Morphology, Texture and Mineralogical Composition of Sandy Beaches in the South of Chile

Abstract

The coast facing the East Pacific near 40°S Latitude is characterized by a wide variety of sandy beaches. Different elevations were sampled along 16 beaches near Valdivia (Chile), to characterize variability in morphological, textural and mineralogical characteristics. Principal Component Analysis carried out with the mean values of 14 variables, showed that the first three components accounted for 73.4% of the total variance (Component I = 38.8%, Component II = 21.7%, Component III = 12.9%) and resulted in ordination of beaches in two main groups: one included fully reflective sites, which differed from the others by their coarser particles and steeper profiles (variables which loaded highest on Component I); the other group was comprised of beaches with dissipative and intermediate characteristics, as well as by sites with mixed characteristics. In the last group it was also possible to distinguish a sub-group of beaches, a distinction primarily based upon percentage of very fine sediments and shoreline orientation (two of the variables which loaded highest on Component I). The beach ordination results, and the interrelationships among the variables are discussed in relation to sediment provenance and hydrodynamic factors which form the beaches.