Daniele Savelli

Structural and sedimentary features in the Tyrrhenian margin off Campania, Southern Italy

Abstract The utilization of multichannel seismic reflection profiles permits the identification of the generally E-W trending Miocene orogenic and Plio-Quaternary post-orogenic features of Apennine (NW-SE) and anti-Apennine (NE-SW) trends in the Campanian margin. The former features are constituted by carbonate and/or allochthonous sheets which were thrust mainly towards the north and northeast during the Miocene tectogenetic phases. The latter are represented by extensional structures which affected the orogenic features during Plio-Quaternary times. The anti-Apennine tectonic trend is responsible for the recent (Late Pliocene—Quaternary) and remarkable block-faulting differential subsidence of the southern margin, as well as for its present morphology. The ragged and disconnected pattern of the allochthonous units over the present-day slope and their accumulation underneath the shelf area suggest that they are the result of gravitational gliding tectonics. Gravity cores and 3.5-kHz subbottom profiles indicate that the Salerno Trough and Capri Basin areas are characterized by a particular neotectonic mobility; this is proved by the thick and coarse-grained sediment accumulation from steep relief produced by block faulting. This faulting created uplift belts serving as sediment source.

Active deformation in the frontal part of the Northern Apennines: insights from the lower Metauro River basin area (northern Marche, Italy) and adjacent Adriatic off-shore

Abstract An integration of seismological data with geological and geomorphological information aided by seismic interpretation was performed to characterise the Quaternary tectonic evolution of the Metauro River basin area (northern Marche) and adjacent off-shore sector of the external Northern Apennines. On-shore, along the Adriatic coast, the youngest age of thrusting and folding post-dates the Early-Middle Pliocene, while Pleistocene deposits appear to be, at least in part, not involved in the deformation. Recent (i.e. post-thrusting) tectonic structures have been recognised both in pre-Quaternary substratum rocks and in Upper Quaternary continental deposits (Upper Pleistocene terrace alluvium, Upper Pleistocene–Holocene slope deposits). These faults are all compatible with a WSW–ENE oriented extension. In the Metauro River basin area, preserved flights of stream terraces have been categorised according to the presence or absence of alluvial suites in relationship to each terrace level. Here, based on both the heights above the valley floor and the areal distribution of stream terraces, a generalised vertical tectonic uplift can be inferred, particularly during the Middle–Late Pleistocene. Moreover, the along-valley distribution of stream terraces provides further constraints on the age of thrusting and folding. In fact, the reconstructed terrace-levels are substantially parallel, and no evidence for any significant deformation by fold activity has been recognised. Local deformation displayed by both terrace surfaces and alluvial/slope-waste deposits suggests, instead, the intervening of some minor differential movements associated with the generalised uplift and/or to Middle–Late Pleistocene normal faulting. Their occurrence appears anyhow to be unrelated with the pattern of folds and associated thrusts. The present-day seismic activity of the study area was considered by analysing 83 seismic events that occurred from 1987 to 2000. The epicentre distribution is very scattered, and depths are generally comprised within the first 20 km of the crust, clustering between 0 and 15 km. Most of the events have magnitude

Diverging drainage in the Marche Apennines (central Italy)

Abstract In the Marche Apennines diverging drainage developed on the surface of mid-Pleistocene fanglomerates or, at places, on correlated erosional glacis. In mountain areas, diverging nets correspond with wide glacis shaped in severe cold climates at the end of the middle Pleistocene. Glacis were formed by deposition of coalescing alluvial fans and concurrent shaping of smooth erosional surfaces along and near their margins. In the coastal zone, wide fans and related fluvial plains were constructed in Crotonian times close to the mouth of trunk streams crossing a just emerged piedmont area. Both the control of the “cone shaped” topography on post-aggradational flow patterns and the entrenching of primitive distributary channels are conceivable in developing the diverging drainage of the study area. Four case studies, from areas differing both in age and in geological and structural settings, attest to the recurrence of this drainage in composing, together with other patterns, the grain of larger nets. Moreover, the diverging drainage of the coast area allows us to infer that superposition is an effective mechanism of net development on Plio-Pleistocene terrains of the Marche Apennine piedmont at the time when they became emergent.

Geomorphological map of the Montelago area (North Marche Apennines, central Italy): constrains for two relict lakes

The hamlet of Montelago (‘Mountain of the Lake’) lies within the northern Marche Apennines close to the watershed of Fosso del Lago (‘Stream of the Lake’): both Italian toponyms clearly suggest the presence of a paleolake. Official geological maps reported lacustrine sediments within the upper basin of the Fosso del Lago stream, where outcrops of lacustrine sediments have also been noted for about five decades. The nineteenth-century Gregorian cadastral map also reports water ponds roughly in the area where lacustrine sediments were found: nonetheless, their position is clearly shifted upstream with respect to the reported lacustrine sediments. In this context, we have recently performed a targeted geomorphological survey addressed at unravelling such apparent discrepancy. Our study confirms the occurrence of lacustrine sediments spanning from Atlantic up to Sub-Boreal exactly in the place reported by previous geological works. The detailed geomorphological map created for the area allowed us to adequately locate previously published subsurface prospecting both highlighting landslide damming as the process responsible for lake formation and providing information for an adequate morphoevolutive reconstruction of the area. Geomorphological mapping also resolved the problem of the different position of the ponds mapped by the Gregorian Cadastre, stating that these had no direct relationships with the former lake but rather consisted of a small man-made reservoir directly connected by broad channels to springs which are currently dried-out.

Geomorphological and anthropic control of the development of some Adriatic historical towns (Italy) since the Roman age

Abstract The geomorphological analysis of historically urbanized areas is the best scientific way to understand how the extant geomorphological factors conditioned urbanization. It also provides a baseline to enable comparisons to be made with the modern environment. This paper considers four urbanized historical sites on the Adriatic coast (Italy) that owe their urban development to particular geomorphological and environmental conditions that were modified over the centuries from the Roman age to the present day. The focus here is on the evolution of the shoreline and associated geomorphic variables (streambeds and river mouths migration). These factors are fundamental for determining the development of a city, both as basic boundary elements – therefore including defence and protection – and also for the development of harbours.

Rocky Cliffs Joining Velvet Beaches: The Northern Marche Coast

The northern Marche coastal area epitomizes many of the elements forming the rich natural, historical and cultural tissue of the Adriatic seaside of central Italy. The natural heritage, partly protected in natural reserves, also amalgamates with tourist facilities that exploit several renowned beach resorts. The northern Marche coastal area, consisting of a coastal plain interposed between two rocky shore sectors, forms a peculiar blend of different geomorphological units with distinctive landforms. The coastal plain joins landwards fossil cliffs and includes the major river mouths. The rapidly recessing rocky shores develop structural landforms, sea-stacks and benches. Both active and relict cliff retreat induces extensive landsliding in the whole sea-facing hillslopes.