Cold working can then go on until the metal becomes brittle again.Metallographic examination, the study of crystal structure, can give information about the cold working and annealing processes in the last stages of the making of an artifact.There are various types of augers and they can be manual- or power-driven.Simple augers bring up samples on the thread of a drill bit.Partial burning reduces the materials to a carbon-rich residue. Many organic materials may not retain their structure and become an amorphous residue.Charred remains are preserved on archaeological sites because carbon is relatively inert in the soil and the microorganisms which would normally break down organic material are unable to make use of this form of carbon.
Unglazed fired pottery, awaiting glazing - the first or preliminary firing of a ware that is subsequently glazed and refired in the glost firing. carbonized, charring CATEGORY: term DEFINITION: The burning or scorching of organic materials, such as plants, seeds, or grains, in conditions of insufficient oxygen which results in their preservation. CATEGORY: term DEFINITION: Converted to charcoal or carbon usually by heat, organic materials may be preserved.It can be counteracted by gentle heating called annealing.Annealing allows crystals within the metal to recrystallize and distribute the stress that has built up.These were the polar continental shelves that escaped glaciation during the ice ages but which were exposed during periods of low , it was a large, flat, vegetated landmass.In 1993, investigations on the climatic interstadial of 11,000-12,000 years ago in Beringia (now submerged under the Bering Strait) and the way it provided for the peopling of the SYNONYMS OR RELATED TERMS: American Paleo-Arctic CATEGORY: culture DEFINITION: A culture in existence approximately 12,000 years ago between Siberia and temperate Alaska. West to cover various Alaskan and Siberian archaeological formations which had developed from the Siberian period, an area now largely submerged under the Bering Strait.Artifacts of 11,500 to 9,000 years ago are known from a number of Alaskan sites, where hunters of caribou (and, in one case, of an extinct form of bison) manufactured blades.which, though limited in its application, has been used successfully to determine the lead content of glass and glaze.They were part of a migratory wave that later reached as far south as South America (about 10,000 years ago).During the Ice Age the fell by several hundred feet, making the strait into a land bridge between Asia and North America, over which a considerable migration of plants and animals, as well as man, occurred.A specimen is subjected to a beam of electrons from a weak radioactive beta source and some electrons are absorbed while others are backscattered" from the surface of the sample and can be counted with a Geiger counter.The percentage of electrons backscattered depends on the atomic number of the elements making up the surface layer of the artifact.