This study investigates the molecular composition of a Holocene oligotrophic sapric peat core from the Mukhrino Carbon Supersite in Western Siberia, with special reference to carbon pool stabilization mechanisms. Using 13C NMR spectroscopy and elemental analysis, we analyzed peat samples across depth gradients to assess organic matter transformation and stability. Results revealed distinct variations in aromaticity, hydrophobicity, and elemental composition with depth, indicating increasing organic matter stabilization in deeper layers. The study highlights the vulnerability of surface peat layers to mineralization under climate change, emphasizing the critical role of Siberian peatlands in global carbon balance. The findings provide insights into peatland carbon dynamics and underscore the need for conservation strategies to mitigate potential carbon emissions from these ecosystems.