In this study, we outline the tectonic and surface processes that have governed the landscape evolution of the outer Apenninic wedge and foreland basin in the Molise area during the late stages of the Apennines formation (Amorosi et al., 2009; Bracone et al., 2012; Amato et al., 2017), with a focus on the Trigno, the Saccione, the Biferno, the Sinarca and the Fortore River valleys. The work has been based on the combination of field data with morphometrical analysis of both the topography and the river drainage systems, resulting from the investigation of a 90m resolution DTM in a GIS environment. This approach has been widely used in literature and represents a useful tool to the landscape evolution reconstruction (Scotti et al., 2013; Buscher et al., 2017). In particular, the morphometrical investigation has been based on the elaboration of some swath profiles running parallel to the coastline and on the determination of the: 1- basin asymmetry (AF); 2- the hypsometrical integral (HI); 3- the river long profile and the derived concavity () and normalized steepness (Ksn) indexes of the main trunks and their tributaries. The results point to a north-westward increase of the medium elevation (e.g. from the Fortore to the Trigno valley, Fig. 1), which is independent from the lithological features of the study area. Also the normalized steepness index enhances an increasing trend towards the north-west (Fig. 2a). River long profile enhance a slight concave up shape for the Fortore river and a rectilinear shape for both the Biferno and the Trigno rivers (Fig. 2b). The hypsometrical integral analysis shows a north-westward increase in the HI value, suggesting a decrease in the maturity of the drainage basins from SE (e.g., from the Fortore River) to NW (e.g., to the Trigno River) (Fig. 2c and 2d). In addition, a slight asymmetry of all of the drainage basins has been recognized, with AF values generally lower than 50 suggesting valley shifting towards the hydrographic right flank (Fig. 2d). This data is also consistent with the river terraces distribution, which form a river terrace step on the hydrographic left flank of most valleys and that are less preserved on the opposite sides. The combination of field, morphostructural and morphometrical data with available stratigraphic constraints has allowed a better reconstruction of the growth and evolution of the outer Apenninic wedge in the Molise segment of the Apennines belt. In fact, it has strongly helped unravelling the features and style of the Apennines outer wedge - foredeep system recent (Late Quaternary) uplift. The picture resulting from the geomorphological data set discussed above points to differential uplift along the strike of the Apennines mountain front, with a general increasing trend of uplift towards the NW.
Long-term morphotectonic evolution of the Molise foothills (southern Apennines) / Valente, Ettore; Ascione, Alessandra; Aucelli, PIETRO PATRIZIO CIRO; Bracone, Vito; Maria Rosskopf, Carmen. - (2017), pp. 66-68. (Intervento presentato al convegno Innovative technologies for monitoring and digitally modeling past and present geomorphological processes tenutosi a Napoli nel 15-16 Giugno 2017).
Long-term morphotectonic evolution of the Molise foothills (southern Apennines)
Ettore Valente
;Alessandra Ascione;Pietro Patrizio Ciro Aucelli;
2017
Abstract
In this study, we outline the tectonic and surface processes that have governed the landscape evolution of the outer Apenninic wedge and foreland basin in the Molise area during the late stages of the Apennines formation (Amorosi et al., 2009; Bracone et al., 2012; Amato et al., 2017), with a focus on the Trigno, the Saccione, the Biferno, the Sinarca and the Fortore River valleys. The work has been based on the combination of field data with morphometrical analysis of both the topography and the river drainage systems, resulting from the investigation of a 90m resolution DTM in a GIS environment. This approach has been widely used in literature and represents a useful tool to the landscape evolution reconstruction (Scotti et al., 2013; Buscher et al., 2017). In particular, the morphometrical investigation has been based on the elaboration of some swath profiles running parallel to the coastline and on the determination of the: 1- basin asymmetry (AF); 2- the hypsometrical integral (HI); 3- the river long profile and the derived concavity () and normalized steepness (Ksn) indexes of the main trunks and their tributaries. The results point to a north-westward increase of the medium elevation (e.g. from the Fortore to the Trigno valley, Fig. 1), which is independent from the lithological features of the study area. Also the normalized steepness index enhances an increasing trend towards the north-west (Fig. 2a). River long profile enhance a slight concave up shape for the Fortore river and a rectilinear shape for both the Biferno and the Trigno rivers (Fig. 2b). The hypsometrical integral analysis shows a north-westward increase in the HI value, suggesting a decrease in the maturity of the drainage basins from SE (e.g., from the Fortore River) to NW (e.g., to the Trigno River) (Fig. 2c and 2d). In addition, a slight asymmetry of all of the drainage basins has been recognized, with AF values generally lower than 50 suggesting valley shifting towards the hydrographic right flank (Fig. 2d). This data is also consistent with the river terraces distribution, which form a river terrace step on the hydrographic left flank of most valleys and that are less preserved on the opposite sides. The combination of field, morphostructural and morphometrical data with available stratigraphic constraints has allowed a better reconstruction of the growth and evolution of the outer Apenninic wedge in the Molise segment of the Apennines belt. In fact, it has strongly helped unravelling the features and style of the Apennines outer wedge - foredeep system recent (Late Quaternary) uplift. The picture resulting from the geomorphological data set discussed above points to differential uplift along the strike of the Apennines mountain front, with a general increasing trend of uplift towards the NW.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.