Glacier fluctuations in the southern Peruvian Andes during the late‐glacial period,constrained with cosmogenic 3He

The occurrence of pronounced climate reversals during the last glacial termination has long been recognised in palaeoclimate records from both hemispheres and from high to low latitudes. Accurate constraint of both the timing and magnitude of events, such as the Younger Dryas and Antarctic Cold Reversal, is vital in order to test different hypotheses for the causes and propagation of abrupt climate change. However, in contrast to higher‐latitude regions, well‐dated records from the Tropics are rare and the structure of late‐glacial tropical climate remains uncertain. As a step toward addressing this problem, we present an in situ cosmogenic ³He surface exposure chronology from Nevado Coropuna, southern Peru, documenting a significant fluctuation of the ice margin during the late‐glacial period. Ten tightly clustered ages from a pair of moraines located halfway between the modern glacier and the Last Glacial Maximum terminus range from 11.9 to 13.9 ka and give an arithmetic mean age of 12.8 ± 0.7 ka (1σ). These data constitute direct evidence for a readvance, or prolonged stillstand, of glaciers in the arid Andes of southwestern Peru. Copyright © 2011 John Wiley & Sons, Ltd.     

Pseudosection modelling for a selected eclogite body from the Koralpe (Hohl), Eastern Alps

In the Kor-, Saualpe and Pohorje regions of the Eastern Alps eclogite bodies occur within metapelitic gneisses. The bodies are between 1 meter and several hundreds of meters in size and some of them were defined by Haüy (1822) as the type locality for the rock type “eclogite”. A growing body of petrological work has documented the metamorphic evolution of the metapelites surrounding the eclogites. However, few phase diagrams have been constructed for the eclogite bodies themselves. Here we use recently available activity models for amphiboles to present new thermodynamic pseudosections for the Hohl locality of the Koralpe eclogites. We show that this eclogite reached peak conditions in a narrow PT field obliquely oriented in PT space between 16.5 and 20.5 kbar and 620°C to 720°C and that its metamorphic evolution was likely to have occurred under water saturated conditions. We conclude that eclogite and the surrounding metapelites have certainly undergone the same metamorphic peak in Eo-alpine time. Comparison of our results with different PT estimates on the eclogite from Pohorje, suggest that a PT gradient from Koralpe to Pohorje is likely.     

Transition enthalpies and entropies of high pressure zinc metasilicates and zinc metagermanates

The enthalpies of transition at T= 298 K between zinc metasilicate assemblages, measured by molten oxide solution calorimetry, are:

Results of a semi-implicit two-step method for the simulation of markedly nonlinear flow in coastal seas

Results of a numerical method for the simulation of nonlinear flow in coastal seas are presented. The method is based on a neutral semi-implicit scheme which is modified into a stability-enhancing two-step algorithm. By means of this method the simulation of highly nonlinear flow patterns is possible in a stable and economic way. Three examples of models of different North Sea coastal regions are discussed under certain aspects to demonstrate the reliability of the method.     

Enhancement of Seismic Data Processing and Interpretation of Fracture Zones on the Upper Part of Granitic Basement in Cuu Long Basin,Vietnam

The fractured granite basement is the primary oil and gas reservoir in the Cuu Long Basin, Vietnam. Due to the complexity of this nonlayered unconventional target, combined with complicated fault and fracture systems, the seismic data quality near and within the basement section is very low. For this reason, it is important to apply improved seismic data processing workflows, filtering and migration techniques, as wells as attribute processing methods to enhance the imaging quality.Our studies show that applying different types of filters, including the f-k, Radon transform and Tau-P, improves signal to noise ratio, removing multiples, revealing basement’s top and its related fractured and fault zones. In addition, the application of multi-arrival-solution migration algorithms, such as Kirchhoff Migration and Controlled Beam Migration, provides improved imaging for identifying basement top and faults and fractures within the basement. Furthermore, the application of seismic attributes such as curvature, apparent dip, or energy gradient, is important in locating faults and fractures, whereas mapping of intensity and orientation of such structures assists the delineation of “sweet spots” and assists the planning of exploration.     

Flood effects on phosphorus immobilisation in a river water filled pit lake—Case study Lake Goitsche (Germany)

Between 1999 and 2002, a former open-cast mine was filled with river water forming the recent Lake Goitsche. During filling initially acid water was neutralised. Phosphorus (P) imported from Mulde River was nearly completely removed from the water column by co-precipitation with iron (Fe) and aluminium (Al) and deposited in the sediment.During extremely high waters of the Mulde River in 2002, a dike breach facilitated a second high import of P into Lake Goitsche with suspended and dissolved matter. The analysis of total phosphorus (TP), however, showed that P again had been eliminated from the water body a few months after the flood event. Sediment investigations before filling with river water, during filling, and after the flood event were used to analyse the process of P immobilisation in a lake with acid mine drainage history.The ratios of Fe to soluble reactive P (SRP) of sediment pore water were up to three orders of magnitudes higher than in natural lakes and can serve as an indicator for potential internal P loading from sediments. The SRP concentrations at the oxic/anoxic boundary were near or below the limit of quantification (< 0.2 μmol/L). Fe and manganese (Mn) redox cycling were responsible for hindering P dissolution from sediment to lake water.Finally it can be stated, that the risk of eutrophication for such a lake seems to be low.     

Spatial distribution and bonding forms of heavy metals in sediments along the middle course of the River Elbe (km 287ċ390)

Sediments of eight groyne fields along the middle course of the River Elbe (river km 287?390) were geochemically studied. The 78 sediment samples were analysed for pH and grain size distribution. The grain size fraction < 2 μm was used for mineralogical and chemical analysis: semiquantitative clay mineral analysis; total element content (Al, Ca, Fe, K, Mn, Cd, Cr, Cu, Ni, Pb, Zn), total inorganic and organic C, and bonding form fractionation with a six‐step sequential chemical extraction. The latter was performed on selected samples (n = 32). The sediments along the Elbe's course are still contaminated with heavy metals far above the local geogenic background level. An enrichment factor of more than 15 was calculated for zinc. Cr and Ni are the elements with the lowest enrichment. The bonding form analysis of selected heavy metals shows a dominance of relatively immobile bonding forms, e. g. the moderately reducible and the residual fraction, which implies a relative low mobility potential. Only Zn poses a higher potential threat to the environment, since it has a higher percentage of the first three extracted phases: adsorbed, carbonate, and easily reducible fraction.     

Fluoreszenz und Gelbstoff im Bottnischen und Finnischen Meerbusen

Zusammenfassung In der folgenden Arbeit wird der erstmalige Versuch unternommen, einen quantitativen Einblick in die gegenseitigen Beziehungen zweier im Meerwasser vorhandenen ausgesprochen organischen Stoffe in ihrer Abhängigkeit vom Salzgehalt zu gewinnen. Derartige Messungen waren bisher noch nicht möglich vor allem wegen der überaus geringen Konzentration, in der die organischen Stoffe im Meerwasser vorzukommen pflegen, sodann auch wegen der verhältnismäßig großen Abbaugeschwindigkeit, der diese Stoffe unter den natürlichen Bedingungen im Meere unterliegen. Bei den hier angestellten Untersuchungen handelt es sich um zwei verhältnismäßig stabile den Humusstoffen nahestehende Verbindungen, die sich einmal durch ihr Vermögen, im ultravioletten Licht zu fluoreszieren und zum anderen durch ihre gelbe Farbe auszeichnen. Als Untersuchungsgebiet wurden der Bottnische und Finnische Meerbusen ausgewählt, die an diesen Stoffen verhältnismäßig reich sind. Legt man vier Ausgangswässer zugrunde, so läßt sich die eigenartige Verteilung dieses Fluoreszenz- und Gelb-Stoffes in dem Untersuchungsgebiet zwangslos aus den gegenseitigen Mischungsvorgängen dieser Wässer deuten. Der Vorzug der neuartigen Methodik für zukünftige Messungen liegt in dreierlei. Erstens verspricht die Bestimmung eine tieferen Einblick in den bisher noch so ungeklärten Mechanismus der Humusbildung, ferner ermöglicht sie eine genauere Kontrolle des Aussüßungsvorganges in den Randmeergebieten als es bisher möglich war, und schließlich scheint sie berufen, bei weiterer Durchentwicklung der Methodik für die Aufklärung der chemisch-biologischen Grundvorgänge im Zusammenhang mit der Produktionsfrage des Meeres eine wichtige Lücke ausfüllen zu können.

---

Fluorescence and contents of yellow substance in the Gulfs of Bothnia and Finland

Summary In the following paper it is tried for the first time to provide a quantitative insight into the relations between two clearly organic substances in the sea-water as depending on salinity. Measurings of this kind could not be made so far especially because the organic substances usually occur in sea-water in very low concentration, furthermore because they decay rather rapidly under the natural conditions prevailing in the sea. The investigations in question deal with two relatively stable compositions closely related to the ulmous substances which are characterized on the one hand by their capability of fluorescence in ultraviolet light and on the other hand by their yellow colour. The investigations are based on water-samples from the Gulfs of Bothnia and Finland, which are relatively abounding in these substances. Assuming four primary kinds of water, the peculiar distribution of these fluorescence and yellow substances in the investigated area can be explained without restriction by mixing processes of these waters. The advantages of the new method of investigation are: firstly that it may be expected to get a deeper insight into the genesis of humus which is only very little elucidated so far, furthermore it allows to control more exactly the process of freshening of the water in marginal seas, and finally, in case of further development it seems to be qualified to fill up a remarkable gap in the elucidation of the fundamental processes in biological chemistry in connection with the problem of marine production.

---

---

Die Veröffentlichung der im wesentlichen bereits vor etwa zehn Jahren abgeschlossenen Arbeit ist durch den Krieg verzögert worden.     

Evaluation and application of dialysis porewater samplers for microbiological studies at sediment-water interfaces

The equilibrium diffusion technique has become a valuable tool for ecological and biogeochemical studies in aquatic environments. In sediment ecosystems, changes in concentration of microbial metabolites with increasing depth can be determined dependably and reproducibly with this technique. Since the permeation characteristics of the membranes employed are crucial, selecting the proper membrane requires knowledge about its behavior under conditions which prevail in the natural environment. Thirteen polymer sheets were evaluated comparing permeation terms for biogeochemically relevant solutes, biodegradability, and mechanical strength. Cellulose-based dialysis membranes are most satisfactory when employed in low temperature anoxic environments. For this membrane, correction terms were calculated to account for diffusion losses during retrieval and sampling. Optimal incubation times can now be predicted from experimentally determined permeation coefficients for several porewater solutes. Dialysis porewater samplers (DPS) have been successfully applied during more than 100 independent experiments for the collection of interstitial water from surface sediments. DPS were used for water depths as deep as 290 meters.     

Das jüngste Großbeben in Anatolien

Ohne Zusammenfassung