Downstream Variation in the Pebble Morphometry of the Trotuş River, Eastern Carpathians (Romania)

Abstract: Riverbed sediments morphometrical analysis can offer, along granulometric and petrographic analysis, relevant information on sediment source origin, transport environment and sedimentation process. Today, there are numerous descriptive indices for clasts shape and size, each one trying to evidence the influence of dynamic conditions and clasts petrography that are mobilized in certain transport environment, their shape at certain moments. Among these, this analysis focused on only 10 morphometric indices. The obtained data, either from direct measurements on 5,027 clasts or after index calculations, were processed and obtained a set of statistical parameter (average, median, standard deviation, etc.). Based on these data was assessed „optimal shape” for Trotuş riverbed gravels. Some parameters (like average value) were used to create frequency histograms for some morphometrical indices in sampling points and to make some mathematical modeling.