they are much older than traditionally suggested.

Acheulian Trihedrals are part of the “Chalossien” of France, which has never been dated by modern techniques and are also frequent at some “Micoquian / KMG” ensembles of Germany (Bocksteinschmiede, Salzgitter Lebenstedt- all dated to MIS3.