Dario Gioia

Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints

Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints Age constraints of geomorphological markers and consequent estimates of long- to short-term denudation rates from southern Italy are given here. Geomorphic analysis of the valley of the Tanagro River combined with apatite fission track data and radiometric dating provided useful information on the ages and evolution of some significant morphotectonic markers such as regional planated landscapes, erosional land surfaces and fluvial terraces. Reconstruction of paleotopography and estimation of the eroded volumes were perfomed starting from the plano-altimetric distribution of several orders of erosional land surfaces surveyed in the study area. Additional data about denudation rates related to the recent and/or active geomorphological system have been obtained by estimating the amount of suspended sediment yield at the outlet of some catchments using empirical relationships based on the hierarchical arrangement of the drainage network. Denudation rates obtained through these methods have been compared with the sedimentation rates calculated for two adjacent basins (the Pantano di San Gregorio and the Vallo di Diano), on the basis of published tephrochronological constraints. These rates have also been compared with those calculated for the historical sediment accumulation in a small catchment located to the north of the study area, with long-term exhumation data from thermochronometry, and with uplift rates from the study area. Long- and short-term denudation rates are included between 0.1 and 0.2 mm/yr, in good agreement with regional data and long-term sedimentation rates from the Vallo di Diano and the Pantano di San Gregorio Magno basins. On the other hand, higher values of exhumation rates from thermochronometry suggest the existence of past erosional processes faster than the recent and present-day exogenic dismantling. Finally, the comparison between uplift and denudation rates indicates that the fluvial erosion did not match the tectonic uplift during the Quaternary in this sector of the chain. The axial zone of the southern Apennines should therefore be regarded as a landscape in conditions of geomorphological disequilibrium.

Morpho-sedimentary features and sediment transport model of the submerged beach of the ‘Pineta della foce del Garigliano’ SCI Site (Caserta, southern Italy)

ABSTRACT In this paper, we present the results of a detailed geomorphological and sedimentological study of a coastal sector of southern Italy, the Pineta della foce del Garigliano SCI (i.e. Site of Community Importance), which is largely affected by shoreline retreat and the degradation of dune habitat. The analysis of shoreline evolution demonstrates that severe erosion processes have occurred over the last 50 years. They caused the complete dismantling of the foredune, whereas the anomalous and advanced position of the secondary dune promoted a progressive loss of vegetation habitat of high environmental value such as juniper (Juniperus oxycedrus ssp. macrocarpa). Morpho-sedimentary data and hydrodynamic models suggest that the main climate events promoted a net longshore transport toward the South. Our analyses confirm that erosion processes are linked to natural factors but several negative human practices have contributed to the acceleration of shoreline retreat and degradation of the dune habitat. In addition to its scientific value, the map and data here presented represent an important tool for beach management purposes.

Landslide inventory map of the upper Sinni River valley, Southern Italy †

In this paper, we present a geomorphological landslide inventory map for an intermountain catchment in the southern Italian Apennines. The study area is seismically active, and it is characterized by high uplift rates produced by Quaternary tectonics. A total of 531 landslides of different types, relative age, and sizes, including some kilometer-scale relict landslides were mapped through the visual interpretation of 1:33,000-scale stereoscopic aerial photographs, and dedicated field surveys. Analysis of the inventory map revealed that recent landslides consist chiefly of reactivations of older landslides, and of the new landslides formed in pre-existing landslide deposits, triggered primarily by intense rainfall events, or prolonged rainfall periods. We expect that the inventory will be used for the evaluation of landslide susceptibility and hazard in the area, and to investigate the long-term geomorphological evolution of a portion of the southern Apennines.

Morphotectonic evolution of connected intermontane basins from the southern Apennines, Italy: the legacy of the pre-existing structurally controlled landscape

The opening kinematics of several Pliocene to Quaternary tectonically controlled continental basins scattered along the axis of the southern Italian Apennines and their morphological features and evolution have been compared to define the behaviour of this particular interconnected negative morphostructure. In particular, three different but morphologically connected intermontane basins have been here investigated from a morphotectonic point of view (from the north: Auletta, Vallo di Diano, and Sanza basins). They are filled by more or less thick marine and/or continental sequences of sediments, Pliocene to Quaternary in age. Such basins are shaped by erosional land surfaces and fluvial dissection. The ages of the morphological de-activation of the terraced surfaces have been roughly defined on the basis of their morpho-stratigraphic relationships with Pliocene and Quaternary deposits, and better constrained by radiometric dating. The NNW–SSE-trending fault of the Alburni Mts, bordering the Auletta basin, indicates former left-lateral transtensional kinematics and later dip-slip kinematics, whereas the N140–150°-striking master fault bounding the Vallo di Diano basin is a normal fault. The Sanza basin can be assimilated to a morphostructural trough coinciding with a long-term transfer zone of the chain, in which a severe change in stress field, uplift rate, climate conditions, and relief production occurred during Pleistocene times. Such a complicated morphostructural setting may be interpreted as a function of the original orientation of the structural depressions, only partially coeval. In this sense, the Vallo di Diano basin should represent the structural low generated by pure extension during the Pleistocene, but probably already living as a Pliocene seaway, whereas both the Auletta and Sanza basins stand for two lateral branches with oblique kinematics, inherited from a pre-existing (i.e. Pliocene in age) set.

Long-term geomorphological evolution of the axial zone of the Campania-Lucania Apennine, southern Italy: a review

Abstract Uplift and erosion rates have been calculated for a large sector of the Campania-Lucania Apennine and Calabrian arc, Italy, using both geomorphological observations (elevations, ages and arrangement of depositional and erosional land surfaces and other morphotectonic markers) and stratigraphical and structural data (sea-level related facies, base levels, fault kinematics, and fault offset estimations). The values of the Quaternary uplift rates of the southern Apennines vary from 0.2 mm/yr to about 1.2–1.3 mm/yr. The erosion rates from key-areas of the southern Apennines, obtained from both quantitative geomorphic analysis and missing volumes calculations, has been estimated at 0.2 mm/yr since the Middle Pleistocene. Since the Late Pleistocene erosion and uplift rates match well, the axial-zone landscape could have reached a flux steady state during that time, although it is more probable that the entire study area may be a transient landscape. Tectonic denudation phenomena — leading to the exhumation of the Mesozoic core of the chain — followed by an impressive regional planation started in the Late Pliocene have to be taken into account for a coherent explanation of the morphological evolution of southern Italy.

Geomorphological, mineralogical, and geochemical evidence of Pleistocene weathering conditions in the southern Italian Apennines

Geomorphological, mineralogical, and geochemical evidence of Pleistocene weathering conditions in the southern Italian Apennines Pleistocene weathering, uplift rates, and mass movements have been studied and correlated in a key-area of the Italian southern Apennines. The study area is the Melandro River valley, developed in a tectonically-controlled Quaternary intermontane basin of the axial zone of the chain. The goal of this paper is to assess ages and geomorphic features of two paleo-landslides and to relate them to values of uplift rates and the climate conditions in the axial zone of the chain during the Pleistocene. Uplift rates have been estimated using elevation and age of flat erosional land surfaces. In the southern area of the basin, the landscape features a wide paleo-landslide which can be ascribed to the upper part of the Lower Pleistocene on the basis of relationships with Quaternary deposits and land surfaces. Another paleo-landslide, in the northern sector of the basin, can be referred to the beginning of the Upper Pleistocene. The correlation between the ages of the two landslides and the temporal trend of the uplift rates allowed us to hypothesize that mass movements occurred in response to uplift peaks that destabilized slopes. Additionally, deciphering weathering conditions by means of the analysis of mineralogical and geochemical signals from landslide deposits and weathered horizons allowed assessment of changes in paleoclimate scenarios during the Pleistocene. The deep weathering was probably caused by the onset of warm-humid climate conditions, which may have acted as a further factor triggering landslide movements in an area already destabilized by the rapid uplift.

Regional-scale landslide inventory, central-western sector of the Basilicata region (Southern Apennines, Italy)

ABSTRACT A detailed landslide inventory map has been drawn for a large sector of the axial-outer zone of the Southern Italian Apennines using photo-aerial interpretation and field survey. Our results reveal a landscape greatly affected by landslide phenomena, which involve about 7% of the entire area. DEM analysis allowed us to assess the influence of landslide processes on the geomorphological evolution and investigate the main predisposing factors, which promote the initiation and evolution of mass movements. In order to understand the influence of lithological and topographic factors on slope processes, an evaluation of the landslide susceptibility has been carried out using the SINMAP model. A statistical comparison between the stability index map and landslides highlights a good prediction ability of the susceptibility assessment. Apart from the implications for mass movement processes and relief evolution, the acquired data can represent a basic contribution to land management and hazard assessment as well as the gathering of basic information on landslide susceptibility of this sector of the southern Apennine chain.

Chronological constraints on a Holocene landslide in an intermontane basin of the southern Apennines, Italy: Morphological evolution and palaeoclimate implications

In this work a detailed geomorphological study aimed to reconstruct the Holocene evolution of a slope largely affected by landsliding is presented. The study area is located in the lower valley of the Tanagro River, flowing in the Auletta basin, a Pliocene to Quaternary tectonic depression located along the elongation axis of southern Apennines. In order to investigate the relationships between landscape evolution and triggering factors, and to better constrain the Holocene palaeoclimate scenario in which the mass movements occurred, geomorphological data have been integrated with those deriving by the stratigraphic, chronological, and minero-geochemical analyses of the deposits genetically related to the landslide events. The investigated landslide shows a complex style of activity, with compound rotational and translational slide in the upper part of the slope evolving into flow in the lower part. The chronological evolution of the landslide activity has been constrained through radiocarbon dating of palustrine deposits, genetically related to the landslide, and of interbedded paleosols. On the basis of the presented data, the main landslide event can be placed at the beginning of the Holocene and it is followed by a period of scarse landslide activity, as demonstrated by the sedimentation of palustrine deposits within an endorheic pond. As the small basin was created by a counterslope rotation related to the main landslide phenomenon, its deposits post-date the age of the landslide. The geomorphological features related to the main gravitative event are strongly modified by reactivations occurred at the beginnings of Sub-Boreal period, which represent, in southern Europe, the warmest and wettest stage of the Holocene. As confirmed by mineralogical and geochemical data, intense and/or prolonged precipitation might have played a major role as triggering factor in reactivating the slope movement.

UAV images and historical aerial-photos for geomorphological analysis and hillslope evolution of the Uggiano medieval archaeological site (Basilicata, southern Italy)

ABSTRACT In this work, we introduce the results of a multi-temporal analysis of UAV (unmanned aerial vehicle) images of the Uggiano castle, a highly degraded medieval archaeological site located about 5 km to the north-west of the Ferrandina town (Basilicata, southern Italy). The geomorphological analysis carried out by multi-temporal images has been integrated with a geological field survey in order to retrace the hillslope evolution of the site as well as the adjacent slopes. This kind of analysis allows to investigate the main stratigraphical and topographic factors responsible for the slope processes, acting along the outer edges of the archaeological site, which is today reduced to a few ruins located at the top of a circular ridge with steep slopes shaped on sandy-conglomerate Pleistocene regressive deposits. The instability phenomena are mainly due to localized erosional processes and falls in conglomerates, which affected the edges of the top surface, where the castle was built. High-resolution images also highlight several collapses of artificial cavities (cisterns) in the central sector of the archaeological site. In addition, a comparison between oblique and vertical UAV images, historical maps, aerial-photo images and the relationships with rainfalls permitted to acquire key data about evolution of slope and erosional processes. Such integrated approach allowed us to individuate in safety conditions the more exposed sectors of archaeological site, where the slope failure processes and collapse cavities occurred, as well as their time activation.

Landslide inventory of the Basilicata region (Southern Italy)

ABSTRACT A 1:10,000 scale landslide inventory map has been prepared for the Basilicata region (southern Italy) through extensive geomorphological analyses based on aerial photo-interpretations and field surveys. The study area (about 8000 km2) includes different morpho-structural domains of the southern Italian Apennines, and our results suggest that mass movement processes are mainly related to the intrinsic fragility of the landscape, which is featured by high relief and widespread outcrops of clay-rich deposits. As a matter of fact, the landslides of the inventory map cover about 4.8% of the surface area of the Basilicata region, whereas the total percentage of the area covered by the landslides reaches a value of 7.7%, if one considers also the landslides surveyed in previous works.