Scale-dependent correlations between soil heavy metals and As around four coal-fired power plants of northern Greece

We analyse the concentration of five trace elements (As, Cu, Ni, Pb and Zn) in the topsoil of the Kozani-Ptolemais basin where four coal-fired power plants run to provide almost 47.8 % of electricity requirements in Greece. We assume that if the power plants have altered the spatial (co)variation of the analysed elements through their toxic by-products, their effect would be observable only on a small spatial scale, since deposition of airborne pollutants is more evident if it is near the emission source. We used Factorial Cokriging to estimate the small-scale correlations among soil elements and to compare them to large spatial-scale correlations. Soil samples were collected from 92 sites. Given the low concentrations in soil heavy metals and As, we observed no serious soil contamination risk. We estimated correlations among the analysed elements on two spatial scales. On the larger scale, Ni and As exhibited higher correlation and received higher weights for the first regionalized factor, contrary to Cu, Pb and Zn which weighted more for the second regionalized factor. On the small spatial scale As associated with neither Ni nor other heavy metals. We conclude that soil arsenic has been altered by enrichment caused by some power plants through fly ash deposition and/or disposal. However, enrichment of soil elements was detectable only on the smaller spatial scale because anthropogenic inputs in soil through airborne emissions and subsequent deposition are evident only in the vicinity of the emission source.     

The objective determination of the instantaneous predominant frequency of seismic signals and inferences onQ of coda waves

A technique to detect spectrum variations versus time along seismic signals is applied to coda waves of local earthquakes (Friuli, Northern Italy). The technique consists of an autoregressive modeling and utilizes nonlinear spectral analysis where the spectrum of stochastic processes is estimated as the transfer function of the filter that whitens the process under analysis. This approach appears to be particularly well suited to those investigations where automatic measurements of the instantaneous frequency have to be carried out on digital data. The detection of variations of the instantaneous frequency along the coda allows computation of seismic-Q in the lithosphere and its frequency dependence: the result obtained is $$Q = 100f^{0.4} $$ which appears to be strongly consistent with that, based on the estimate of the coda amplitude decay in the band including the most significant frequencies of the signals under analysis.     

A new dynamical Climatology: Its aim and method

Summary By dynamical climatology is understood here the branch of mathematical meteorology which aims at a deduction of the mean properties of the atmospheric perturbations that are compatible with a given mean field of temperature, wind and pressure. First of all, the fundamental equations of the author's theory of perturbations are recalled and a general equation for the pressure variations at sea level is deduced. From this equation the different elements of dynamical climatology are then derived, for instance the stability of the mean field, the mean trajectories of the perturbations, the frequencies with which they are visited, the regions of deepening and filling or of birth and death of the perturbations, etc. These results explain many observational facts and empirical rules about the mean behaviour of the atmospheric disturbances at sea level throughout the year.

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Zusammenfassung Unter dynamischer Klimatologie wird hier der Zweig der mathematischen Meteorologie verstanden, der auf die Ableitung der mittleren Eigenschaften atmosphärischer Störungen, die mit einem gegebenen mittleren Temperatur-, Wind- und Druckfeld vereinbar sind, abzielt. Zunächst wird an die fundamentalen Gleichungen der Störungstheorie des Verfassers erinnert, um dann die allgemeine Gleichun; der Druckschwankungen auf dem Meeresniveau abzuleiten. Diese Gleichung führt dann zur Bestimmung der verschiedenen Elemente der dynamischen Klimatologie, z. B. zur Bestimmung der Stabilität des mittleren Feldes, der mittleren Trajektorien der Störungen, der Häufigkeit, mit welcher diese durchlaufen werden, der Gebiete der Vertiefung und Auffüllung oder des Entstehens und Verschwindens der Störungen usw.

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Résumé On entend ici par climatologie dynamique la partie de la météorologie mathématique qui a pour but la déduction des propriétés moyennes des perturbations atmosphériques qui sont compatibles avec un champ moyen donné de température, vent et pression. Tout d'abord on rappelle les équations fondamentales de la théorie des perturbations de l'auteur et l'on en déduit une équation générale des variations de la pression au niveau de la mer. Cette équation conduit à la détermination des éléments de la climatologie dynamique, tels que la stabilité du champ moyen, les trajectoires moyennes des perturbations, la fréquence avec laquelle elles sont parcourues, les régions de creusement et de comblement ou de naissance et de disparition des perturbations, etc. Ces résultats expliquent de nombreux faits d'observation et des règles empiriques sur le comportement moyen des perturbations atmosphériques au niveau de la mer pour les différentes époques de l'année.

     

Seismic signals in geothermal areas of active volcanism: a case study from ‘La Fossa’, Vulcano (Italy)

Since the last eruption (1888–1890) volcanism at Vulcano, Aeolian Archipelago, southern Tyrrhenian Sea, has taken the form of persistent fumarolic activity. The gas-vapour phases of the geothermal systems are mainly discharged within two restricted areas about 1 km apart from each other, in the northern part of the island. These areas are La Fossa crater, and the beach fumaroles of the Baia di Levante. Fluids released at the two main fumarolic fields display quite different chemical and temperature characteristics, implying different origins. The local seismicity essentially takes the form of discrete shocks of shallow origin (depth1 km) at La Fossa, usually with energy < 10¹³ ergs. They are thought to be related to the uprise of pressurized hot gases and vapours discharged at the crater fumaroles. The present investigation points to the existence of two principal categories of seismic events (called M-shocks and N-shocks). These are short events (normally < 10 s). M-type shocks are thought to be due to resonance vibrations within the interior of the volcano, probably driven by the excitation of shock-waves within cavities deeply affected by deposition and alteration of self-sealant hydrothermal minerals. N-type events display features that resemble those of volcano-tectonic earthquakes, but have no recognizable S-phases. Here they are tentatively attributed to microfracturing of rocks which have been extensively hydrothermally altered. Results of the present study permit a preliminary conceptual model of the local shallow seismic processes in the framework of geochemical modelling of fumarolic activity and geological inferences from geothermal drilling.     

On granitoid emplacement and related structures. A review

Granitoid magmas are emplaced at the upper crust under a complex interaction of gravitational processes and horizontal tectonics. Natural intrusive bodies show a wide variety of structural patterns that must be strongly related with their dynamic history of ascent and emplacement. Comparisons of natural structural patterns with experimental and numerical models are necessary to interpret in a coherent fashion the emplacement mechanism involved.From natural, experimental, numerical and theoretical considerations one can reach important conclusions on the problem of ascent and final emplacement of granitoid magmas in the Earth's crust. The present paper reviews the principal emplacement mechanisms referred to in the literature; that is, doming, diapirism, ballooning, stoping, cauldron subsidence and dike propagation.Dike propagation is the most effektive process in magma transport from deep zones in the crust and upper mantle. Extensional fractures for dike propagation and magma ascent can be developed at depth in the crust according to the modern dike propagation theory. In orogenic domains, magmas reach the upper crust through narrow channels or dikes and are accumulated in a final reservoir in the form of a discordant supracrustal pluton or a ballooning pluton if, during emplacement, any regional deformation acts simultaneously.

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Zusammenfassung Die Intrusion granitischer Magmen in die obere Krust ist das Ergebnis eines komplexen Zusammenspiels von schwerkraftbedingten Prozessen und horizontalen, tektonichen Bewegungen. Die gro\e Vielfalt tektonischer Strukturen von granitischen Plutonen spiegelt die Geschichte der Dynamik, ihres Aufstieges und ihrer Platznahme wider. Um den jeweils vorhandenen Intrusionsmechanismus zusammenhängend deuten zu können, sind Vergleiche der natürlichen, tektonischen Elemente mit experimentellen und numerischen Modellen notwendig. Hieraus lassen sich gegebenenfalls weitreichende Schlüsse zum Problem des Aufstiegs und der endgültigen Platznahme der Magmen in der Erkruste ziehen.In dieser Arbeit werden die wesentlichen Aufstiegsmechanismen von Magmen aus der Literatur diskutiert. Im Einzelnen sind dieses: Aufwölbung, Diapirismus, Aufweitung, Abbau, Kraterbildung und Gangentwicklung.Das Vordringen von Gängen ist der wirksamste Proze\ des Magmentransports aus tieferen Zonen der Kruste und des oberen Mantels. Ausdehnungsklüfte lassen sich als Ursache für das Vordringen von Gängen und den Magmenaufstieg nach der heutigen Theorie über die Entwicklung von Gängen in der tiefen Kruste herleiten. In orogenen Zonen erreichen Magmen die obere Erdkruste durch enge Kanäle oder Gänge und reichern sich dort auch in Form eines dikordanten, subkrustalen oder aufgweiteten Plutons an, wenn gleichzeitig mit der Platznahme regionaltektonische Deformationen ablaufen.

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Resumen Los magmas graníticos se emplazan en la corteza superior bajo una compleja interaccion entre procesos gravitatorios y tectónica horizontal. Los cuerpos intrusivos naturales muestran una amplia variedad de patrones estructurales que pueden estar directamente relacionados con la dinámica de ascenso y emplazamiento. Para explicar de forma cohérente el mecanismo de emplazamiento implicado en un plutón es necesario establecer comparaciones entre patrones estructurales de plutones y modelos experimentales y numéricos.A partir de consideraciones naturales, experimentales, numéricas y teóricas, se pueden extraer importantes conclusiones sobre el problema del ascenso y emplazamiento de magmas en la corteza. En este trabajo se revisan los principales mecanismos de emplazamiento referidos en la literatura; es decir, doming, diapirismo, ballooning, stoping, cauldron subsidence y propagación de diques.Propagación de diques es el proceso más efectivo en el transporte de magmas desde zonas profundas en la corteza y manto superior. De acuerdo con la moderna teoría de propagación de diques, las fracuras extensionales pueden producirse en profundidad en la corteza. En dominios orogénicos, los magmas alcanzan la corteza superior a través de estrechos canales o diques y se acumulan en un reservorio final, bien en forma de plutones discordantes supracrustales, o bien en la forma de un »ballooning pluton« si durante el emplazamiento actûa alguna deformación regional.

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Low-order stabilized finite element for the full Biot formulation in soil mechanics at finite strain

This article presents a novel finite element formulation for the Biot equation using low-order elements. Additionally, an extra degree of freedom is introduced to treat the volumetric locking steaming from the effective response of the medium; its balance equation is also stabilized. The accuracy of the proposed formulation is demonstrated by means of numerical analyses.     

Observations of shocked [FeII] and H2 line profiles in orion bullet wakes

Recent near-IR imaging of the Orion molecular cloud has revealed a complex of dense bullets, visible as [FeII] emitting HH-objects at the tips of H₂ wakes, ejected explosively from the cloud core. Having resolved individual bow-shock structures for the first time in this bright source, we have observed [FeII] 1.644µm velocity profiles of selected bullets and H₂ 1-0 S(1), 2.122µm velocity profiles for a series of positions along and across the corresponding bow-shock wakes. We present observed profiles for the bullet M42 HH1 and its associated wake and compare with theoretical bow-shock models.     

Solar constant and sunspots

Summary The relationship, already found by the authors, between sunspot numbers and the solar constant, as deduced from the highest global irradiance values at noon, is here reexamined and confirmed. Some attempts at explanation and further inferences are presented.     

U–Pb geochronology of the southern Brasília belt (SE-Brazil): sedimentary provenance, Neoproterozoic orogeny and assembly of West Gondwana

The Brasília belt borders the western margin of the São Francisco Craton and records the history of ocean opening and closing related to the formation of West Gondwana. This study reports new U–Pb data from the southern sector of the belt in order to provide temporal limits for the deposition and ages of provenance of sediments accumulated in passive margin successions around the south and southwestern margins of the São Francisco Craton, and date the orogenic events leading to the amalgamation of West Gondwana.Ages of detrital zircons (by ID–TIMS and LA-MC-ICPMS) were obtained from metasedimentary units of the passive margin of the São Francisco Craton from the main tectonic domains of the belt: the internal allochthons (Araxá Group in the Áraxá and Passos Nappes), the external allochthons (Canastra Group, Serra da Boa Esperança Metasedimentary Sequence and Andrelândia Group) and the autochthonous or Cratonic Domain (Andrelândia Group). The patterns of provenance ages for these units are uniform and are characterised as follows: Archean–Paleoproterozoic ages (3.4–3.3, 3.1–2.7, and 2.5–2.4 Ga); Paleoproterozoic ages attributed to the Transamazonian event (2.3–1.9 Ga, with a peak at ca. 2.15 Ga) and to the ca. 1.75 Ga Espinhaço rifting of the São Francisco Craton; ages between 1.6 and 1.2 Ga, with a peak at 1.3 Ga, revealing an unexpected variety of Mesoproterozoic sources, still undetected in the São Francisco Craton; and ages between 0.9 and 1.0 Ga related to the rifting event that led to the individualisation of the São Francisco paleo-continent and formation of its passive margins. An amphibolite intercalation in the Araxá Group yields a rutile age of ca. 0.9 Ga and documents the occurrence of mafic magmatism coeval with sedimentation in the marginal basin.Detrital zircons from the autochthonous and parautochthonous Andrelândia Group, deposited on the southern margin of the São Francisco Craton, yielded a provenance pattern similar to that of the allochthonous units. This result implies that 1.6–1.2 Ga source rocks must be present in the São Francisco Craton. They could be located either in the cratonic area, which is mostly covered by the Neoproterozoic epicontinental deposits of the Bambuí Group, or in the outer paleo-continental margin, buried under the allochthonous units of the Brasília belt.Crustal melting and generation of syntectonic crustal granites and migmatisation at ca. 630 Ma mark the orogenic event that started with westward subduction of the São Francisco plate and ended with continental collision against the Paraná block (and Goiás terrane). Continuing collision led to the exhumation and cooling of the Araxá and Passos metamorphic nappes, as indicated by monazite ages of ca. 605 Ma and mark the final stages of tectonometamorphic activity in the southern Brasília belt.Whilst continent–continent collision was proceeding on the western margin of the São Francisco Craton along the southern Brasília belt, eastward subduction in the East was generating the 634–599 Ma Rio Negro magmatic arc which collided with the eastern São Francisco margin at 595–560 Ma, much later than in the Brasília belt. Thus, the tectonic effects of the Ribeira belt reached the southernmost sector of the Brasília belt creating a zone of superposition. The thermal front of this event affected the proximal Andrelândia Group at ca. 588 Ma, as indicated by monazite age.The participation of the Amazonian craton in the assembly of western Gondwana occurred at 545–500 Ma in the Paraguay belt and ca. 500 Ma in the Araguaia belt. This, together with the results presented in this work lead to the conclusion that the collision between the Paraná block and Goiás terrane with the São Francisco Craton along the Brasília belt preceded the accretion of the Amazonian craton by 50–100 million years.     

The Cabo Frio upwelling overrides geographical patterns in the population dynamics of the shrimp Artemesia longinaris Spence Bate, 1888 (Decapoda: Penaeidae)

Upwelling areas are among the most productive ecosystems on the planet, influencing the biology of marine organisms. This study investigated the population dynamics of the shrimp Artemesia longinaris in two regions in southeastern Brazil, one inside (Macaé—Rio de Janeiro State) and one outside (Ubatuba—State of São Paulo) the Cabo Frio upwelling area. The aim was to verify the influence of the upwelling phenomenon on the abundance, growth, longevity, size of sexual maturity, and reproductive period of the species. In total, 188,902 individuals were captured at Macaé and 3,461 at Ubatuba. Individuals captured at Macaé showed larger maximum size, higher longevity, and slower growth rate, besides reaching sexual maturity at larger sizes than at Ubatuba. Continuous reproduction was observed in both regions, with juvenile recruitment peaks in spring and summer. Local conditions observed at Macaé were influenced by the Cabo Frio upwelling zone, characterized by productive and cooler waters that are around 20°C during most of the year. The upwelling phenomenon is probably the main factor influencing the population parameters studied here, changing the geographic patterns previously observed for the variation of these parameters in A. longinaris.