Chemical analysis of trace elements in biogenic carbonates: development of a novel proxy for paleoclimatology

生物碳酸盐岩中微量元素的化学鉴别技术已成为古气候研究的新指标。X射线光吸收光谱（XAS）是一种无损分析技术，用于表征和识别成分复杂的天然物质中的痕量元素。此外，XAS和X射线荧光分析（XRF）相结合，使用微聚焦X射线束允许确定环境重要的微量元素的化学状态及其在生物碳酸盐中的空间分布。一系列的XRF/XAS制图分析阐明了日本粉红珊瑚（C。elatius）强烈依赖于它们的化学形式。目前的研究表明，形态分析有助于更准确地了解微量元素的生物碳酸盐作为古气候的代理。

The novel analytical techniques which chemically distinguish the trace elements in biogenic carbonate have been developed as a new proxy for paleoclimatology. X-ray photoabsorption spectroscopy (XAS) is a nondestructive analytical technique for characterizing and identifying trace elements in compositionally complex natural materials. Furthermore, the combination of XAS and X-ray fluorescence analysis (XRF) using a micro-focused X-ray beam allow determination of both the chemical state of environmentally important trace elements and their spatial distribution in biogenic carbonates. A series of XRF/XAS mapping analyses clarified that the spatial distributions of sulfur compounds in Japanese pink coral (C. elatius) was strongly dependent on their chemical forms. The present research demonstrates that speciation analysis contributes to a more precise understanding of trace elements in biogenic carbonates as a proxy for paleoclimatology.