Mineralogy,chemistry, and grain size composition of recent sediments in the northern Tyrrhenian Sea: Contribution to the study of sediment transport and distribution

As a contribution to an environmental study on Tuscany's marine shelf, textural, mineralogical, and chemical characteristics of recent sediments in the northern Tyrrhenian Sea between Elba Island and Livorno have been analyzed. The data provide clear information on sediment sources and movement patterns. The main sediment source appears to be the Cecina River; very subordinate is the contribution of the Fine River. As to sediment movement patterns, the surveyed basin appears to be divided into two subbasins: (1) a greater, southern subbasin, bounded by Tuscany mainland, Elba Island and Elba Ridge, and Capraia Isle, and Vada Shoals; and (2) a smaller, northern subbasin, enclosed between Vada Shoals and Meloria Shoals (off Livorno port).In the former the coarse-grade Cecina River sediments are transported southward along most of the mainland coast by littoral drift and coastal current; a northward flowing countercurrent seems to be active only in the southernmost part. Silts and clays are distributed in concentric belts around basin's central part, being transported mainly by slow circular water movements. In the marginal western zone, very little terrigenous influx is coupled with a high biologic productivity, and biogenic debris sedimentation prevails there.In the northern subbasin the sediment contribution from Fine River is more appreciable. Here the environmental energies are very low and the coarse sediments are restricted to a few small pocket beaches where they are deposited by local creeks. Most of the subbasin area is occupied by sapropelitic muds, again distributed by slow small-scale gyres.     

Diel activity and short‐distance movement pattern of the European spiny lobster,Palinurus elephas,acoustically tracked

This paper presents the results of the application of an ultrasonic telemetry system to the investigation of short‐term movements in the European spiny lobster, Palinurus elephas, in a coastal area of NW Sicily (Central Mediterranean Sea). Ten lobsters were tagged with miniaturized transmitters and released over a favourable habitat and their movements then recorded by means of nine automated receivers with the objective of investigating post‐release displacement, home‐range extension, movement patterns, activity rhythm and the influence of lunar light intensity on lobster activity. Acoustic detection data were used to assess activity and home range using estimates of horizontal and vertical movements and minimum convex polygons, respectively. Continuous wavelet transform (CWT) analysis was applied to time series of position data. Acoustic data from five of 10 lobsters were successfully recorded across a 78‐day study period between April and June 2008. All of them displayed an activity pattern characterized by diurnal sheltering and nocturnal foraging, with higher activity (i.e., longer distances travelled) at night. Their home range measured between 1629 and 8641 m², and all lobsters relocated every 4.6 days on average, probably in search of unexploited feeding grounds. For this reason we hypothesize a nomadic movement pattern for our tagged lobsters. CWT analyses highlighted a 24‐h periodicity in lobster activity, with higher activity from sunset to sunrise. No clear influence of moon phase on lobster activity was detected.     

Chandra and XMM–Newton observations of the low-luminosity X-ray pulsators SAX J1324.4−6200 and SAX J1452.8−5949

We present results from our Chandra and XMM–Newton observations of two low-luminosity X-ray pulsators  SAX J1324.4−6200  and  SAX J1452.8−5949  which have spin periods of 172 and 437 s, respectively. The XMM–Newton spectra for both sources can be fitted well with a simple power-law model of photon index,  Γ∼ 1.0  . A blackbody model can equally well fit the spectra with a temperature,   kT ∼  2 keV, for both sources. During our XMM–Newton observations,  SAX J1324.4−6200  is detected with coherent X-ray pulsations at a period of 172.86 ± 0.02 s while no pulsations with a pulse fraction greater than 18 per cent (at 95 per cent confidence level) in 0.2–12 keV energy band are detected in  SAX J1452.8−5949  . The spin period of  SAX J1324.4−6200  is found to be increasing on a time-scale of     which would suggest that the accretor is a neutron star and not a white dwarf. Using subarcsec spatial resolution of the Chandra telescope, possible counterparts are seen for both sources in the near-infrared images obtained with the son of infrared spectrometer and array camera (SOFI) instrument on the New Technology Telescope. The X-ray and near-infrared properties of  SAX J1324.4−6200  suggest it to be a persistent high-mass accreting X-ray pulsar at a distance  ≤8 kpc  . We identify the near-infrared counterpart of  SAX J1452.8−5949  to be a late-type main-sequence star at a distance ≤10 kpc, thus ruling out  SAX J1452.8−5949  to be a high-mass X-ray binary. However, with the present X-ray and near-infrared observations, we cannot make any further conclusive conclusion about the nature of  SAX J1452.8−5949  .     

Hydrogeological and thermal characterization of shallow aquifers in the plain sector of Piemonte region (NW Italy): implications for groundwater heat pumps diffusion

The low annual and seasonal variability of the shallow groundwater temperature in the alluvial plain aquifers of the Piemonte region (NW Italy) confirmed the potentiality of the low-enthalpy open-loop groundwater heat pumps (GWHP) diffusion to contribute to the reduction of regional greenhouse gas emissions. The distribution of mean groundwater temperatures ranged from a minimum of 10.3°C to a maximum of 17.9°C with a mean of 14.0°C. Differences among diverse areas were slight according with the modest variations in the general climatic condition. Like the air, temperature distribution of the shallow groundwater temperatures is generally similar to topographic elevations in reverse manner. Higher temperature values recorded were typical of summer months (June, July). On the opposite lower values were measured in January and February. No significant difference phase (time) difference between air and groundwater temperature appeared in the data analysis. Besides air-temperature influence (seasonal variability) seemed strictly connected to the depth to groundwater in the measure point and it was negligible when the value was over 9.5 m. For the application of the open-loop systems, extensive examinations of the hydrogeological local conditions should be conducted at site scale and groundwater heat transport modelling should be developed.     

Potential use of microbial community investigations to analyse hydrothermal systems behaviour: the case of Ischia Island,Southern Italy

The Ischia hydrothermal system was analysed through hydrogeological and microbial community investigations. Mesophilic communities were detected in two cold springs, suggesting a negligible influence of thermal circuits in freshwater sub‐systems which are mainly or only fed by local precipitations. Thermophilic and extremely thermophilic bacteria were detected in two wells, according to higher water temperatures (61 and 85 °C), even if the two communities show significant differences. In one well, thermophilic and extremely thermophilic bacteria are associated with strains belonging to ε‐Proteobacteria isolated in different sulphur‐rich carbonate environments. This association suggests a greater influence on ascending hot fluids that interact with the carbonate basement of volcanic rocks. In the other well, thermophilic and extremely thermophilic bacteria are associated with strains isolated in cold hypersaline environments or in aquatic habitats where terrestrial and marine components are coupled. This association supports the fact that seawater intrusion can affect this part of Ischia, according to results of hydrogeological and geochemical surveys. Differences in groundwater temperature and bacterial communities are probably mainly due to differences in permeability between volcanic rocks and differences in hydrogeologic behaviour between faults in the upper carbonate basement, above the deep magma chamber, that influence relationships between ascending hot fluids and local recharge. This study contributes to discussion of the reliability of the actual behaviour models of the Ischia system, based on the results of geochemical and isotopic investigations, and, in a wider context, it shows that microbial community investigations may be a valuable supplementary tool for analysing hydrothermal system behaviour. Copyright © 2010 John Wiley & Sons, Ltd.     

Transgressive dune formation along a cliffed coast at 75 ka in Sardinia,Western Mediterranean: a record of sea‐level fall and increased windiness

Transgressive dunes develop frequently along strandplain coastlines; however, they may also form along rocky coasts dominated by cliffs and embayments. Two lithified transgressive dune systems developed along the cliffed Alghero coast (NW Sardinia, Italy) have been investigated. One aeolian system forms a cliff‐front anchored aeolian dune accumulation; the other is a valley‐head anchored sand‐ramp system. Optically stimulated luminescence ages indicate that both systems formed around 75 ka. This period, which corresponds to the beginning of MIS 4, was characterized by a relatively low sea‐level stand (15 m below the present sea level) and was preceded by a sea‐level highstand (+1 m asl) around 81 ka (MIS 5a). Our results show that this rapid sea‐level fall exposed an enormous amount of marine sand, which was transported inland by strong northerly winds and deposited in front of cliffs or in valley heads. Therefore, sediment supply and sea‐level fall seem to be critical factors controlling dune formation along rocky coasts, which generate time‐transgressive aeolianites. Terra Nova, 00, 000–000, 2010     

Estimation of debris‐flow magnitude in the Eastern Italian Alps

The estimation of debris‐?ow magnitude is an essential step in the assessment of debris‐?ow hazard. Although different methods have been developed for the assessment of debris‐?ow magnitude, this is still a dif?cult task because of the complexity of ?ow processes and the lack of data to test estimation procedures in many mountainous regions. Data on debris‐?ow magnitude from 127 basins in the Eastern Italian Alps have been collected from scienti?c and technical journals, technical reports, historical documents gathered from local archives, and ?eld surveys. These data were used to develop and test different predictive approaches, encompassing regression equations, geomorphological surveys and probabilistic analysis of time series. Regression techniques were used to correlate debris‐?ow magnitude to morphometric parameters and geological characteristics of the basins. Values of the channel debris yield rate (contribution per unit length of channel), proposed in the literature, were compared with data from the study area for identifying reference values for channel stretches of different morphological characteristics. Although limited to the few basins in which suf?cient data were available, the probabilistic analysis of time series of debris‐?ow magnitude provides indications about the relations between magnitude and frequency of debris ?ows. Some observations about the capability and drawbacks of considered methods are presented and the combined use of different approaches for the estimation of debris‐?ow magnitude is suggested. Copyright © 2004 John Wiley & Sons, Ltd.     

Factors Controlling Seismic Susceptibility of the Sele Valley Slopes: The Case of the 1980 Irpinia Earthquake Re-Examined

Most of the documented slope failures triggered by the 1980 Irpinia earthquake (M_s 6.9) occurred in the upper Sele valley epicentral area (southern Italy). The early investigations revealed some puzzling characteristics of the slope failure distribution, i.e., (i) the higher landslide concentration on the valley slopes located farther away from the earthquake fault; (ii) the predominance of re-activations over first-time movements. The analyses of factors controlling the landslide concentrations indicates that the differences in hydrological setting and in slope were the two main causal factors whereas the seismic shaking, according to the radiation pattern modelling, could have been characterised by a relatively low rate of decrease across the valley. The aspect of the slopes did not play a significant role. The differences in groundwater conditions between the western and eastern valley sides were probably enhanced by the earthquake. In addition to the probable pore-water pressure rise, the seismic shaking caused large increases in the flow of springs draining the western aquifer, and this made the adjacent flysch slopes more prone to landsliding. Data from the available literature suggest that the effects of earthquake-induced groundwater release on seismic landslide distribution is especially important for normal-fault events. The Sele valley case also indicates that the slope of the pre-existing landslides is an important factor controlling their susceptibility to seismic re-activations.     

Development of water management strategies in southern Mesopotamia during the fourth and third millennium B.C.E.

The last two decades witnessed increasing scholarly interest in the history of water management in southern Mesopotamia. Thanks to many geoarchaeological research projects conducted throughout the central and southern Iraqi floodplains, a general understanding of the macrophases of anthropogenic manipulation of this vast hydraulic landscape has been achieved. However, current narratives mostly rely on studies at a regional scale and are based on excessively long chronological phases (often spanning a whole millennium). A finer-tuned analysis at a submillennial scale is needed to better appreciate the dynamics that led to the development of artificial canals and irrigation systems and the creation of harbours in cities and other navigation-related facilities. The Iraqi-Italian QADIS project is addressing this issue through a systematic geoarchaeological investigation in the south-eastern area of the Qadisiyah province. We aim to update the current narrative by analysing case studies involving specific periods of occupation. We performed 17 boreholes to propose a date on the functioning period of the hydraulic works in five selected archaeological sites of this region. This approach allowed us to understand changes in water management strategies in both the short and the medium term (i.e., on a scale of centuries). In this paper, we present the results for the fourth and third millennia B.C.E. This period witnessed a crucial passage from the basic exploitation of natural watercourses for irrigation and occasional navigation to the emergence of the first system of artificial canals and intraurban harbours.