Abstract Zircon crystals from diamondiferous kyanite gneisses of the Barchi-Kol area (Kokchetav massif, Northern Kazakhstan) have been investigated by a combined application of cathodoluminescence (CL), Raman spectroscopy and electron probe microanalysis (EPMA). The zircon crystals exhibit up to four distinct domains characterised by significantly different CL signatures and parameters of the ν3(SiO4) (1008 cm–1) Raman band (i.e. full width at half maximum, position and intensity). Extremely metamict zircon cores (Domain I) host inclusions of low-pressure minerals (quartz and graphite) and the outer mantles (Domain III) are populated by ultrahigh-pressure relicts (diamond and coesite), whereas inner mantles (Domain II) and overgrowth rim zones (Domain IV) are inclusion free. Both the zircon cores and rims have very low Ti concentrations, implying formation temperatures below 760°C. The Ti content in the inner mantles (up to 40 ppm) is indicative of temperatures in the 760–880°C range. The temperature estimates for the outer mantles are 900–940°C, indicating a pronounced overlap with the peak metamorphic values yielded by the Zr-in-rutile geothermometer for the same rocks (910–950°C). The internal textures of the zircons and the occurrence of index minerals within the distinct domains allow us to unravel the stages of the complex metamorphic history recorded in the zircon. Our data show that the zircon cores are inherited seeds of pre-metamorphic (magmatic?) origin, the inner mantles were formed on the prograde metamorphic stage, the outer mantles record ultrahigh-pressure metamorphism and the outermost rims mark the retrograde metamorphic stage. The observed zircon internal textures are thus clearly correlated with distinct growth events, and in some examples reflect a major part of the metamorphic history. It is concluded that the combined application of the CL, Raman spectroscopy and EPMA techniques to zircon offers significant potential for deciphering the metamorphic evolution of deeply-subducted rocks.

中文翻译：

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来自 Kokchetav 地块含金刚石蓝晶石片麻岩的锆石：使用集成阴极发光-拉曼光谱-电子微探针方法揭示生长阶段

摘要 通过阴极发光 (CL)、拉曼光谱和电子探针微量分析 (EPMA) 的组合应用，研究了来自 Barchi-Kol 地区（Kokchetav 地块，哈萨克斯坦北部）含金刚石蓝晶石片麻岩的锆石晶体。锆石晶体表现出多达四个不同的域，其特征是 ν3(SiO4) (1008 cm-1) 拉曼带（即半高全宽、位置和强度）的 CL 特征和参数显着不同。极变质晶锆石核（域 I）包含低压矿物（石英和石墨）的包裹体，外地幔（域 III）由超高压残余物（金刚石和柯石英）填充，而内地幔（域 II）和过度生长边缘区域（域 IV）不含任何杂质。锆石核心和边缘的 Ti 浓度都非常低，意味着地层温度低于 760°C。内地幔中的 Ti 含量（高达 40 ppm）表明温度在 760-880°C 范围内。外地幔的温度估计值为 900-940°C，表明与金红石中锆地温计测得的相同岩石（910-950°C）的峰值变质值明显重叠。锆石的内部结构和不同区域内指标矿物的出现使我们能够解开锆石中记录的复杂变质历史的各个阶段。我们的资料表明，锆石核是前变质（岩浆？）成因的遗传种子，内地幔形成于顺行变质阶段，外地幔记录超高压变质作用，最外缘标志着逆行变质阶段。观察到的锆石内部结构因此与不同的生长事件明显相关，并且在一些例子中反映了变质历史的主要部分。结论是，CL、拉曼光谱和EPMA技术在锆石上的联合应用为破译深俯冲岩石变质演化提供了巨大的潜力。