Raman spectroscopic data (raw and processed) for Palaeogene charcoal samples A1, A2, B, and A1 thin section (A1-TS), including application of FWHMRa geothermometry as per Theurer et al. (2022). Spectral data collected and processed in Renishaw WiRE 3.4 software. Those data presented in sheet 'HDHG Method 3' refer to spectral data processed in MATLAB, implementing 'peak-fit' and secondary deconvolution codes, as per O'Haver (2015, 2022) and Schito et al. (2020, 2022), respectively. O'Haver, T. (2015). A Pragmatic Introduction to Signal Processing [Online]. Retrieved from https://terpconnect.umd.edu/~toh/spectrum/CurveFittingC.html O'Haver, T. (2022). peakfit.m [Code]. MATLAB Central File Exchange. Retrieved from https://www.mathworks.com/matlabcentral/fileexchange/23611-peakfit-m Schito, A. & Corrado, S. (2020). An automatic approach for characterization of the thermal maturity of dispersed organic matter Raman spectra at low diagenetic stages. Journal of the Geological Society of London - Special Publications. 484, 107–119. doi: 10.1144/SP484.5 Schito, A., Pensa, A., Corrado, S., Vona, A., Trolese, M., Morgavi, D., et al. (2022). Calibrating carbonization temperatures of wood fragments embedded within pyroclastic density currents through Raman spectroscopy. Minerals, 12, 203. doi: 10.3390/min12020203 Theurer, T., Naszarkowski, N., Muirhead, D. K., Jolley, D. & Mauquoy, D. (2022). Assessing modern Calluna heathland fire temperatures using Raman spectroscopy: Implications for past regimes and geothermometry. Frontiers in Earth Science, 10, 827933. doi: 10.3389/feart.2022.827933