Depth Profiling Analyses of REE Abundances and U-Pb Ages from Zircon Crystals Using Sensitivity-enhanced ICP-Time of Flight-Mass Spectrometry (ICP-TOF-MS)
Depth Profiling Analyses of REE Abundances and U-Pb Ages from Zircon Crystals Using Sensitivity-enhanced ICP-Time of Flight-Mass Spectrometry (ICP-TOF-MS)
复制标题
使用灵敏度增强的 ICP 飞行时间质谱 (ICP-TOF-MS) 对锆石晶体中的 REE 丰度和 U-Pb 年龄进行深度剖面分析
DOI：
10.1111/ggr.12446
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Takafumi Hirata
中科院分区：
文献类型：
--
作者：
Masaki Nakazato;Hisashi Asanuma;Sota Niki;Hideki Iwano;Takafumi Hirata
利用基于飞行时间的电感耦合等离子体质谱（ICP - ToF - MS）结合激光烧蚀取样，对锆石中稀土元素（ree）丰度和U - Pb年龄进行了深度剖面测量。为了提高离子的透射率，我们将Nu Instruments的干等离子体锥应用于ICP - ToF - MS系统。使用多点激光烧蚀（msLA）方案进一步提高了分析物的信噪比。此外，在分析区域周围建造一个“护城河”，避免了从不同层释放的颗粒混合的风险。利用该技术，在0.59 ~ 0.66 μm取样深度范围内，对3种参考物质锆石（91500、Plešovice和OD‐3）的稀土元素丰度和U‐Pb年龄进行了重复性分析。该方法还应用于喜马拉雅造山带的锆石样品。稀土丰度和U - Pb同位素比值的组合表明，研究中观测到的U - Pb同位素比值的不一致趋势主要是由于颗粒（薄外层、内缘和核心）中三种组分的混合。得到的地球化学数据表明，msLA技术和ICP - ToF - MS系统的结合是解码导致样品形成的多种热事件的有力工具。
Depth‐profiling measurements of both the abundances of rare earth elements (REEs) and U‐Pb ages from zircons were conducted using a time‐of‐flight based inductively coupled plasma‐mass spectrometer (ICP‐ToF‐MS) coupled with laser ablation sampling. To improve ion transmission, a dry plasma cone from Nu Instruments was applied to the ICP‐ToF‐MS system employed. The signal‐to‐noise ratios for the analytes were further improved using a multiple spot‐laser ablation (msLA) protocol. Moreover, constructing a ‘moat’ around an analysis area obviated the risk of mixing of particles released from different layers. With the technique developed here, reproducible analyses of REE abundances and U‐Pb ages for three reference material zircons (91500, Plešovice and OD‐3) were performed for sampling depths in the range 0.59–0.66 μm. The present technique was also applied to zircon samples collected from the Himalayan orogen. The combination of REE abundances and U‐Pb isotopic ratios suggested that the discordant trend in U‐Pb isotopic ratios observed in this study was mainly due to mixing among three components in grains (thin outer layer, inner rim and core). The geochemical data obtained demonstrate that the combination of the msLA technique and ICP‐ToF‐MS system is a powerful tool to decode the multiple thermal events contributing to sample formation.