In archaeology, a prismatic blade is a long, narrow, specialized lithic flake with parallel margins. Prismatic blades are removed from polyhedral blade cores through pressure reduction. This process results in a very standardized finished tool and waste assemblage. While the prismatic blade industry is most often associated with obsidian (especially in Pre-Columbian Mesoamerica), it is not limited to that material; chert, flint, and chalcedony blades are not uncommon. Archaeology, archeology, or archæology (from Greek: αρχαίος, archae, ancient; and λόγος, logos, knowledge) is the study of human cultures through the recovery, documentation and analysis of material remains and environmental data, including architecture, artifacts, biofacts, human remains, and landscapes. ... In archaeology, a lithic flake is a thin, sharp fragment of stone that results from the process of lithic reduction. ... In archaeology, a lithic core is a distinctive artifact that results from the practice of lithic reduction. ... In lithic reduction, pressure flaking is a method of trimming the edge of a stone tool by removing small lithic flakes by pressing on the stone with a sharp instrument rather than striking it with a percussor. ... Small pieces of stone debris that break off during the manufacturing of stone tools. ... Obsidian from Lake County, Oregon Counterclockwise from top: obsidian, pumice and rhyolite (light color) Obsidian is a rock which is a type of naturally occurring glass, produced by volcanoes (igneous origin) when a felsic lava cools rapidly and freezes without sufficient time for crystal growth (see glass transition temperature). ... The pre-Columbian era incorporates all period subdivisions in the history and prehistory of the Americas before the appearance of significant European influences on the Americas continent. ... The cultural areas of Mesoamerica Mesoamerica or Meso-America (Spanish: Mesoamérica) was a geographical culture area extending from central Honduras and northwestern Costa Rica on the south, and, in Mexico, from the Soto la Marina River in Tamaulipas and the Rio Fuerte in Sinaloa on the north. ... Chert Chert (IPA: ) is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils. ... A flint nodule from the Onondaga limestone layer, Buffalo, New York. ... Chalcedony knife, AD 1000-1200 Bloodstone redirects here. ...

Morphology

An obsidian prismatic blade fragment from Chunchucmil, Yucatán, Mexico

Prismatic blades are often trapezoidal in cross section (see image), but very close in appearance to an isosceles trapezoid. Triangular blades (in cross-section) are also common. The ventral surface of the prismatic blade is very smooth, sometimes bearing slight rippling reflecting the direction of applied force and a very small bulb of applied force (indicative of pressure reduction). Flake scars are absent on the ventral surface of these blades, though eraillure flakes are sometimes present on the bulb . The dorsal surface, on the other hand, exhibits scar ridges running parallel to the long axis of the blade. These facets are created by the previous removal of blades from the core. The proximal end contains the blade's striking platform and its bulb of applied force, while the distal end will consist of a snap break, a feather termination, or a stepped termination. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Map of Northwest Yucatan, showing major ecological zones and archaeological sites related to Chunchucmil Chunchucmil was a large, sprawling pre-Columbian Maya city located in the western part of what is now the state of Yucatán, Mexico. ... Yucatán is the name of one of the 31 states of Mexico, located on the north of the Yucatán Peninsula. ... A trapezoid (in North America) or trapezium (in Britain and elsewhere) is a quadrilateral, which is defined as a shape with four sides, which has a pair of parallel sides. ... An isosceles trapezoid. ... In lithic analysis, a subdivision of archaeology, a bulb of applied force (also known as a bulb of percussion or simply bulb of force) is a defining characteristic of a lithic flake. ... In lithic analysis (a subdivision of archaeology), an eraillure is a small secondary flake removed from a lithic flakes bulb of force, which is a lump left on the dorsal surface of a flake after it is detached from a core of tool stone during the process of lithic... In lithic reduction, the striking platform is the point on the proximal portion of a lithic flake on which the detachment blow fell; this may be natural or prepared. ...

Production

Obsidian prismatic blade production was ubiquitous in Mesoamerica, and these tools can be found at a large majority of Mesoamerican archaeological sites from the Preclassic period on until the arrival of the Spanish in the early 16th century. Ethnohistoric sources recount the process of prismatic blade production. Fray Motolinia, a Spanish observer, recorded: An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or historic or contemporary), and which has been investigated using the discipline of archaeology. ... Mesoamerican chronology The chronology of Pre-Columbian Mesoamerica is usually divided into the following eras: Paleo-Indian Period c. ... Aztec empire The Spanish conquest of the Aztec Empire was one of the most important campaigns in the Spanish colonization of America. ... (15th century - 16th century - 17th century - more centuries) As a means of recording the passage of time, the 16th century was that century which lasted from 1501 to 1600. ... Fray Toribio de Benavente ( ? Benavente, Spain- 1568, Mexico City) also known as Motolinia was a Franciscan missionary and among the first 12 clerics to arrive in New Spain in May 1524. ...

"It is in this manner: First they get out a knife stone (obsidian core) which is black like jet and 20 cm or slightly less in length, and they make it cylindrical and as thick as the calf of the leg, and they place the stone between the feet, and with a stick apply force to the edges of the stone, and at every push they give a little knife springs off with its edges like those of a razor."^[1]

The production of prismatic blades creates not only a very standardized final product, but also a standardized waste assemblage.^[2] The analysis of obsidian debitage can reveal whether or not prismatic blade production occurred at a site and, if it had, what stages of production the process included. In other words, the types of manufacturing waste present (e.g., rejuventation flakes and/or blades, platform rejuvenation flakes, etc.) at a site can inform archaeologists about the stage in which blades were being produced.^[3] A sample of jet Jet is a geological material that is not considered a mineral in the true sense of the word, but rather, a mineraloid derived from decaying wood under extreme pressure, thus organic in origin. ... Small pieces of stone debris that break off during the manufacturing of stone tools. ...

See also

• Obsidian use in Mesoamerica

Obsidian was an important part of the material culture of Pre-Columbian Mesoamerica. ...

Notes

References

• Clark, John E. (1997) Prismatic blademaking, craftsmanship, and production: an analysis of obsidian refuse from Ojo de Agua, Chiapas, Mexico. Ancient Mesoamerica 8:137-159.
• Clark, John E., and Douglas D. Bryant (1997) Technological typology of prismatic blades and debitage from Ojo de Agua, Chiapas, Mexico. Ancient Mesoamerica 8: 111-136.
• Hester, Thomas R., Robert N. Jack and Robert F. Heizer. The Obsidian of Tres Zapotes, Veracruz, Mexico. University of California Archeology Research Facility. No. 13 pp. 65-131, 1971.