Seeing Sediments in a New Light: Hyperspectral Imaging for Paleoenvironmental Insights

Le résumé fourni par la source

The application of hyperspectral imaging (400–2500 nm) to lacustrine sediment cores enables detailed, non-invasive characterization of sediment composition and structure. This method provides unprecedented spatial and spectral resolution, facilitating the detection and quantification of proxies for environmental change, including organic content, mineralogy, and pigment concentrations. Its integration into paleolimnological studies significantly enhances our ability to decode both natural variability and anthropogenic impacts.We developed and applied an innovative, non-destructive hyperspectral imaging approach (400–2500 nm) at very high spatial resolution for the study of lake sediment archives. This work led to several major scientific contributions:Quantification of refractory organic matter: We demonstrated the ability of hyperspectral data to detect and map inputs of fossil organic matter (e.g., coal-derived material) associated with glacial erosion, particularly in polar environments (e.g., Svalbard).Detection of past fire events: By integrating hyperspectral imaging with geochemical and paleoecological data, we identified spectral signatures related to biomass burning, enabling reconstruction of fire history in Mediterranean lacustrine sediments.Reconstruction of primary productivity: Through a critical assessment of existing hyperspectral indices, we proposed a new, more robust index to trace variations in labile organic matter and lake productivity.Sediment source tracing: We developed multivariate analysis tools to discriminate sediment sources within cores, enabling a fast and quantitative "source-to-sink" assessment of sediment transport dynamics.Contaminant identification and quantification: Hyperspectral imaging has proven to be a valuable tool for detecting and mapping contaminants in environmental archives such as lake sediments.Its ability to capture detailed spectral signatures across hundreds of narrow bands allows for the identification of specific compounds, including heavy metals, organic pollutants, and anthropogenic particles. This non-destructive technique enables high-resolution spatial analysis of contamination patterns, helping to trace pollution sources and assess historical trends in environmental degradation. By providing rapid and reproducible results, hyperspectral imaging complements traditional chemical analyses and opens new avenues for large-scale environmental monitoring.These results highlight the versatility and potential of hyperspectral imaging as a powerful tool to investigate both natural and anthropogenic drivers in continental environments.

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