Environmental changes at the inner sector of Rيa de Muros (NW Spain) during Middle to Late Holocene

A multiproxy approach has been performed on sediments collected by gravity and box coring at the inner part of the Rيa de Muros to reconstruct its environmental evolution since the Middle Holocene. This reconstruction is based on the chronological framework provided by radiocarbon dating of foraminifera samples. distinct facies were identified in the sedimentary record. The oldest, characterised by coarse-grained sediments and a strong terrestrial signature, is likely linked to the progradation of the delta-fan of the Maior River during a period of standstill subsequent to the Holocene sea-level maximum (ca. 6900 cal yr BP). The second facies started to deposit approximately 2865 ± 335 cal yr BP and is characterized by the deposition of finer-grained, marine-influenced sediments linked to a period of reduced local hydrodynamic energy, most likely due to a progression of sea-level rise. The third facies started to deposit approximately 1720 ± 180 cal yr BP and shows a progressively stronger marine influence. The characteristics of the last facies are explained as the result of the added effects of progressive sea-level rise and an intensified upwelling reaching the inner rيa. This facies shows clear anthropogenic features since 555 ± 65 cal yr BP, associated with the important mediaeval development of the area. tained results suggest that high-resolution studies are key to resolve possible sea-level oscillations during the late Holocene and allow distinguishing local/regional changes superimposed to the global signals.