Geochronology and palaeoclimatic context of submerged siliciclastic beachrock formation in the western mediterranean sea

This article describes the geomorphological and petrological characteristics of 19 submerged beachrocks lo-cated on the north Catalan coast (western Mediterranean Sea). Their length ranges between 8 and 1039 m, their width between 1.5 and 86.5 m and their thickness between 0.4 and 3.25 m. They are siliciclastic beachrocks consisting of well-rounded gravels with a very coarse sand matrix, and they have a low proportion of bioclasts (<1%). Cementation occurred in the swash zone and adjacent foreshore due to the precipitation of high magnesium calcite. From absolute dates (¹⁴C and optically stimulated luminescence) and anthropic artifacts, three phases of formation attributable to the Late Holocene were identified. Phase I corresponds to the warm and humid Roman Period and was recorded at a level below-3.75 m mean sea level (MSL). Phase II corresponds to the warm and arid Medieval Climate Anomaly and was recorded at +0.25 m to-2.5 m MSL. Phase III corresponds to the Little Ice Age and Industrial Period and was recorded at levels ranging from +0.5 m to-3.0 m MSL. Good temporal correspondence between the chronology of the cementation phases and warm and/ or dry palaeoclimatic conditions can be established.