## 4 Results and Discussion
### Sedimentological Processes and Facies Recognition  
The statistical elaboration of the biogeochemical and sedimentological variables highlights the presence of three main factors explaining, on overall, 94.6% of the total variance. These factors mainly represent the three key BSFs in the coastal marine area of the Southern Marche. The most significant _facies_ (BSF1) explains 79.2% of the total variance and is characterized by sediments with (Figure 3a) high contents of clay and fine silt, some elements (i.e., Al, Ti, Mg, K, Na, P, Fe, Co, Cu, Zn, Ni, Pb, V, Ga, Li, Y, and Zr mainly linked to clay minerals), OC that is directly linked to the Organic Matter (OM), and TN that is contained both in the OM and in the clay minerals. The SBF1 is therefore sedimentological facies consisting primarily of fine pelitic sediments with abundant clay minerals and OM. The  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & **Mean** & **Median** & **Min** & **Max** & **Dev. Std. ** & \(n\) \\ \hline As & C\({}_{f}\) & 1.0 & 1.0 & 0.3 & 3.1 & 0.5 & 41 \\  & EF & 1.8 & 1.6 & 0.7 & 4.8 & 0.8 & 41 \\  & I  
extracted scores of these facies increase seaward, starting from values close to zero, that imply absence of politic sediment, clay minerals and OM, near coast, to values close to 1 (i.e., sediments made up of almost all fine sediments) (Figure 3b). By considering the areal distribution of the fine peitic, organic and clay-rich sediments of BSF1 and the general cyclonic circulation of the Adriatic Sea as well as the reworking and removing action of the wave near the coast, the sediments of the BSF1 are inferred to be mainly sourced from the fine load of the Po River as well as from that of the Apennine rivers in the northern part of the study area. For this reason, the BSF1 facies can be assimilated and named as the _Padanic Facies_ of [PERSON] et al. (2014) [4]. The fine particles introduced in the Adriatic Sea in front of the river mouths and are then resuspended by the wave action and transported southwards by the WAC [2]. As a result, the fine particles settle at greater depths in a belt area aligned to the coastline, where the action of the wave motion on the seabed is weaker [4]. Furthermore, the WAC confines the suspended sediments near the coast, preventing their spreading eastward limiting their sedimentation towards the center of the basin. The fine sediments of the BSF1 are subject to a continuous reworking process acting on the sea bottom. This consists in repeated resuggension and redeposition processes, due to strong storms that result in the transportation and dilution processes of the BSF1 sediments southward. As a consequence of this sedimentological and hydrographic set up, the present offshore sediment accumulation is very feeble, and the relict sediments connected to the last sea level rise tend to surface in the deeper side of the north-central Adriatic Sea. The BSF1 facies approaches towards the coast between the Chienti and the Ete Vivo rivers and in front of the Tronto river where it also shows a maximum (Figure 3b). This distribution near the coast suggests that the Chienti, Tenna and, to a greater extent, the Tronto rivers discharge more fine sediment than the other rivers in the southern Marche. Figure 3: Histogram of the factor scores (**a**) and map of the areal distribution of the of the BSF1 (**b**). The second facies (BSF2) represents 14.5% of the total variance and is marked by high contents of sand, IC, Ca, Sr, OC/TN, pH, and Eh (Figure 4a). Calcium and IC are typical of sediments with abundant carbonate, while high values of pH and Eh are associated to coarse grain-sizes. Based on these characteristics, it can be inferred that the BSF2 is mainly made up of a coarse sandy sediment enriched in carbonates.