Stone tool

PaleolithicA stone tool is, in the most general sense, any tool made either partially or entirely out of stone. Although stone tool-dependent societies and cultures still exist today, most stone tools are associated with prehistoric (particularly Stone Age) cultures that have become extinct. Archaeologists often study such prehistoric societies, and refer to the study of stone tools as lithic analysis. Ethnoarchaeology has been a valuable research field in order to further the understanding and cultural implications of stone tool use and manufacture. A stone tool is, in the most general sense, any tool made either partially or entirely out of stone. Although stone tool-dependent societies and cultures still exist today, most stone tools are associated with prehistoric (particularly Stone Age) cultures that have become extinct. Archaeologists often study such prehistoric societies, and refer to the study of stone tools as lithic analysis. Ethnoarchaeology has been a valuable research field in order to further the understanding and cultural implications of stone tool use and manufacture. Stone has been used to make a wide variety of different tools throughout history, including arrow heads, spearpoints and querns. Stone tools may be made of either ground stone or chipped stone, and a person who creates tools out of the latter is known as a flintknapper. Chipped stone tools are made from cryptocrystalline materials such as chert or flint, radiolarite, chalcedony, obsidian, basalt, and quartzite via a process known as lithic reduction. One simple form of reduction is to strike stone flakes from a nucleus (core) of material using a hammerstone or similar hard hammer fabricator. If the goal of the reduction strategy is to produce flakes, the remnant lithic core may be discarded once it has become too small to use. In some strategies, however, a flintknapper reduces the core to a rough unifacial or bifacial preform, which is further reduced using soft hammer flaking techniques or by pressure flaking the edges. More complex forms of reduction include the production of highly standardized blades, which can then be fashioned into a variety of tools such as scrapers, knives, sickles and microliths. In general terms, chipped stone tools are nearly ubiquitous in all pre-metal-using societies because they are easily manufactured, the tool stone is usually plentiful, and they are easy to transport and sharpen. Archaeologists classify stone tools into industries (also known as complexes or technocomplexes) that share distinctive technological or morphological characteristics. In 1969 in the 2nd edition of World Prehistory, Grahame Clark proposed an evolutionary progression of flint-knapping in which the 'dominant lithic technologies' occurred in a fixed sequence from Mode 1 through Mode 5. He assigned to them relative dates: Modes 1 and 2 to the Lower Palaeolithic, 3 to the Middle Palaeolithic, 4 to the Advanced and 5 to the Mesolithic. They were not to be conceived, however, as either universal—that is, they did not account for all lithic technology; or as synchronous—they were not in effect in different regions simultaneously. Mode 1, for example, was in use in Europe long after it had been replaced by Mode 2 in Africa. Clark's scheme was adopted enthusiastically by the archaeological community. One of its advantages was the simplicity of terminology; for example, the Mode 1 / Mode 2 Transition. The transitions are currently of greatest interest. Consequently, in the literature the stone tools used in the period of the Palaeolithic are divided into four 'modes', each of which designate a different form of complexity, and which in most cases followed a rough chronological order. Stone tools found from 2011 to 2014 at Lake Turkana in Kenya, are dated to be 3.3 million years old, and predate the genus Homo by half million years. The oldest known Homo fossil is 2.8 million years old compared to the 3.3 million year old stone tools. The stone tools may have been made by Australopithecus afarensis or Kenyanthropus platyops— (a 3.2 to 3.5-million-year-old Pliocene hominin fossil discovered in 1999) the species whose best fossil example is Lucy, which inhabited East Africa at the same time as the date of the oldest stone tools. Dating of the tools was by dating volcanic ash layers in which the tools were found and dating the magnetic signature (pointing north or south due to reversal of the magnetic poles) of the rock at the site. Grooved, cut and fractured animal bone fossils, made by using stone tools, were found in Dikika, Ethiopia near (200 yards) the remains of Selam, a young Australopithecus afarensis girl who lived about 3.3 million years ago.