| 词汇 | obsidian |
| 释义 | obsidian noun[ U ] uk /ɒbˈsɪd.i.ən/ us /ɑːbˈsɪd.i.ən/ a type of almost black rock that is like glass黑曜岩，黑曜石 Scientifica/Corbis Documentary/GettyImages Geology: types of rock agglomerate arenaceous arenite asthenosphere asthenospheric emery flinty gneiss haematite indurated intrusive lahar limestone lodestone magma marl marmoreal sandstone schist shale Examples of obsidianobsidian In other words, as the rate of import increases, the proportion of the obsidian assemblage that is green decreases. The obsidian cobbles are easily detached from their parent rock by water erosion and carried downstream. The former were possibly the same individuals who exchanged the green obsidian to small centers and then to small sites. Unworked and worked shell ornaments, shell "trumpets," and several clusters of obsidian projectile points were distributed following symmetrical patterns, mainly along the periphery. The majority of the skull burials contain fewer than three objects, and only three of the 11 contexts contain obsidian. Not smooth but rather marred by dense, small pockmarks; its par ticulate inclusions are finer and denser than those of any other obsidian sources. Table 3 shows the quantities of transparent green obsidian versus graystriated, clear gray, and black obsidian found at each of the three frontier sites. The inclusion of more information on the other techniques that are applicable to obsidian studies would have been very useful. Both of these city-states provide evidence of specialized production, exchange, and consumption of obsidian tools. For obsidian, sampling and analyzing all sources is a realistic goal. Aspects of social organization are addressed through the obsidian data, as are some insights into tool production and by whom. All components of the rock, except the obsidian cobbles, are susceptible to weathering and are easily transformed into clay, as the matrix is quite porous. City-states in the agricultural periphery and those with regionally restricted raw materials such as obsidian had a greater emphasis on non-subsistence craft production. Earlier work using obsidian hydration dating is now questioned on methodological grounds. Obsidian hydration dates were obtained from samples taken from 13 of the tombs, using methods current in the late 1970s. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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