ALBERT

Description: The Gioia Basin is a small trough located in the southeastern Tyrrhenian Sea between the Aeolian island arc and Sicily and Calabria. It is experiencing a post-rift margin evolution, while tectonic deformation and high rates of vertical movement are still affecting the Sicilian and Calabrian mainland. The analysis of the evolution of the post-rift depositional systems along the various sectors of the Gioia Basin margin has been carried out through the combined interpretation of multibeam bathymetry and seismic reflection data. Two seismic units have been identified and their component geomorphological elements ascertained through the analysis of seismic facies distribution. In general, the depositional architecture of the margin, the sedimentary environments and facies and related geomorphological elements that are active in the shaping of the margin appear to be mainly controlled by the physiography of the basin itself and by the geology of the hinterland that results from the structural evolution of the adjacent land areas. An evolution from a generalized slope bypass setting to a prograding offlapping slope architecture is recognized and explained as due to the transition from an out-of-grade to a graded profile progressing from the early post-rift stage to the later margin growth stage. Along the Sicilian margin, a constructional apron, mainly consisting of channel levee deposits, makes up much of the studied sedimentary package and reflects a high sediment supply related to the large size of river catchments on land. In contrast, the northeastern Sicilian basin sector is a destructional margin that flanks a region where small river drainage systems result in a low sediment supply to the basin and a continued high uplift rate promotes slope instability; as a consequence, the basin infill is here almost completely made up of mass-wasting deposits. In the Calabrian margin, a first phase of low sediment supply probably coinciding with the filling of the further inland Gioia Tauro half-graben was followed by the establishment of the Gioia-Mesima channel-canyon system that, furnishing an effective sediment flux to the margin, allows the formation of an intraslope depositional body consisting of channelized turbidite lobes.

Description: USP2a alters chemotherapeutic response by modulating redox Cell Death and Disease 4, e812 (September 2013). doi:10.1038/cddis.2013.289 Authors: B Benassi, M Marani, M Loda & G Blandino

Description: The elevation and extent of coastal marshes are dictated by the interplay between the rate of relative sea-level rise (RRSLR), surface accretion by inorganic sediment deposition, and organic soil production by plants. These accretion processes respond to changes in local and global forcings, such as sediment delivery to the coast,...

Description: The effective discharge constitutes a key concept in river science and engineering. Notwithstanding many years of studies, a full understanding of the effective discharge determinants is still challenged by the variety of values identified for different river catchments. The present paper relates the observed diversity of effective discharge to the underlying heterogeneity of flow regimes. An analytic framework is proposed, which links the effective ratio (i.e. the ratio between effective discharge and mean streamflow) to the empirical exponent of the sediment rating curve and to the streamflow variability, as resulting from climatic and landscape drivers. The analytic formulation predicts patterns of effective ratio versus streamflow variability observed in a set of catchments of the continental United States, and helps in disentangling the major climatic and landscape drivers of sediment transport in rivers. The findings highlight larger effective ratios of erratic hydrologic regimes (characterized by high flow variability) compared to those exhibited by persistent regimes, which are attributable to intrinsically different streamflow dynamics. The framework provides support for the estimate of effective discharge in rivers belonging to diverse climatic areas.

Description: Marshes display impressive biogeomorphic features, such as zonation, a mosaic of extensive vegetation patches of rather uniform composition, exhibiting sharp transitions in the presence of extremely small topographic gradients. Although generally associated with the accretion processes necessary for marshes to keep up with relative sea level rise, competing environmental constraints,...

Description: Widely used sequence stratigraphic models predict that specific facies assemblages alternate in the stratigraphy of deep-sea fans, depending on the cyclic nature of sea-level variations. Our work tests this assumption through facies reconstruction of submarine fans that are growing in a small basin along the tectonically active Sicilian margin. Connected canyons have heads close to the coastline; they can be river connected or littoral cell–connected, the first receiving sediment from hyperpycnal flows, the latter intercepting shelf sediment dispersal pathways. Hyperpycnal flows directly discharge river-born sediment into the head of the river-connected canyon and originate a large turbidite fan. A drift formed by the longshore redistribution of sediment of a nearby delta introduces sediment to the head of the littoral cell–connected canyon, forming turbidity currents that flow within the canyon to reach the basin plain. However, since sediment failure and landslide processes are common in the slope part of the system, a mixed fan, consisting of both turbidites and mass-transport deposits, is formed. Disconnected canyons, with heads at the shelf edge far from the coastline, are fed by canyon head and levee-wedge failures, resulting in mass-transport or mixed fan deposition, the latter developing when the seafloor gradient or the lithology of the failed sediment allows turbidity current formation. Connected canyons form in areas with high uplift rates, where the shelf is narrow and steep and the shelf edge is at a relatively shallow depth. Disconnected canyons develop where there are lower uplift rates or subsidence, where the shelf is large and relatively gentle with a deeper shelf edge. It is deduced that the relative vertical movements of fault-bound blocks control whether canyons are connected to the coast at the present day. The role of tectonics in controlling the canyon feeding processes and the facies of submarine fan growth during highstand periods is therefore highlighted. A further view that arises from our paper is that in active margins, the slope portion of fan systems, through seafloor instability and variations in channel gradient, is a key factor in determining the final deep-sea fan facies, regardless of the distance between the coast and the canyon. The concomitant growth of turbidites, mass-transport deposits, and mixed fans demonstrates that models that predict changes in submarine fan facies on the basis of sea-level cycles do not necessarily apply to systems developed along tectonically active margins.