MORPHOLOGY AND SEDIMENTARY PROCESSES OF THE SUBAQUEOUSTORDERA RIVER DELTA, NW MEDITERRANEAN (SPAIN)

摘要

Boundaries and sedimentary processes of coarse grained deep water deltasrncan be well understood if we consider small time period enough to assume the sandrnbody progradation. When we consider large periods, including the last sea level rise, itrnis very difficult to establish the succession of deltaic growth stages, or even thernexistence and chronology of relict bodies at different depths.rnThe Tordera River delta, located in the NE of Barcelona (NW MediteraneanrnSea) presents a coarse sand delta dominated by the NE to SE surge regime (“llevant”).rnA 8 km long bar or submerged spit is developed to the SW from its mouth, firstlyrnparallel and then progressively divergent to the coast, finishing in an extensive sandrnbank at about 10m depth.rnTordera River is the main feeder of the coastal system until the town ofrnBarcelona with the formation 60 km coarse sand beaches that constitutes the Maresmernsedimentary cell. Some decades back, the continuous sand transport has beenrninterrupted and a great part of these beaches has been eroded or had to be protected byrnworks or nourished artificially. The cause of this regressive tendency was granted tillrnnow to the construction of marinas, dredging activities and other activities.rnThe present knowledge of the deltaic system, its build-up evolution with somernrelict deltas at different depths, its chronology and sedimentary processes, acquired inrnthe last twenty years and synthesised in this paper, allows us to determine the mainrncauses of the drastic changes in sedimentary transport along the Maresme sedimentaryrncell. The own evolution of the delta sedimentary system can be the main response tornthe question and a great contribution to the ICZM policies.