Sedimentary features of incipient beachrock deposits along the coast of Simeto River Delta (eastern Sicily, Italy).

The occurrence of beachrock outcrops along the coast of the Simeto River delta, the greater watercourse of Sicily, is described in this work. The delta is located into a microtidal context, where the wave energy action prevails on the coastal depositional processes as controlling factor. The deposits are constituted by discontinuous levels, 1-1,2 meters thick of very well cemented arenitic sediments of recent age. The present human-induced changes of the precarious equilibrium regulating the sediment supply to the coast during last century, in the high part of the Simeto River drainage basin, caused strong erosion, with marked coastal land-loss examples. Because of that, the studied horizons have been quickly exposed from their original cover. As a consequence, they have been comprised into a vadose-freatic horizon, affected by percolation of meteoric and marine waters. Precipitation of calcite- and aragonite-rich solutions has determined their rapid cementation. For this reason, these discontinuous levels cropping out along the southern sector of Plaia di Catania beach are considered as recent incipient beachrocks sensu Kneale and Viles (2000). Beachrock formation, principally due to strong erosional rates characterising the Catania coastal plain, is also attributed to the high tectonic uplift rate, which has affected the whole eastern margin of Sicily, at least since the Upper Pleistocene.