(View exact match)sieveCATEGORY: artifact
DEFINITION: A container with a perforated bottom through which material is shaken or poured.
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DEFINITION: A technique developed to assist in the recovery of plant, insect, and molluscan remains from archaeological deposits; a method of screening in which minute pieces of flora are separated from the soil by agitation with water. The technique works on the principle that organic material such as carbonized seeds, snail-shells, and beetle wing-cases have a lower specific gravity than inorganic materials such as soil and stone, and will thus float on the top of a suitable liquid medium while the rest will sink. Water is commonly used for flotation, though there are disadvantages since it has a fairly low specific gravity and heavier material such as fruit stones will sink. Other media have been used, such as carbon tetrachloride solution or zinc chloride solution. Flotation of samples by hand is called wet sieving. Samples of material are slowly poured into water, any lumps are broken up, and the flot is drawn off with a sieve. The method is more controlled than flotation by machine, and the recovery rate is better. For large-scale excavations, machines are used. Operating principles vary: samples are poured into a large container of water, or water and paraffin, which is agitated by air injection or by currents of inflowing water. The addition of a floculating agent increases surface tension, though not all machines are 'froth flotation' machines. The flot is carried off the surface through a mesh, or series of meshes to allow preliminary sorting. Samples retrieved are sent away for specialist identification and analysis by an archaeobotanist.shovel testSYNONYMS OR RELATED TERMS: shovel testing, shovel pit testing
DEFINITION: A subsurface detection technique using either posthole diggers or shovels to quickly determine the density and distribution of archaeological remains. Samples of soil from carefully selected test pits that are sieved for artifacts. Also, a shovel-sized sample taken at various intervals across a site.sievingCATEGORY: technique
DEFINITION: A technique of particle size analysis used to determine the size grades of pebble gravel, sand, and coarse silt in sediment and soils of archaeological deposits. The archaeologist processes all the earth from the site through a fine mesh, then does dry screening in a shaker frame or wet sieving with flowing water. It improves the recovery rate of artifacts. For lighter soils, dry sieving may be effective. Wet sieving is used for more claylike material and for recovering bones, shells, seeds, and other biological remains. The sieved residues are then dried and sorted by hand. The sample is placed on the top sieve of a series of nested sieves. Sieve mesh sizes are standardized. Wet sieving as part of a flotation technique is used to recover small remains from sites.wet sievingCATEGORY: technique
DEFINITION: A method used to separate organic material (seeds, snails, insects, etc.) from soil before drying, identification, and analysis. It is a more time-consuming method of extraction than flotation by machine, but has the advantage of being more accurate in its results since there is more control over extraction from the sample. The sample is poured into a sieve in a bowl of water, the lumps of soil are carefully broken up, and the organic material is trapped in the mesh while the soil particles are removed.