section_path: Chronology/Three-age chronology/Lower Paleolithic/Acheulean in Africa
section_name: Acheulean in Africa
paragraph_text: Acheulean in Africa
  
  The end of Oldowan in Africa was brought on by the appearance of Acheulean, or Mode 2, stone tools. The earliest known instances are in the 1.7–1.6 mya layer at Kokiselei, West Turkana, Kenya. At Sterkfontein, South Africa, they are in Member 5 West, 1.7–1.4 mya. The 1.7 is a fairly certain, fairly standard date. Mode 2 is often found in association with H. erectus. It makes sense that the most advanced tools should have been innovated by the most advanced Hominan; consequently, they are typically given credit for the innovation.
  
  A Mode 2 tool is a biface consisting of two concave surfaces intersecting to form a cutting edge all the way around, except in the case of tools intended to feature a point. More work and planning go into the manufacture of a Mode 2 tool. The manufacturer hits a slab off a larger rock to use as a blank. Then large flakes are struck off the blank and worked into bifaces by hard-hammer percussion on an anvil stone. Finally the edge is retouched: small flakes are hit off with a bone or wood soft hammer to sharpen or resharpen it. The core can be either the blank or another flake. Blanks are ported for manufacturing supply in places where nature has provided no suitable stone.
  
  Although most Mode 2 tools are easily distinguished from Mode 1, there is a close similarity of some Oldowan and some Acheulean, which can lead to confusion. Some Oldowan tools are more carefully prepared to form a more regular edge. One distinguishing criterion is the size of the flakes. In contrast to the Oldowan "small flake" tradition, Acheulean is "large flake:" "The primary technological distinction remaining between Oldowan and the Acheulean is the preference for large flakes (>10 cm) as blanks for making large cutting tools (handaxes and cleavers) in the Acheulean." "Large Cutting Tool (LCT)" has become part of the standard terminology as well.
  
  In North Africa, the presence of Mode 2 remains a mystery, as the oldest finds are from Thomas Quarry in Morocco at 0.9 mya. Archaeological attention, however, shifts to the Jordan Rift Valley, an extension of the East African Rift Valley (the east bank of the Jordan is slowly sliding northward as East Africa is thrust away from Africa). Evidence of use of the Nile Valley is in deficit, but Hominans could easily have reached the palaeo- Jordan River from Ethiopia along the shores of the Red Sea, one side or the other. A crossing would not have been necessary, but it is more likely there than over a theoretical but unproven land bridge through either Gibraltar or Sicily.
  
  Meanwhile, Acheulean went on in Africa past the 1.0 mya mark and also past the extinction of H. erectus there. The last Acheulean in East Africa is at Olorgesailie, Kenya, dated to about 0.9 mya. Its owner was still H. erectus, but in South Africa, Acheulean at Elandsfontein, 1.0–0.6 mya, is associated with Saldanha man, classified as H. heidelbergensis, a more advanced, but not yet modern, descendant most likely of H. erectus. The Thoman Quarry Hominans in Morocco similarly are most likely Homo rhodesiensis, in the same evolutionary status as H. heidelbergensis.