Geomorfologia e Sedimentologia dei depositi quaternari del Rio Corr’e Pruna (Sardegna sud-orientale)

Geomorphology and Sedimentology of Quaternary deposits of Rio Carr’e Pruna (SE Sardinia)

Abstract

A total of 66 sandy samples of Corr’e Pruna River has been analyzed in order to determine the geological meaning of certain textural parameters. Samples consist of a mixture of gravel and medium to fine sand and all grain size frequency distributions are bimodal. Sediments of Stream Gutturu Frascu consist of very coarse sands with a median of -1 to 0,35 0 units and a standard deviation of 0,75 to 1,00 0 units. All the curves are nearly normal with skewness ranging from -0,12 to 0,25. Sands of Corr’e Pruna channel are coarse with a median of -1 to 1 0 units, a standard deviation of 0,52 to 0,98 0 units and a skewness ranging from -0,10 to 0,32. Sands of terraces T 1 are coarse and medium with a median of -0,70 to 1 0 units, a standard deviation of 0,60 to 1,70 0 units and skewness ranging from 0,07 to 0,24. Sands of terraces T 2 are coarse and medium with a median of – 0,12 to 0,70 0 units, a standard deviation of 0,54 to 1,41 0 units and a skewness ranging from -0,02 to 0,10. These four sedimentological kinds have been confronted analytically and experimental results have been verificated. Comparison between sample means and variances have been carried out by statistical tests of significance: Student’s t-test and F-test. Initially, F test has been applied simultaneously to four fundamental grain size frequency distributions, successively, t-test has been applied to all possible combination of sets of samples. Experimental and theoretical results suggest that conditions of the old depositing agent seem to have an excellent analogy with the conditions of the actual depositing agent.