Visualizing trace element distribution in quartz using cathodoluminescence, electron microprobe, and laser ablation-inductively coupled plasma-mass spectrometry
Visualizing trace element distribution in quartz using cathodoluminescence, electron microprobe, and laser ablation-inductively coupled plasma-mass spectrometry
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DOI：
10.2138/am.2011.3701
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发表时间：
2011-05
影响因子：
3.1
通讯作者：
B. Rusk;A. Koenig;H. Lowers
中科院分区：
文献类型：
--
作者：
B. Rusk;A. Koenig;H. Lowers
摘要石英晶体的阴极发光织构揭示了晶体生长过程中物理和化学涨落的连续历史。这种CL纹理反映了微量元素浓度的变化，可以通过电子探针或激光烧蚀电感耦合等离子体质谱法（LA-ICP-MS）映射。四种不同存款类型（卡林型Au，浅成热液银，斑岩铜，MVT铅锌）的热液石英的微量元素图揭示了微量元素之间的相关性和微量元素浓度和CL结构之间的相关性。微量元素的分布反映了石英沉淀物理化学条件的变化。这些图表明Al是热液石英中含量最丰富的微量元素。在低于300 °C的温度下生长的晶体中，相邻生长区之间的Al浓度可能变化高达两个数量级，没有扩散的证据。一价阳离子Li、Na和K在可检测的情况下总是与Al相关，其中Li是三种阳离子中最丰富的。在大多数样品中，Al比一价阳离子的组合总量更丰富;然而，在MVT样品中，Al/Li摩尔比为约0.8。锑在超热石英（~ 200 - 300 °C）中的浓度高达~ 120 ppm，但在MVT、卡林或斑岩-Cu石英中检测不到。锑的浓度不一致与其他微量元素或CL纹理。钛的丰度仅足以在-400 °C以上温度下沉淀的斑岩型矿床中的石英中进行测绘。在这样的石英，钛浓度与CL强度呈正相关，表明因果关系。与此相反，在石英从其他存款类型，有任何微量元素和CL强度波动的浓度之间没有一致的相关性。
Abstract Cathodoluminescent (CL) textures in quartz reveal successive histories of the physical and chemical fluctuations that accompany crystal growth. Such CL textures reflect trace element concentration variations that can be mapped by electron microprobe or laser ablation-inductively coupled plasmamass spectrometry (LA-ICP-MS). Trace element maps in hydrothermal quartz from four different ore deposit types (Carlin-type Au, epithermal Ag, porphyry-Cu, and MVT Pb-Zn) reveal correlations among trace elements and between trace element concentrations and CL textures. The distributions of trace elements reflect variations in the physical and chemical conditions of quartz precipitation. These maps show that Al is the most abundant trace element in hydrothermal quartz. In crystals grown at temperatures below 300 °C, Al concentrations may vary by up to two orders of magnitude between adjacent growth zones, with no evidence for diffusion. The monovalent cations Li, Na, and K, where detectable, always correlate with Al, with Li being the most abundant of the three. In most samples, Al is more abundant than the combined total of the monovalent cations; however, in the MVT sample, molar Al/Li ratios are -0.8. Antimony is present in concentrations up to -120 ppm in epithermal quartz (-200-300 °C), but is not detectable in MVT, Carlin, or porphyry-Cu quartz. Concentrations of Sb do not correlate consistently with those of other trace elements or with CL textures. Titanium is only abundant enough to be mapped in quartz from porphyry-type ore deposits that precipitate at temperatures above -400 °C. In such quartz, Ti concentration correlates positively with CL intensity, suggesting a causative relationship. In contrast, in quartz from other deposit types, there is no consistent correlation between concentrations of any trace element and CL intensity fluctuations.