An Obsidian Clovis Point as compared to a Obsidian Blade found in Sarasota, Florida. (1)
Microwear; the distinction of flaking which results from deliberate retouch from that caused by wear from usage has been the source of much confusion. (2) In the opinion of a team from Harvard University after experimentation; "the distinction should be made on the basis first of size and second of the patterning of the scars. There are definite mechanical limits to the size of scars which can be produced by contact during usage with worked materials, even the "hardest" such as antler. " (3)
Flake initiation; each of the flake types is initiated by cracking in a different manner. Once the flake is initiated it propagates through the piece based upon the compression or stiffness of controlled forces. (Cotterell et al. 1985)
Pressure flaking; (compression, wedging initiation) The cracks that form compression or bipolar flakes are initiated and propagated in a different manner from Conchoidal flakes. With wedging initiation the force of application load is concentrated in the center of the radii and a crack is formed at what would have been the center of the Hertzian cone. This may also occur with blunt hammers when a great deal of force is applied. (Cotterell and Kamminga 1987:2.13c)
Bipolar reduction; is a typical kind of flaking technology in which wedging is used as an initiation technique. No bulb of force is produced with bipolar technology or with wedging initiation (Crabtree 1972). In bipolar technology the objective piece is placed on an anvil or hard surface and struck from above with a hard hammer (Goodyear 1993). Bipolar technology is often used when the objective piece is too small to be reduced by hand-held methods or when the tool maker is trying to maximize the use of a limited raw-material source (Andrefsky 1994b).
Wedging initiation; can occur when detrital particles are wedged into an existing flaw on the surface of the objective piece. Wedging initiation may also occur when the point of applied force is away from the edge of the objective piece; hand-held cores or nodules can be split in this way. (Cotterell and Kamminga 1987:688)
Percussion bulb; (Hertzian cone - Bulb of Force) A BB pellet making an impact with a pane of glass forms a Hertzian Cone at the point of impact or the point of applied force and a series of concentric cracks develop. When making stone tools, the application of force is usually near the edge of an objective piece. This results in the formation of only a partial Hertzian cone (Crabtree 1974:54).
Terminations;there are four kinds of termination: feathered, step, hinged, and plunging. Feathered terminations are considered continuations of flake propagation; step terminations are produced as a result of discontinuous propagation, and hinge and plunging terminations are caused by increases in the bending forces that cause the force of impact to turn towards or away from the objective piece. (Cotterell and Kamminga 1990:145) (4)
Ventral side of the Obsidian Blade pictured in the comparison at the top of the page.
Conchoidal fractures; are initiated or started by the formation of a Hertzian cone at the point of applied force. At the point of impact or the point of applied force, a series of concentric cracks develops. A crack is initiated at the point of contact and travels into the objective piece to begin forming the cone. This increases outward pressure and causes the crack to curve away from the objective piece and this action forms the bulb of force. Cotterell and Kamminga state that "the partial cone propagates initially into the body of the nucleus to complete the bulb of force" (1987:687). They also state that because Conchoidal flakes require a great deal of pressure to initiate they are more easily produced with a hard hammer. (Cotterell and Kamminga 1987:686)
Conchoidal fracturing, is only one of the Lithic Tool Technologies used to produce this piece.
Distribution of Scars; "If on the other hand the antler is used to deliberately detach microflakes from the main flake by careful pressure flaking or soft-hammer percussion, the flakes may be much larger; they are also likely to be more regular in shape and size along the edge, have sharper edges, encroach further over the surface of the flake, and finally have a more regular distribution along the edge (see above) than any of the scars produced through usage." (3)
Water-action damage; The orientation of the scars was random with no standardization of scar size or shape on each flake. Both of these features are quite unlike the damage caused by deliberate usage, in which the pressure is uniform and comes from one direction. (Experimentation in the Formation of Edge Damage / Tringham et al. 1974:192)
Summary of Damage; We are confident, therefore, that in analysis the lithic material of a prehistoric assemblage, there is no difficulty in distinguishing the damage resulting from deliberate usage from that which results from accidental or natural agencies. The main criteria of the former are its regularity of scar orientation on each edge and its concentration in a particular area or areas of the flakes perimeter. Recent accidental scarring of the edge of a prehistoric flake is characterized by a lack of any patination on the surface of the scar. (Experimentation in the Formation of Edge Damage / Tringham et al. 1974:192)
Bending flakes; are those formed by cracks that originate away from the point of applied force. Stresses are imposed upon the objective piece that attempts to bend brittle material. Some of the most commonly occurring bending flakes are ones that are produced as a result of applying force on the acute edge on the objective piece. For example, the sharp edge of a biface may snap or chip off in the formation of a bending flake when force is applied near the acute bifacial edge. The resulting bending flake will have a striking platform that is composed of a part of the original bifacial edge. Bending Flakes are believed to originate as a result of a soft hammer or pressure flakers. (Cotterell and Kamminga 1990:142)
The bending initiation may be
best understood by considering the manner in which a fishing pole may snap under stress.
Assuming for example that a fishing line is snagged at the bottom of the lake and constant
pressure is exerted upon the fishing pole held parallel to the surface; with enough force
applied the pole will snap away from the point of applied force. In other words, the pole snaps
somewhere in the middle, but not at the end where the force is applied. The bending of
the fishing rod is similar to bending forces on the striking platform of an objective
piece. (William Andrefsky 2004:28)
The bending initiation may be best understood by considering the manner in which a fishing pole may snap under stress. Assuming for example that a fishing line is snagged at the bottom of the lake and constant pressure is exerted upon the fishing pole held parallel to the surface; with enough force applied the pole will snap away from the point of applied force. In other words, the pole snaps somewhere in the middle, but not at the end where the force is applied. The bending of the fishing rod is similar to bending forces on the striking platform of an objective piece. (William Andrefsky 2004:28)
When bending forces ultimately result in a bending flake, the flake is initiated away from the point of applied force. Since the initiation occurs away from the point of applied force, there are no concentric rings of stress associated with the point of initiation. As such, no Hertzian cone is formed and no bulb of force develops on the ventral surface of the flake. Instead, the initial crack travels into the objective piece at approximately a 90 degree angle then turns toward the outside of the objective piece. (Cotterell and Kamminga 1987:690) This results in a flake that has few undulations on the ventral surface and very few secondary detachments or little flake shatter. (William Andrefsky 2004:28)
Obsidian Hydration Testing
The Hydration Front
Resolving Relative Humidity?
Almost all of the obsidian pieces, could be
I've named this type a "Finger Knife"
The reason is, several have a relief cut into the side of the tool for your fingers.
Some are shaped like scrapers, all are very small
and were found laying in a tight radiating pattern.
Almost as if they fell from a pouch and hit the ground, then spread out from there.
I have almost 1000 pieces of obsidian and if I were an Indian carrying that many pieces for trade or barter, I wouldn't want them to be very big or heavy. (Laszlo logic) My impression is that, what I have here are cores ready to be traded and finished by the end user or at the time of trade. Why carry a thousand sharpened tools when all you need are a few? Besides, the edges would only get broken or dulled, by rubbing up against one another.
These are very close, click here Tools and see below.
Obsidian pieces found in Sarasota resting on top of a print-out from the Kengamine Website.
Showing similarities of the Sarasota obsidian, in size and shape, to that of Kengamine.
Note in these pieces, several varieties of Lithic
tool technologies were used.
These are a
close match to the ones found in Sarasota.
Above:Stone tools found by A. Rutot, below the Late Oligocene sands at Boncelles, Belgium in 1907.
Some of the shapes found look to represent finger knives,
scrapers, eccentrics, cores and some Obsidian Balls (Apache Tears). With the find of
obsidian balls; first indications would be, they were brought Florida from Arizona.
Most Apache Tears in the United States are found in Superior, Arizona. But
Obsidian balls can also be found wherever magma is thrown high into the air, and then
cools into balls in the soft ash.
Obsidian Balls (known in America as Apache Tears)
Mount Scenery, Saba. The Netherlands Antilles.
Mount Scenery is a lava dome which forms
the summit of the Saba
At an elevation of 877 m. The Saba volcano is potentially dangerous; the latest eruption
was around the year 1640 and included explosions and pyroclastic flows.
Radiometric dating and geochemistry of effusive volcanics have been combined with geomorphological observations in order to provide a general evolution model of the volcanic island of Basse Terre, Guadeloupe (French West Indies). More than forty new Cassignol-Gillot K-Ar ages distributed within the entire island, together with the twenty ages (Blanc, 1983; Carlut et al., 2000) previously obtained with the same technique, makes the Guadeloupe Island the best place to study the evolution of volcanic processes within the Lesser Antilles Arc. Dating was performed on the carefully separated groundmass in order to avoid K loss due to weathering and excess argon carried by mafic minerals. Ages obtained are relatively younger than previously thought on Basse Terre and range from a few ka to 2.79+-0.04 Ma. (5)
Obsidian in the rough.
Late Pleistocene American obsidian tools
Obsidian as a trade good.
SYMPOSIUM: All Things Bright and Beautiful : Overlooked Meanings of Obsidian
Above touches base on the far reaching trade of Obsidian for barter and spiritual uses.
Additional views of the finger knife pictured above. Obsidian is mother nature's glass and reflects differently depending on the angle of the light.
I surmise, you can achieve a razor sharp edge by shaping the tool on the core first and then using bipolar initiation to remove the tool from the core. I have several samples of both; tools on cores, shaped and ready to be removed and tools already removed with two intersecting sides forming a sharp edge, with no evidence of Conchoidal fractures.
Photograph of cores to follow.
(1) Flake termination types (hinge termination) based upon Cotterell and Kamminga (1987).
(2) Semeonov, op. cit. (in note 3) 44-64; Bordes, op. cit. (in note 8) 3-4; H. Movius et al. "The Analysis of Certain Major Classes of Upper Paleolithic Tools," BASPR 26 (1968) 5-8, 15, has a very clear statement on the nature of "deliberate retouch."
(3) Ruth Tringham, Glenn Cooper, George Odell, Barbara Voytek, and Anne Whitman, Harvard University. et al. "Experimentation in the Formation of Edge Damage: A New Approach to Lithic Analysis. Journal of Field Archaeology/Vol. 1, (1974):181.
(4) Schematic illustration of flake termination types based upon Cotterell and Kamminga (1987): (a) feathered termination; (b) hinge termination; (c) step termination; (d) plunging termination (Lithics: Macroscopic Approaches to Analysis, Second Edition). William Andrefsky, Jr. Washington State University, Pullman. Cambridge University Press. Chapter 2:21 Basics of Stone Tool Production.
MCC:level 1 Friday 1340h , Presiding:A J Pietruszka, San Diego State
University; J Grocott, Kingston University V53A-0601 1340h
Time Evolution of the Basse Terre Island (Guadeloupe, French West Indies) Effusive
Volcanism from New K-Ar Cassignol-Gillot Ages.
,Rates and Timescales of Magmatic Processes III Posters
Presiding:A J Pietruszka, San Diego State University; J Grocott, Kingston University V53A-0601 1340h Time Evolution of the Basse Terre Island (Guadeloupe, French West Indies) Effusive Volcanism from New K-Ar Cassignol-Gillot Ages.
(6) Dr. Robert Tykot, 2008
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