High-resolution, quantitative imaging of epidote from the Ann Mason fault block, Yerington district, Nevada, using scanning electron microscopy (SEM), X-ray fluorescence (XRF), and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) has revealed at least two types of epidote (type 1 and type 2), each with different major and trace element chemistry. Type 1 epidote is coarser grained, typically greater than 50 μm in diameter, and forms euhedral crystals that display twins and sector zones enriched in Fe, Sr, and Mn. Type 2 epidote is finer grained, typically less than 30 μm in diameter, irregularly zoned with respect to Fe and Al, and forms polycrystalline aggregates that include void space. Two sources of intragranular compositional variability are defined in this study—one related to different generations of epidote only visible on the microscale, and the other related to crystallographic features such as sector zones and twins. Intragranular compositional variations within Yerington epidotes highlight the potential importance of detailed sample characterization in complex alteration environments prior to undertaking mineral chemistry studies in the context of resource exploration. Based on statistical analysis of LA-ICP-MS spot data from one sample, the optimal number of spot analyses to adequately represent the range in element concentrations within zoned or twinned crystals is determined to be at least 40.

中文翻译：

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水热绿帘石的微观分析：对在复杂变化环境中使用激光烧蚀-电感耦合等离子体-质谱矿物化学的影响

使用扫描电子显微镜 (SEM)、X 射线荧光 (XRF) 和激光烧蚀电感耦合等离子体质谱法 (LA-ICP) 对内华达州耶灵顿区 Ann Mason 断块的绿帘石进行高分辨率定量成像-MS) 已经揭示了至少两种类型的绿帘石（1 型和 2 型），每种都有不同的主要和微量元素化学。1 型绿帘石颗粒较粗，直径通常大于 50 微米，形成自形晶体，显示出富含 Fe、Sr 和 Mn 的孪晶和扇形区。2 型绿帘石颗粒更细，直径通常小于 30 微米，相对于铁和铝不规则地分区，并形成包含空隙空间的多晶聚集体。本研究定义了颗粒内成分变异的两个来源——一个与仅在微观尺度上可见的不同代绿帘石有关，另一个与扇形区和孪晶等晶体特征有关。在资源勘探的背景下进行矿物化学研究之前，Yerington 绿帘石内的颗粒内成分变化突出了复杂蚀变环境中详细样品表征的潜在重要性。根据对来自一个样品的 LA-ICP-MS 点数据的统计分析，确定能够充分代表分区或孪晶晶体内元素浓度范围的最佳点分析次数至少为 40。在资源勘探的背景下进行矿物化学研究之前，Yerington 绿帘石内的颗粒内成分变化突出了复杂蚀变环境中详细样品表征的潜在重要性。根据对来自一个样品的 LA-ICP-MS 点数据的统计分析，确定能够充分代表分区或孪晶晶体内元素浓度范围的最佳点分析次数至少为 40。在资源勘探的背景下进行矿物化学研究之前，Yerington 绿帘石内的颗粒内成分变化突出了复杂蚀变环境中详细样品表征的潜在重要性。根据对来自一个样品的 LA-ICP-MS 点数据的统计分析，确定能够充分代表分区或孪晶晶体内元素浓度范围的最佳点分析次数至少为 40。