Beach and dune deposits on the Mediterranean coast of Andalusia (Spain) in the light of morphoscopic analysis of quartz grains

Abstract

This work aimed to investigate the abrasion of quartz grains from beach and dune deposits on the Mediterranean coast of Andalusia. Five sites were established on the coasts of Malaga and Almeria provinces: Genoveses, Monsul, Carraca, Malagueta, and Artola. Grain size and mineral composition were determined for 15 samples taken from beaches (6) and dunes (9). Quartz abrasion was established using the morphoscopic method. Investigated deposits, with two exceptions, are primarily medium-grained and moderate sorting. The share of quartz is relatively small – in aeolian sands, it is on average 38.3% and is higher than in beach sands (average 26.4%). The average proportion of fresh and angular NU grains is significantly higher in aeolian sands (58.9%) than beach sands (43.4%), indicating morphoselection’s important role during wind transport. In beach sands, there are, on average, 32.4% of grains with aeolian abrasion (RM and EM/RM), which is twice as much as in dune sands (15.5%). The multiple predominances of EM/RM grains over RM grains indicate a relatively short aeolian activity.