age constraints and denudation rate of a multistage fault line scarp an example from southern italy

AbstractThe morphological evolution of a carbonate fault line scarp from southern Italy, generated by transpressional faulting and evolved by slope replacement, has been reconstructed. 14C dating of faulted slope deposits (ages included between 18 ka and ∼8 ka BP) have been performed to constrain the Late Pleistocene — Holocene evolution of that scarp. Long-to short-term denudation rates have been also evaluated for the understanding of the mountain front origin. The slope shows well-defined triangular facets combined with the presence of N-S-striking mountainward-dipping fault planes. The envelope of the slope foot appears slightly curved in a planimetric view and shows an E-W-trending offset in its southern part, making such a feature quite different from the recurrent rectilinear fault scarps, often related to normal faulting. Morphostructural analysis showed that: i) the oldest displacement was generated by a fault with a reverse component of movement; ii) the slope represents an inherited feature, only recently exhumed, and developed starting from a high-angle curved surface; iii) the upper Pleistocene — Holocene extensional faulting has only affected the slope foot and associated waste deposits, causing a series of collateral morphological effects, as fluvial cut of preexisting valleys and the genesis of conspicuous mass movements

Post-lacustrine evolution of a tectonically-controlled intermontane basin: Drainage network analysis of the Mercure basin, southern Italy

Topographic analysis, drainage network morphometry, river profile analysis, and spatial distribution of fluvio-lacustrine terraces have been used to reconstruct the drainage network evolution in the Mercure River basin, a large intermontane tectonic basin of the axial zone of southern Apennines. Morphotectonic evolution of the study area is mainly controlled by poly-kinematics high-angle WNW-ESE and NE-SW faults, which promoted the development of a complex landscape with relict landscapes and/or low-relief erosional surfaces that occurred in a staircase arrangement at the top of the landscapes or at higher altitudes than the basin infill. The creation of the accommodation space for the deposition of the thick basin infill was related to an important tectonic phase of block-faulting along N120°-trending normal faults, which occurred in the final part of the Lower Pleistocene. Such an evolution strongly controls the longitudinal profile forms of channels draining the northern sector of the study area, which are featured by a well-developed concave-up segment in river profiles of these channels between an upward trait with lower values of channel steepness and the trace of the master fault. River profiles in north-western and south-east sectors of the Mercure River basin exhibit clear knickpoints at altitudes comparable with those of the superimposed orders of relict landscapes related to the initial formation of the tectonic basin and the subsequent evolution of the endorheic basin, with a post-lacustrine geomorphological evolution of the drainage network that is controlled by fluvial incision occurring at rates comparable than those reconstructed by independent morphotectonic markers. The erosion of the threshold of the endorheic basin occurring during the base-level fall of the MIS 12 promoted a dramatic base-level fall of about 150 m, which corresponds to a mean incision rate of about 0.35 mm/yr. Post-lacustrine evolution of the Mercure basin strongly controls the morphometric features of the drainage network, which preserves a centripetal pattern with several planimetric anomalies such as counterflow and high-angle confluences, local-scale fluvial capture phenomena and drainage divide migrations

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

SEMI-AUTOMATIC CLASSIFICATION OF LANDFORMS AS A TOOL TO STRESS GEOARCHAEOLOGICAL ISSUES: AN EXAMPLE FROM THE METAPONTO COASTAL BELT, SOUTHERN ITALY

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A geoarchaeological study of the metaponto coastal belt, southern Italy, based on geomorphological mapping and gis-supported classification of landforms

In this work we tried to infer the settlement rules and archaeological site patterns in pilot coastal area with high “archaeological potential” through the analysis of the spatial relationships between landform unit maps deriving from a GIS-supported procedure of landform extraction integrated with geomorphological analyses and archaeological evidence. This approach has been tested in the coastal Ionian sector of the Basilicata region, where a detailed geoarchaeological research has been carried out in the frame of the multidisciplinary MeTIBas project (the Italian acronyms for Innovative Methods and Technologies for the Cultural Heritages in the Basilicata region), funded by the European Community. The study area extends on the southernmost part of the Bradano Foredeep, southern Italy, and roughly coincides with the Greek settlement territory of Metaponto and its Chora (the area of influence of Greek colonists). Archaeological investigations, regarding about 1400 sites, consisted of a re-examination of literature data and new field surveys. The relationships between landscape elements deriving from the procedure here proposed and archaeological sites have been statistically investigated to derive settlement patterns and rules. Results highlight a preferential distribution of the identified categories of archaeological sites on gently-dipping marine terrace surfaces and near their edges, thus implying that settlement dynamics of the Metaponto territory partially driven by the topographic position

The Subsurface Geology and Landscape Evolution of the Volturno Coastal Plain, Italy: Interplay between Tectonics and Sea-Level Changes during the Quaternary

The Volturno alluvial-coastal plain is a relevant feature of the Tyrrhenian side of southern Italy. Its plan-view squared shape is due to Pliocene-Quaternary block-faulting of the western flank of the south-Apennines chain. On the basis of the stratigraphic analysis of almost 700 borehole logs and new geomorphological survey, an accurate paleoenvironmental reconstruction before and after the Campania Ignimbrite (CI; about 40 ky B.P.) eruption is here presented. Tectonics and eustatic forcing have been both taken into account to completely picture the evolution of the coastal plain during Late Quaternary times. The upper Pleistocene-Holocene infill of the Volturno plain has been here re-organized in a new stratigraphic framework, which includes seven depositional units. Structural analysis showed that two sets of faults displaced the CI, so accounting for recent tectonic activity. Yet Late Quaternary tectonics is rather mild, as evidenced by the decametric vertical separations operated by those faults. The average slip rate, which would represent the tectonic subsidence rate of the plain, is about 0.5 mm/yr. A grid of cross sections shows the stratigraphic architecture which resulted from interactions among eustatic changes, tectonics and sedimentary input variations. On the basis of boreholes analysis, the trend of the CI roof was reconstructed. An asymmetrical shape of its ancient morphology—with a steeper slope toward the north-west border—and the lack of coincidence between the present course of the Volturno River and the main buried bedrock incision, are significant achievements of this study. Finally, the morpho-evolutionary path of the Volturno plain has been discussed

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