激光剥蚀-电感耦合等离子体飞行时间质谱元素成像技术在地球科学领域中的应用进展

LA-ICP-TOFMS Elemental Imaging in Geosciences: Advances and Applications

  • 摘要: 元素成像技术可原位获取固体样品中元素的空间分布特征,是精准解析地质样品微结构和元素组成、反演关键元素富集机制、矿物成岩成矿演化本质等常规分析手段难以揭示的精细地质过程的核心技术支撑。岩矿微区成像常用技术普遍存在成像效率低、痕量元素检测能力不足等瓶颈,难以满足多元素同步检测、大范围快速成像的分析需求。激光剥蚀电感耦合等离子体飞行时间质谱(LA-ICP-TOFMS)兼具多元素同时检测(几乎全元素)与高速采集能力(采集速率超过10 ms/像素点),是突破上述技术瓶颈的重要候选方案,但目前其在地球科学领域的应用仍相对匮乏。本文系统梳理了LA-ICP-TOFMS的分析原理、性能优势与技术局限,评述了该技术在地球科学领域的应用进展,涵盖矿物标样研制领域,利用其快速成像能力评估稀土元素等微量元素微区均一性;多金属结核研究领域,明确了Co、Ni、Cu、Mn等关键金属的赋存状态,并揭示沉积环境氧化还原条件演变对结核金属富集的控制机制;硅酸盐矿物成岩成矿研究领域,实现了稀土、高场强元素等关键元素的原位同步成像,精准刻画了岩浆结晶、热液交代过程中金属元素迁移规律,为成矿环境约束提供新的技术手段;生物矿化研究领域,元素成像揭示了深水竹节珊瑚早期到后期矿化模式的转变,证实了珊瑚虫生理活动对Callogorgia珊瑚骨骼矿化过程的调控作用等。总体而言,LA-ICP-TOFMS在地球科学领域的应用仍处于探索阶段,但可为推动地球科学研究从宏观现象观测向微观机制解析转化提供关键技术支撑,在地质样品微区元素成像、精细地质过程反演等领域具有广阔的应用前景。

     

    Abstract: Elemental imaging is crucial for deciphering the microstructure and associated elemental compositions of geological samples, revealing fine-scale enrichment processes and the evolution of mineral petrogenesis that are inaccessible to conventional techniques. However, conventional imaging methods are often hampered by low imaging efficiency and limited sensitivity for trace elements, which constrains simultaneous multi-element analysis and rapid mapping over large areas. Laser ablation-inductively coupled plasma-time of flight mass spectrometry (LA-ICP-TOFMS) provides a promising solution by enabling simultaneous, high-speed virtually all element analysis with pixel dwell times < 10 ms. This review summarizes its analytical principles, key advantages, and current limitations, with emphasis on applications in rapid evaluation of reference material development, the mechanisms of critical metal enrichment in polymetallic nodules, and the study of mineral formation and biomineralization processes. Although LA-ICP-TOFMS remains at an exploratory stage in geoscience research, it offers considerable potential to advance studies from macroscopic observation toward microscopic mechanistic interpretation and to support micro-scale elemental imaging and fine-scale geological process reconstruction.

     

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