Recent sedimentation in Valencia Lagoon : preliminary results

The Valencia lagoon is one of the most interesting ecosytems on the Valencian coast. Historically it has undergone a considerable reduction in surface area due to natural processes and mostly to human impact. Studies about lagoon sedimentation are of increasing scientific and economic value. This work concerns the sediment characteristics and the rates of sedimentation within the Valencia Lagoon based on sedimentological analyses and 14 C dates from cores. The sedimentological analyses confirm the change in the lagoonal environment from a saline situation to that of a freshwater situation. The lower quantities of plant remains in the cores at the same levels where shells are more abundant, as well as the increase in shell size, and accompanying increase in clay content support the hypothesis of a change from marine to a continental environment as the present is approached. The results of the carbon-dating of shell-rich layers establish a sedimentation rate lower than previous estimates and lead to the conclusion that a great quantity of sediments is being trapped in the peripheral marshy area and does not reach the aquatic lagoon.