2:30 PM - 2:45 PM
[SCG55-04] Development of in-situ geochemical analysis for REE-rich mud using LA-ICP-MS
Keywords:REE-rich mud, LA-ICP-MS, Seafloor resources
Deep-sea sediments enriched in rare-earth elements (REE), known as REE-rich mud, are widely distributed across the Pacific Ocean, which has attracted considerable attention as a potential REE resource [1]. Especially, REE-rich mud with extremely high REE concentrations lies within Japan’s Exclusive Economic Zone (EEZ) around Minamitorishima Island and expectations for its development has been growing [2, 3].
Previous studies on the formation processes of REE-rich mud in the Minamitorishima EEZ have established the chemostratigraphy of the seafloor sediments and suggested the presence of erosional surfaces beneath the REE-enriched layers, indicating a potential relationship between the formation of REE-enriched layers and erosional processes [4]. However, the spatial resolution of bulk chemical analyses, which have been previously applied in research on REE-rich mud, is insufficient for investigating microscale variations in the sedimentary structure and chemical composition of sediments around the erosional surface.
To overcome this limitation, we employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for in situ geochemical analysis of REE-rich mud with high spatial resolution. As sample preparation protocols and analytical methods for LA-ICP-MS analysis of unconsolidated pelagic clay have not yet been established, we first aimed to develop such methods and then apply them to REE-rich mud samples from the Minamitorishima EEZ.
In this study, we first established a sample preparation method, including drying, resin embedding, and polishing, for unconsolidated pelagic clay using preliminary test samples. These preparation methods were then applied to the REE-rich mud samples from the MR15-E01 Leg2 PC04 core collected from the Minamitorishima EEZ. We selected samples from the lithological boundary of different sediment colorations. Subsequently, we conducted LA-ICP-MS analyses, obtained distribution images of the major and trace elements, and quantified the elemental concentrations of the samples using matrix-matched standard reference materials.
In this presentation, we introduce the optimized methods for the LA-ICP-MS analysis of unconsolidated seafloor sediments. Furthermore, based on the obtained geochemical data, we discuss preliminary insights into the formation processes of REE-rich mud in the Minamitorishima EEZ.
[1] Kato et al. (2011) Nature Geosci. 4, 535–539. [2] Iijima et al. (2016) Geochem. J. 50, 557–573. [3] Takaya et al. (2018) Sci. Rep. 8, 5763. [4] Tanaka et al. (2020) Ore Geol. Rev. 119, 103392.
Previous studies on the formation processes of REE-rich mud in the Minamitorishima EEZ have established the chemostratigraphy of the seafloor sediments and suggested the presence of erosional surfaces beneath the REE-enriched layers, indicating a potential relationship between the formation of REE-enriched layers and erosional processes [4]. However, the spatial resolution of bulk chemical analyses, which have been previously applied in research on REE-rich mud, is insufficient for investigating microscale variations in the sedimentary structure and chemical composition of sediments around the erosional surface.
To overcome this limitation, we employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for in situ geochemical analysis of REE-rich mud with high spatial resolution. As sample preparation protocols and analytical methods for LA-ICP-MS analysis of unconsolidated pelagic clay have not yet been established, we first aimed to develop such methods and then apply them to REE-rich mud samples from the Minamitorishima EEZ.
In this study, we first established a sample preparation method, including drying, resin embedding, and polishing, for unconsolidated pelagic clay using preliminary test samples. These preparation methods were then applied to the REE-rich mud samples from the MR15-E01 Leg2 PC04 core collected from the Minamitorishima EEZ. We selected samples from the lithological boundary of different sediment colorations. Subsequently, we conducted LA-ICP-MS analyses, obtained distribution images of the major and trace elements, and quantified the elemental concentrations of the samples using matrix-matched standard reference materials.
In this presentation, we introduce the optimized methods for the LA-ICP-MS analysis of unconsolidated seafloor sediments. Furthermore, based on the obtained geochemical data, we discuss preliminary insights into the formation processes of REE-rich mud in the Minamitorishima EEZ.
[1] Kato et al. (2011) Nature Geosci. 4, 535–539. [2] Iijima et al. (2016) Geochem. J. 50, 557–573. [3] Takaya et al. (2018) Sci. Rep. 8, 5763. [4] Tanaka et al. (2020) Ore Geol. Rev. 119, 103392.