F11Anth110-Lec12

F11Anth110-Lec12 - behavior behavioral b h i l strategy =...

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Unformatted text preview: behavior behavioral b h i l strategy = problem solving raw material percussors objective & detached pieces; tool reductive process geometry of fracture components of ST t f curated; expedient; opportunistic pp reliability; maintainability; transportability bili approaches to classification of technology: first question is the object an artifact at all? artifact/feature = geofact = measured attributes ceramics and pottery structure of clay properties of clay shrinkage & temper constraints forming & firing glazes l constraints on ST design of ST 2 and some less mundane problems problems... technology = behavioral strategies to solve mundane problems... problems prosthetic teeth... teeth external fat storage... storage mating strategies p prehistoric "credit default swap" general approaches classification of technologies unaltered materials: stone technology gy stone, bone, wood, antler, shell, plant & animal fibers (including leather) synthetic materials: ceramics, glass & fiaence, metals use of fire (pyrotechnology) very important in development of synthetic materials e.g., ceramics (firing); glass (casting, blowing); metals (smelting, alloying, casting, annealing) pyrotechnology makes use of heat and oxidation to alter slow chemical reactions to generate new materials synthetics today often use other chemical reactions not dependent upon e fire 5 chipped ground elements of stone (lithic) technology stone raw materials raw material & percussors (load applicators) brittle fractures easily fracture follows a single crack that propagates under applied force homogeneous material is composed of a uniform mix of constituents (e.g., crystal sizes) material is structurally similar in all directions i il i ll di ti isotropic stone raw material manuport antler billet appropriate materials rare... amorphous percussors (load applicators) increasing accuracy and precision; decreasing flake size hard hammers (e.g., hammer stones) soft hammers (e.g., antler billets) (e g indirect percussors (e.g., hammer, punch & vice) pressure flaker (e.g., punch) nonnon-crystalline materials e.g., e g glass nothing to impede direction, or propagation of force through stone very small crystals that do not impede... i d cryptocrypto-crystalline e.g., chert, chalcedony crystalline y crystals that impeded propagation to various degrees q quartzite, sandstone, hornfels, , , , basalt elements of stone (lithic) technology (lithic) core: material from which mass is removed flake: removed mass tool: objects with modified edges or form with inferred function core flake flake tool: detached objective reductive process designs change as reduction proceeds d i d becomes harder to b h d implement designs as pieces get smaller i ll possible to mimic designs to solve same problems? fracture mechanics h id l f conchoidal fracture 136 exterior platform angle < 90 90 exterior angles hard to control as core gets smaller design = creating ridges Levallois (MP) core technology from North Africa Van Peer 1992 design is about control of micro-topography micro topography in addition to gross geometric angles ceramics = technologies where objects are modeled or molded from clay and then made durable by firing pottery = clay containers f l i formed by h d made d b hand, d on a mold or thrown on a wheel; often decorated d h fired and then fi d spindle whorl Blade Core from Tell Halif, Israel Pez Dispenser from amazon.com pottery figurines clay as a mineral sedimentary particles <4-2m <4in diameter (weathering prod.) ( gp ) SiO2 and Al2O3 SiO2 varies from 43-65% 43 K+ orthoclase/albite orthoclase/albite ++, Na++ plagioclase Ca p g Fe++, Mg++ H2O Kaolinte: Al2(Si2O5)(OH)4 Kaolinte: Si tetrahedron Si tetrahedral sheet (from above) t t h d l h t (f b ) clay deposit = soils with >35% clay particles Al octahedron Al octahedral sheet (from above) clay as a raw material 1:1 (kaolintie) 2:1 (montmorillonite) H2O Mg, K, C O, Ca... finefine-grained, earthy material, plastic when wet flows like fluid when pressure is applied stays put applied, when no pressure applied product of mineral surface area-water interaction area clay particle thickness : diameter = 1:12 octahedral sheet tetrahedral sheet smaller the mineral size, the greater the surface area size and the more plastic the clay sedimentary particle size-sorting determines the sizequality (sand:silt:clay ratios) of any given clay source (sand:silt:clay clay is made durable by firing shrinkage Shrinkage crack and temper common forms of temper p sand ground shell g volcanic ash ground pottery sherds organics (e.g., grass) forming clay constraints g y ceramic technology is ADDITIVE constraints ability to withstand bili ih d shear forces gravity and applied forces Jomon, Japan 5 4ka 5-4ka shear plasticity (when wet) & brittleness (when fired) limit i li i size and geometry d bending g Crushed shell temper in Nocona Plain ware sherds, Texas Manufacturing firing = using high heat to convert plastic clay into non-plastic nonceramic loss of water: up to 600C oxidation of carbon and iron: up to 900 C id ti f b di t vitrification (transformation of clay to glass-like material): >1000 C glass waterproofing "bonfire" firing in Rajasthan, India simple "open top" kiln ...
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