Grain-size end-members and environmentally sensitive grain-size components: A comparative study in the mud shelf depocenters off southern Brazil

The current study aims to do a comparative analysis of the results obtained with two End-Member (EM) grain-size modeling techniques (AnalySize and BasEMMA) and the Environmental Sensitive Grain-Size (ESGS) modeling for sediment samples collected in the mudbelts of the southern Brazilian shelf. The methods were compared using grain-size data from the south Brazilian shelf, and the results are discussed here. It is the first time that the concept of ESGS, in its present form, is utilized outside China. The results show that despite its relative ease of use, the ESGS is not fully comparable to the EM analyses, and only two grain-size ESGS classes were recognized as analogous to EMs. The comparison of the AnalySize and BasEMMA procedures also revealed significant differences between the techniques. A comparative analysis between the two EM techniques revealed advantages in the BasEMMA, especially in the better correlation of the end-members with the original grain size distribution. The analysis of the geographical distribution of the EM abundances allowed point sources of sandy populations to be recognized as well as the contribution of the Rio de la Plata as a source of silty sediments to be inferred.