| 词汇 | zircon |
| 释义 | zircon noun[ U or C ] uk /ˈzɜː.kɒn/ us /ˈzɜ˞ː.kɑːn/ a mineral in the form of crystals (= regular shapes) from which the chemical element zirconium is obtained: 锆石 A tiny crystal of zircon found in northwestern Australia is estimated to be about 4.3 billion years old.在澳大利亚西北部发现的一颗锆石小晶体据估计是在43亿年前形成的。 Zircons, made primarily of the elements zirconium, oxygen and silicon, are extremely hard and durable.锆石主要由锆、氧和硅等元素组成，非常坚硬耐磨。 Reimphoto/iStock/Getty Images Plus/GettyImages Zircon has a tremendous capacity to resist breakdown during erosion, weathering, melting, and metamorphism. Zircon is found mainly in silica-rich rocks such as granite. The relative amounts of oxygen isotopes in the zircons points to the presence of water. Geology: mineralogy beneficiation crude crystal crystalline deposit gemologist gemology gold dust graphite idiomorphic intercrystalline magnesium mineral pyrite quasicrystal seam silicon unmined vermiculite vulcanicity Examples of zirconzircon Both zircon and monazite are abundant in the rock. The absence of severe rounding in this group of detrital zircons suggests a proximal source area. At the upper part of the section rounded and weakly zoned zircons (type 3) also appear. The zircons are clear and long-prismatic, and show minor rounding at their terminations. The sample gave a small yield of < 100 m zircons. In the lower unit, the zircons range in length from 50 to 300 microns and in the upper unit from 100 to 350 microns. Nine fractions of zircons separated from the upper unit were also analysed. The ion microprobe method is capable of dating 10-30 m sized domains within single zircon crystals. Tiny grains of zircon are found as an accessory mineral within plagioclase crystals in most zones of both layers. Modern zircon-based age determinations are largely lacking for the members of the trans-suture suite of intrusions. While the former do represent an appropriate zircon source, they cannot be divorced from inappropriate zircon sources of the latter. 53 isotope systematics and the provenance of detrital zircons of these different terrane assemblages, as they display distinct differences. The analysed zircons are 150-200 m in length and have only a few cracks and inclusions. All zircons show well-developed crystal zoning; many have cracks, few have inclusions. Alternatively, zircons from the metagranites could be inherited. 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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