GPS monitoring of vertical ground motion in northern Ardenne–Eifel: five campaigns (1999–2003) of the HARD project

We present the HARD project of GPS monitoring of vertical ground motion in NE Ardenne and Eifel (western Europe). Its main purposes are to get a better insight into the present-day rates of vertical ground motion in intraplate settings and to identify the various causes of these motions. Since 1999, we have carried out yearly campaigns of simultaneous GPS measurements at 12 sites situated so as to sample the different tectonic subunits of the study area and especially to record potential displacements across the seismogenic Hockai fault zone. Five campaigns (1999–2003) have been processed currently. Key issues of the data processing with the Gamit software are discussed and first results are presented. Though temporally consistent in many cases, the obtained vertical motion rates are spatially highly variable. They are also much too high (several mm/year) to support a tectonic interpretation, and a long-term influence of groundwater level variations is proposed to account for the observed motions. This influence should be distinguished from seasonal variations and from inter-survey variations linked to the varying degree of soil and subsoil drying off during the successive spring surveys.     

Size Fractionation (Dissolved, Colloidal and Particulate) of Trace Metals in the Thur River, Switzerland

The distribution of some trace metals (Cu, Zn, Ni, Co,Fe, Mn) and of DOC over a particulate (> 1 m),a colloidal (size < 0.45 m and molecular weight > 10 kD) and an ultrafiltered fraction (< 10 kD)was determined at several sites on the Thur River,Switzerland, at various times of the year. Thecomplexation of Cu by strong ligands in theultrafiltrate and in the conventional filtrate (<0.45 m) was compared using a ligand-exchange/CSV method.The <0.45 m concentrations of Cu (from anaverage of 7 nM to 24 nM), Zn (<5–23 nM), Ni (5–13 nM),Co (1.5–3 nM) and Mn (7–92 nM)increased downstream. The major part of Cu, Zn, Niand Co usually occurred in the ultrafiltratefraction at all sites, whereas Fe and Mn were mostlyin the particulate fraction, under conditions of lowsuspended matter content (< 10 mg L^-1) in theriver. The percentage of metal in the colloidalfraction, with respect to the 0.45-m filtrate,decreased in the order: Cu (median 11%) > Zn Ni(median 5–6%) > Mn Co (median < 5%). DOCalso consisted mostly of molecules in the < 10 kDrange.Cu was strongly complexed by natural organic ligandsin all filtrate and ultrafiltrate samples. A largepart of the strong Cu binding ligands consisted ofcompounds in the < 10 kD range, but colloidalligands with similar properties also occurred. Cu wasdistributed among the dissolved and the colloidalligands, roughly in proportion to organic carbon.The colloidal fraction (as defined here) did notincrease in its proportional amount downstream and wasonly of limited significance in transporting traceelements in the Thur River under low discharge conditions.     

On the way to a better state? The role of NGOs in the planning and implementation of protected areas in Brazil

Protected areas are considered some of the most versatile as well as important instruments of nature conservation and environmental policies. The `classic' model of nature conservation aims at the isolation of large areas in order to preserve their `pristine' nature from human interference. However, the transfer of this model to developing countries led to serious conflicts with local people. From a socio-geographical viewpoint, protected areas can be understood as regulative tools for the shaping and controlling of space. This approach helps to recognise the influence of distinct modes of appropriation of space and nature on the emergence and course of conflicts. In the present article it is used to analyse the leading role played by Brazilian NGOs in the transformation of the classic model of protected area management at the beginning of the nineties. Two case studies – dealing with the implementation of the Amazonian Mamirauá Reserve and with the reform of the Brazilian protected area legislation – are used to illustrate not only the success of the new approaches, but also the expectations and contradictions which surround the future development of protected areas in Brazil.     

A numerically calibrated reference level (MP28) for the terrestrial mammal-based biozonation of the European Upper Oligocene

The fauna of the Enspel (Westerwald) and the neighbouring Kärlich (Neuwied basin) fossil deposits correspond to the Upper Oligocene Mammal Paleogene (MP) reference level 28 and 28–30, respectively. Basaltic flows and a trachyte tuff terminating and predating the fossil deposit sedimentation allow to numerically calibrate the MP reference levels by radioisotope dating. Laser fusion ⁴⁰Ar/³⁹Ar step heating on volcanic feldspars yield a time interval of 24.9–24.5 Ma for reference level MP28 at Enspel and a maximum age of 25.5 Ma for the time interval MP28–MP30 at Kärlich. Interpolation between the time intervals determined for the Enspel reference level MP28 and the age of the global Oligocene/Miocene boundary of 24.0 ± 0.1 Ma taken from literature results in time intervals of 24.5–24.2 Ma and 24.2–23.9 Ma for the younger reference levels MP29 and MP30, respectively. These intervals of ≤ 0.4 m.y. for MP reference levels of the latest Oligocene are short relative to older Oligocene MP reference levels 21–27 between 34 and 25 Ma. Since subdivision into MP reference levels essentially is based on assemblages of mammal taxa and on evolutionary changes in tooth morphology of mammals short MP time intervals during the latest Oligocene indicate a rapid evolutionary change relative to the early Oligocene.     

Shortage in the midst of plenty: Labour strategies in four Central and Eastern European cities

Labour shortage was an integral feature of the communist system of economic management and one that seemed most unlikely to persist in the face of systemic transformation. A casual examination of the unemployment rates that have emerged throughout most of Central and Eastern Europe (CEE) during the course of the past decade might suggest that this early assumption was correct. However, within the region the aggregate rate of joblessness, as well as the behaviour of national output, mask the fact that certain, major urban centres appear to have weathered well the storms caused by exposure to western markets and stringent fiscal and monetary policies. In these centres transformation has meant, to a greater or lesser degree, industrial modernisation and this begs the question of whether the human capital portfolios of the inherited labour force match up to the requirements of the new environment. This paper examines the meaning of the concept of labour shortage and presents the findings from a survey of employers in four leading cities of three major CEE economies designed to elicit if, and how, manpower requirements are being met in the present climate. The results indicate that, somewhat paradoxically, labour shortage persists in the more flexible markets of the post-communist era and that firms do not expect the situation to change radically in the near future. This revised version was published online in July 2006 with corrections to the Cover Date.     

Geochronology of the Spessart Crystalline Complex,Mid-German Crystalline Rise

Summary New Rb-Sr and K-Ar datings help to clarify the geologic history of the Spessart Crystalline Complex, Mid-German Crystalline Rise. The oldest dates, refined by new measurements, are recorded by whole-rock Rb-Sr analyses of the orthogneisses of the Rotgneiss Complex. These confirm a late Ordovician to Silurian age which is interpreted as the time of intrusion of the granitic precursors.Hornblendes, muscovites. and biotites from different lithostratigraphic units and rock types of the Spessart Crystalline Complex yielded K-Ar dates mainly in the range 324 to 318 Ma, an interval which conforms to the analytical precision. Two hornblendes and one muscovite show slightly older dates up to 328 Ma. On the other hand, there is a tail of younger hornblende dates towards 311 Ma, and two hornblendes gave dates as low as 293 and 274 Ma for no immediately obvious reason.The concordant dates around 324 Ma on the three different minerals may be interpreted as marking the time of a rapid uplift and cooling at about the boundary between Early and Late Carboniferous, presumably soon after culmination of the Variscan deformation and amphibolite facies metamorphism.

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Geochronologie des Spessart-Kristallins, mitteldeutsche Kristallinschwelle

Zusammenfassung Neue Rb-Sr- und K-Ar-Datierungen liefern einen Beitrag zum Verständnis der geologischen Geschichte des Spessart-Kristallins. Die älteste radiometrische Datierung, die bislang im Spessart-Kristallin zur Verfügung steht, leitet sich aus Rb-Sr-Gesamtgesteinsanalysen von Orthogneisen des Rotgneis-Komplexes ab. Die bereits von früheren Bearbeitern gefundenen spät-ordovizischen bis silurischen Daten wurden durch neuere Messungen bestätigt. Sie werden als Intrusionsalter des granitischen Ausgangsmaterials der Rotgneise interpretiert.Hornblenden, Muscovite und Biotite aus unterschiedlichen lithostratigraphischen Einheiten und Gesteinstypen des Spessartkristallins erbrachten K-Ar-Daten vorwiegend zwischen 324 und 318 Ma, d. h. einen Streubereich, der etwa der analytischen Genauig keit entspricht. Zwei Hornblenden und ein Muscovit ergaben etwas ältere Daten bis 328 Ma. Auf der anderen Seite beobachtet man eine Reihe von jüngereren Hornblendedaten bis 311 Ma, und zwei Hornblenden von nur 293 und 274 Ma, die sich nicht ohne weiteres erklären lassen.Die konkordanten Alterswerte um 320 Ma, die für die drei Mineralarten gewonnen wurden, können als die Zeit einer raschen Hebung und Abkühlung etwa an der Grenze Unter-/Oberkarbon interpretiert werden, die vermutlich bald nach dem Höhepunkt der variscischen Deformation und amphibolit-faziellen Metamorphose erfolgte.

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Dedicated to Borwin Grauert on the occasion of his 60th birthday.

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With 6 Figures     

Post-Svecokarelian andinotype evolution in central Sweden

Granitoids and associated volcanics, postorogenic in relation to the Svecokarelian orogeny, constitute a belt in central Sweden. Evidence presented in this paper suggest that the belt originated in an Andinotype orogenic environment. The inferred development of the belt was characterized by fracture-controlled high-level emplacement of batholiths in an ensialic setting. Voluminous venting of ignimbrites and formation of grabens through cauldron subsidence accompanied the recurrent intrusive activity. Block movements and episodes of burial metamorphism appear to have been prominent features throughout the history of the post-Svecokarelian belt.

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Zusammenfassung Granitoide Plutonite und verwandte Vulkanite, post-orogen im Verhältnis zur Svekokarelischen Orogenese, bilden einen Gürtel in Mittelschweden. Es wird gezeigt, daß der Gürtel in einer andinotypen Orogenese gebildet wurde. Die vorgeschlagene Entwicklung des Gürtels ist geprägt durch spaltentektonisch kontrollierte Platznahme von Batholithen in einem seichten Niveau der Kruste in ensialischem Mileau. Umfangreiche Eruptionen von Ignimbriten sowie die Bildung von Grabenbrüchen durch Kalderen-Einstürzungen begleiten die erneute intrusive Tätigkeit. Blockbewegungen und episodische Versenkungsmetamorphosen sind charakteristisch während der gesamten Entwicklungsgeschichte des post-svekokarelischen Gürtels.

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Résumé Des granitoïdes et des volcanites associées, postorogéniques par rapport à l'orogénese svécokarélienne, forment une ceinture en Suède centrale. La présente étude suggère que la mise en place de ces roches s'est effectuée dans un environment orogénique Andinotype. L'évolution de la ceinture c'est caractérisée par la mise en place; contrée par des fractures, de batholites peu profonds, en milieu ensialique. Des volumineuses éruptions d'ignimbrites et la formation de grabens par «cauldron subsidence» ont accompagné la mise en place des batholites. Des mouvements verticaux de blocs, ainsi que des épisodes de métamorphisme d'enfouissement («burial metamorphism») semblent être des faits dominants du développement historique de la ceinture post-svécokarélienne.

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Correlation of the Quaternary terrace sequence in the Lower Rhine valley and northern Alpine foothills of central Europe

Thirteen glacial terraces are known from the western part of the northern Alpine foothills between the Lech and Iller Rivers. In the Lower Rhine region of West Germany, a similar number of terraces are capped by interglacial floodloams and soils. Whereas the environment during individual interglaciations did not differ substantially, the glaciations were progressively more severe. The Main Terrace system of the Rhine may be an exception. The duration of the Quaternary, starting at the base of Praetiglian, is estimated at approximately 2 million yr by paleomagnetic dating. The major cold-warm climatic cycles of the earliest Pleistocene lasted approximately 100,000 yr, the same as those of the Brunhes Chron. The intervening Main Terrace system has not yet been climatically subdivided. Correlation with the Netherlands is possible because of an abundance of paleobotanic and paleomagnetic evidence. In the Alpine foothills, stratigraphically useful indicators of warm climates are missing, but analogies in terrace development permit comparison with the Lower Rhine and Danube. The terrace sequence in the Alpine foothills is incomplete, as are those along most of the other rivers in Europe. Some of the older terraces may have been eroded.