Fakultät für Geowissenschaften - Digitale Hochschulschriften der LMU Archiv

A homogeneous design for landfill bodies is generally agreed. However the manner in which waste is deposited may result in a sequence of layers that causes inhomogeneity. The goal of this research was to investigate the influences of such inhomogeneities on long-term leaching of highly soluble salts and ecotoxic species. This long-term leaching of was observed for 25 months. Laboratory column tests and field experiments (test bodies and lysimeters) were performed with municipal solid waste incineration residues. Laboratory columns were irrigated with tap water. Control field experiments were exposed to natural precipitation. Due to the fact that municipal solid waste incineration residues are continually landfilled on monofills, the percolating landfill-leachates are highly saline. Therefore extended experiments were carried out and these were treated with saline solutions: either solely or in addition to natural precipitation. Highly saline irrigation-media artificial leachates produced in the lab, actual landfill leachate or a concentrate from reverse osmosis was used, depending on the experiment. Besides irrigation, the application of residues, as the top or intermediate layers, provided continuous supply of highly saline solutions. Commonly, column experiments are conducted under water-saturated conditions. For this research however, unsaturated conditions were chosen to understand real landfill conditions. All experiments were performed as parallel experiments. One test had a uniform-grain setup and acted as a control. The application of a fine-grained bottom ash layer within a column filled mainly with coarse-grained bottom ash provided the inhomogeneous setup. Grain size changeover as a barrier layer within a column should change the permeability along the profile of the column. In some cases the barrier layer was compacted. The results of long-term the solid sample and leachate investigations pointed out that the application of a barrier layer by means of grain size changeover had mainly physical effects. With the control experiment, water contents of solid samples increased in general from the top of the experiments to the basis. In contrast, the following was observed for the application of a barrier layer:  impounding of leachate,  slowdown of leachate percolation time,  increased water retention capacity. Mainly the zone within the barrier layer showed the highest water content. A general observation was that the setting beneath the barrier layer was much drier. Another observation was that irrigation with saline water enhances water retention within the column. Additionally model experiments with plastic shots pointed out that the irrigation with small amount of water intensifies the physical effect of the barrier layer. Unsaturated water conditions which are common in landfills together with reduced permeability provide the basis for salt accumulations around the zone of the fine grained ash layer. An investigation on the distribution of the elements along the profile showed that impounding of the leachate at the barrier layer is linked to higher eluate soluble species concentrations: the tendency of accumulation was observable especially for the zone within and beneath the barrier layer and in the near-bottom samples for the control as well as extended experiments. Concerning a uniform setup the salt distribution along the profile was homogeneous up to gradual. In general the observations indicated that the application of a barrier layer by means of grain size changeover impounds the leachate. Thus, increased concentrations of different species of saline solutions in combination with changing water contents within the layers caused precipitation of the highly soluble salts out of the pore solution. The formation of salt accumulations is time-dependent. Most of the chemical and mineralogical progressions occurred only after a longer period:  tendencies for the leachate progression changed several times during the long term,  different processes depend on the pH-value (e.g. if the pH-value decreases Ca-concentrations will increase) and  this supports the vital importance of long term leaching. A main conclusion is that unsaturated conditions in combination with physical and chemical processes provide conditions conducive for salt accumulations around the zone of the barrier layer. The effects of inhomogeneities because of compaction and/or grain size changeover, as investigated in this research, furnish an explanation for actual observations at the Waldering monofill. In a particular filler part a salt horizon of several meters was encountered. This highly saline layer consists mainly of Halite and Sylvite. Hence there is the possibility that salt accumulations up to salt horizon are generated even in a humid climate. In principle the MSWI-residues afford high contents of saline species. Due to the application of a barrier layer the following advantages can be derived for landfill operations:  due to their high water retention capacity, salt accumulations cause little amounts of leachate,  high water retention capacity combined with the intensifying effect of salty crusts within the zone of the fine grained ash layer provides strong buffering concerning rainstorms.

Die vorliegende Arbeit behandelt Fragen aus dem interdisziplinären Gebiet der Nanowissenschaften durch Untersuchungen mittels Rastertunnelmikroskopie und Computerchemie. Sie steht im Kontext der Entwicklung nanotechnologischer Herstellungsverfahren, die sich auf die "bottom-up"- Fertigungsstrategie beziehen. Diese Strategie verfolgt das Ziel, aus einzelnen elementaren Bausteinen (z.B. Molekülen) grössere funktionelle Strukturen und Systeme kontrolliert zusammenzusetzen. Kern dieser Arbeit ist die Vorstellung eines neuartigen Strukturbildungsprozesses auf molekularer Ebene und die Erschliessung dessen Potentials. Für diesen Prozess wird der Begriff "supramolekulare Festphasenbenetzung" vorgeschlagen. Damit wird ausgedrückt, dass die Ergebnisse als eine neue Bedingung für supramolekulare, spontane Strukturbildung (engl. self-assembly) interpretiert werden, die bei Raumtemperatur an der Grenze zwischen zwei festen Phasen stattfindet. Das vorgestellte Modell beschreibt diesen Prozess durch Nanokristalle, die – in einer Matrix suspendiert – bei Kontakt mit einer Kristalloberfläche ein Verhalten zeigen, das trotz vorhandener Festkörpereigenschaften (kristalline Ordnung) dem Verhalten flüssiger Tropfen bei der Benetzung von Oberflächen verwandt ist. Darauf aufbauend wird das technologische Potential des neuen Prozesses erschlossen: 1. Adsorbatstrukturen von einer Reihe organischer Halbleiter werden erstmals beschrieben. Damit wird zudem gezeigt, dass sich durch supramolekulare Festphasenbenetzung unlösliche Halbleitermoleküle sehr einfach und unter Umgebungsbedingungen geordnet adsorbieren lassen – ein Ergebnis, das sonst nur mit grossen Aufwand (z.B. Molekularstrahlepitaxie im Vakuum) möglich wäre. 2. Ein Erklärungsmodell wird entwickelt, mit dem sich die bislang unverstandene Möglichkeit molekularer Datenspeicherung mittels PTCDA- Moleküle theoretisch erklären und auf weitere, unter (1) vorgestellte Moleküle erweitern lässt. 3. Die Entwicklung eines Nanofabrikationskonzeptes wird vorgestellt, das eine lokale Kontrolle des Wachstums von Nanostrukturen ermöglicht. Der Vorteil gegenüber einer klassischen, Molekül für Molekül durchgeführten Nanostrukturierung liegt darin, dass durch die Spitze eines Rastertunnelmikroskops allein die Information über Wachstumsrichtungen in das System lokal einzubringen ist, die eigentliche Bildung der Strukturen jedoch durch selbständig ablaufende und somit qualitativ und zeitlich hoche¢ziente Wachstumsprozesse stattfindet ("geführtes Wachstum"). Damit lässt sich die bisherige Beschränkung von self-assembly auf streng periodische Strukturen durchbrechen und die vordefinierte Bildung komplexer Strukturen erreichen. 4. Ein Verfahren wird vorgestellt, das eine lokale Adsorption von Molekülen zu geordneten Schichten innerhalb einer Lage fremder Moleküle erlaubt und somit den Aufbau heterogener Adsorbatschichten ermöglicht.

In this thesis I advance the integration of mineral thermodynamics into convection modeling. I have compiled a thermodynamic model of mantle mineralogy in the five component CFMAS system (CaO-FeO-MgO-Al2O3-SiO2), including mineral phases that occur close to typical chemical models of the mantle and reasonable mantle temperatures. In this system I have performed a system Gibbs free energy minimization, including pure end-member phases and a non-ideal formulation for solid solutions. Solid solutions were subdivided into discrete pseudocompounds and treated as stoichiometric phases during computation of chemical equilibrium by the simplex method. I have complemented the thermodynamic model with a model of shear wave properties [Stixrude and Lithgow-Bertelloni, 2005] to obtain a full description of aggregate elastic properties (density, bulk and shear moduli) that provide a useful basis for the consideration of seismic and geodynamic models of the Earth's mantle. By using this new thermodynamic database for the mantle I have coupled the resulting density dynamically (through the buoyancy term) with mantle convection models. I have linked the database with a high-resolution 2-D convection code (2DTERRA), dynamically coupling the thermodynamic model (density) with the conservation equations of mantle flow. The coupled model is run for different parameterisations of viscosity, initial temperature conditions, and varying internal vs. external heating. A common feature of all the models is that the convecting flow creates a characteristic discontinuity of temperature around 660 km depth in order to compensate for the entropy change due to the phase transitions. I have studied the importance and the possible consequences of such a thermal regime on the excess temperature of plumes and on the transition zone thickness. The thermodynamic mantle mineralogy model provides the conversion of the temperature field into seismic velocities so that predictions from mantle convection can be compared to seismic observations in terms of radial profiles or lateral variations. This approach allows us to predict a number of seismic observables from the convection model, all of which agree remarkably well with observations from seismic tomography.

Deterministic earthquake scenario simulations are playing an increasingly important role in seismic hazard and risk estimation. The numerical calculation of the complete 3D wavefield in the observed frequency band for a seismically active basin remains a computationally expensive task. This expense restricts seismologists either to calculating source models with homogeneous media (e.g., Gallovic and Brokesoová, 2004, 2007a,b), or to calculating single source scenario in 3D media (e.g., Olsen and Archuleta, 1996; Olsen, 2000; Ewald et al., 2006) while the complex effects of the media and the source on the ground motion are getting more and more attention. At the same time, with the development of the instrument, ground rotation introduced by an earthquake becomes a more and more important topic. Our aim is to provide a tool with which we can calculate a large number of different finite-source scenarios for a particular fault or fault system located in a 3D structure which will enable us to estimate ground motion (translation and rotation) variations due to source and 3D structure. In order to avoid having to run numerical expensive 3D code for each kinematic source scenario we propose the concept of “numerical Green’s functions” (NGF): a large seismic fault is divided into sub-faults of appropriate size for which synthetic Green’s functions at the surface of the seismically active area are calculated and stored. Consequently, ground motions from arbitrary kinematic sources can be simulated for the whole fault or parts of it by superposition. To demonstrate the functionalities of the method a strike-slip NGF data base was calculated for a simplified vertical model of the Newport-Inglewood fault in the Los Angeles basin. As a first example, we use the data base to estimate variations of surface ground motion (e.g., peak ground velocity (PGV)) due to hypocentre location for a given final slip distribution. The results show a complex behavior, with dependence of absolute PGV and its variation on asperity location, directivity effect and local under-surface structure. Hypocentral depth may affect peak ground velocity in a positive or negative way depending on the distance from the fault and the receiver location with respect to basin structure. Finite-fault source inversions reveal the spatial complexity of earthquake slip over the fault plane. In this study, several possible earthquake scenarios of Mw 7.0 are simulated with different quasi-dynamic finite source models for the Newport-Inglewood fault in the Los Angeles basin. We investigate the effects of the various slip histories on peak ground velocities and the related variations in ground motion prediction for our study area. The results confirm that the fault perpendicular components of motion are dominated by directivity effects while the fault parallel component is influenced both by the slip distribution and the basin structure. There are theoretical considerations suggesting that observations/calculations of the rotation part of earthquake-induced ground motions may provide additional information for earthquake risk hazard analysis after reports on rotational effects on structures (like twisting of tombstones or statues). For the first time, we carry out a systematic study of earthquake scenario simulations in 3D media with a specific focus on the rotational part of the motions. We simulate several M7 earthquakes with various hypocentre locations and slip histories on the Newport-Inglewood fault embedded in the 3D Los Angeles Basin. We investigate source and basin structure effects on the rotational components of ground motion (e.g., peak ground rotation rates and their variation, horizontal gradients) and compare with the effects on translations. Igel et al. (2005) shows a similarity of the observed waveforms between transverse acceleration and the vertical rotation rate in the teleseismic range benefiting from the recently developed ring laser instruments. The vertical rotation rate is found to be surprisingly similar to the horizontal translations in waveform which is explained with the plane wave propagation in the global range. That condition could not be hold any more in the near-field range, but some information could be extracted from the comparison between the translations and the rotation rate. As a final application, we investigate the source-dependent variations on rotational ground motions and compare with the results for translations. The thesis is structured as follows: Chapter 1: An insight into the present standard procedures carried out in the Seismic Hazard Assessment (SHA) is shown and then the different methodologies for predicting ground motions are described and compared, which are working individually or cooperate with each other. In recent years, one of those methods – deterministic calculations have been used widely and its consumption both in terms of CPU time and memory motivated the development of one new tool. We name that tool Numerical Green’s Function (NGF) method. Chapter 2: An introduction to the different solutions of the wave propagation is given and the state-of-the-art technologies are described. We will introduce in detail the techniques adopted. We show how to implement the source, how to solve the wave propagation problem, and how to efficiently absorb the energies outgoing from the working area, or reflect them at the free surface boundary. To correctly account for the rupture process, which has been found to be the most important contributor to the ground motion in the near-source region, different tools are developed which can be divided into two groups: kinematic description and dynamic description of the source. These two descriptions are briefly compared. Then we focus on the “quasi-dynamic” method developed by Guatteri et al. (2004) which combines, to some extent, the two different approaches. This method is used to provide us the rupture processes we will consider. Chapter 3: Green’s function stands for the response on the surface due to an impulse dislocation at the source. A large earthquake rupture can be represented with a group of impulse dislocations, and thus the ground motion on the surface can be achieved by the superposition of its Green’s functions. In this chapter, we follow the representation theorem published in Aki and Richards (2002) to give the theoretical basis of that method and briefly describe the two groups of that method: composite method and integral method. Finally we introduce our new method – Numerical Green’s Function, present the basic equations and analyze its relationship with the representation theorem and empirical Green’s function method. Chapter 4: Discretization of the fault plane into elements and assumption the source parameters identical inside each element will introduce errors in the calculated seismic motions and these errors are expected to depend on some few parameters such as the fault geometry, the rupture velocity, the sub-fault size, the cut-off frequency for low-pass filtering the ground motions, the directivity effect, etc.. In this chapter we design a hypothetic velocity structure and investigate how the errors introduced by the fault discretization will change with those parameters. The results are considered to provide some clues for our next step – selecting a seismic active fault and discretizing it into pieces with optimal sizes for which the Green’s functions will be calculated and stored. Chapter 5: The working area of this study, the Newport Inglewood fault embedded in the Los Angeles basin is introduced. The Los Angeles basin is chosen as our working area because of the high seismicity and that the most reliable information about the subsurface structure could be achieved. One active fault, the Newport-Inglewood fault inside this region is considered as a possible place where an M7.4 earthquake could happen in the future decades. Also its near vertical straight fault plane facilitates the implementation of this fault into the finite difference method. After choosing the fault and velocity structure, we re-address the optimal size of sub-fault by simulating a few M7 earthquakes and investigate the peak ground velocity and the waveform difference introduced by the different discretizations. The importance of the directivity effect on the ground motion in the near-source region has been recognized and is one of the main targets of the next generation of the attenuation relationship. A brief introduction to the physics of wave propagation is given in order to make the following discussions and illustrations of our results understandable for readers without previous knowledge. We analyze the different directivity effect supposed to happen between different component, or different kinds of motion (translation and rotation). Chapter 6: This chapter addresses the problem of the variations of surface ground motion (e.g., peak ground velocity) due to hypocentre location for a given final slip distribution. A complex behavior about the dependence of absolute PGV and its variation on asperity location, directivity effect and local structure is presented. Hypocentral depth may affect PGV in a positive or negative way depending on the distance from the fault and the location with respect to the basin structure. The directivity effect is found to control the seismic motion generation for a specific final slip distribution. Chapter 7: Inversions of the spatial and temporal evolution of earthquake slip on fault planes provide compelling evidence that fault displacement is spatially variable at all resolvable scales. Investigations of strong ground motion also indicate the spatial variability of the rupture velocity. This source physics complexity appeals for thorough description of the source process when calculating seismic motion. The method developed before hand allows efficient simulation of arbitrary slip histories. In this chapter, we investigate how the various slip histories affect peak ground velocities and the related variations in ground motion prediction for our study area. The fault perpendicular components of motion are confirmed to be dominated by directivity effects while the fault parallel component is influenced both by the slip distribution and the basin structure. Chapter 8: The rotational motions excited by earthquakes are believed to be capable of providing more information for the aim of earthquake hazard analysis. But to the present time, those information are hard to be acquired. The first reason is that the spacing of the accelerograph recording sites is too large to get the indirect rotational motion measurement from the accelerograph recordings. The second reason is that the small amplitude of the rotational motion is beyond the recording capability of the present instruments. At the present time, the answers lie in the numerical simulation. In this section, for an M7.0 earthquake which is considered to happen on the Newport-Inglewood fault embedded in the Los Angeles basin, different parameters responsible for the ground rotation variation, like the hypocentre location, directivity effect and slip history, are systematically investigated. In the teleseismic range where plane wave assumption can be made, Igel et al. (2005) investigates the relationship between the translation and the rotation in terms of the amplitude ratio and waveform similarity. In this section, we find the waveform similarity between one horizontal acceleration and the vertical rotation rate even in the near-source region. We also calculate the amplitude ratio between the acceleration and the rotation rate and compare the results with the medium properties. That ratio is found to be somehow correlative to the basin depth. Chapter 9: The most important results in this work are briefly summarized. Future promising prospectives are also described. Appendix A: The individual peak ground velocity distributions corresponding to the varying hypocentres of the grid presented in chapter 6 are presented as a table for better illustration in case of interest. Three components of velocity and rotation rates are summarized here. Appendix B: The peak ground velocity distributions are grouped into different tables corresponding to the varying slip histories (chapter 7). Three components of velocity and rotation rate are summarized here.

Den Fragen der Erarbeitung des Naturgefahrenmanagements in Gebirgsystemen SO-Kasachstans und in den Ländern des Zentralasiens insgesamt wurde bisher keine gebührende Aufmerksamkeit zuteil. Die Naturkatastrophen der letzten Jahrzehnte sowie die Erfahrung mit Maßnahmen zum Schutz des Ile-Alatau vor Naturgefahren haben gezeigt, dass die Lösung dieser Probleme für die weitere nachhaltige Entwicklung dieser Region von erstrangiger Bedeutung ist. In dieser Arbeit wurde vom Autor umfangreiches Material zur komplexen Untersuchung der Gebiete des Ile-Alatau zusammengetragen und analysiert (u. a. durch eigene Forschungen, die im Rahmen der Forschungsprojekte des Institutes für Geografie des Ministeriums für Bildung und Wissenschaft der Republik Kasachstan durchgeführt wurden). Die Hauptmethoden der Arbeit waren Auswertung vorhandener Daten- und Kartenmaterialien, Auswertung von Fernerkundungsdaten, eigene Geländearbeiten und Kartierungen zu Naturrisiken, Recherchen bei Behörden, Befragungen. In der Dissertation wurden zunächst die Naturbedingungen (u. a. Orographie, Relief, Geologie, Klima und Vegetation) sowie der Stand der Naturrisikoforschung im Ile-Alatau dargestellt. Eine Klassifikation der wichtigsten Naturgefahren im Ile-Alatau wurde vorgenommen und die historischen Naturkatastrophen beschrieben. Die Statistiken und Materialien über den durch Lawinen, Muren und Erdrutsche entstandenen Schaden wurden untersucht. Die regionale und zeitliche Verteilung, die Charakteristik, Ursachen und Auswirkungen der ausgewählten Naturgefahren (Lawinen, Muren, Hangrutschungen, Bergstürze/Steinschläge) wurden analysiert. Es wurden Daten über die Verteilung gefährdeter Zonen in den Einzugsgebieten des Ile Alatau angeführt. Die Analyse dieser Daten hat gezeigt, wo die Lawinengefahr im Ile-Alatau territorial am stärksten verbreitet ist. Im zentralen Teil sind über 50 % der Fläche davon betroffen. Die maximale Murengefahr wird auch im zentralen Teil des Ile-Alatau verzeichnet. Die größten Bergstürze und Hangrutschungen wurden von Erdbeben verursacht. Alle diese untersuchten Naturprozesse mit verschiedenen Auswirkungen finden im untersuchten Gebiet jährlich statt. Auf dieser Basis der Analyse wurde dann das Risiko bewertet, das von den ausgewählten Naturgefahren ausgeht. Grundlage dafür war die Analyse der Häufigkeit, der Verbreitung und des Ausmaßes der Prozesse. Eine Einteilung des Gebiets nach Gefährdung durch natürliche Prozesse und nach deren Risiko wurde vorgenommen. Dazu wurden Karten der Naturgefahren und deren Risiko erstellt. Nach Datenschutzgesetz der Republik Kasachstan darf der Autor keine Karten in Großmaßstab veröffentlichen. Diese sind nur zur internen Benutzung in Kasachstan zugelassen. Die zur Zeit getroffenen Schutzmaßnahmen im Ili-Alatau wurden unter Bewertung ihrer Wirksamkeit untersucht. Die ökonomische Effektivität der Durchführung der Lawinenschutzmaßnahmen wurde für das Einzugsgebiet des Flusses Kischi Almaty berechnet. Ein unter den Bedingungen des Ile-Alatau am besten geeignetes Schema des Naturgefahren- und Risikomanagements bei Umsetzung von Präventivmaßnahmen, bei Sicherungs- und Rettungsmaßnahmen und bei Wiederherstellungsmaßnahmen wurde vorgeschlagen. Die Arbeit enthält ebenfalls Empfehlungen zur Verbesserung der Funktion der Dienste des Naturgefahrenmanagements. Konkrete Empfehlungen zum Schutz des Territoriums und der Bevölkerung vor Naturgefahren und zur Verminderung des Schadens wurden gegeben. Gebiete, die von den natürlichen Prozessen am stärksten gefährdet sind, wurden erfasst und die notwendigen optimalen Maßnahmen für ihren Schutz empfohlen. Die Erfahrung der im Ile-Alatau durchgeführten Arbeiten ermöglicht es, Naturgefahren zu analysieren und zu bewerten, um ein Naturgefahrenmanagement zu erarbeiten, das eine nachhaltige Entwicklung auch in anderen Gebirgssystemen Kasachstans und in anderen Ländern Zentralasiens gewährleistet.

By storing and transporting vast amounts of energy derived from solar insolation, the oceans play an important role in shaping Earth’s climate. On the largest scale, ocean currents smooth the temperature gradients between the equator and the poles by redistributing excess energy from the tropics to higher latitudes. Much of this excess heat is transported by the so-called Ocean Conveyor Belt (Broecker, 1991), a global network of ocean currents driven by thermohaline convection. Changes in the pattern and strength of thermohaline circulation affect the redistribution of heat, and thereby significantly influence climate on local to global scales. The reconstruction of paleocurrents has long been a subject of paleoceanographic research. Among the various methods employed in tracing paleocurrents (and modern currents), the Sm-Nd isotope system is experiencing ever increasing attention. First applied in an oceanographic context by O’Nions et al. (1978), it is by now established as a standard tool, as shown by numerous recent publications (e.g. Rutberg et al., 2000; Tütken et al., 2002; Weldeab et al., 2002; Benson et al., 2003; Farmer and Barber, 2003; Piotrowski et al., 2004; Bayon et al., 2002, 2003, 2004; Lacan and Jeandel, 2001, 2004, 2005, and many more). Two lines of application of the Sm-Nd isotope system to oceanography/paleoceanography can be distinguished, both of which were followed for this thesis. The first approach uses the isotopic composition of Sm and Nd hosted in detrital minerals to infer the provenance of terrigenous sediments. This information can be used to draw conclusions about the direction and distance of sediment delivery. The second approach uses the isotopic signature of Nd as a tracer of different water masses. Due to the oceanic residence time of Nd being shorter than the global turnover rate of seawater (500-1000 years vs ~1000 years; Tachikawa et al., 2003), different bodies of water acquire distinct Nd isotopic signatures as a function of the age of adjacent continents. Apart from directly analyzing the Nd isotopic compositions of water samples to trace the modern distribution of different watermasses (e.g. Lacan and Jeandel, 2001, 2004), suitable archives of seawater-derived Nd can be employed to study paleocurrents. Possible archives are fossil remains of marine organisms (e.g. foraminifers; Burton and Vance, 2000), or, most widely used for the recent geological past, Fe-Mn nodules and crusts (e.g. Frank et al., 2002). With slow growth rates on the order of mm/Ma, however, Fe-Mn nodules do not offer the high temporal resolution necessary to study Late Quaternary climate change. Attention has therefore recently turned to authigenic Fe-Mn oxyhydroxides finely dispersed throughout the sediment column (e.g. Rutberg et al., 2000; Bayon et al., 2002, 2003, 2004; Piotrowski et al., 2004). For this thesis, both lines of application of the Sm-Nd isotope system to paleoceanography were followed. The samples were taken from a sediment core collected from the Yermak Plateau in the north-eastern Fram Strait. Situated between Greenland and the Svalbard Archipelago, the Fram Strait is the only deep connection between the Arctic Ocean and, via the Greenland-Iceland-Norwegian (Nordic) Seas, the North Atlantic. The Nordic Seas are an area of deep-water formation important for the global thermohaline circulation. There, the processes of deep-water formation are in a state of equilibrium that is most sensitive to changes in surface water salinity, which, in turn, is strongly influenced by the outflow of water of low salinity from the Arctic Ocean. This makes the history of water exchange between the Atlantic and the Arctic Ocean through the Fram Strait a subject of key interest for climate research. In particular, it was attempted to reconstruct the provenance of sediments deposited on the western Yermak Plateau over the last 129 000 years. This was done by analyzing samples from the sediment core and from potential source areas for their Sm-Nd isotopic compositions. The current understanding is that under present interglacial conditions sediment is delivered to the Yermak Plateau by ice drift from the Siberian shelf areas (Kara- and Laptev Sea) and as suspended load of Atlantic water advected from the south. To resolve these assumed differences in provenance and transport mechanism, the majority of the samples was split into the grain-size fractions clay, fine silt, coarse silt, and sand for Sm-Nd analyses. The position of the investigated core on the upper slope of the western Yermak Plateau limits delivery of sand-size (or coarser) material to ice rafting. The sand fractions of the core samples were therefore interpreted to be exclusively of ice rafted origin, and thus used as an indicator of changes in the pattern of surface currents. Clay- to silt-size material, on the other hand, yields a mixed signal of ice rafting and suspended-load delivery. Based on a comparison of the isotopic compositions of the core samples with those of the samples from potential source areas, a number of conclusions can be drawn: Most core sample show only little isotopic variation between their constituent size fractions (mostly less than analytical uncertainty). Only sand fractions show considerable differences. This can probably be explained by the sand samples’ small sample size relative to their coarse grain size; as a result, most sand fractions probably are not representative. The generally good agreement between the isotopic compositions suggests a common origin of ice rafted detritus (IRD) and suspended load. The possibility of suspended particulate matter transport from the Siberian shelf areas of the Kara- and Laptev Seas to the Yermak Plateau in significant amounts can be excluded. An origin of IRD in the Kara and Laptev Sea is therefore equally unlikely. Instead, a common provenance of IRD and suspended particulate matter from the Svalbard/Barents Sea area is a plausible scenario, supported by isotope-independent data from the literature (e.g. grain-size distribution, mineralogical composition, faunal abundance, etc.). The moderate downcore Nd isotopic variation suggests that, despite repeated large-scale glaciations in the Svalbard/Barents Sea area, the general modern-type circulation in the Fram Strait area has been active for most of the last 129 000 years. The largest deviation from modern conditions is indicated for the peak of the last glacial phase, approximately 20 000 years ago. Then, large amounts of IRD were delivered to the Yermak Plateau by icebergs calving from the Scandinavian ice sheet. Moreover, the occurrence of chalk fragments confirms iceberg drift from as far south as the North Sea. A similar finding has previously been reported for samples from the southern Fram Strait by Spielhagen (1991). Regarding the second analytical approach, i.e. the Nd isotopic analysis of finely dispersed authigenic Fe-Mn oxyhydroxides, implementation of the experimental technique was targeted first. The method of Fe-Mn oxyhydroxide extraction by means of leaching with a mixed reagent (acetic acid and hydroxylamine-hydrochloride) largely is based on the work of Chester and Hughes (1967). Modifications of their method have been reported in Tessier et al. (1979), Chao and Zhou (1983), and Hall et al. (1996), and have recently been compared by Bayon et al. (2002). Based on the experimental protocol described by Bayon et al. (2002), five core samples were processed and analyzed for their rare earth element (REE) concentrations by ICP-MS at the European Union Large Scale Geochemical Facility at the University of Bristol, England, financed by the EU. In addition, nine core samples were processed and the leachates analyzed for their Nd isotopic composition in Munich. The REE patterns of the leachates show an enrichment of the middle REE that is atypical for authigenic Fe-Mn phases. The isotopic analysis also yielded controversial results: downcore, the Nd isotope curves for the leachates and the detrital phases run approximately parallel, suggesting a systematic genetic relationship between the analyzed Nd fractions. A similar relationship appears to exist between data reported in Rutberg (2000), Rutberg et al. (2000), and Piotrowski et al. (2004) for a sediment core from the south-eastern Atlantic. To answer the questions raised by these controversial results, a sequential leaching experiment was designed. Several aliquots of one core sample were treated for different durations with different concentrations of the leaching reagents, and at intermediate steps were analyzed for their Sm-Nd isotopic composition. The results of this leaching experiment point towards a conceptual weakness of the method. In order to avoid contamination by non-authigenic sediment components, all experimental methods described in the literature focus on adjusting the concentration of the hydroxylamine-hydrochloride used to reduce Fe and Mn to their soluble states. This approach, however, does not take into account the dissolution of acid-soluble phases by acetic acid, which in all cases is used at a strength of 4.4 mol·l-1. Consequently, the leaching reagent is sufficiently corrosive to attack easily-soluble detrital minerals and release non-seawater-derived Nd (Hannigan and Sholkovitz, 2001; Dubinin and Strekopytov, 2001). Phosphatic phases are therefore a likely source of nonseawater-derived Nd. Apatite, for instance, is a common component of clastic sedimentary rocks, is easily dissolved by weak acids, and can account for the middle REE enrichment in the leachates. Its high Nd concentrations would mask any seawater signal. To conclude, it appears as though the available extraction techniques are not yet sufficiently refined to reliably determine the Nd isotopic composition of finely dispersed Fe-Mn oxyhydroxides as a proxy for paleoseawater composition.

A method is developed to incorporate prior fuzzy knowledge about reflectance behavior of land cover types into the segmentation of reflectances from moderate scale remote sensing data. The procedure is applied to aggregated Landsat TM data and to MODIS data and used to derive land cover type specific leaf area index.

Community participation and decentralization within the public health sector are the key elements of the Health Care Reform 2002 in India. Focus of research is the implementation of health policy in rural areas of Himachal Pradesh, West Bengal and Maharashtra. Status of participation in the selected districts, status of decentralization in the public health system and prerequisites for successful participation are examined to predict outcomes of the Health Care Reform on quality of health care.