This
article describes the geomorphological and petrological characteristics
of 19 submerged beachrocks located 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. |