Molecular composition of sedimentary humic acids from South West Iberian Peninsula: A multi-proxy approach

► Molecular structural features of humic acids from recent coastal sediments investigated. ► Analytical tools: elemental and isotopic analysis, 13C-CP/MAS NMR and Py-GC/MS. ► Combination of tools revealed clear differences in terrestrial/marine contribution. ► Vascular plant matter contributing to all humic acids present.