Characterising the composition of olivine and iron oxides in a sample of the Sericho meteorite by Raman spectroscopy using Principal Component Analysis

Raman spectroscopy is a key technique for planetary exploration, providing mineralogical insights under strict constraints on power, mass, and data transmission. This study applies Principal Component Analysis (PCA) to Raman imaging data from the Sericho pallasite meteorite, composed mainly of Mg-rich olivine and Fe-Ni alloy. PCA efficiently reduced the complex dataset to only five principal components retaining most of the molecular information. Using PCA scores, averaged Raman spectra were calculated to significantly simplifying spectral interpretation, highlighting olivine as the dominant mineral and goethite, disordered hematite as well as disordered carbon as minor phases in the sample. In addition, PCA scores associated with the x-y coordinate of the Raman image enables identifying distinct mineralogical domains revealing the spatial distribution of iron oxyhydroxides primarily at interfaces and fractures of the olivine inclusions. Additionally, PCA-filtered spectra enabled spatially resolved quantification of olivine composition, showing a 5–10% magnesium enrichment in olivine cores compared to interfaces with iron oxyhydroxides, suggesting weathering origins of the Fe-Ni alloy. These results demonstrate the strong potential of PCA for data reduction, visualization, and interpretation of complex Raman datasets, making it a powerful tool for in situ mineralogical analysis during future robotic or human planetary missions where fast real-time data processing is key for informed decision-making.