@phdthesis{Duenkeloh2011, author = {D{\"u}nkeloh, Armin}, title = {Water Balance Dynamics of Cyprus - Actual State and Impacts of Climate Change}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-75165}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {A completely revised and enhanced version of the water balance model MODBIL of the regional water balance dynamics of Cyprus was developed for this study. The model is based on a physical, process-oriented, spatially distributed concept and is applied for the calculation of all important water balance components of the island for the time period of 1961-2004. The calibrated results are statistically analysed and visualised for the whole island area, and evaluated with respect to the renewability of natural water resources. Climate variability and changes of the past decades are analysed with regard to their influence on water balances. A further part of the study focusses on the simulation of impacts of potential climate change. The water balances are simulated under changing climatic conditions on the base of theoretical precipitation, temperature and relative humidity changes and the revealed impacts on the water balances and renewable resources are discussed. Furthermore, a first principal water balance scenario is developed for the assessment of the regional hydrological changes expected for Cyprus by the end of the 21st century. The scenarios are based on recently calculated climate change assessments for this part of the Mediterranean, under an assumed further increase of greenhouse gasses in the atmosphere.}, subject = {Wasserhaushalt}, language = {en} } @phdthesis{Nitzsche2007, author = {Nitzsche, Thomas}, title = {Origin of magnetic anomalies in pyroclastic rocks of the Messel volcano : insights into a maar-diatreme-structure}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-23231}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2007}, abstract = {Im Jahre 2001 wurde im Zentrum der Grube Messel, ca. 25 km s{\"u}dlich von Frankfurt gelegen, eine 433 m tiefe Bohrung abgeteuft. Geowissenschaftliche Ergebnisse, die durch die Bohrung gewonnen wurden, konnten die Herkunft des rundlichen Beckens durch eine Maar-Diatrem-Struktur erkl{\"a}ren. Die erbohrten Kerne sind vom Hangenden zum Liegenden durch lakustrine Sedimente (0-240 m) und vulkaniklastische Gesteine gekennzeichnet, letztere werden durch Lapillituffe (240-373 m) and der Diatrem-Brekzie (373 433 m) beschrieben. Die Lapillituffe, auf die hier das Hauptaugenmerk gelegt wurde, sind makro- und mikroskopisch schwer differenzierbar und erscheinen als ein einzig massig auftretender, unsortierter vulkaniklastischer K{\"o}rper, der haupts{\"a}chlich aus millimeter- bis zentimeter-großen juvenilen Klasten und Nebengesteinsbruchst{\"u}cken aufgebaut ist. Die hier vorliegende Arbeit pr{\"a}sentiert die gesteinsmagnetischen Eigenschaften von Kernproben der Messel Vulkaniklastika und erkl{\"a}rt die Herkunft der magnetischen Anomalien, die w{\"a}hrend des Bohrprojekts 2001 detektiert wurden. Das magnetische Verhalten des eruptierten Materials bezieht sich auf feink{\"o}rnige und eisenreiche (Titano) Magnetite, die verteilt in den juvenilen Lapilli auftreten. Experimente der temperaturabh{\"a}ngigen Suszeptibilit{\"a}t sowie isothermale remanente Magnetisierungs- und Hystereseuntersuchungen an den vulkaniklastischen Proben zeigen im Sinne der Zusammensetzung, Koerzivit{\"a}t und Korngr{\"o}ße (Pseudo-Einbereichsteilchen) sehr {\"a}hnliche ferrimagnetische Eigenschaften. Das eruptierte Material mit seinen ferrimagnetischen Mineralen besaß bei der Ablagerung ein sehr {\"a}hnliches Potential zum prim{\"a}ren Remanenzerwerb. Entmagnetisierungsversuche offenbaren Unterscheide im magnetischen Stabilit{\"a}tsverhalten der erworbenen nat{\"u}rlich remanenten Magnetisierung (NRM). Aufheizexperimente beweisen die Akquisition einer thermisch remanenten Magnetisierung durch Temperatureffekte, die bei der Eruption und der Ablagerung des vulkanischen Gesteins im Diatrem auftraten. Die obere Lapillituffh{\"a}lfte wurde bei relativ niedrigen Temperaturen (<300 °C), die unter H{\"a}lfte bei hohen Temperaturen (>>300 °C) abgelagert. Um den gesteinsmagnetischen Charakter der Messel Maar-Diatrem-Fazies besser zu verstehen, sind zus{\"a}tzlich die Partikelkorngr{\"o}ße, der relative Anteil und die Form der juvenilen Fragmente sowie deren chemische Zusammensetzung n{\"a}her untersucht und analysiert worden. Die Methodik der Bildanalyse sowie der Haupt- und Spurenelementanalyse des juvenilen Anteils erm{\"o}glicht eine klare Unterteilung der Lapillituffe. Die Kombination der Resultate der Partikelanalytik mit den gesteinsmagnetischen Befunden beg{\"u}nstigt die Einteilung der Vulkaniklastika in eine relativ heiße, geochemisch undifferenzierte und eine k{\"a}ltere, differenzierte Eruptionsphase. Somit liegt am Ende der vulkanischen Aktivit{\"a}t von Messel ein bivalentes Stadium zugrunde. Dabei sind die juvenilen Fragmente f{\"u}r die Temperaturentwicklung und W{\"a}rmebedingungen innerhalb des vulkaniklastischen Materials verantwortlich und tragen zur Herkunft der magnetischen Feldanomalien bei. Basierend auf gravimetrischen Parametern und den Ergebnissen der Magnetisierungs-eigenschaften der Pyroklastika erm{\"o}glicht ein 3D Potentialfeld-Modell der Messel Maar-Diatrem-Struktur die an der Erdoberfl{\"a}che gemessenen negativen Anomalien zu erkl{\"a}ren, sowie die Massen und Volumina der erbohrten Lithozonen zu berechnen.}, subject = {Messel Grube}, language = {en} } @phdthesis{Werner2006, author = {Werner, Mario}, title = {The stratigraphy, sedimentology, and age of the Late Palaeozoic Mesosaurus Inland Sea, SW-Gondwana : new implications from studies on sediments and altered pyroclastic layers of the Dwyka and Ecca Group (lower Karoo Supergroup) in southern Namibia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-21757}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {The Mesosaurus Inland Sea covered, in the Late Paleozoic, vast areas (~5 Mio km2) of the SW-Gondwanan continental interior. Major depocentres are represented by the Karoo basins of SW-Africa and the Paran{\´a} Basin in South America. These areas were interconnected prior to the break-up of Gondwana and the subsequent opening of the South Atlantic Ocean. In Namibia and South Africa deposits of the Mesosaurus Inland Sea are preserved in the successions of the glacial Dwyka Group and the postglacial Ecca Group (Karoo Supergroup). These deposits comprise the major part of a 60-70 Ma depositional cycle and are the main focus of this study. The large-scale transgressive part of this cycle started in the Late Carboniferous with continental glacial deposits followed by marine glacial and postglacial inland sea deposits. During the Early Permian the Mesosaurus Inland Sea reached its greatest extent, which was accompanied by widespread deposition of Corg-rich sediments. The large scale regressive part is recorded by successions ranging from deep water offshore pelites and turbidite sandstones to shallow water shoreface and deltaic sandstones, deposited in a brackish environment. Shallow water inland sea sediments are in turn overlain by fluvio-lacustrine deposits, which are assigned to the Beaufort Group and form the upper part of the cycle. This successive change in the depositional environment from marine to brackish to freshwater is also reflected in the fossil record. During Dwyka times a marine association of the Gondwana faunal province was able to colonize parts of the Mesosaurus Inland Sea. Later, during lower Ecca times, the connection to the Panthalassan Ocean became insufficient to retain normal marine conditions, leading to strong faunal endemism in an isolated and brackish inland sea environ¬ment. The most well-known and widespread representatives of this endemic fauna are mesosaurid vertebrates and megadesmid bivalves. Numerous altered tuffs occur as interlayers within argillaceous sediments of the Dwyka and Ecca Group of southern Namibia. The vast majority of these altered tuffs are represented by soft and crumbly to hard and indurated, clay-mineral-rich, bentonitic layers. Another, much rarer type is represented by very hard, chert-like tuff layers, which are predominantly albitic in composition. Furthermore, tuff layers within the Gai-As Formation of the Huab area are rich in potassium feldspar and have a porcelain-like appearance. The diagenetically modified matrix is mainly crypto- to microcrystalline. Polished tuff specimen show, in some tuffs, plane lamination or bedding with two or more subunits forming a tuff layer. Some display a weakly developed lamination. Only in very rare cases were structures reminiscent of sedimentary micro-cross lamination observed. The sedimentary textures and structures of the tuffs indicate that they have been deposited mainly as distal ash-fall layers by suspension settling in water. Some may have also been deposited or modified under the influence of weak bottom currents. The primary, pyroclastic macro-components of the tuffs are mainly represented by crystals of quartz, plagio¬clase, and biotite. In some thin sections pseudo¬morphs after pyroxene or hornblende were observed. Euhedral zircon and apatite crystals were observed in almost every tuff. Vitric or formerly vitric macro-components are very rare. The matrix of the majority of the investigated tuffs is predominantly composed of clay minerals. However, the matrix of the tuffs originally consisted most probably of fine vitric ash particles. Soon after deposition the volcanic ash was diagenetically altered to smectitic clay minerals. At a later stage smectite was progressively replaced by illite under prograde conditions. Nowadays the matrix of the bentonitic tuffs is strongly illite-dominated and only in the softer tuff layers a minor smectite content can be detected. Both the primary macrocrystic components as well as the geochemistry of the altered tuffs indicate that their source magmas were mainly of intermediate composition. The abundance of splintery quartz and feldspar crystal fragments within the tuffs hints at a highly explosive plinian or phreatoplinian eruption style of the source volcanoes, which were most probably located within a subduction-related volcanic arc region along the southern margin of Gondwana. New single zircon U-Pb SHRIMP datings of tuff layers provide a much more reliable age control of the investigated sedimentary succession. U-Pb SHRIMP ages for tuff layers from the glaciogenic Dwyka Group in southwestern Africa range from 302.0 ± 3.0 to 297.1 ± 1.8 Ma. The basal part of the early post-glacial Prince Albert Formation is dated at around 290 Ma. SHRIMP ages for tuff layers from the upper part of the Prince Albert Formation, the Whitehill Formation, and the middle part of the Collingham Formation indicate that the Mesosaurus Sea reached its greatest extent at around 280 Ma.}, subject = {Karru}, language = {en} } @phdthesis{Kackstaetter2003, author = {Kackstaetter, Uwe R.}, title = {Contaminant diffusion and sorption of an artificial leachate in selected geologic barriers of Frankonia, Bavaria, Germany}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-16151}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {The geologic barrier represents the final contact between a landfill and the environment. Ideally suited are clays and mudstones because of sufficient vertical and lateral extent, low hydraulic conductivities and high sorptive characteristics. Since hydraulic conductivity is no longer the single criteria to determine transport and retardation of contaminants in geologic landfill barrier materials, diffusive and sorptive characteristics of 4 different clay and mudstone lithologies in Northern Bavaria, were investigated. Cored samples from various depths were included in this study and subjected to evaluations of geochemistry, mineralogy, physical parameters, sorption and diffusion. A transient double reservoir with decreasing source concentration was designed and constructed using clear polycarbonate cylinders for undisturbed clay plugs of 2 to 4cm thickness. Samples were also fitted with internal electrical conductivity probes to determine the migration of the diffusive front. A multi chemical species synthetic landfill leachate was contrived to simulate and evaluate natural pollutant conditions. A computational method for determining mineralogy from geochemical data was also developed. It was found that sorptive processes are mostly controlled by the quality and type of fine grained phyllosilicates and the individual chemical species involved exhibited linear, Freundlich, as well as Langmuir sorption properties. Effective diffusion and sorption coefficients were also determined using POLLUTEv6 (GAEA, 1997) software and receptor reservoir concentrations for K, Na, Ca, Cu, NH4, Cl, NO3, SO4, and concentration totals at predetermined time intervals. Anion exclusion proved to be a major factor in the diffusion process and was used to explain many observed anomalies. Furthermore, diffusion coefficients were found not to be static with a multi chemical species leachate, but actually varied during the course of the experiment. Strong indications point toward the major role of pore space quality, shape, and form as control of diffusive properties of a geologic barrier. A correlation of CECNa of the samples with De may point to a possible deduction of diffusive properties for multi species leachates without extensive and time consuming laboratory tests}, language = {en} } @phdthesis{AlOuran2005, author = {Al-Ouran, Nedal}, title = {Environmental assessment, documentation and spatial modeling of heavy metal pollution along the Jordan Gulf of Aqaba using coral reefs as environmental indicator}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14090}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {Two phases of reef sampling were carried out. The first included regular samples taken along the coastline of Aqaba (27km long) at depths of 4-15m, and used to determine spatial distribution of pollution. The second phase included three 20cm-deep cores obtained from within the industrial zone. These cores were drilled from pre-dated communities, where the growth rate was determined earlier to be 10mm y-1, therefore the core obtained represented a period of 20 years (i.e. 1980-2000). The cores were used to reconstruct the metal pollution history at the most heavily used site along the coast (industrial zone).All samples were examined with respect to their metal content of Cd, Pb, Cu, Zn, Ni, and Cr. Almost all of them have shown records above the calculated background values. Mean values of Cd, Pb, Cu, Zn, Ni and Cr recorded along the coast were 1,25; 4,26; 9,76; 11,40; 2,29 and 10,522, µg g-1 respectively, and for core samples 1.4; 4.2; 5.7; 6.4; 2.3 and 8.21 µg g-1 respectively. Spatial distribution of metal enrichment in reef samples have shown a general and clear increasing trend towards the south. Same increasing trend was also in core samples where the six metals have shown a prominent increasing trend towards the core surface indicating an increase of coastal activities during the last twenty years. High and relatively high values were recorded at the oil port, the industrial area and main port, and thus categorized as highly impacted areas. Intermediate metal content were recorded in samples of the north beach, and thus classified as being relatively impacted, where the lowest metal concentrations were observed at the marine reserve, the least impacted site along the coast. The high enrichment of metal is attributed mainly to anthropogenic impacts. The natural inputs of the six metals studied in the Gulf of Aqaba are generally very low, due to the geographic positions and the absence of wadi discharge and as a result of low rainfall. Several potential sources of heavy metals were investigated. The industrial-related activities, port operations and phosphate dust were among the main sources currently threatening the marine ecosystem in Aqaba. Applying the Principle Components Analysis method (PCA) to all samples taken along the coastline has resulted in categorizing three different groups according to their metal enrichment, the first is composed of samples taken from the north beach and the main port with intermediate to high enrichment, the second joined the samples of the marine park and the marine reserve with low and relatively low enrichment, and the last group joined samples of the industrial zone and the oil port with high enrichment. The Principle Component Scores were also utilized to confirm the spatial distribution and relationships of the examined heavy metals along the coast. Two models (interpolated by SURFER \&\#61666; 7.0 and ArcView\&\#61666; 3.2a) were developed, the first was based on the PC scores of the first component, and shows clearly the positive anomalies in metal concentrations along the coast. The second model was developed by plotting the second factor scores on a landuse map of Aqaba. According to these models, it has shown that the positive anomalies are associated with three different zones; industrial area, the main port and the oil port. The results have shown that coral reefs can be used as good environmental indicator for assessments and monitoring processes, and they can provide data and information on both the spatial distribution of pollution and their history. The present work is the first to document the environmental status along the whole coast of Aqaba and the first to use coral reef as a tool/ indicator.}, subject = {Golf von Akaba}, language = {en} } @phdthesis{Kukulus2004, author = {Kukulus, Matthias}, title = {A quantitative approach to the evolution of the central Walvis Basin offshore NW-Namibia : structure, mass balancing, and hydrocarbon potential}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11075}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {Rifting and breakup of Westgondwana in the Late Jurassic/ Early Cretaceous initiated the formation of the South Atlantic and its conjugated pair of passive continental margins. The Walvis Basin offshore NW-Namibia is an Early Cretaceous to recent depositional centre with a typically wedge-shaped postrift sedimentary succession covering an area of 105000km2. A 2D model transect across the central Walvis Basin and adjacent onshore areas is used as a case study to investigate quantitatively the denudational history of the evolving passive margin and the related contemporaneous depositional postrift evolution offshore. The database for both the onshore and offshore part of the model traverse is well constrained by own field work, published data as well as by seismic and well data supported by samples. The ultimate goal of this project is to present an integrated approach towards a quantitative link between surface processes and internal processes in terms of a mass and process balance.}, subject = {Namibia }, language = {en} } @phdthesis{Krapf2003, author = {Krapf, Carmen}, title = {Ephemeral river systems at the Skeleton Coast, NW-Namibia - Sedimentological and geomorphological studies on the braided river dominated Koigab Fan, the Cenozoic succession in the Uniabmond area and comparative studies on fluvio-aeolian interaction between ephemeral rivers and the Skeleton Coast Erg}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-6013}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {The Skeleton Coast forms part of the Atlantic coastline of NW Namibia comprising several ephemeral rivers, which flow west-southwest towards the Atlantic Ocean. The area is hyper-arid with less than 50 mm average annual rainfall and a rainfall variability of 72\%. Therefore, the major catchment areas of the rivers are about 100-200 km further inland in regions with relatively high annual rainfall of 300-600 mm. The coastal plain in the river downstream areas is characterized by a prominent NNW trending, 165 km long belt of 20-50 m high, locally compound, barchanoid and transverse dunes. This dune belt, termed Skeleton Coast Erg, starts abruptly with a series of barchans and large compound dunes 15 km north of the Koigab River and extends from 2-5 km inland sub-parallel to the South Atlantic margin of NW Namibia over a width of 3-20 km. As the SSE-NNW trending dune belt is oriented perpendicular to river flow, the dunefield dams and interacts with the west-southwestward flowing ephemeral river systems. This study focused on three main topics: 1) investigation and classification of the Koigab Fan, 2) the investigation of the Cenozoic succession in the Uniabmond area and 3) comparative studies of fluvio-aeolian interaction between five ephemeral rivers and the Skeleton Coast Erg. Sedimentological and geomorphological investigations show that the Koigab Fan represents a yet undocumented type of a braided fluvial fan system, which operates in an arid climatic, tropical latitude setting, is dominated by ephemeral mixed gravel/sand braided rivers, lacks significant vegetation on the fan surface, has been relatively little affected by human activity, is a perfect study site for recording various types of fluvio-aeolian interaction and thereby acts additionally as a model for certain Precambrian and Early Palaeozoic fan depositional systems deposited prior to the evolution of land plants. The Cenozoic succession in the Uniabmond area consists of three major unconformity-bounded units, which have been subdivided into the Red Canyon, the Whitecliff, and the Uniabmond Formation. The Tertiary Red Canyon Fm. is characterized by continental reddish sediments documenting an alluvial fan and braided river to floodplain depositional environment. The Whitecliff Fm. displays a wide variety of continental and marine facies. This formation provides the possibility to examine fluvio-aeolian interactions and spectacular, steep onlap relationships towards older sediments preserved in ancient seacliffs. The Whitecliff Fm. has been subdivided into four sedimentary cycles, which resulted from sea level changes during the Plio- to Middle Pleistocene. The following Uniabmond Fm. provides a unique insight into the depositional history of the NW Namibian coast during the Last Pleistocene glacial cycle. The formation has been subdivided into four units, which are separated by unconformities controlled by sea level changes. Unit 1 represents deposits of an Eemian palaeo-beach. The overlying Units 2-4 build up the sedimentary body of the Uniab Fan, again a braided river dominated fan, which is nowadays degraded and characterized by deeply incised valleys, deflation surfaces and aeolian landforms. The Uniabmond Fm. is overlain by the dunes of the Skeleton Coast Erg, whose development is related to the Last Glacial Maximum (LGM). The damming of river flow by aeolian landforms has been previously recognized as one of several principal types of fluvio-aeolian interaction. Five ephemeral rivers (from S to N: Koigab, Uniab, Hunkab, Hoanib, Hoarusib), which variously interact with the Skeleton Coast Erg, were chosen for the purpose of this study to consider the variability of parameters within these fluvio-aeolian systems and the resulting differences in the effectiveness of aeolian damming. The fluvio-aeolian interactions between the rivers and the dune field are controlled by the climate characteristics and the geology of the river catchment areas, the sediment load of the rivers, their depositional architecture, the longitudinal river profiles as well as the anatomy of the Skeleton Coast Erg. Resulting processes are 1) aeolian winnowing of fluvially derived sediments and sediment transfer into and deposition in the erg; 2) dune erosion during break-through resulting in hyperconcentrated flow and intra-erg mass flow deposits; 3) the development of extensive flood-reservoir basins caused by dune damming of the rivers during flood; 4) interdune flooding causing stacked mud-pond sequences; and 5) the termination of the erg by more frequent river floods.}, subject = {Namibia }, language = {en} } @phdthesis{Hassouneh2003, author = {Hassouneh, Mohammed H.}, title = {Interpretation of Potential Fields by Modern Data Processing and 3-dimensional gravity Modeling of the Dead Sea Pull-Apart Basin / Jordan Rift Valley (JRV)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-4834}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {This work presents the analysis, 3D modeling and interpretation of gravity and aeromagnetic data of Jordan and Middle East. The potential field data delineate the location of the major faults, basins, swells, anticlines, synclines and domes in Jordan. The surface geology of Jordan and the immediate area east of the Rift is dominated by two large basins, the Al-Jafr basin in the south and the Al-Azraq-Wadi as Sirhan basin to the northeast. These two basins strike southeast-northwest and are separated by an anticlinal axis, the Kilwah-Bayir swell. The Karak Wadi El Fayha fault system occurs along the western flank of the swell. The Swaqa fault occurs on the southwest hinge of Al-Azraq basin and the Fuluq fault occurs on its northeast hinge. In the south west of Jordan, Wadi Utm-Quwaira and Disi-Mudawara fault zones are shown clearly in the aeromagnetic and gravity maps. The previous major faults are well correlated with the structural map of Jordan published by Bender (1968). 3D modeling of gravity data in the Dead Sea basin (DSB) was used together with existing geological and geophysical information to give a complete structural picture of the basin. The 3D models of the DSB show that the internal structure of the Dead Sea basin (DSB) is controlled by longitudinal faults and the basin is developed as a full graben bounded by sub-vertical faults along its long sides. In the northern planes of the 3D model, the accumulation of Quaternary (salt and marl) and Mesozoic (pre-rift) sediments are thinner than in the central and southern planes of the model. In the northern planes, the thickness of the Quaternary sediments is about 4 km, 5 km in the southern planes and it exceeds 8 km in the central planes of the DSR. The thickness of the pre-rift sediments reaches 10-12 km in the northern and southern planes and exceeds 15 km in the central planes of the DSR. The planes of the 3D models show that the depth to the crystalline basement under the eastern shoulders of the DSR is shallower than those beneath the western shoulders. It is about 3-5 km beneath the eastern shoulders and 7-9 km under the western shoulder of the DSR. The gravity anomaly maps of residual and first derivative gravity delineate the subsurface basins of widely varying size, shape, and depth along the Rift Valley. The basins are created by the combination of the lateral motion along a right-tending step over and normal faulting along the opposite sides. Al Bakura basin occupies the upper Jordanian River valley and extends into the southern Tiberias Lake. Bet Shean basin to the south of Al Bakura basin plunges asymmetrically toward the east. The Damia basin, comprising the central Jordan Valley and Jericho areas to the north of the Dead Sea is shallow basin (~600-800m deep). The Lisan basin is the deepest basin in the Rift. The 3D gravity models indicate a maximum of ~12 km of basin fill. Three basins are found in Wadi Araba area, Gharandal, Timna (Qa'-Taba) and Aqaba (Elat) basin. The three basins become successively wider and deeper to the south. The three regional gravity long E-W profiles (225 km) from the Mediterranean Sea crossing the Rift Valley to the east to the Saudi Arabia borders, show the positive correlation between topography and free air anomaly and strong negative Bouguer anomaly under the central part of the Dead Sea Basin (DSB) and normal regional Bouguer anomaly outside of the DSB in the transform valley. Depth to the top of the bedrock in the under ground of Jordan was calculated from potential field data. The basement crops out in the south west of Jordan and becomes deeper to northwards and eastwards to be about ~ 8 km below ground surface in the Risha area.}, subject = {Jordantal}, language = {en} } @phdthesis{Kuells2000, author = {K{\"u}lls, Christoph}, title = {Groundwater of the North-Western Kalahari, Namibia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-1180680}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2000}, abstract = {A quantitative model of groundwater flows contributing to the Goblenz state water scheme at the north-western fringe of the Kalahari was developed within this study. The investigated area corresponds to the Upper Omatako basin and encompasses an outer mountainous rim and sediments of the Kalahari sand desert in the centre. This study revealed the eminent importance of the mountainous rim for the water balance of the Kalahari, both in terms of surface and ground water. A hydrochemical subdivision of groundwater types in the mountain rim around the Kalahari was derived from cluster analysis of hydrochemical groundwater data. The western and south-western secondary aquifers within rocks of the Damara Sequence, the Otavi Mountain karst aquifers of the Tsumeb and Abenab subgroups as well as the Waterberg Etjo sandstone aquifer represent the major hydrochemical groups. Ca/Mg and Sr/Ca ratios allowed to trace the groundwater flow from the Otavi Mountains towards the Kalahari near Goblenz. The Otavi Mountains and the Waterberg were identified as the main recharge areas showing almost no or only little isotopic enrichment by evaporation. Soil water balance modelling confirmed that direct groundwater recharge in hard-rock environments tends to be much higher than in areas covered with thick Kalahari sediments. According to the water balance model average recharge rates in hard-rock exposures with only thin sand cover are between 0.1 and 2.5 \% of mean annual rainfall. Within the Kalahari itself very limited recharge was predicted (< 1 \% of mean annual rainfall). In the Upper Omatako basin the highest recharge probability was found in February in the late rainfall season. The water balance model also indicated that surface runoff is produced sporadically, triggering indirect recharge events. Several sinkholes were discovered in the Otavi Foreland to the north of Goblenz forming short-cuts to the groundwater table and preferential recharge zones. Their relevance for the generation of indirect recharge could be demonstrated by stable isotope variations resulting from observed flood events. Within the Kalahari basin several troughs were identified in the pre-Kalahari surface by GIS-based analyses. A map of saturated thickness of Kalahari sediments revealed that these major troughs are partly saturated with groundwater. The main trough, extending from south-west to north-east, is probably connected to the Goblenz state water scheme and represents a major zone of groundwater confluence, receiving groundwater inflows from several recharge areas in the Upper Omatako basin. As a result of the dominance of mountain front recharge the groundwater of the Kalahari carries an isotopic composition of recharge at higher altitudes. The respective percentages of inflow into the Kalahari from different source areas were determined by a mixing-cell approach. According to the mixing model Goblenz receives most of its inflow (70 to 80 \%) from a shallow Kalahari aquifer in the Otavi Foreland which is connected to the Otavi Mountains. Another 15 to 10 \% of groundwater inflow to the Kalahari at Goblenz derive from the Etjo sandstone aquifer to the south and from inflow of a mixed component. In conclusion, groundwater abstraction at Goblenz will be affected by measures that heavily influence groundwater inflow from the Otavi Mountains, the Waterberg, and the fractured aquifer north of the Waterberg.}, subject = {Kalahari}, language = {en} } @phdthesis{Wanke2000, author = {Wanke, Ansgar}, title = {Karoo-Etendeka Unconformities in NW Namibia and their Tectonic Implications}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-3234}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2000}, abstract = {In north-western Namibia the fills of the Karoo-Etendeka depositories can be subdivided into (1) a Carboniferous-Permian, (2) a Triassic-Jurassic and (3) a Cretaceous megasequence, each recording extensional periods related to successive rifting phases in the evolving South Atlantic. The tectonic environment of the depositories in north-western Namibia changes successively from the coast towards the continental interior, which is reflected by the facies distribution and the position of time-stratigraphic gaps. Close to the present-day coastline synsedimentary listric faults, trending parallel to the South Atlantic rift (N-S), caused the formation of wedge shaped sediment bodies. Here, the Karoo Supergroup is only represented by the Permian succession in the Huab area. A hiatus within the Permian can be recognised by the correlation with the main Karoo Basin in South Africa and the Brazilian Paran{\´a} Basin. This stratal gap correlates with a pre-Beaufort Group unconformity in the main Karoo Basin that might be related to an orogenic pulse in the Cape Fold Belt. The Permian succession itself is unconformably overlain by the Lower Cretaceous Etendeka Group. This hiatus extending from the Upper Permian to the Lower Cretaceous has probably been induced by a combination of rift shoulder uplift and additional crustal doming associated with Etendeka flood volcanism. The enhanced tectonism during the Early Cretaceous controlled accommodation space for the alluvial-fluvial and aeolian deposits of the lower Etendeka Group. Disconformities within those deposits and the overlying lava succession attribute to distinct phases of tectonic and volcanic activity heralding the South Atlantic breakup. Towards the south-east, the Karoo succession becomes successively more complete. In the vicinity of Mt. Brandberg Early Triassic strata (Middle Omingonde Formation) follow disconformably above the Upper Permian/Lowermost Triassic Doros Formation. The sedimentation there was essentially controlled by the SW-NE trending Damaraland Uplift. South of the Damaraland Uplift the SW-NE trending Waterberg-Omaruru Fault zone is interpreted as a sinistral oblique-slip fault that compartmentalised the South Atlantic rift. This fault controlled accommodation space of the entire Triassic Omingonde Formation and the Early Jurassic Etjo Formation in its associated pull-apart and transtension structures. A locally well developed angular unconformity defines a hiatus between the two formations. Correlation with the main Karoo Basin in South Africa confirms that this gap is of a regional extent and not only a local, fault induced feature. Furthermore, it might also correlate with an orogenic pulse of the Cape Fold Belt. In general, the Mesozoic megasequences record the long-lived history of the southern Atlantic rift evolution. Rifting has been controlled by orogenic pulses derived from the Samfrau active margin throughout the Mesozoic. The associated intracratonic E-W extension caused the formation of grabens and conjugated oblique-slip zones. The generation of voluminous flood basalts marks the climax of intracratonic extension that was accompanied by enhanced uplift of the rift shoulders.}, subject = {Namibia }, language = {en} } @phdthesis{Klock2001, author = {Klock, Heike}, title = {Hydrogeology of the Kalahari in north-eastern Namibia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-1181287}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {This study has focused on hydrogeological and hydrochemical settings of the Northern Namibian Kalahari Catchment which is the Namibian part of the Makgadikgadi-Kalahari-Catchment. Recharge has been the subject of process-understanding, quantification and regionalisation. Within the semiarid study area a bimodal surface constitution is prominent: hardrocks areas allow for fast infiltration along karsts and joints, whereas areas covered by unconsolidated sediments receive minor diffuse recharge and locally some preferred flow path recharge develops along shrinkage cracks and rootlets. Five substratum classes have been soil physically studied: Pans and vleis, brown to red soils, dune sand, soil with an aeolian influence, and calcrete. Aeolian sands are most promising for the development of direct diffuse recharge. Recharge by preferred flow might occur in all soil classes either due to joints in calcrete or structures and rootlets in soils. All soil classes contribute to indirect recharge because even the dune sand allows, albeit very locally, the generation of runoff. The occurrences of recharge through the unconsolidated soil and the hardrocks have been confirmed by hydrograph interpretation and by a study of hydrochemical data which identified groundwater of flood water and flood water after soil passage composition. Other prominent hydrochemical processes in the Kalahari are associated with the carbonate-equilibrium-system, mixing with highly mineralised water that is either sulphate (central area) or chloride dominated (fringe area) and development of sodium hydrogencarbonate water types. The latter is mostly generated by feldspar weathering. Variations of the hydrochemical compositions were observed for shallow groundwaters. They do not only reflect the recharge amount but also the recharge conditions, e.g. a wetter year is allowing more vegetation which increases the hydrogencarbonate content. Inverse determination of recharge by the chloride mass balance method gives recharge amounts between 0.2 and locally more than 100 mm/a. The least favoured recharge conditions are found for Kalahari covered areas, the largest amount occurs in the Otavi area. The distribution of recharge areas within the catchment is rather complex and regionalisation of recharge for the entire catchment was done by a forward approach using satellite images and by an inverse approach using hydrochemical data. From the inverse hydrochemical approach a basin-wide balanced recharge amount of 1.39 mm/a is achieved. The forward approach gave a basin-wide figure of 0.88 (minimum assumption) to 4.53 mm/a (maximum assumption). A simplistic groundwater flow model confirmed the results from the minimum recharge regionalisation by satellite images and the result from the hydrochemical approach. Altogether a mutually verified basin-wide recharge figure of ca. 1 mm/a turns out.}, subject = {Kalahari}, language = {en} } @phdthesis{Gehring2001, author = {Gehring, Iris}, title = {Volcanostratigraphy using geophysical methods on La Fossa di Vulcano (S-Italy)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-1181941}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {For many active volcanoes all over the world a civil protection program, normally combined with hazard maps, exists. Optimising of hazard maps and the associated hazard assessment implies a detailed knowledge of the volcanostratigraphy, because the deposits provoke information on the potential behaviour during a new activity cycle. Pyroclastic deposits, however, may vary widely in thickness and distribution over very short lateral distances. High resolution characterisation of single strata often cannot be archived, if solely sedimentological and geochemical methods are used. Gamma-ray measurements taken in the field combined with grain-size depended magnetic susceptibility measurements made in the laboratory are used in this work to optimise the resolution of volcanostratigraphic investigations. The island of Vulcano is part of the Aeolian Archipelago sited of the northern coast of Sicily. La Fossa cone is the active centre of Vulcano, where fumarolic and seismic activity can be observed. The cone was built up during the last 6,000 years, whereby the last eruption period is dated to historic times (1888-1890). For the tuff cone La Fossa the most likely volcanic hazards are the emplacement of pyroclastic deposits as well as gas hazards (especially SOx and CO2), due to this the detailed knowledge of the stratigraphy is mandatory. Most of the population resides in Vulcano Porto and the nearby sited peninsula of Vulcanello, which are highly endangered locations for a future eruption scenario. Measurements, made in standard outcrops, allow a characterisation of the successions Punte Nere, Tufi Varicolori, Palizzi, Commenda, and Cratere Attuale. A discrimination of all successions by solely one of the methods is rarely possible. In some cases, however, the combination of the methods leads to clear results. It can also be noticed that the exposition as well as the sedimentation type (wet-surge or dry-surge deposits) affect the measurements. In general it can be assumed that the higher the magma is evolved the higher the g -ray values and the lower the susceptibility values. Measurements from the Wingertsberg (Laacher See deposits, Eifel, W-Germany) show clearly that a higher degree of magma evolution correlates with lower susceptibility and higher gamma-ray values. Variations of the values can be observed not only by the change of the degree of magmatic evolution but also by the inhomogeneous deposition conditions. Particularly the gamma-ray measurements show lower values for the wet-surge deposits than for the dry-surge deposits, even though the erupted material has the same geochemical composition. This can be explained especially by reactions inside of the moist eruption cloud and short-time after deposition, when easily soluble elements like K, U, and Th can be leached by these aggressive fluids. Even extended exposition and high water content can provoke depletion of various elements within the complete or parts of the outcrop, too. If the deposits are affected by a fumarolic activity especially the susceptibility values show significant variations, whereas in general extreme low values are observed. Contamination of deposits also can occur, if they are overlain by weathered deposits of higher concentration of K, U, and Th. Weathering and mobilisation within the upper deposits can generate an element enrichment within the lower deposits. In general the element ratios of the barried underlying deposits are less affected than the exposed ones. After gauging the values of the well defined succession for standard outcrops undefined outcrops were measured. These outcrops are not clearly classified by sedimentological and geochemical methods, thus a correlation with the combined geophysical methods is useful. In general the combination of the methods allows a correlation, although in some cases more than one interpretation is possible. But in connection with time marker horizons as well as sedimentological features an interpretation is feasible. These situations show that a classification solely based on geophysical methods is possible for many cases but, if the volcanic system is more complex, a combination with sedimentological and geochemical methods may be needed. The investigations on Vulcano, documented in this work, recommend a re-interpretation of the dispersial of some successions of La Fossa cone, especially the presumption that Tufi Varicolori only exist inside of the Caldera of La Fossa. As a consequence the eruption and energy model especially for Tufi Varicolori have to be reviewed.}, subject = {Vulcano}, language = {en} } @phdthesis{AlFarajat2001, author = {Al-Farajat, Mohammad}, title = {Hydrogeo-Eco-Systems in Aquaba/Jordan - Coasts and Region}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-1182066}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {The coast of Aqaba and the Aqaba region (Jordan) were investigated on their hydrogeo-ecosystem. The results of the research were translated into digits to build a geo-spatial data base. The fillings of the graben aquifer receive indirect type of recharge through the side wadis which drain the highlands. Surface water balance was modeled for a period of 20 years of daily climate records using MODBIL program which attributes direct recharge to wet years only. The hydrodynamic fresh water/seawater interface in the coastal zones was investigated by applying vertical geoelectric surveys and models of several methods to confirm its coincidence with the aquifer's flow amounts, where human impacts in terms of over-pumping allowed more encroachment of seawater into land, and unintended recharge which led to seaward interface migration. A groundwater balance and solute transport were approached by developing a flow model from the hydrogeological and hydrochemical data. The nature of soil cover and aquifer whose physical properties enhance human impacts indicated the vulnerability of groundwater to pollution. This certainly threatens the marine ecology which forms the sink where the in-excess flow ends. The constructed digital background was exported into GIS to sub-zone the study area in terms of the aquifer's vulnerability to pollution risks using DRASTIC index. However, it was unable to meet all geo-spatial factors that proved to have significant impacts on the vulnerability. Consequently, a comprehensive index -SALUFT- was developed. This suggests the suitable land use units for each zone in the light of vulnerability grades aiming at protecting the available groundwater resources.}, subject = {Golf von Akaba}, language = {en} } @phdthesis{Bangert2000, author = {Bangert, Berthold}, title = {Tephrostratigraphy, petrography, geochemistry, age and fossil record of the Ganigobis Shale Member and associated glaciomarine deposits of the Dwyka Group, Late Carboniferous, southern Africa}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-2233}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2000}, abstract = {Thin, pyroclastic marker beds are preserved in argillaceous units of the Dwyka Group in southern Nambia and South Africa which are the earliest witnesses of volcanism in Karoo-equivalent strata of southern Africa. The aim of this study is to present the field appearance of these marker beds, to characterise their mineralogy, geochemistry and heavy mineral contents and to present new radiometric age data from their juvenile zircons. Carboniferous-Permian Karoo deposits in the Aranos Basin of southern Namibia include the glacially dominated, Carboniferous Dwyka Group and the shelf sediments of the overlying Permian Ecca Group. The Dwyka Group can be subdivided into four upward-fining deglaciation sequences, each capped by relatively fine-grained glaciolacustrine or glaciomarine deposits. The uppermost part of the second deglaciation sequence comprises a thick fossiliferous mudstone unit, referred to as the "Ganigobis Shale Member". An abundance of marine macro- and ichnofossils as well as extrabasinally derived ashfall tuff beds characterise the more than 40 m thick mudstones and provide the basis for an integrated high-resolution biostratigraphic and tephrostratigraphic framework. The Ganigobis Shale Member contains remains of paleoniscoid fishes, bivalves, gastropods, scyphozoa, crinoid stalks, sponges and sponge spicules, radiolaria, coprolites and permineralised wood. These mostly marine body and trace fossils record the extent of the first of a series of marine incursions into the disintegrating Gondwanan interior as early as the Carboniferous. Within the Ganigobis Shale Member 21 bentonitic tuff beds displaying a thickness of 0.1 and 2.0 cm were determined which in part can be traced laterally over tens of kilometres indicating an ashfall derivation. Further bentonitic tuff beds of the Dwyka Group were detected in cut banks of the Orange River near Zwartbas in the Karasburg Basin (southern Namibia). The 65 tuff beds vary between 0.1 and 4.0 cm in thickness. Due to a similar fossil content and age of the background deposits, the tuff beds are thought to have originated from the same source area as those from the Aranos Basin. Thin-sections reveal the derivation of the tuff beds as distal fallout ashes produced by explosive volcanic eruptions. The matrix consists of a micro- to cryptocrystalline clay mineral-quartz mixture. Rare fragments of splinter quartz, completely recrystallized ash-sized particles of former volcanic glass and few apatite and zircon grains are the only juvenile components. The tuff beds contain as non-opaque, juvenile heavy minerals mostly zircon, apatite, monazite and sphene but also biotite, garnet, hornblende and tourmaline. Geochemical analyses point to an original, intermediate to acid composition of the tuff samples. LREE enrichment and Eu-anomalies show that the parent magma of the tuff beds was a highly evolved calc-alkaline magma. Tectonomagmatic discrimination diagrams point to a volcanic arc setting. Bedding characteristics and the lack of any Carboniferous-Permian volcanic successions onshore Namibia makes an aeolian transport of the ash particles over larger distances likely. Siliceous ashes could thus have been transported by prevailing south-westerly winds from arc-related vents in South America to southern Africa. A second, more local source area could have been located in an intracontinental rift zone along the western margin of southern Africa which is indicated by north-south directed ice-flow directions in the Late Carboniferous. SHRIMP-based age determinations of juvenile magmatic zircons separated from the tuff beds allow a new time calibration of Dwyka Group deglaciation sequences II - IV and the Dwyka/Ecca boundary. Zircons of the Ganigobis Shale Member yield SHRIMP-ages of 302-300 Ma. This dates the uppermost part of the second deglaciation sequence in southern Namibia to the Late Carboniferous (Gzelian) and provides a minimum age for the onset of Karoo-equivalent marine deposition. The age of the uppermost argillaceous part of the third deglaciation sequence (297 Ma) was determined from zircons of a tuffaceous bed sampled in a roadcut in the Western Cape Province, South Africa. The deposits correlate with the Hardap Shale Member in the Aranos Basin of southern Namibia which are part of much more widespread Eurydesma transgression. The age of the Dwyka/Ecca boundary was determined by SHRIMP-measurements of juvenile zircons from two tuff beds of the basal Prince Albert Formation sampled in the Western Cape Province (South Africa). The zircons revealed ages of 289 - 288 Ma which date the Dwyka/Ecca boundary at about 290 Ma. According to these ages, deglaciation sequences II-IV lasted for 5 Ma on average.}, subject = {S{\"u}dafrika}, language = {en} } @phdthesis{Wijnen2002, author = {Wijnen, Jeroen Johan Andreas}, title = {A groundwater flow and particle tracking model of the Ira{\´i}-basin, Paran{\´a}, Brazil}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-531}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2002}, abstract = {Die Bev{\"o}lkerungsexplosion in der Region von Curitiba w{\"a}hrend der letzten Jahre verursachte eine große Zunahme des Wasserbedarfs; die zunehmend unkontrollierte Besiedlung stellt dabei ein großes Problem f{\"u}r die Umwelt dar. Die gr{\"o}ßte Bedrohung f{\"u}r die Wasserversorgung dieser Region ist die urbane Invasion in Gebiete, wo die Herkunft der Wasserressourcen liegen. Diese Invasion geht langsam aber stetig voran und bedroht kostbare und nicht ersetzbare Ressourcen. Vor diesem Hintergrund wurde ein Gebiet in der direkten N{\"a}he der Großstadt Curitiba als Studienobjekt ausgew{\"a}hlt. In diesem Gebiet, dem Ira{\´i}-Becken, wurde w{\"a}hrend der Untersuchungszeit ein Trinkwasserspeicher geplant und gebaut. Es besteht die große Gefahr, dass das Ira{\´i}-Reservoir kontaminiert wird, obwohl das engere Gebiet rundum den See gesch{\"u}tzt werden soll. Die Verschmutzungsgefahr geht haupts{\"a}chlich von zwei Nebenfl{\"u}ssen aus, die durch mehr oder weniger besiedeltes Gebiet str{\"o}men. Im Arbeitsgebiet befinden sich Brunnen, die der Trinkwasserversorgung dienen. Um die negativen Folgen einer m{\"o}glichen Verschmutzung des Reservoirs absch{\"a}tzen zu k{\"o}nnen, wurde ein Grundwasserfließmodell erstellt. Die erforderliche Wasserbilanz und die r{\"a}umliche Verteilung der Verschmutzungsempfindlichkeit wurde mit dem hydrologischen Modell "MODBIL" abgesch{\"a}tzt. Weitere Methoden zur Absch{\"a}tzung der Verschmutzungs-empfindlichkeit wurden angewandt, um die differierenden Ergebnisse der angewendeten unterschiedlichen Methoden mit einander vergleichen und bewerten zu k{\"o}nnen. Mit dem kalibrierten Grundwasserfließmodell ist mit der gegebenen hydraulischen Situation vor und nach der Konstruktion des Reservoirs, ein einfaches Particle Tracking Transport Modell eingesetzt worden, um mit unterschiedlichen Szenarien die Beeinflussung vom Reservoirwasser auf das Grundwasser zu simulieren.}, subject = {Curitiba }, language = {en} }