Radiological characterization of granitoid outcrops and dimension stones of the Variscan Corsica-Sardinia Batholith     

Antonio Puccini  Gerti Xhixha  Stefano Cuccuru  Giacomo Oggiano  Merita Kaçeli Xhixha  Fabio Mantovani  Carlos Rossi Alvarez  Leonardo Casini 《Environmental Earth Sciences》2014,71(1):393-405

This study focuses on the radiological characterization of granitoid outcrops and dimension stones using in situ gamma-ray spectrometry. Extensive measurements were performed on 210 granitoid outcrops of the Corsica-Sardinia Batholith. The large statistical sample allowed us to improve the analysis by considering a log-normal distribution of radioelements and propagating the uncertainties using Monte Carlo method. The activity concentrations of ⁴⁰K, ²²⁶Ra (²³⁸U) and ²³²Th in C-SB area were 1,177 _?304 ⁺⁴⁰⁸ , 60 _?23 ⁺³⁶ and 69 _?25 ⁺³⁸  Bq/kg (at 1σ uncertainty). The median abundance of K, U and Th on the Variscan C-SB was higher than the average values of the upper continental crust and was comparable with Variscan belt. This corresponds to an outdoor absorbed dose rate of 124 _?26 ⁺³³  nGy/h at 1σ uncertainty which is 3σ higher than the population-weighted average absorbed dose rate (60 nGy/h). Seven commercial granites (Rosa Beta, Ghiandone, Giallo San Giacomo, Rosa Cinzia, Grigio Malaga, Bianco Sardo and Grigio Perla) were investigated to characterize their radiological hazard through 147 measurements taken in 73 extractive quarries. All of the commercial granites were categorized as A2 material based on their activity concentration indices, excluding (at the 3σ level) any restriction on their utilization as superficial materials. Rosa Beta, Grigio Malaga, Grigio Perla and Bianco Sardo can also be used as bulk materials as they can be included in the A1 category. In the case of Ghiandone, Giallo San Giacomo and Rosa Cinzia, we are confident of an A1 classification only at the 1σ level.  相似文献   

Phylogeography of the bluespotted cornetfish,Fistularia commersonii: a predictor of bioinvasion success?          下载免费PDF全文

Alexis M. Jackson  Kimberly Tenggardjaja  Gerardo Perez  Ernesto Azzurro  Daniel Golani  Giacomo Bernardi 《Marine Ecology》2015,36(4):887-896

Biological invasions result in huge ecological and economic impacts; therefore, a great amount of effort is dedicated to predicting the potential success of newly established or candidate bioinvaders. Thus far, over 90 species of fish have entered the Mediterranean Sea via the Suez canal, the so‐called Lessepsian bioinvaders. The bluespotted cornetfish, Fistularia commersonii, is remarkable in its ability to disperse within the Mediterranean and has been dubbed ‘the Lessepsian sprinter’. In just a few years, starting in 2000, it expanded over the entire area, from the Suez Canal to Gibraltar. Theoretical predictions correlate the dispersal capabilities of an invader in its native range (using the population genetic metrics, F_st, as a proxy) with its dispersal capability in its invading area (continuous extent of spread, CES). Here, we estimated the population genetic characteristics of Indo‐Pacific native populations of F. commersonii in order to determine if this Lessepsian ‘sprinter’ fits the predictive model of dispersal. Indeed, we found that even in the case of such a very rapid range expansion, the predicted relationship between F_st and CES is fulfilled in F. commersonii.  相似文献   

浅源强震至浅源特大地震震级M_e的快速测定     

D.D.Giacomo  H.Grosser  S.Parolai  P.Bormann  许若冰 《世界地震译丛》2009,(2):8-14

提出了根据20°～90°距离范围之内的宽频带远震P波信号快速测定浅源地震能量震级Me的新程序。为了完成这项工作,我们根据地球参考模型AK135Q用数字模拟方法计算了不同周期的频谱振幅衰减函数。根据这些函数,我们校正了远震记录频谱的传播路径效应,计算了地震辐射能量Es和震级Me。我们用累积的P波窗模拟实时或近实时的程序,并用61个浅源地震进行验证。结果表明,我们的方法可在地震发震时刻后的7～15min内迅速可靠地测定出震级Me因此,这一程序适用于快速反应系统的实施。  相似文献   

Review of Modeling Approaches to Groundwater Flow in Deformed Carbonate Aquifers     

Giacomo Medici  Luca Smeraglia  Anita Torabi  Chartlotte Botter 《Ground water》2021,59(3):334-351

We discuss techniques to represent groundwater flow in carbonate aquifers using the three existing modeling approaches: equivalent porous medium, conduit network, and discrete fracture network. Fractures in faulted stratigraphic successions are characterized by dominant sets of sub-vertical joints. Grid rotation is recommended using the equivalent porous medium to match higher hydraulic conductivity with the dominant orientation of the joints. Modeling carbonate faults with throws greater than approximately 100 m is more challenging. Such faults are characterized by combined conduit-barrier behavior. The barrier behavior can be modeled using the Horizontal Flow Barrier Package with a low-permeability vertical barrier inserted to represent the impediment of horizontal flow in faults characterized by sharp drops of the piezometric surface. Cavities can occur parallel to the strike of normal faults generating channels for the groundwater. In this case, flow models need to account for turbulence using a conduit network approach. Channels need to be embedded in an equivalent porous medium due to cavities a few centimeters large, which are present in carbonate aquifers even in areas characterized by low hydraulic gradients. Discrete fracture network modeling enables representation of individual rock discontinuities in three dimensions. This approach is used in non-heavily karstified aquifers at industrial sites and was recently combined with the equivalent porous medium to simulate diffusivity in the matrix. Following this review, we recommend that the future research combines three practiced modeling approaches: equivalent porous medium, discrete fracture network, and conduit network, in order to capture structural and flow aspects in the modeling of groundwater in carbonate rocks.  相似文献   

Soil slip susceptibility assessment using mechanical–hydrological approach and GIS techniques: an application in the Apuan Alps (Italy)     

Giacomo D’Amato Avanzi  Francesco Falaschi  Roberto Giannecchini  Alberto Puccinelli 《Natural Hazards》2009,50(3):591-603

This study aims at contributing to the soil slip susceptibility assessment in a typical basin of the southern Apuan Alps, Italy. On June 1996, this basin (Cardoso Torrent, 13 km² large) was hit by an extremely heavy rainstorm (maximum intensity of about 160 mm/h), which caused many landslides (debris slide–debris flows) and valley bottom flows (hyperconcentrated flows), destruction and deaths. Detailed surveys provided the characterization of the main factors (geological, geomorphologic, hydrological, hydrogeological and geotechnical) which contributed in triggering landslides. In order to evaluate the soil slip susceptibility in this area, a physically based model was applied and a GIS analysis of digital elevation model was performed. This approach couples a mechanical model based on an infinite slope form of the Mohr–Coulomb failure criterion, and a steady-state hydrological one (a modified version of Shalstab, which considers the cohesion of the debris material potentially involved in landsliding). GIS techniques allowed evaluating the effects of topographic convergence and drainage area on slope failure. In this way, based on the infiltration rate, the triggering of the June 1996 landslides was simulated and the critical rainfall thresholds assessed at about 200–250 mm/24 h.  相似文献   

Structural evolution of the '41st parallel zone': Tyrrhenian Sea     

Giacomo Spadini  Forese-Carlo Wezel 《地学学报》1994,6(6):552-562

The present study is based on the interpretation of more than 1300 km of 16 kJ sparker seismic profiles recorded in July 1990, during the Cruise T-41 of the Geological Institute of Urbino. The investigated area extends along the 41st parallel in the central Tyrrhenian Sea between the northern Sardinian margin to the west and the Latium–Campanian margin to the east. This zone, situated on continental crust, marks the boundary between the northern Tyrrhenian and the southern Tyrrhenian domains. A kinematic reconstruction is presented, based on the age-dating of the recognized structures (i.e. normal faults, reverse faults, anticline and flower structures). The evolution of the ‘41st parallel zone’ can be described in terms of polyphase tectonics characterized by different orientations of the stress field during time. The direction of the normal fault-trends, turned clockwise, striking NE–SW in the late Tortonian–Messinian, E–W in the early Pliocene, NNW–SSE in the late Pliocene and N–S during the Quaternary. The concurrence of compressional and strike-slip deformations suggests oblique shear motions across the 41st parallel. The occurrence of late Pliocene–Quaternary tectonic activity in the northern Tyrrhenian Sea, locally characterized by inversion tectonics, suggests active mechanisms (intraplate compression?) superimposed on the post-rift subsidence.  相似文献   

Eine durch Tiefengesteinskontakt veränderte Uranlagerstätte     

P. Ramdohr  Giacomo Cevales 《Mineralium Deposita》1980,15(3):383-390

Zusammenfassung Die vorliegende Untersuchung befaßt sich mit einer Uranvererzung der permischen Sandsteine, welche sich in unmittelbarer Nähe des granodioritisch-tonalitischen Adamello-Plutons befunden hat. Geographisch liegen diese Vererzungen im westlichen Teil des Massivs, etwa bei 2120 m ü. d. M. In bezug auf den Mineralbestand und die Verwachsungen ist zu betonen, daß eine wohl zu erwartende allgemeine Mobilisierung und Rekristallisation der ursprünglichen Vererzung- — und des Nebengesteins —, zusammen aber mit z. T. auffallend mangelhaften Gleichgewichtseinstellungen vor sich gegangen sind. Bemerkenswert ist u. a. die Neubildung einer noch nicht bekannten Vanadium- und Eisen-Silikat-Verbindung.

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In this paper is investigated a uranium deposit in permian sandstones, which was situated in immediate neighbourhood to the granodioritic-tonalitic Adamello-pluton. The deposit occurs in the western part of the massiv, at an altitude of 2100 meter. With regard to the mineral associations and the related intergrowths it should be pointed out that the obvious phenomena related to the mobilisation and the recrystallisation of the ore — and of the ore bearing rocks —, are sometimes characterized by an evidently uncomplete equilibrium. Remarkable is the formation of a still unknown vanadium- and ironbearing opaque mineral.

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The switching between zonal and blocked mid-latitude atmospheric circulation: a dynamical system perspective     

Davide Faranda  Giacomo Masato  Nicholas Moloney  Yuzuru Sato  Francois Daviaud  Bérengère Dubrulle  Pascal Yiou 《Climate Dynamics》2016,47(5-6):1587-1599

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Acoustically estimated size distribution of sperm whales (Physeter macrocephalus) off the east coast of New Zealand     

Giacomo Giorli  Kimberly T. Goetz 《新西兰海洋与淡水研究杂志》2020,54(2):177-188

ABSTRACT

The length-frequency distribution of sperm whales (Physeter macrocephalus) was studied on the east coast of NZ using passive acoustic recorders moored offshore of Kaikoura, Cape Palliser and Castlepoint. Sperm whale’s echolocation signals are unique among odontocete species. Their clicks are composed by multiple pulses resulting from the sound transmission within the whale head. The total length of the whales can be estimated by measuring the time delay between these pulses. A total of 997 length measurements were obtained from click trains using cepstral analysis (mean?=?14.6?m; min?=?9.6?m; max?=?18.3?m; std?=?1?m). The size-frequency distributions at all three locations were similar, although animals smaller than 12?m were not present offshore of Kaikoura. Animals of various sizes appeared to be present all year round, with no apparent seasonality in the occurrence of any size class.  相似文献   

Innovative monitoring tools for the complex spatial dynamics of river chemistry: case study for the Alpine region     

Caterina Gozzi  Roberta Sauro Graziano  Francesco Frondini  Antonella Buccianti 《Environmental Earth Sciences》2018,77(16):579

Chemical reactions in aqueous geochemical systems are driven by nonequilibrium conditions, and their dynamics can be deduced through the distributional analysis (identification of probability laws) of complex compositional indices. In this perspective, compositional data analysis offers the possibility to investigate the behavior of the composition as a whole instead of isolated chemical species, with the awareness that multispecies systems are characterized by the simultaneous interactions among all their parts. We addressed this problem using D???1 isometric log-ratio coordinates describing the D compositional dataset of the river chemistry of the Alpine region (D number of variables), thus working in the \({{\mathbb{R}}^{D - 1}}\) statistical sample space. The D???1 coordinates were chosen using the decreasing variance criterion so that each one could provide information about different space–time properties for the investigated geochemical system. Coordinates dominated by heterogeneity appear to be able to capture regime shifts only on a long-time period and monitor processes on a very wide scale. On the other hand, coordinates characterized by lower variability present multimodality, thus capturing the presence of alternative states in the analyzed spatial domain also for the current time. Further developments are needed to determine the ranges of conditions for which variability and other statistics can be useful indicators of regime shifts on different time–space scales in geochemical systems.  相似文献