Vincenzo Amato

New morphostratigraphic and chronological constraints for the Quaternary paleosurfaces of the Molise Apennine (southern Italy)

New morphostratigraphic and chronological constraints for the Quaternary paleosurfaces of the Molise Apennine (southern Italy) The Molise Apennines feature numerous relicts of paleosurfaces, mostly of erosional origin, which represent the remnants of gently-rolling ancient landscapes now hanging at different altitudes above the local base-levels of erosion. Their genesis can be related to prolonged periods of relative tectonic stability alternating with periods of uplift, or to the interplay between steady tectonic uplift and climatic fluctuations. Four orders of paleosurfaces were recognized: I (> 1,100 m a.s.l.), II (900-1,000 m a.s.l.), III (750-850 m a.s.l.), IV (600-720 m a.s.l.). The most ancient orders (I and II) are cut into the bedrock and are located at the top of the Matese and Montagnola di Frosolone massifs. The youngest paleosurfaces (III—IV), partially cut into Quaternary deposits, are found along the valley flanks of the main river systems and within the Boiano, Carpino, Isernia and Sessano intramontane basins. The present study deals with the dating of the Sessano Basin Paleosurface (SBP) which is related to the IV order and is cut into the basin infill. The 40Ar/39Ar age of a tephra layer (437 ± 1.9 ka), intercalated at the top of the succession, supported by archaeo-stratigraphic, palynological and paleopedological data, allowed the SBP surface to be constrained to 350-300 ka. The SBP chronological position represents an important morphostratigraphic marker: it is the first ante quem and post quem date that allows the chronological position of the other orders of paleosurfaces to be better constrained.

Long-term landscape evolution of the Molise sector of the central-southern Apennines, Italy

Abstract This paper concerns the reconstruction of the main stages of the long-term landscape evolution of the Molise portion of the central-southern Apennines along a transect divided into three sectors (SW, Central and NE). Analysis mainly focused on geomorphological, stratigraphical and structural data supported by chronological constraints, coming from an overall review of past literature and several studies carried out by the authors of the paper during the last 20 years. The results obtained allowed the elaboration of a conceptual model of the long-term evolution of the Molise sector of the central-southern Apennines. Starting from the Pliocene, the emersion of the Molise area occurred gradually from SW to NE, allowing a polycyclic landscape to evolve under the major controls first of compression then transtensional to extensional tectonics as well as climatic variations. Principal markers of the Quaternary geomorphological evolution of the Molise area are represented by the infill successions of the intermontane tectonic depressions located in its internal, SW sector and by four orders of palaeosurfaces that developed between the Early Pleistocene and the beginning of the Late Pleistocene across the region. These markers testify to the alternation of phases of substantial tectonic stability and uplift whose spatial-temporal distribution could be assessed along the investigated transect. Results highlight that the most important stages of landscape evolution occurred during the Early and Middle Pleistocene. At the beginning of the Late Pleistocene, the Molise sector of the Apennine chain had already reached its present setting and further landscape evolution occurred under the major control of climate and land-use.

Geomorphic response to late Quaternary tectonics in the axial portion of the Southern Apennines (Italy): A case study from the Calore River valley: Geomorphic response to the Quaternary tectonics in the Calore R valley

The present study focuses on themorphotectonic evolution of the axial portion of the SouthernApennine chain between the lower Calore River valley and the northern Camposauro mountain front (Campania Region). A multidisciplinary approach was used, including geomorphological, field-geology, stratigraphical, morphotectonic, structural, Ar/Ar and tephrostratigraphical data. Results indicate that, from the Lower Pleistocene onwards, this sector of the chain was affected by extensional tectonics responsible for the onset of the sedimentation of Quaternary fluvial, alluvial fan and slope deposits. Fault systems are mainly composed of NW-SE, NE– SWandW-E trending strike-slip and normal faults, associated toNW-SE andNE–SWoriented extensions. Fault scarps, stratigraphical and structural data and morphotectonic indicators suggest that these faults affected the wide piedmont area of the northern Camposauro mountain front in the Lower Pleistocene–Upper Pleistocene time span. Faults affected both the oldest Quaternary slope deposits (Laiano Synthem, Lower Pleistocene) and the overlying alluvial fan system deposits constrained between the lateMiddle Pleistocene and the Holocene. The latter are geomorphologically and chrono-stratigraphically grouped into four generations, I generation: late Middle Pleistocene–early Upper Pleistocene, with tephra layers Ar/Ar dated to 158±6 and 113±7 ka; II generation: Upper Pleistocene, with tephra layers correlated with the Campanian Ignimbrite (39 ka) and with the slightly older Campi Flegrei activity (Ar/Ar age 48±7 ka); III generation: late Upper Pleistocene–Lower Holocene, with tephra layers correlated with the Neapolitan Yellow Tuff (~15ka); IV generation: Holocene in age. The evolution of the first three generations was controlled by Middle Pleistocene extensional tectonics, while Holocene fans do not show evidence of tectonic activity. Nevertheless, considering the moderate to highmagnitude historical seismicity of the study area, we cannot rule out that some of the recognized faults may still be active. Copyright

First assessment of the local seismic amplification susceptibility of the Isernia Province (Molise Region, Southern Italy) by the integration of geological and geomorphological studies related to the first level seismic microzonation project

This paper presents the results of the geological and geomorphological investigation carried out during the first level seismic microzonation project in the Isernia Province territory. The study area falls in one of the most seismically active areas of the Apennine chain and it has been struck, in historical times, by destructive earthquakes that caused several causalities and diffuse damages to the buildings. The analysis points out the occurrence of geological features that can determine possible site amplification phenomena related to areas with extensive outcrops of thick continental deposits or to unstable areas (both covering about 48% of the investigated areas). The latter are sometimes combined with geomorphological features such as scarps, isolated peaks, and ridges that are also responsible for possible site amplification. In addition, a susceptibility to local seismic amplification index has been introduced which highlights that more than 64% of the investigated area, along with a significant percentage of buildings, fall within the highest categories of susceptibility to local seismic amplification.