The Paleoenvironment and Lithic Taphonomy of Shi’Bat Dihya 1, a Middle Paleolithic Site in Wadi Surdud,Yemen     

Luca Sitzia  Pascal Bertran  Stphane Boulogne  Michel Brenet  Rmy Crassard  Anne Delagnes  Marine Frouin  Christine Hatt  Jacques Jaubert  Lamya Khalidi  Erwan Messager  Norbert Mercier  Alain Meunier  Stphane Peign  Alain Queffelec  Chantal Tribolo  Roberto Macchiarelli 《Geoarchaeology》2012,27(6):471-491

The Shi'bat Dihya 1 site in western Yemen, dated by optically stimulated luminescence to 55 ka, provides insight into the Middle Paleolithic peopling of the Arabian Peninsula. The archaeological layer is interstratified within thick, sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack of soil development, and gypsum precipitation indicate a high accretion rate of the floodplain during Marine Isotope Stage 3, in connection with a (semi)‐arid environment. Rapid overbank sedimentation was likely a result of the remobilization of loess material deposited on the Yemeni Great Escarpment at the periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric and size analyses of the lithic artifacts, together with spatial projections, indicate site modifications by floods. Primary modifications include (1) selective accumulation of medium‐sized lithic pieces as a result of hydraulic sorting, (2) bimodal orientation of artifacts, and (3) ripple‐like arrangement of lithics and bone/tooth fragments. The overrepresentation of teeth may also be a consequence of sorting. Although floods have distorted the original site patterning, long‐distance transport of artifacts by water can be excluded, as indicated by relatively high refitting rate, close proximity of artifacts derived from the same block of raw material, and lack of abrasion of the pieces. Therefore, the site is considered “geologically” in situ because its remobilization by water occurred shortly after human abandonment. This study also stresses that the effective preservation of a site cannot be assessed without careful taphonomic study, even in a potentially favorable depositional context such as silty alluvium.  相似文献   

Shallow landslides triggered by rainfalls: modeling of some case histories in the Reggiano Apennine (Emilia Romagna Region, Northern Italy)   总被引：3，自引：1，他引：2  

Lorella Montrasio  Roberto Valentino  Gian Luca Losi 《Natural Hazards》2012,60(3):1231-1254

On April 10–11, 2005, the Emilia Romagna Apennine was affected by an intense rainfall event that triggered dozens of soil slips in the Province of Reggio Emilia. These shallow landslides occurred mainly on slopes of cultivated lands, often blocking roads, causing damages to crops and economic loss. Based on the analysis of an inventory of aerial photographs, it was possible to locate 45 sites where soil slips have occurred. In this paper, the area of study is described from a geological and climatic point of view. The authors analyze both the predisposing factors, related to the morphology of the territory, and the phenomena triggering factors, related to the rain trend. Once the geometrical features and characteristics of the soil slopes were available, a physically based triggering model, recently developed by the authors, was locally applied at each site. The model, which is based on the limit equilibrium method and on the hypothesis of infinite slope, is briefly described. It assumes a partial saturation condition of the soil and provides the safety factor of each slope as a function of time-variable rainfall intensity. The choice of the input parameters of the model is explained in detail. It is underlined, in particular, how the only parameter that has been determined through a procedure of back analysis, i.e., the discharge capability, is comparable to the typical permeability values obtained through field measurements by other authors, for similar kinds of soils and conditions. In this article, the results of the application of our model to the study areas, within a three-year time frame, are presented. Furthermore, on the basis of the analysis carried out, some observations on the operating mode of the model are carried out and its ability to predict a phenomenon triggering is evaluated.  相似文献   

Surface displacements of two landslides evaluated by GPS and inclinometer systems: a case study in Southern Apennines, Italy     

Stefano Calcaterra  Claudio Cesi  Caterina Di Maio  Piera Gambino  Katia Merli  Margherita Vallario  Roberto Vassallo 《Natural Hazards》2012,61(1):257-266

This paper reports experimental data on surface and deep displacements evaluated by means of GPS stations and inclinometers in two rototranslational deep landslides in a clayey slope of the Italian Southern Apennines. The displacements of the landslides cause continuous damage to buildings and infrastructures. To study these phenomena and control their effects, the local public administration provided financial support for a geotechnical investigation that started in 2004. Laboratory tests, in situ pore pressure and inclinometer measurements were carried out. In July 2006, systems of fixed-in-place inclinometer probes with continuous data acquisition were installed in two of the eleven guide casings, in correspondence to the slip surfaces detected by previous periodical measurements. In the meanwhile, a GPS network was installed, consisting in six permanent stations and ten non-permanent ones. Among the latter, five were installed on the top of five inclinometer casings. The experimental results show that, in the case under study, the surface displacements evaluated by means of the GPS stations are consistent with the surface displacements evaluated by means of the inclinometer measurements. This implies mutual data validation, availability of considerable amount of continuous data, as well as monitoring continuity when, for some reason, one of the instruments goes out of use.  相似文献   

The beach placer iron deposit of Portman Bay,Murcia, SE Spain: the result of 33 years of tailings disposal (1957–1990) to the Mediterranean seaside     

José Ignacio Manteca  José Ángel López García  Roberto Oyarzun  Carlos Carmona 《Mineralium Deposita》2014,49(6):777-783

Between 1957 and 1990, the Peñarroya Mining and Metallurgical Company (SMMPE) disposed about 60 million tonnes of tailings materials directly to the Mediterranean Sea. A substantial part of it (12.5 Mt) was dragged back by the sea currents progressively infilling the Portman Bay (Murcia, SE Spain), thus making the shoreline advance between 500 and 600 m seaward. The Roberto froth flotation plant processed mineral from manto-type deposits belonging to the Sierra de Cartagena-La Unión lead-zinc district. One of the mineral assemblages present in these deposits comprises greenalite, magnetite, sulfides, carbonates, and silica. Despite that magnetite recovery was undertaken by SMMPE between 1959 and 1967, we estimate that magnetite contained in the tailings hosts a substantial resource that could be as large as 2.3 Mt of iron ore. The ore contains magnetite ± hematite ± siderite. Tidal waves and sea currents led to gravimetric classification of the tailings material, with concentration of the dense iron oxides in the sandy fractions, eventually forming a coastal placer iron deposit. A major problem for magnetic separation is the intimate intergrowth between magnetite, hematite, and siderite. Besides, the sands contain large concentrations of Pb (0.27 %), Zn (0.72 %), and As (559 ppm).  相似文献   

Shallow-landslide susceptibility in the Costa Viola mountain ridge (southern Calabria,Italy) with considerations on the role of causal factors   总被引：2，自引：1，他引：1  

Giulio G. R. Iovine  Roberto Greco  Stefano L. Gariano  Annamaria D. Pellegrino  Oreste G. Terranova 《Natural Hazards》2014,73(1):111-136

The “Costa Viola” mountain ridge (southern Calabria), in the sector between Bagnara Calabra and Scilla, is particularly exposed to geo-hydrological risk conditions. The study area has repeatedly been affected by slope instability events in the last decades, mainly related to debris slides, rock falls and debris flows. These types of slope movements are among the most destructive and dangerous for people and infrastructures, and are characterized by abrupt onset and extremely rapid movements. Susceptibility evaluations to shallow landslides have been performed by only focusing on source activation. A logistic regression approach has been applied to estimating the presence/absence of sources in terms of probability, on the basis of linear statistical relationships with a set of territorial variables. An inventory map of 181 sources, obtained from interpretation of air photographs taken in 1954–1955, has been used as training set, and another map of 81 sources, extracted from 1990 to 1991 photographs, has been adopted for validation purposes. An initial set of 12 territorial variables (i.e. lithology, land use, soil sand percentage, elevation, slope angle, aspect, across-slope and down-slope curvatures, topographic wetness index, distance to road, distance to fault and index of daily rainfall) has been considered. The adopted regression procedure consists of the following steps: (1) parameterization of the independent variables, (2) sampling, (3) calibration, (4) application and (5) evaluation of the forecasting capability. The “best set” of variables could be identified by iteratively excluding one variable at a time, and comparing the ROC results. Through a sensitivity analysis, the role of the considered factors in predisposing shallow slope failures in the study area has been evaluated. The results obtained for the Costa Viola mountain ridge can be considered acceptable, as 98.1 % of the cells are correctly classified. According to the susceptibility map, the village of Scilla and its surroundings fall in the highest susceptibility class.  相似文献   

Small-scale landfills: impacts on groundwater and soil     

Rodrigo Augusto Bellezoni  Cristiano Kenji Iwai  Vagner Roberto Elis  Wanderley da Silva Paganini  Jorge Hamada 《Environmental Earth Sciences》2014,71(5):2429-2439

In Brazil, the large quantities of solid waste produced are out of step with public policies, technological developments, and government budgets for the division. In small municipalities, the common lack of technological knowledge and financial conditions for suitable waste disposal has resulted in a large number of illegal dumps. Therefore, small sanitary landfill facilities are working with simplified operations focusing on cost reduction and meeting the economic and technological standards of the city without endangering the environment or public health. Currently, this activity is regulated at a federal level although there is some uncertainty regarding the risk of soil and aquifer contamination as theses facilities do not employ liners. Thus, this work evaluates a small landfill to identify changes in soil and groundwater using geotechnical parameters, monitoring wells, and geophysical tests performed by electrical profiling. It is verified that based on current conditions, no contaminants have migrated via underground water aquifers, and overall no significant changes have occurred in the soil. It is concluded that, despite its simplicity, the method investigated is a viable alternative for the final disposal of municipal solid waste from small cities, especially in developing countries.  相似文献   

The 2dF Galaxy Redshift Survey: power-spectrum analysis of the final data set and cosmological implications     

Shaun Cole  Will J. Percival  John A. Peacock  Peder Norberg  Carlton M. Baugh  Carlos S. Frenk  Ivan Baldry  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Matthew Colless  Chris Collins  Warrick Couch  Nicholas J. G. Cross  Gavin Dalton  Vincent R. Eke  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Karl Glazebrook  Carole Jackson  Adrian Jenkins  Ofer Lahav  Ian Lewis  Stuart Lumsden  Steve Maddox  Darren Madgwick  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2005,362(2):505-534

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Periodic orbits and non-integrability of Armbruster-Guckenheimer-Kim potential     

Jaume Llibre  Luci Roberto 《Astrophysics and Space Science》2013,343(1):69-74

In this paper we study the periodic orbits of the Hamiltonian system with the Armburster-Guckenheimer-Kim potential and its $\mathcal{C}^{1}$ non-integrability in the sense of Liouville-Arnold.  相似文献   

Editorial: High-Energy Density Laboratory Astrophysics 2010     

Roberto C. Mancini  Tomasz Plewa  Michael Dopita 《Astrophysics and Space Science》2011,336(1):1

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The Australia telescope 20 GHz survey: hardware, observing strategy, and scanning survey catalog     

Paul Jacob Hancock  Paul Roberts  Michael J. Kesteven  Ronald D. Ekers  Elaine M. Sadler  Tara Murphy  Marcella Massardi  Roberto Ricci  Mark Calabretta  Gianfranco de Zotti  Philip G. Edwards  Jennifer A. Ekers  Carole A. Jackson  Mark Leach  Chris Phillips  Robert J. Sault  Lister Staveley-Smith  Ravi Subrahmanyan  Mark A. Walker  Warwick E. Wilson 《Experimental Astronomy》2011,32(2):147-177

The Australia Telescope 20 GHz (AT20G) survey is a large area (2?? sr), sensitive (40 mJy), high frequency (20 GHz) survey of the southern sky. The survey was conducted in two parts: an initial fast scanning survey, and a series of more accurate follow-up observations. The follow-up survey catalog has been presented by Murphy et al. (MNRAS 402:2403, 2010). In this paper we discuss the hardware setup and scanning survey strategy as well as the production of the scanning survey catalog.  相似文献