Results 231 to 240 of about 26,858 (250)
Some of the next articles are maybe not open access.
Science, 1976
The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95° to 245°C. An expression relating hydration rate to temperature was derived for each sample. The SiO 2 content and refractive index are related to the hydration rate, as are the CaO, MgO, and original ...
William D. Long, Irving Friedman
openaire +3 more sources
The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95° to 245°C. An expression relating hydration rate to temperature was derived for each sample. The SiO 2 content and refractive index are related to the hydration rate, as are the CaO, MgO, and original ...
William D. Long, Irving Friedman
openaire +3 more sources
2014
Obsidian: Obsidian is an aluminosilicate, or rhyolitic, glass, formed by rapid cooling of volcanic magma under the proper geologic conditions. As any other glass, it is not a crystal, and thus it lacks the lattice structure typical of crystals at the atomic level. However, glasses do possess some degree of spatial order.
openaire +2 more sources
Obsidian: Obsidian is an aluminosilicate, or rhyolitic, glass, formed by rapid cooling of volcanic magma under the proper geologic conditions. As any other glass, it is not a crystal, and thus it lacks the lattice structure typical of crystals at the atomic level. However, glasses do possess some degree of spatial order.
openaire +2 more sources
Obsidian hydration: A new paleothermometer
Geology, 2006The natural hydration of obsidian was first proposed as a dating technique for young geological and archaeological specimens by Friedman and Smith (1960), who noted that the thickness of the hydrated layer on obsidian artifacts increases with time. This approach is, however, sensitive to temperature and humidity under earth-surface conditions. This has
Lawrence M. Anovitz +4 more
openaire +2 more sources
Endeavour, 1986
Abstract The accurate dating of uncovered artifacts is of fundamental importance in archaeology. Since the war radiocarbon has proved immensely valuable for specimens with an organic content. For sites producing obsidian or other natural glasses this has been rivalled during the past decade by obsidian hydration dating.
openaire +2 more sources
Abstract The accurate dating of uncovered artifacts is of fundamental importance in archaeology. Since the war radiocarbon has proved immensely valuable for specimens with an organic content. For sites producing obsidian or other natural glasses this has been rivalled during the past decade by obsidian hydration dating.
openaire +2 more sources
The Obsidian Industry of Teotihuacán [PDF]
American Antiquity, 1967 AbstractSeveral areas with extensive obsidian-working debris on the surface have been found in Teotihuacán. These date from the Late Preclassic, Classic, and Postclassic periods. During the Late Preclassic and Classic periods there seems to have been a continuous expansion of the city's obsidian industry, accompanied by an increasing trend toward ...
openaire +1 more source
Obsidian Provenance Research in the Americas
Accounts of Chemical Research, 2002The characterization of archaeological materials to support provenance research has grown rapidly over the past few decades. Volcanic obsidian has several unique properties that make it the ideal archaeological material for studying prehistoric trade and exchange.
openaire +2 more sources
Teotihuacán, Tepeapulco, and Obsidian Exploitation
Science, 1978Current cultural ecological models of the development of civilization in central Mexico emphasize the role of subsistence production techniques and organization. The recent use of established and productive archeological surface survey techniques along natural corridors of communication between favorable niches for cultural development within the ...
openaire +3 more sources
1997
A freshly-made surface of obsidian (volcanic glass of rhyolitic composition) will absorb water which slowly penetrates by diffusion into the body of the artifact. Although the depth of penetration can be measured by various methods, it is generally determined by microscopic examination on thin sections of the artifact cut normal to the surface.
Fred Trembour +2 more
openaire +2 more sources
A freshly-made surface of obsidian (volcanic glass of rhyolitic composition) will absorb water which slowly penetrates by diffusion into the body of the artifact. Although the depth of penetration can be measured by various methods, it is generally determined by microscopic examination on thin sections of the artifact cut normal to the surface.
Fred Trembour +2 more
openaire +2 more sources
Obsidian Hydration Rate Development
MRS Proceedings, 1988AbstractSince the seminal work of Friedman and Smith [1] obsidian hydration dating (OHD) has undergone several important stages of development and refinement. This paper will summarize the history of research and developments as to elucidate some areas for future research.Archaeologists have taken a pragmatic and empirical approach towards OHD and ...
openaire +2 more sources