Laser-ablation inductively-coupled plasma tandem mass-spectrometry (LA-ICP-MS/MS) allows for rapid and interference free analyses of Rb and Sr isotopes, permitting in situ Rb–Sr dating of minerals. However, the general lack of matrix matched reference materials remains one of its main obstacles, affecting both precision and accuracy. This study systematically investigates the impact of matrix effects and down-hole fractionation (DHF) on the in situ Rb–Sr ages of an igneous phlogopite mineral (MDC) analysed by an ICP-MS/MS using two different LA systems: (i) a RESOlution ArF (193 nm) excimer and (ii) a NWR (213 nm) Nd-YAG laser system. A phlogopite reference material (Mica-Mg), originating from the same location as the MDC, was prepared as a pressed nano-powder pellet (NP) and used in this study as a primary reference material. The results revealed that the accuracy of the Rb–Sr ages is typically within about 3% (for 70% of analysed samples), but occasionally higher ranging between 4 to 8% (ca. 30% of cases). We hypothesize that the above bias and uncertainty in the Rb–Sr ages are related to matrix effects between Mica-Mg-NP and MDC, due to their specific ablation characteristics and different physical properties. In addition, the elemental fractionation effects observed in this study for ⁸⁷Rb/⁸⁶Sr are also dependent on laser wavelength (i.e., 193 nm vs. 213 nm). Hence, developing an improved nano-powder reference material, or a mineral or glass with better matrix matching to natural phlogopite minerals would be desirable to further improve the accuracy of in situ Rb–Sr dating. Currently, regular monitoring of secondary and matrix-matched reference minerals such as the MDC phlogopite can be used to assess and evaluate the accuracy of in situ Rb–Sr dating of phlogopite, yielding ages within accuracy of ca. 3% or better.

中文翻译：

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通过LA-ICP-MS / MS评估金云母原位Rb-Sr定年过程中的元素分离和基质效应：对矿物年龄的准确性和精确度的影响

激光烧蚀电感耦合等离子体串联质谱（LA-ICP-MS / MS）可以对Rb和Sr同位素进行快速且无干扰的分析，从而可以对矿物进行Rb-Sr原位测年。然而，普遍缺乏基质匹配的参考物质仍然是其主要障碍之一，影响了准确性和准确性。这项研究系统地研究了基质效应和井下分离（DHF）对原位的影响使用两种不同的LA系统通过ICP-MS / MS分析的火成金云母矿物（MDC）的Rb-Sr年龄：（i）RESOlution ArF（193 nm）准分子和（ii）NWR（213 nm）Nd-YAG激光系统。从与MDC相同的位置制备金云母参考材料（Mica-Mg），制成压制纳米粉粒（NP），并在本研究中用作主要参考材料。结果显示，Rb–Sr年龄的准确性通常在3％以内（对于70％的分析样品），但偶尔会更高，介于4％至8％之间（大约30％的情况）。我们假设上述Rb–Sr年龄的偏差和不确定性与Mica-Mg-NP和MDC之间的基质效应有关，这是由于它们的特定消融特性和不同的物理特性。此外，在这项研究中观察到的⁸⁷ Rb / ⁸⁶ Sr的元素分馏效应还取决于激光波长（即193 nm对213 nm）。因此，需要开发一种改进的纳米粉末参考材料，或具有与天然金云母矿物更好的基质匹配性的矿物或玻璃，以进一步提高原位精度。Rb–Sr约会。目前，对次生和基质匹配的参考矿物（例如MDC金云母）的常规监测可用于评估和评估金云母原位Rb-Sr定年的准确性，产生的年龄在ca的准确性之内。3％或更高。