The importance of talc and chlorite “hybrid” rocks for volatile recycling through subduction zones; evidence from the high-pressure subduction mélange of New Caledonia

The transfer of fluid and trace elements from the slab to the mantle wedge cannot be adequately explained by simple models of slab devolatilization. The eclogite-facies mélange belt of northern New Caledonia represents previously subducted oceanic crust and contains a significant proportion of talc and chlorite schists associated with serpentinite. These rocks host large quantities of H₂O and CO₂ and may transport volatiles to deep levels in subduction zones. The bulk-rock and stable isotope compositions of talc and chlorite schist and serpentinite indicate that the serpentinite was formed by seawater alteration of oceanic lithosphere prior to subduction, whereas the talc and chlorite schists were formed by fluid-induced metasomatism of a mélange of mafic, ultramafic and metasedimentary rocks during subduction. In subduction zones, dehydration of talc and chlorite schists should occur at sub-arc depths and at significantly higher temperatures (∼ 800°C) than other lithologies (400–650°C). Fluids released under these conditions could carry high trace-element contents and may trigger partial melting of adjacent pelitic and mafic rocks, and hence may be vital for transferring volatile and trace elements to the source regions of arc magmas. In contrast, these hybrid rocks are unlikely to undergo significant decarbonation during subduction and so may be important for recycling carbon into the deep mantle. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A Spatial Data Infrastructure Approach for the Characterization of New Zealand's Groundwater Systems

The future information needs of stakeholders for hydrogeological and hydro‐climate data management and assessment in New Zealand may be met with an Open Geospatial Consortium (OGC) standards‐compliant publicly accessible web services framework which aims to provide integrated use of groundwater information and environmental observation data in general. The stages of the framework development described in this article are search and discovery as well as data collection and access with (meta)data services, which are developed in a community process. The concept and prototype implementation of OGC‐compliant web services for groundwater and hydro‐climate data include demonstration data services that present multiple distributed datasets of environmental observations. The results also iterate over the stakeholder community process and the refined profile of OGC services for environmental observation data sharing within the New Zealand Spatial Data Infrastructure (SDI) landscape, including datasets from the National Groundwater Monitoring Program and the New Zealand Climate Database along with datasets from affiliated regional councils at regional‐ and sub‐regional scales. With the definition of the New Zealand observation data profile we show that current state‐of‐the‐art standards do not necessarily need to be improved, but that the community has to agree upon how to use these standards in an iterative process.     

Klimazonen der Verwitterung und ihre Bedeutung für die jüngste geologische Geschichte Deutschlands

Ohne Zusammenfassung     

Beitrag zu einer Definition für Starkregen im Ostalpengebiet

Zusammenfassung Schon vor etlichen Jahren hat man die Unzulänglichkeiten der früheren Starkregendefinitionen klar formuliert (vor allem in England) und nunmehr durch die Betonung der Häufigkeitn eine verbesserte Definition gefordert. Mit Hilfe von deutschen Auswerteverfahren für Ombrographenregistrierungen wird in vorliegender Arbeit der Versuch unternommen, auf dieser neuen Basis eine für Österreich gültige, aber allgemein vergleichbare Definition der Starkregen zu finden, und es ergibt sich, daß als Starkregen in Österreich ein Regenfall zu bezeichnen ist, der die Intensität eines Idealregens erreicht oder überschreitet, der alle Jahre höchstens einmal in dieser Stärke an jeder Station des betreffenden Gebietes (aber natürlich nicht unbedingt überall gleichzeitig) vorkommen würde (n=1). AlsPlatzregen ist ein Regenfall anzusehen, der die Intensität eines höchstens alle zwei Jahre (n=1/2), und alsstarker Platzregen ein solcher, der die Intensität eines höchstens alle acht Jahre (n=1/8) vorkommenden Regens erreicht bzw. überschreitet. Auf eine formelmäßige Erfassung dieser Grenzkurve wird hier verzichtet, weil solcherart kaum ein einfacher und praktisch verwendbarer Ausdruck gegeben werden könnte; vielmehr werden die zu den festgelegtenn gehörigen Intensitätswerte für vier regengeographisch verschiedene Hauptgebiete Österreichs in einer Tabelle gegeben.

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Summary Already several years ago the definitions for heavy rainfall were strongly criticized as being insufficient (above all in England) and a better definition with emphasis on the frequency was claimed. Using German evaluation methods for rain-gauge records, this paper makes an attempt of finding a new definition for heavy rainfall being valid particularly for Austria, but comparable generally. It is concluded that, in Austria, a rainfall is to be defined as heavy rain which reaches or surpasses the intensity of an ideal rain occurring with that intensity at most once in a year at every station of the area in question, but not necessarily everywhere at the same time (n=1). A rainfall is considered as downpour if it reaches, respectively surpasses the intensity of a rain occurring at most once every two years (n=1/2), and as heavy downpour a case with an intensity occurring once every eight years at most (n=1/8). A formula of this limit curve is not given as there exists no simple and practically applicable expression for it. Intensity values, however, referring to then given above are presented in a table for four geographical rain areas of Austria.

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Résumé Il y a plusieurs années déjà on a souligné (en Angleterre surtout) les insuffisances des anciennes définitions des pluies de grande intensité et on en a suggéré une meilleure en mettant l'accent sur les fréquencesn. Utilisant le procédé allemand de dépouillement des enregistrements d'ombrographes, on tente ici de trouver sur cette nouvelle base une définition des pluies violentes, valable pour l'Autriche, mais permettant une comparaison générale. Il s'ensuit qu'en Autriche on considère comme pluie intense celle qui atteint ou dépasse l'intensité d'une «pluie idéale» qui se produirait au maximum une fois chaque année (n=1) avec cette intensité en chaque station de la région en question (mais pas nécessairement partout en même temps). Unepluie intense ou battante (Platzregen) est celle qui atteint ou dépasse la pluie maximum de deux ans (n=1/2), et unepluie torrentielle (starker Platzregen) celle qui atteint ou dépasse le maximum de huit ans (n=1/8). On renonce ici à préciser numériquement les limites de ces différents cas, car on ne pourrait donner une expression analytique simple et pratique; on se borne donc à présenter sous forme de tableau pour quatre régimes pluvieux d'Autriche les valeurs de l'intensité de pluie correspondant aux différentes valuers den.

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Mit 6 Textabbildungen.     

Eine Kartierung der Bewegungsspuren im obersten Höllental (Schwarzwald)

Ohne Zusammenfassung     

Junge Vulkano-Plutone in Südwestafrika

Ohne Zusammenfassung     

Public climate-change skepticism,energy preferences and political participation

Many studies have shown a general decline of public concern about climate change or vice versa a rise in public climate-change skepticism, in particular in the U.S. and other Anglo-Saxon countries. There is a vivid debate on whether this is a global phenomenon, on which factors explain the decline, and on the broader societal implications of these trends in the context of the transformation toward a low-carbon society. We add to this literature by presenting the results of a recent general population survey in Germany in which we looked for systematic linkages between public climate-change skepticism on one hand, and energy preferences and political participation on the other. Germany is an interesting testbed as it is currently involved in a large-scale restructuring of its system of energy supply toward renewable energy sources (the “Energiewende”). Our results indicate that climate-change skepticism has not diffused widely in Germany, but that it correlates with less support of renewable energy sources. However, skepticism correlates negatively with political participation, and there is no strong political outlet for public climate-change skepticism in Germany. Alternative potential barriers for the successful implementation of the “Energiewende” are also discussed.