1,721,083 research outputs found
The long term denudation rate in the Southern Apennine chain (Italy): a GIS aided estimation of rock volume eroded since Middle Pleistocene time.
No full textThe long term denudation rate in the Southern Apennine chain (Italy): a GIS aided estimation of rock volume eroded since Middle Pleistocene time.
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Note illustrative della Carta Geologica d’Italia in scala 1:50.000, Foglio geologico n. 405 “Campobasso”
No full textPast coastal evolution indicates low resilience of Mediterranean coastal plains to ongoing climate change
No full textGlobal sea-level rise represents one of the most evident impacts of anthropogenic climate change. It is expected to trigger widespread environmental changes, such as major coastal erosion and progressive inundation of large portions of low-elevated coastal zones. Such impacts will be of remarkable importance in the most vulnerable coastal areas, such as large alluvial plains. However, is it possible to define a common response for this type of coastal environment to climate change? Furthermore, what are the drivers that mostly control their evolution? We evaluate the potential resilience of six major western Mediterranean coastal plains to future Relative Sea-Level Rise (RSLR– i.e., sea-level variation due to the combined effect of eustatic sea-level rise and local subsidence) by examining the Holocene coastal response to past sea-level variations. In each investigated coastal plain, we statistically reconstruct the past variability in the sea-level rise rates and analyze the geomorphic response (i.e., retreat, stability, or progradation) of the coastline to these changes. Then, we compare these data with the local RSLR rates expected for the next decades (up to the year 2100), calculated considering sea-level projections under three different climate scenarios (i.e., SSP2-4.5, SSP3-7, SSP5-8.5) and corrected for the local coastal subsidence trends characterizing each coastal plain. This allows us to predict the potential morphodynamic response of each plain to future RSLR by applying a newly developed coastal plain sensitivity index (CPSI), integrating the past and recent coastal trends. Results indicate that only under the SSP2-4.5 scenario, a low probability (< 13%) of natural resilience (intended as shoreline in equilibrium/stable shoreline) is observed. Under all the other scenarios, the investigated coastal plains are destined for an irreversible retreat trend
Historical trends of rain and air temperature in the Dominican Republic
No full textThe present work aims to characterize trends in air temperature and precipitation from the late 1930s to 2007 in the Dominican Republic, establishing whether some climate change patterns can be identified in the distribution of climate types of this country. The time series to be analysed present many quality issues and challenges, essentially due to abundance of missing data and inhomogeneous measurements. A number of statistical corrections have hence been applied: time series have been first filtered, then homogenized with respect to purposely built reference series, then completed through multiple imputation. Trend estimation has finally been performed on the annual and monthly scale. The analysis of homogenized and imputed series shows that significant trends occurred since 1930s, both in rain and air temperature. A pattern in the distribution of rain trends is evident in the country during the period 1939–2007, which reflects the influence of the orographic structure of the country on the atmospheric dynamics that dominate in the Caribbean region: significant negative annual trends are detectable in leeward areas, behind the main mountainous chains, while positive trends are generally evident in windward regions, exposed to trade winds. All the analysed series demonstrate an increase in air temperature: in Santo Domingo, minimum air temperature increased 3.0 ± 0.5°C since 1936, while the maximum air temperature increased 1.8 ± 0.4°C in the same period. Furthermore, an increase of rain erosivity can be detected on the South coast of the country, in some areas of the Cordillera Central and in the Northeast. Another important result is the increase of potential evapotranspiration, while significant uniform trends cannot be identified for extreme events
Alcune tipologie di versante ricorrenti in Appennino meridionale: forme, depositi e processi morfodinamici. .
No full textEvaluation of the erosion rate in the Southern Apennines (Italy) based on geological-geomorphological data / Valutazione del tasso di erosione in Appennino Meridionale da dati geologico-geomorfologici
No full textThe object of this study is the estimation of the long-term erosion rate in the southern portion of the Apennines chain (southern Italy). This was done with the aim of validating the hypothesis, proposed by MAZZOLI et al.. (2008), that thin-skinned extensional tectonics played a major role in the exhumation of formerly deeply buried tectonic units. More in detail, the study aimed at providing data on the erosional component of the rock exhumation which, based on Apatite Fission Tracks data reported in MAZZOLI et al. (2008), has affec- ted in the last 10 Ma the deepest units in the southern Apennines fold–and-thrust belt. The erosion rate was estimated based on the evaluation of the volume of deposits delivered by a large hydrographic basin to a conti- nental environment sedimentary basin. The accumulation basin is the Sant’Arcangelo basin (hereinafter BSA), which developed as a marine environment wedge-top basin (originally connected to the Apennines foreland basin) during the Middle Pliocene and evolved as an alluvial-lacustrine basin in the late part of the Early Pleistocene in response to the thrusting related uplift of a ridge located to the E of it (VEZZANI, 1966, 1967; CARBONE, 1991; PIERI, 1994; ZAVALA, 2000; PATACCA & SCANDONE, 2001; GIANNANDREA & LOIACONO, 2003; BENVENUTI et al., 2006). The drainage basin correlated to the BSA covers a large portion of the eastern slope of the Southern Apennines, and includes elevations formed of formerly deep-seated structural units (namely, Lagonegro units and Apulian platform unit) exhumed during Pliocene-Quaternary times. Literature data and field surveys allowed the identification of the sedimentary unit (Castronuovo-San Lorenzo unit, CSL, composed of lacustrine deposits passing laterally and upwards into alluvial plain sediments) which was deposited within the BSA when the basin was isolated from the neighboring foreland basin. The CSL ranges in age from around 1 to 0,7 Ma (PATACCA & SCANDONE, 2001; MAT- TEI et al., 2004; SABATO et al., 2005). G.I.S. elaborations allowed the reconstruction of the top and bottom surfaces and volume of the CSL. The calculated volume value was corrected accounting for the erosion which affected the CSL top surface, for the original width of the deposition area, for the suspended load loss, and for the sediment porosity. The paleo-hydrographic basin coeval to the CSL was reconstructed based on geomorphological/geological evidences, which include the compositional analysis of pebbles of different units of the BSA succession. The obtained 0,25 ± 0,07 mm/a erosion rate value is comparable to the values, averaged over the last 0,7 Ma and spanning from 0,2 to 0.3 mm/a, estimated for the eastern chain margin-foreland basin area in both the southern and northern Apennines (AMATO et al., 2003; CYR & GRANGER, 2008). These values, which can be considered as representative of erosion which has affected the Apennines over the Quaternary, are much lower than the Pliocene-Quaternary rock exhumation of formerly buried units estimated by AFT data, and this points to the important contribution of the extensional tectonics in the exhumation processes in the Southern Apennines
Alcune tipologie di versante ricorrenti in Appennino meridionale: forme, depositi e processi morfodinamici. .
No full textHydromorphology meets mammal ecology: morphological quality index, recent channel adjustments and otter resilience
No full textThe need for a multidisciplinary approach for characterizing water bodies in terms of morphological, chemical and ecological quality has
hastened the growth of hydromorphology as a cross-disciplinary topic at the interface of hydrology, geomorphology and ecology. Many
authors have analysed how hydroecology may affect freshwater biodiversity, although little is known about how this biodiversity might
be affected by river morphological quality. We examined how well the presence of the semi-aquatic Eurasian otter can be predicted by
the rivers’ morphological quality and its adjustments over the last decades. We tested the morphological quality index (MQI) methodology
in 38 reaches of five rivers in southern Italy, 23 of which were positive to otter presence. In each reach, we examined 28 indicators contributing
to the MQI and its 11 sub-indices. The results showed a significant relationship between the probability of the presence of otters, MQI,
and some sub-indices. The best performing sub-indices were related to channel adjustments and the continuity of river processes. A more
detailed analysis of channel adjustments showed a detrimental effect of channel incision (>3m) and a positive effect of narrowing, particularly
where it occurred simultaneously with the development of forest in the new floodplain. The continuity of river processes has driven the
migration of river banks and the development of ponds and secondary channels, likely increasing the availability of dens and resting sites and
the hunting capabilities of otters. Our results stressed the importance of fluvial dynamics and sustainable adaptive river management for the
habitat quality of semi-aquatic species
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