Organic matter sources for tidal marsh sediment over the past two millennia in the Minho River estuary (NW Iberian Peninsula)

► A 1 m core from the Minho tidal marsh comprised almost 2000 yr of sediment record. ► Bulk geochemical parameters and biomarker assemblages matched with recorded climatic episodes and anthropogenic activity. ► Results indicate major land derived OM, with maximum terrestrial signature during the Little Ice Age. ► Significant decrease in the riverine OM input found in 1960-1985 AD section.