Diagrams with composition fields of the pelitic fraction of bottom sediments in the estuarine parts of different modern river’s categories: another approach to verification

Abstract

According to analytical data given in publications [Savenko, 2006; Bayon et al., 2015], compared the position of data points of pelitic fraction of bottom sediments in the estuarine parts of a number of large rivers (rivers of category 1 according to [Bayon et al., 2015]: Amazon, Congo, Mississippi, Niger, Yangtze, Mackenzie, Volga, Danube, Mekong, Amu Darya, Northern Dvina and Loire) and their suspended material on the (La/Yb)N – Eu/Eu* and (La/Yb)N – Th diagrams. The first samples were subjected to special processing. The samples of the latter were not processed before the study. It has been established that the data points of both sample’s groups in the above diagrams are localized in the field of fine-grained (pelitic) suspension of large rivers, demonstrating some scatter for specific rivers, but generally not going beyond its limits. This gives additional reason to believe that for decoding the categories of rivers that formed certain sedimentary sequences, not only specially prepared samples can be used, but also data obtained from bulk/unprocessed samples. At the example of a fine-grained suspension of Zambezi river (South Africa) some features of the use of (La/Yb)N – Eu/Eu* and (La/Yb)N – Th diagrams were considered.