Modern ethnicities
28-517: Diaspora Performing arts Government agencies Television Radio Newspapers The Elmenteitan culture was a prehistoric lithic industry and pottery tradition with a distinct pattern of land use, hunting and pastoralism that appeared and developed on the western plains of Kenya , East Africa during the Pastoral Neolithic c.3300-1200 BP. It was named by archaeologist Louis Leakey after Lake Elmenteita (also Elementaita ),
56-563: A core of tool stone during the process of lithic reduction . This phenomenon is named after the German physicist Heinrich Rudolf Hertz , who first described this type of wave-front propagation through various media. Although it might not be agreed by all, natural phenomena which have been grouped with the Hertzian cone phenomena include the crescentic " chatter marks " made on smoothed bedrock by glacial ice dragging along boulders at its base,
84-421: A flake , or collectively as debitage . The objective piece, or the rock being reduced by the removal of flakes, is known as a core . Once the proper tool stone has been selected, a percussor or pressure flaker (e.g., an antler tine ) is used to direct a sharp blow, or apply sufficient force, respectively, to the surface of the stone, often on the edge of the piece. The energy of this blow propagates through
112-492: A soda lake located in the Great Rift Valley , about 120 km (75 mi) northwest of Nairobi . The Elmenteitan was first described by Louis Leakey from excavations at Gamble's Cave (the type site) in 1931 and Njoro River Cave in 1938. Leakey had noticed a locally distinct cluster of the lithic industry and a universal pottery tradition in a restricted area on the plains west of the central Great Rift Valley and at
140-427: A "punch", which itself is struck by a percussor, similar to the use of a hammer and chisel to shape stone), or by pressure. Additionally, flakes may be initiated in a Hertzian , bending, or wedging fashion. When a flake is detached from its core in a Hertzian fashion, the flake propagates in a conchoidal manner from the point of impact or pressure, usually producing a partial Hertzian cone. The cone of force often leaves
168-426: A core or previously formed Hertzian cones on the surface. Eraillures , also referred to as "bulbar scars", are tiny flake scars that appear on some bulbs of applied force. The reason they form is not entirely understood. Of those flakes that do exhibit eraillures, very few have more than one. Secondary and tertiary flakes display dorsal flake scars, which are simply the markings left behind by flakes detached prior to
196-452: A distinctive bulb of applied force on the flake and a corresponding flake scar on the core. A bending initiation results when a flake initiates not at the point where the force was applied, but rather further away from the edge of the core, resulting in a flake with no Hertzian cone or bulb of applied force and few if any of the characteristics ripples or undulations seen on the ventral surface of conchoidally produced flakes. Wedging initiation
224-664: A great variety of smaller microlithic tools. Typical Elmenteitan artifact assemblages also include ceramic bowls and shallow stone vessels. Ceramic vessels are mainly undecorated. Several rare, but very distinctive ornamental designs such as irregular punctuation and rim millings have also been found. Occasionally small bowls with out-turned rims, handles with holes or horizontal lugs have been discovered as well. Domestic cattle and small stock were raised and herded in combination with hunting, fishing and foraging. Patterns and degree of subsistence economy varied greatly depending on location and local and temporal climate. Regular cremation of
252-461: A wider part of Kenya and Tanzania. Occupants of these sites used a variety of obsidian sources, had greater diversity in material culture, and mainly buried their dead in cairns. These findings suggest that the heterogeneous SPN category likely encompasses multiple groups. At Elmenteitan sites, lithic assemblages are distinguished by a high percentage of long symmetrical two-edged obsidian blades which were used unmodified and also served as blanks for
280-400: Is a characteristic indicating the manner in which the distal end of a flake detached from a core. Flake terminations may be feathered, hinged, stepped, or plunging (also known as overshot or outrepassé ). Feathered terminations are often very sharp, as the flake gradually reduces to a very fine thickness before the force exits the core and removes the flake. Hinged terminations are the result of
308-420: Is marked with the negative scars of these removals. The surface area of the core which received the blows necessary for detaching the flakes is referred to as the striking platform . Flakes may be produced by a variety of means. Force may be introduced by direct percussion (striking the core with a percussor such as a rock or antler), indirect percussion (striking the core with an object, sometimes referred to as
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#1732854509566336-421: Is the cone produced when an object passes through a solid , such as a bullet through glass. More technically, it is a cone of force that propagates through a brittle , amorphous , or cryptocrystalline solid material from a point of impact. This force eventually removes a full or partial cone in the material. This is the physical principle that explains the form and characteristics of the flakes removed from
364-479: Is the result of a strong hammer blow. At impact, concentric radii emanate from the point of percussion, but unlike conchoidal fracture, the force travels along what would be the center of the Hertzian cone. The bipolar reduction technique is typified by its use of wedge initiation. Like bending initiation, no bulb of applied force results from wedging initiation, although in the bipolar technique, flakes may appear to have two points of percussion, on opposite ends, because
392-642: Is usually at least twice as long as it is wide. There are numerous specialized types of blade flakes. Channel flakes are characteristic flakes caused by the fluting of certain Paleo-Indian projectile points ; such fluting produced grooves in the projectile points which may have facilitated hafting. Prismatic blades are long, narrow specialized blades with parallel margins which may be removed from polyhedral blade cores, another common lithic feature of Paleo-Indian lithic culture. Prismatic blades are often triangular in cross section with several facets or flake scars on
420-455: The Mau Escarpment . Elmenteitan sites are found between the central Rift Valley and the western Lake Victoria Basin of Kenya. The occupants of all these sites used obsidian sourced from Mount Eburu . They left behind distinctive lithic and ceramic traditions and practiced primarily cremation burial. This contrasts with the contemporaneous SPN pastoral tradition whose sites are found across
448-408: The amount of cortex indicates when in the sequence of reduction the flake came from. Primary flakes are those whose dorsal surfaces are entirely covered with cortex; secondary flakes have at least a trace of cortex on the dorsal surface; and tertiary (interior) flakes lack cortex, having derived entirely from the interior of the core. Primary flakes and secondary flakes are usually associated with
476-528: The ancient remains of Elmenteitan has proven that the population of the Savanna Pastoral Neolithic were also responsible for the pastoralist Elmenteitan culture that lived in the Rift Valley during the same period. Lithic flake In archaeology , a lithic flake is a "portion of rock removed from an objective piece by percussion or pressure," and may also be referred to as simply
504-470: The core has been fractured by a hammer and anvil technique. The core is placed on a hard surface or "anvil" and is struck above by a hammer, thus the fracture may propagate from both ends simultaneously. The end which received the blow or pressure is referred to as the proximal end of the flake; the terminal end is referred to as the distal end. The side displaying the bulb of force but without flake scars (barring an errailure flake scar or additional working of
532-536: The dead took place in caves (e.g. Egerton Cave, Keringet Caves). Njoro River Cave , first excavated in 1938 by Mary Leakey , served as a mass-burial site. Associated finds include beads, blades, stone bowls, palettes and pottery vessels. Instances of dental avulsion in some individuals from Elmenteitan burial sites has led to associations with the early spread of Southern Nilotic speaking groups into south-western Kenya. The exact direction from which they entered southern Kenya remains unclear. Recent genetic analysis of
560-519: The detachment of the subject flake. These flake scars are one of the lines of evidence used to infer the method of lithic reduction, or the process by which raw material is turned into useful objects. Flakes can be modified into formal tools, which result from additional working of the piece to shape a flake into a desired form, or they can be used without further modification, and are then referred to as expedient tools. For example, scrapers, which may be made by additional removals, known as retouchings, to
588-501: The dorsal surface. Prismatic blades begin to appear in high frequencies during the transition between the Middle and Upper Paleolithic.This lithic technology basically replaces the Levallois reduction technology. The striking platform is the point on the proximal portion of the flake on which the detachment blow fell or pressure was placed. This may be natural or prepared. Termination type
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#1732854509566616-423: The edge of a piece, or burins , which are created by a burin blow on the tip of a blade which produces a chisel-like edge which may have been used for graving and carving wood or bone. Because they require less labor to create, expedient flakes can be used strategically as a useful tool for a situation that does not necessarily require a sharpened tool necessary for cutting. Hertzian cone A Hertzian cone
644-443: The flake) is called the ventral (or interior) surface, while the opposite side, displaying the flake scars of previous removals, or the cortical or original rock surface, is the dorsal (or exterior) surface. On most natural cobbles or nodules of source material, a weathered outer rind called a cortex covers the unweathered inner material. Flakes are often differentiated by the amount of cortex present on their dorsal surfaces, because
672-502: The force rolling away from the core, resulting in a rounded distal end. Step terminations result when a flake prematurely breaks or snaps during removal, leaving a distal end that is often squared off. Plunging flakes are the result of the force rolling back towards the core and often taking off its "bottom". Hinge, step, and plunging terminations, although sometimes deliberately formed, are usually errors called "abrupt terminations". Abrupt terminations are often indicative of internal flaws in
700-476: The initial stages of lithic reduction , while tertiary flakes are more likely to be associated with retouching and bifacial reduction activities. Prominent bulbs of force generally indicate that a hard hammer percussor ( hammerstone ) was used to detach the flake; flakes displaying this characteristic are referred to as conchoidal flakes. Hard hammer flakes are indicative of primary reduction strategies (e.g., core reduction, roughing of blanks and preforms , and
728-442: The like). More moderate and diffuse bulbs may indicate the use of a soft hammer percussor—such as bone , wood , or antler —which produces the bending flakes often associated with bifacial thinning and trimming. The relative abundance of each type of flake can indicate what sort of lithic work was going on at a particular spot at a particular point in time. A blade is defined as a flake with parallel or subparallel margins that
756-401: The material, often ( but not always ) producing a Hertzian cone of force which causes the rock to fracture in a controllable fashion. Since cores are often struck on an edge with a suitable angle (<90°) for flake propagation, the result is that only a portion of the Hertzian cone is created. The process continues as the flintknapper detaches the desired number of flakes from the core, which
784-453: The numerous crescentic impact marks sometimes seen on pebbles and cobbles, and the shatter cones found at bolide impact sites. James Byous, working independently (at privately funded Dowd Research, Savannah, Georgia USA) has made a protracted study of Hertzian cones. Some of his work may be found via sharing points or directly at Dowd Research. He has produced a comprehensive glossary on Hertzian fractures and related terms. A Hertzian cone
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