550 Geowissenschaften
Refine
Has Fulltext
- yes (117)
Is part of the Bibliography
- yes (117)
Year of publication
Document Type
- Doctoral Thesis (117) (remove)
Keywords
- Fernerkundung (19)
- Klimaänderung (11)
- Modellierung (11)
- Namibia (10)
- Geomorphologie (6)
- Hydrogeologie (6)
- remote sensing (6)
- Geoinformationssystem (5)
- Geologie (5)
- Klima (5)
Institute
- Institut für Geographie und Geologie (55)
- Institut für Geologie (24)
- Institut für Geographie (23)
- Institut für Mineralogie und Kristallstrukturlehre (7)
- Philosophische Fakultät (Histor., philolog., Kultur- und geograph. Wissensch.) (7)
- Graduate School of Science and Technology (3)
- Institut für Paläontologie (1)
- Theodor-Boveri-Institut für Biowissenschaften (1)
Sonstige beteiligte Institutionen
- Deutscher Akademischer Austauschdienst (DAAD) (1)
- Deutsches Klimaservice Zentrum (GERICS) (1)
- Deutsches Zentrum für Luft & Raumfahrt (DLR) (1)
- Deutsches Zentrum für Luft- und Raumfahrt (DLR) (1)
- Deutsches Zentrum für Luft- und Raumfahrt e.V. (1)
- Lehrstuhl für Fernerkundung der Uni Würzburg, in Kooperation mit dem Deutschen Fernerkundungsdatenzentrum (DFD) des Deutschen Zentrums für Luft- und Raumfahrt (DLR) (1)
- Université d'Abomey-Calavi, Benin (1)
In der vorliegenden Studie wurden auf der Basis langer mitteleuropäischer Zeitreihen der Temperatur und des Niederschlags sowie rekonstruierter monatlicher Bodenluftdruckfelder für den Bereich Nordatlantik-Europa Untersuchungen zur langperiodischen klimatischen und zirkulationsdynamischen Variabilität im Zeitraum 1780-1995 durchgeführt. Der im Rahmen dieser Arbeit betrachtete Zeitraum umfaßt damit neben dem 20. Jahrhundert, das durch eine zunehmende menschliche Einflußnahme auf das Globalklima gekennzeichnet ist, eine historische, bezüglich ihrer Klimacharakteristik anthropogen nahezu unbeeinflußte Periode.
Vor dem Hintergrund der zeitlichen Limitierung bisheriger zirkulationsdynamischer und synoptisch-klimatologischer Forschungsarbeiten auf die letzten etwa 100 Jahre wurden folgende zentrale Zielsetzungen formuliert:
- Erfassung und Darstellung der räumlich differenzierten, niederfrequenten thermischen und hygrischen Variabilität in Mitteleuropa seit 1780, auf einer möglichst umfassenden und hinsichtlich ihres klimatologischen Aussagewertes optimierten
Datenbasis.
- Untersuchung der korrespondierenden nordatlantisch-europäischen Zirkulationsveränderungen und ihrer Relevanz für die zeitlichen Variationen von Temperatur und Niederschlag in Mitteleuropa.
- Analyse der zeitlichen Variabilität der Beziehungen zwischen großräumiger atmosphärischer Zirkulation und regionalem Klima auf multidekadischer Zeitskala.
Ein erster wesentlicher Arbeitsschritt umfaßte die Überprüfung der Homogenität der verfügbaren - im Rahmen der Arbeit teilweise wesentlich erweiterten - mitteleuropäischen Temperatur- und Niederschlagszeitreihen (72 bzw. 62 Stationsreihen) mittels verschiedener absoluter und relativer Homogenitätstests. Für einen beträchtlichen Teil der Zeitreihen wurden signifikante Inhomogenitäten diagnostiziert, die unter Verwendung homogener Referenzreihen homogenisiert werden konnten.
Um die angestrebte räumlich differenzierte Analyse der klimatischen Veränderungen seit 1780 zu ermöglichen, erfolgten - basierend auf nichthierarchischen Clusteranalysen der Matrizen der paarweisen Korrelationen zwischen allen Temperatur- bzw. Niederschlagsreihen - objektive Regionalisierungen von Temperatur und Niederschlag.
Für die resultierenden acht thermischen und neun hygrischen Regionen Mitteleuropas wurden regionale Temperatur- und Niederschlagsreihen berechnet, die bezüglich ihrer langperiodischen Variabilität analysiert wurden. Im Vordergrund standen dabei die Ermittlung der zeitlichen Abfolge thermischer bzw. hygrischer Anomaliephasen seit 1780 sowie der klimatische Vergleich der sog. frühinstrumentellen Periode (1780-1860) mit einer modernen Referenzperiode (1915-1995).
Als wesentliches Ergebnis konnte eine gegenüber dem Zeitraum 1780-1860 verminderte kontinentale Prägung des mitteleuropäischen Klimas - mit wärmeren, feuchteren Wintern und kühleren Sommern - in diesem Jahrhundert (1915-1995) festgestellt werden.
Als Grundlage für die Analyse der korrespondierenden zirkulationsdynamischen Variabilität wurde eine automatische - hauptkomponenten- und clusteranalytische - Klassifikation rekonstruierter monatlicher nordatlantisch-europäischer Bodenluftdruckfelder erarbeitet. Ein zweiter automatischer Klassifikationsalgorithmus wurde in Anlehnung an die Großwettertypenklassifikation nach Hess/Brezowski unter besonderer Berücksichtigung der Strömungsverhältnisse über Europa entwickelt.
Die aus den Klassifikationsverfahren resultierenden Druckmusterklassen repräsentieren wesentliche Zustandsformen der atmosphärischen Zirkulation im nordatlantisch-europäischen Bereich. Basierend auf der Untersuchung der zeitlichen Veränderungen der Auftrittshäufigkeiten der verschiedenen Druckmusterklassen konnten die folgenden wesentlichen Aussagen zur zirkulationsdynamischen Variabilität seit 1780 formuliert werden:
- Die zeitliche Entwicklung der Auftrittshäufigkeiten der einzelnen Zirkulationstypen und der daraus aggregierten Zirkulationsformen - zonal, gemischt, meridional
- zeigt keine deutlichen langzeitlichen Trends, sondern ist von Schwankungen unterschiedlicher Periodenlänge und Amplitude gekennzeichnet.
- Einige rezent zu beobachtende Veränderungstendenzen (beispielsweise die Zunahme der winterlichen Zonalzirkulation seit den 1970er Jahren) erscheinen bei Betrachtung des 216-jährigen Gesamtzeitraums als nicht außergewöhnliche Ereignisse im Rahmen langperiodischer (dekadischer bis säkularer) zirkulationsdynamischer
Variabilität.
Aus dem direkten zirkulationsdynamischen Vergleich der beiden Zeiträume 1780-1860 und 1915-1995 ergeben sich folgende saisonal differenzierte Unterschiede:
- In den Wintermonaten Dezember und Januar sind in diesem Jahrhundert deutlich größere Auftrittshäufigkeiten von Zirkulationstypen mit südwestlicher bis nordwestlicher Richtungsorientierung des Isobarenverlaufs bei gleichzeitig reduzierten Häufigkeiten winterkalter meridionaler Druckmuster festzustellen. Zeitliche Veränderungen umgekehrten Vorzeichens manifestieren sich hingegen im Februar.
- Bei intrasaisonal variierenden Befunden im Frühjahr überwiegt bei saisonaler Betrachtung eine Zunahme meridionaler Strömungskonfigurationen auf Kosten der zonalen und vor allem der gemischten Zirkulationsform.
- Im Sommer dominiert eine Abnahme der zonalen Zirkulationsform zugunsten meridionaler Zirkulationstypen, die eine Anströmung aus dem nördlichen Richtungssektor implizieren.
- Für die Herbstmonate September mit November ergeben sich in diesem Jahrhundert vor allem gesteigerte Häufigkeiten von Strömungskonfigurationen, die die Heranführung von Luftmassen aus westlichen bis nordwestlichen Richtungen bedingen.
- Eine möglicherweise grundlegende Modifikation der nordatlantisch-europäischen Zirkulation in diesem Jahrhundert deutet sich bezüglich des häufigeren Wechsels zwischen stark zonal bzw. meridional geprägten Phasen - vor allem im Winter - an.
Mittels eines einfachen empirischen Modellansatzes wurde anschließend analysiert, inwieweit sich die diagnostizierten klimatischen Unterschiede zwischen den beiden Zeiträumen 1780-1860 und 1915-1995 aus den festgestellten zeitlichen Veränderungen der Zirkulationsstrukturen ergeben. Es wurde deutlich, daß nur ein Teil der Temperatur- und Niederschlagsveränderungen zwischen historischem Zeitraum und diesem Jahrhundert durch differierende Auftrittshäufigkeiten witterungsklimatisch homogener Zirkulationstypen erklärt werden kann. Ein beträchtlicher Anteil der klimatischen Unterschiedlichkeiten der beiden Vergleichszeiträume ist offensichtlich auf zeitlich variierende Witterungscharakteristika der einzelnen Strömungskonfigurationen („within-type changes“ - zirkulationstypinterne Veränderungen) zurückzuführen.
Das Ausmaß der typinternen klimatischen Modifikationen konnte durch die Berechnung der in den beiden Vergleichszeiträumen ausgebildeten typspezifischen mittleren Temperatur- und Niederschlagsverhältnisse quantifiziert werden. Die Fraktionierung der zirkulationstypspezifischen Temperatur- bzw. Niederschlagsänderungsbeträge in einen durch variierende Auftrittshäufigkeiten bedingten sowie einen auf typinterne Veränderungen zurückzuführenden Anteil belegt, daß in allen Jahreszeiten internen klimatischen Modifikationen der Zirkulationstypen mit südwestlicher bis nordwestlicher Isobarenverlaufsrichtung eine gewichtige Rolle bei der Generierung zeitlicher Unterschiede der mitteleuropäischen Temperatur- und Niederschlagscharakteristik zukommt.
Als Ursache der zirkulationstypinternen Veränderungen konnten zum einen unterschiedliche Ausgestaltungen der typspezifischen Druckmuster im historischen und im rezenten Zeitraum identifiziert werden (beispielsweise zeitlich variierende Druckgradienten bei generell übereinstimmenden Strömungskonfigurationen), zum anderen deuten sich auf der täglichen Zeitskala Veränderungen der Persistenzen einzelner Zirkulationstypen an.
Diese zirkulationsdynamischen Modifikationen stellen aber nicht in allen Fällen einen hinreichenden Erklärungsansatz für die diagnostizierten „within-type changes“ dar, so daß zusätzlich andere verursachende Faktorenkomplexe in Betracht gezogen werden müssen (beispielsweise modifizierte thermische und hygrische Luftmasseneigenschaften aufgrund veränderter Energieflüsse zwischen Ozean und Atmosphäre).
Mit Blick auf diese Resultate wurden die Beziehungen zwischen großräumiger Zirkulation und regionalem bodennahem Klima mittels kanonischer Korrelationsanalysen monatlicher Bodenluftdruckfelder und regionaler mitteleuropäischer Temperatur- und Niederschlagszeitreihen detaillierter hinsichtlich ihrer zeitlichen Variabilität untersucht. Die wesentlichen Ergebnisse lassen sich wie folgt zusammenfassen:
- In allen Jahreszeiten zeigen sich im Zeitraum 1780-1995 ausgeprägte zeitliche Schwankungen des statistisch beschreibbaren Zusammenhangs zwischen großräumiger atmosphärischer Zirkulation und regionalem Klima (Temperatur und Niederschlag in Mitteleuropa).
- Ein Vergleich der beiden Perioden 1780-1860 und 1915-1995 hinsichtlich der Kopplungsmechanismen zwischen Bodenluftdruckverteilung und Klima ergibt teilweise hochsignifikante Unterschiede.
- Die Modellierung von Temperatur und Niederschlag in Mitteleuropa aus monatlichen Druckfeldern jeweils einem der Zeitabschnitte 1780-1860 und 1915-1995 unter Verwendung der im jeweils anderen Zeitraum etablierten statistischen Zusammenhänge erbringt nur in einem Fall (Januartemperaturen) befriedigende Übereinstimmungen zwischen den modellierten und beobachteten Klimaverhältnissen.
Die in dieser Arbeit vorgestellten Untersuchungsergebnisse lassen die Schlußfolgerung zu, daß sich die im 20. Jahrhundert zu verzeichnenden Zirkulationsveränderungen im nordatlantisch-europäischen Sektor bislang noch in das Spektrum natürlicher zirkulationsdynamischer Variabilität einfügen.
Diese Aussage stellt aber weder die wahrscheinliche Mitwirkung des anthropogen verstärkten Treibhauseffekts an den in diesem Jahrhundert beobachteten Zirkulationsdynamischen Entwicklungen im euro-atlantischen Bereich in Frage, noch kann sie als Argument für die Aufschiebung notwendiger klimapolitischer Entscheidungen oder für die verzögerte Entwicklung und Umsetzung von Handlungsstrategien zur wirksamen Reduzierung klimawirksamer Treibhausgasemissionen aufgefaßt werden.
Zirkulationsdynamische Telekonnektivität des Sommerniederschlags im südhemisphärischen Afrika
(2003)
Die Arbeit befasst sich mit den durch Telekonnektionen etablierten Zusammenhängen zwischen der globalen troposphärischen Zirkulation der Atmosphäre und der sommerlichen Niederschlagsvariabilität im südhemisphärischen Afrika auf interannueller Zeitskala. Ziel der Arbeit ist die Erfassung maßgeblicher Telekonnektionen sowie deren Überprüfung hinsichtlich kausal nachvollziehbarer zirkulationsdynamischer Erklärungsmodelle, die - über formalstatistische Signifikanzkriterien hinausgehend - eine Beurteilung der Fernkopplungen in Hinblick auf ihre Bedeutung für den Niederschlag im südhemisphärischen Afrika gestattet. Die hierzu durchgeführten Arbeitsschritte umfassen im Wesentlichen: i.) hauptkomponentenbasierte Regionalisierung des Niederschlags im südhemisphärischen Afrika, ii.) Entwurf einer sog. multisaisonalen Analysemethode zur Ermittlung der intrasaisonalen Persistenz der Kopplungen, iii.) intensive Nutzung und Weiterentwicklung bivariater Techniken der Telekonnektionsanalyse, iv.) Anwendung und Ergebnisvergleich verschiedener multivariater Methoden (SFPCA, CCA, SVD), v.) Neuentwicklung einer dreistufigen Methodenkombination zur Extraktion sog. Hauptkopplungsmodi, vi.) zirkulationsdynamische Analyse der Hauptkopplungsmodi hinsichtlich plausibler Kopplungsmechanismen. Für acht Hauptkopplungsmodi konnten Erklärungsmodelle für den Transport von Anomaliesignalen zwischen den jeweils involvierten Telekonnektionszentren des globalen Druckfeldes und den korrelierten Niederschlagsschwankungen in den Regionen des südlichen Afrikas aufgezeigt werden, die sich sowohl hinsichtlich der räumlichen Verteilung der Zentren als auch prozessual in vier Hauptgruppen zusammenfassen lassen: 1.) ENSO-Telekonnektionen: Das pazifische ENSO-System stellt sich als dominierender Modus hinsichtlich der Telekonnektionen des südhemisphärischen Niederschlags in Afrika dar. Während eine positive Abhängigkeit des frühsommerlichen Niederschlags in Ostafrika durch Variationen der tropischen Walkerzirkulation des Indischen Ozeans etabliert wird, werden die insgesamt stärksten Kopplungen im südwestlichen Kontinetalbereich im Spätsommer festgestellt. Als Kopplungsmechanismus wird hier eine höhenkonvergente Strömungskonfiguration über dem Südostatlantik und Südafrika erkannt, die über Anomalieimpulse der Walkerzirkulation des Atlantiks mit den pazifischen ENSO-Anomalien verknüpft ist. 2.) Wellendynamik der südhemisphärischen Westwinddrift: Zwei Hauptkopplungsmodi beschreiben die Einbindung der Höhentrogaktivität über dem südlichen Afrika in Telekonnektionsmuster der Südhemisphäre. Beide beeinflussen die Niederschlagsvariabilität im Süden Afrikas durch die Modifikation von Höhentroglagen über der Südostküste Südafrikas, die in ihrem westlichen Rückseitenbereich konvektionshemmend wirken und einen Impuls zu anomal trockenen Verhältnissen in den betroffenen Niederschlagsregionen ausüben. 3.) Auftrittshäufigkeit und Intensität tropischer Zyklonen im südwestlichen Indischen Ozean: Die auf saisonaler Zeitskala mit tropischen Zyklonen assoziierten großskaligen Zirkulationsanomalien überwiegen bzw. kompensieren Effekte der Niederschlagserhöhung durch Starkregenereignisse im südöstlichen Afrika. Sowohl eine Verlagerung des Hauptkonvektionsgebietes als auch die Auswirkungen auf die Luftmassenadvektion über dem Subkontinent verursachen tendenziell trockenere Verhältnisse in Regionen des südöstlichen und zentralen südhemisphärischen Afrikas bei verstärkter Zyklonalaktivität im Spätsommer. 4.) Telekonnektionen mit der Zirkulation der subtropischen und mittleren Breiten der Nordhemisphäre: Vier Hauptkopplungsmodi repräsentieren Zusammenhänge v.a. der frühsommerlichen Niederschlagsvariabilität in Ostafrika. Die Schlüsselrolle bei der prozessualen Verzahnung der außertropischen Zirkulation mit innertropischen Konvektionsanomalien nimmt die Höhenströmung im Bereich des Subtropenjetstreams über Südwestasien ein, welche mit der Variabilität der Meridionalströmung im hochtroposphärischen Strömungsast der Hadleyzelle über Nordostafrika verknüft ist. Diese wiederum ist mittels Horizontaldivergenzanomalien an die Konvektionstätigkeit über dem äquatornahen Ostafrika gekoppelt. ; Neben Telekonnektionen des südafrikanischen Niederschlags bezüglich der atmosphärischen Zirkulation wurden Zusammenhänge mit der Variabilität der Meeresoberflächentemperaturen untersucht. Bis auf das ENSO-System und den sog. Dipolmodus im Indischen Ozean, konnten keine weiteren bedeutenden, auf der interannuellen Zeitskala wirksamen ozeanischen Einflüsse auf die Atmosphäre festgestellt werden, die zur weiteren Erklärung von Niederschlagstelekonnektionen beitragen. Die Ergebnisse der Arbeit lassen den Einsatz der Methoden bei der Analyse zeitversetzter Telekonnektionen im Rahmen prognostischer Modellierung der telekonnektiv beeinflussten Niederschlagsvariabilität im südhemisphärischen Afrika als aussichtsreich erscheinen.
The study investigates the water resources and aquifer dynamics of the igneous fractured aquifer-system of the Troodos Mountains in Cyprus, using a coupled, finite differences water balance and groundwater modelling approach. The numerical water balance modelling forms the quantitative framework by assessing groundwater recharge and evapotranspiration, which form input parameters for the groundwater flow models. High recharge areas are identified within the heavily fractured Gabbro and Sheeted Dyke formations in the upper Troodos Mountains, while the impervious Pillow Lava promontories - with low precipitation and high evapotranspiration - show unfavourable recharge conditions. Within the water balance studies, evapotranspiration is split into actual evapotranspiration and the so called secondary evapotranspiration, representing the water demand for open waters, moist and irrigated areas. By separating the evapotranspiration of open waters and moist areas from the one of irrigated areas, groundwater abstraction needs are quantified, allowing the simulation of single well abstraction rates in the groundwater flow models. Two sets of balanced groundwater models simulate the aquifer dynamics in the presented study: First, the basic groundwater percolation system is investigated using two-dimensional vertical flow models along geological cross-sections, depicting the entire Troodos Mountains up to a depth of several thousands of metres. The deeply percolating groundwater system starts in the high recharge areas of the upper Troodos, shows quasi stratiform flow in the Gabbro and Sheeted Dyke formations, and rises to the surface in the vicinity of the impervious Pillow Lava promontories. The residence times mostly yield less than 25 years, the ones of the deepest fluxes several hundreds of years. Moreover, inter basin flow and indirect recharge of the Circum Troodos Sedimentary Succession are identified. In a second step, the upper and most productive part of the fractured igneous aquifer-system is investigated in a regional, horizontal groundwater model, including management scenarios and inter catchment flow studies. In a natural scenario without groundwater abstractions, the recovery potential of the aquifer is tested. Predicted future water demand is simulated in an increased abstraction scenario. The results show a high sensitivity to well abstraction rate changes in the Pillow Lava and Basal Group promontories. The changes in groundwater heads range from a few tens of metres up to more than one hundred metres. The sensitivity in the more productive parts of the aquifer-system is lower. Inter-catchment flow studies indicate that - besides the dominant effluent conditions in the Troodos Mountains - single reaches show influent conditions and are sub-flown by groundwater. These fluxes influence the local water balance and generate inter catchment flow. The balanced groundwater models form thus a comprehensive modelling system, supplying future detail models with information concerning boundary conditions and inter-catchment flow, and allowing the simulation of impacts of landuse or climate change scenarios on the dynamics and water resources of the Troodos aquifer-system.
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.
Summary
Introduction. Rapid and uncontrolled industrialisation and urbanisation in most developing countries are resulting in land, air and water pollution at rates that the natural environment cannot fully renew. These contemporary environmental issues have attracted local, national and international attention. The problem of urban garbage management is associated with rapid population growth in developing countries. These are pertinent environmental crises of sustainability and sanitation in Sub-Saharan Africa and other Third World countries. Despite efforts of the various tiers of government (the case of Nigeria with three tiers: Federal, State and Local governments) in managing solid waste in urban centres, it is still overflowing open dumpsites, litters streets and encroaches into water bodies. These affect the quality of urban living conditions and the natural environment.
Sub-Saharan and other developing countries are experiencing an upsurge in the accumulation and the diversity of waste including E-waste, waste agricultural biomass and waste plastics. The need for effective, sustainable and efficient management of waste through the application of 3Rs principle (Reduce, Reuse, and Recycle) is an essential element for promoting sustainable patterns of consumption and production. This study examined waste management in Imo State, Nigeria as an aspect correlated to the sustainability of its environment.
Materials and methods. To analyse waste management as a correlate of environmental sustainability in Sub-Saharan Africa, Imo State, in eastern Nigeria was chosen as a study area. Issues about waste handling and its impact on the environment in Imo have been reported since its creation in 1976; passing through the State with the cleanest State capital in 1980 to a ‘dunghill’ in 2013 and a ‘garbage capital’ on October 1, 2016. Within this State, three study sites were selected – Owerri metropolis (the State capital) Orlu and Okigwe towns. At these sites, households, commercial areas, accommodation and recreational establishments and schools, as well as dumpsites were investigated to ascertain the composition, quantity, distribution, handling patterns of waste in relation to the sustainability of the State’s environment. This was done conveniently but randomly through questionnaires, interviews, focus group discussions and non-participant observation; these were all heralded by a detailed deskwork. Data were entered using Microsoft Office Excel and were explored and analysed using the Statistical Package for Social Sciences - SPSS.
Data were made essentially of categorical variables and were analysed using descriptive statistics. The association between categorical variables was measured using Cramer’s V the Chi-Square that makes the power and the reliability of the test. Cramer’s V is a measure of association tests directly integrated with cross-tabulation. The Chi-Square test of equal proportions was used to compare proportions for significant differences at 0.05 levels. The statistical package - the Epi Info 6.04d was also used since a contingency table had to be created from several sub-outputs and determine the extent of association between the row and column categories.
The scale variable ‘quantity of waste generated’ was described using measures of central tendency. It was screened for normality using the Kolmogorov-Smirnov and Shapiro-Wilk tests for normality; in all context, the normality assumption was violated (P<0.05). Five null hypotheses were tested using Logistic Regression model. The explanatory power of individual conceptual component was calculated using the Cox & Snell R2 and that of individual indicators was also appraised using the Likelihood Ratio test.
In the context of this work, the significance of the variability explained by the model (baseline model) was appraised using the Omnibus Tests of Model Coefficients, the magnitude of this variability explained by the model using the Cox & Snell R2 and the effects of individual predictors using the Likelihood Ratio test.
Qualitatively, data from open-ended items, observations and interviews were analysed using the process of thematic analysis whereby concepts or ideas were grouped under umbrella terms or keywords. The results were presented using tables, charts, graphs, photos and maps.
Findings and discussions. The total findings and analyses indicated that proper waste handling in Imo State, Nigeria has a positive impact on the environment. This was assessed by the community’s awareness of waste management via sources like the radio and the TV, their education on waste management and schools’ integration of environmental education in their program. Although most community members perceived the State’s environment as compared to it about 10 years’ back has worsened, where they were conscious of proper waste handling measures, the environment was described to be better. This influence of environmental awareness and education on environmental sustainability appraised using Logistic Regression Model, portrayed a significant variability (Omnibus Tests of Model Coefficients: χ2=42.742; P=0.014), inferring that environmental awareness and education significantly predict environmental sustainability.
The findings also revealed that organic waste generation spearheaded amongst other waste types like paper, plastic, E-waste, metal, textile and glass. While waste pickers always sorted paper, plastics, aluminium and metal, some of them also sorted out textile and glass. Statistically (P<0.05), in situations where waste was least generated (i.e., 1-2kg per day), community members maintained that the environmental quality was better in comparison to 10 years’ back. Waste items like broken glass and textile as well as the remains of E-waste after the extraction of copper and brass were not sorted for and these contributed more to environmental degradation.
Similarly, the influence of wealth on environmental sustainability was appraised using Logistic Regression Model including development index related indicators like education, occupation, income and the ability to pay for waste disposal. Harmonising the outcome, farmers, who were mostly the least educated claimed to notice more environmental improvement. In addition, those who did not agree to pay for waste disposal who were mostly those with low income (less than 200,000 Naira, i.e. about 620 Euros monthly) perceived environmental improvement more than those with income above 200,000 Naira. This irony can be attributed to the fact that those with low educational backing lack the capacity to appreciate environmental sustainability pointers well as compared to those with a broader educational background with critical thinking.
The employment and poverty reduction opportunities pertaining to waste management on environmental sustainability was appraised using qualitative thematic analysis. All community members involved in sorting, buying and selling of waste items had no second job. They attested that the money earned from their activities sustained their livelihood and families. Some expressed love for the job, especially as they were their own masters. Waste picking and trading in waste items are offering employment opportunities to many communities around the world. For instance, in the waste recycling, waste composting, waste-to-energy plants and die Stadtreiniger in Würzburg city. The workers in these enterprises have jobs as a result of waste.
Waste disposal influence on environmental sustainability was appraised using the Binary Logistic Regression Model and the variability explained by the model was significant. The validity was also supported by the Wald statistics (P<0.05), which indicates the effect of the predictors is significant. Environmental sustainability was greatly reliant on indicators like the frequency at which community members emptied their waste containers; how/where waste is disposed of, availability of disposal site or public bin near the house, etc. Imolites who asserted to have public waste bins or disposal sites near their houses maintained that the quality of the State’s environment had worsened as such containers/disposal sites were always stinking as well as had animals and smoke around them. Imolites around disposal sites complained of traits like diarrhoea, catarrh, insect bites, malaria, smoke and polluted air.
Conclusions. The liaison between poor waste management strategies and the sustainability of the Imo State environment was considered likely as statistically significant ineffectiveness, lack of awareness, poverty, insufficient and unrealistic waste management measures were found in this study area. In these situations, the environment was said to have not improved. Such inadequacies in the handling of generated waste did not only expose the citizenry to health dangers but also gave rise to streets and roads characterized by filth and many unattended disposal sites unleashing horrible odour to the environment and attracting wild animals. This situation is not only prevalent in Imo State, Nigeria but in many Sub-Saharan cities.
Future Perspectives. To improve the environment in Sub-Saharan Africa, it is imperative to practice an inclusive and integrated sustainable waste management system. The waste quantity in this region is fast growing, especially food/organic waste. The region should aim at waste management laws and waste reduction strategies, which will help save and produce more food that it really needs. Waste management should be dissociated from epidemic outbreaks like cholera, typhoid, Lassa fever and malaria, whose vectors thrive in filthy environments. Water channels and water bodies should not be waste disposal channels or waste disposal sites.
Vulnerabilitätsabschätzung der erdbebengefährdeten Megacity Istanbul mit Methoden der Fernerkundung
(2008)
Urbane Räume zählen zu den dynamischsten Regionen dieser Erde. Besonders Megacities zeigen bereits heute Trends und Dimensionen der Urbanisierung, deren regionale und globale Folgen noch kaum vorhersehbar, und erst ansatzweise erforscht sind. Die enorme räumliche Konzentration von Menschen, Werten und Infrastruktur auf engem Raum ist für diese urbanen Räume die Grundlage einer hohen Verwundbarkeit (Vulnerabilität). Gerade im Kontext von Naturgefahren potenzieren sich die Risiken, die durch den schnellen strukturellen, sozioökonomischen und ökologischen Wandel entstehen. Das übergeordnete Ziel dieser Dissertation ist daher die Analyse von Potentialen der Fernerkundung zur Abschätzung von Risiko und Vulnerabilität am Beispiel der erdbebengefährdeten Megacity Istanbul. Um die Zielstellung systematisch zu verfolgen, wird ein konzeptioneller, thematischer Leitfaden entwickelt. Dieser besteht aus einer Systematisierung der abstrakten Überbegriffe ‚Risiko’, ‚Vulnerabilität’ und ‚Gefährdung’ in einem Indikatorensystem. Konkrete, messbare Indikatoren für das System ‚urbaner Raum’ erlauben eine quantitative Abschätzung von Einzelaspekten, addieren sich aber auch zu einer ganzheitlichen Perspektive des Risikos. Basierend auf dieser holistischen Idee, erlaubt das Indikatorensystem Potentiale, aber auch Limitierungen der Fernerkundungsdaten und Bildverarbeitungsmethoden für die Abschätzung von Risiko und Vulnerabilität zu identifizieren. Anhand des Leitfadens werden zielgerichtet Methoden zur automatisierten Extraktion räumlicher Informationen aus Fernerkundungsdaten entwickelt. Ein objektorientierter, modularer Klassifikationsansatz ermöglicht eine Landbedeckungsklassifikation höchst aufgelöster Daten im urbanen Raum. Dieses modulare Rahmenwerk zielt auf eine einfache und schnelle Übertragbarkeit auf andere höchst auflösende Sensoren bzw. andere urbane Strukturen. Zur Anpassung der Methoden werden neben IKONOS Daten der Megacity Istanbul und der erdbeben- und tsunamigefährdeten Küstenstadt Padang in Indonesien, Quickbird Daten für die zukünftige Megacity Hyderabad in Indien getestet. Die Resultate zeigen die detaillierte und hochgenaue Erfassung kleinräumiger, heterogener urbaner Objekte mit Genauigkeiten von über 80 %. Auch mittel aufgelöste Landsat Daten werden mit einem objektorientierten modularen Rahmenwerk mit hohen Genauigkeiten klassifiziert, um komplementäre temporale und gesamtstädtische Analysen hinzuzufügen. Damit wird eine aktuelle, flächendeckende und multiskalige Informationsbasis generiert, die als Ausgangsprodukt zur Analyse urbaner Vulnerabilität dient. Basierend auf diesen Informationsebenen werden dem konzeptionellen Leitfaden folgend Indikatoren zur Abschätzung von Vulnerabilität und Risiko extrahiert. Der Fokus ist dabei die Entwicklung von Methoden zur automatisierten, interpreterunabhängigen Ableitung vulnerabilitäts- und gefährdungsrelevanter Indikatoren. Die physische Analyse des kleinräumigen urbanen Raums konzentriert sich dabei auf die Typisierung des Gebäudebestandes mit Parametern wie Dichte, Höhe, Alter, Größe, Form sowie Dachtyp. Indirekt wird zudem mittels dieser Parameter die Bevölkerungsdichteverteilung abgeleitet. Weitere Standortfaktoren ergeben sich aus Lageparametern wie Distanzen zu Hauptverkehrsachsen, Freiflächenanalysen oder der Geländeoberfläche. Schließlich führt die Vulnerabilitätsabschätzung den modellhaften, thematischen Leitfaden mit den abgeleiteten Indikatoren zusammen. Dazu erfolgt eine Normierung der unterschiedlichen abgeleiteten Indikatoren auf einen einheitlichen Vulnerabilitätsindex. Dieser zielt auf eine räumliche und zeitliche Vergleichbarkeit und die Möglichkeit, die vielfältigen Informationsebenen zu kombinieren. Damit wird das Zusammenspiel verschiedenster Indikatoren simuliert und erlaubt daraus Identifizierung und Lokalisierung von Brennpunkten im Desasterfall. Über das fernerkundliche Potential hinaus, werden die Resultate in einer interdisziplinären Methode zu einem synergetischen Mehrwert erhoben. Statt einer quantitativen Abschätzung der physischen Gebäudeparameter, ermöglicht eine Methode des Bauingenieurwesens in Kombination mit der fernerkundlichen Gebäudetypisierung eine Abschätzung der wahrscheinlichen Schadensanfälligkeit von Gebäuden im Falle eines Erdbebens. Exemplarisch wird das Potential der Resultate für Entscheidungsträger anhand eines Erdbebensszenarios aufgezeigt. Risiko und Vulnerabilität lassen sich dadurch räumlich sowohl nach betroffenen Häusern und betroffenen Menschen als auch nach räumlichen Standortfaktoren wie beispielsweise Zugänglichkeit quantifizieren. Dies ermöglicht gezielt präventiv zu agieren oder während und nach einem Desaster gezieltes Krisenmanagement zu betreiben. Im Hinblick auf die zentrale Fragestellung dieser Dissertation lässt sich resümieren, dass die Aktualität sowie die geometrische und thematische Qualität der Resultate aus Fernerkundungsdaten, den Anforderungen des komplexen, kleinräumigen und dynamischen urbanen Raums gerecht werden. Die Resultate führen zu der Erkenntnis, dass das Potential der Fernerkundung zur Abschätzung von Vulnerabilität und Risiko vor allem in der direkten Ableitung physischer Indikatoren sowie der indirekten Ableitung demographischer Parameter liegt.
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.
West Africa is one of the fastest growing regions in the world with annual population growth rates of more than three percent for several countries. Since the 1950s, West Africa experienced a fivefold increase of inhabitants, from 71 to 353 million people in 2015 and it is expected that the region’s population will continue to grow to almost 800 million people by the year 2050. This strong trend has and will have serious consequences for food security since agricultural productivity is still on a comparatively low level in most countries of West Africa. In order to compensate for this low productivity, an expansion of agricultural areas is rapidly progressing. The mapping and monitoring of agricultural areas in West Africa is a difficult task even on the basis of remote sensing. The small scale extensive farming practices with a low level of agricultural inputs and mechanization make the delineation of cultivated land from other land cover and land use (LULC) types highly challenging. In addition, the frequent cloud coverage in the region considerably decreases the availability of earth observation datasets. For the accurate mapping of agricultural area in West Africa, high temporal as well as spatial resolution is necessary to delineate the small-sized fields and to obtain data from periods where different LULC types are distinguishable. However, such consistent time series are currently not available for West Africa. Thus, a spatio-temporal data fusion framework was developed in this thesis for the generation of high spatial and temporal resolution time series.
Data fusion algorithms such as the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) enjoyed increasing popularity during recent years but they have hardly been used for the application on larger scales. In order to make it applicable for this purpose and to increase the input data availability, especially in cloud-prone areas such as West Africa, the ESTARFM framework was developed in this thesis introducing several enhancements. An automatic filling of cloud gaps was included in the framework in order to use even partly cloud-covered Landsat images for the fusion without producing gaps on the output images. In addition, the ESTARFM algorithm was improved to automatically account for regional differences in the heterogeneity of the study region. Further improvements comprise the automation of the time series generation as well as the significant acceleration of the processing speed through parallelization. The performance of the developed ESTARFM framework was tested by fusing an 8-day NDVI time series from Landsat and MODIS data for a focus area of 98,000 km² in the border region between Burkina Faso and Ghana. The results of this test show the capability of the ESTARFM framework to accurately produce high temporal resolution time series while maintaining the spatial detail, even in such a heterogeneous and cloud-prone region.
The successfully tested framework was subsequently applied to generate consistent time series as the basis for the mapping of agricultural area in Burkina Faso for the years 2001, 2007, and 2014. In a first step, high temporal (8-day) and high spatial (30 m) resolution NDVI time series for the entire country and the three years were derived with the ESTARFM framework. More than 500 Landsat scenes and 3000 MODIS scenes were automatically processed for this purpose. From the fused ESTARFM NDVI time series, phenological metrics were extracted and together with the single time steps of NDVI served as input for the delineation of rainfed agricultural areas, irrigated agricultural areas and plantations. The classification was conducted with the random forest algorithm at a 30 m spatial resolution for entire Burkina Faso and the three years 2001, 2007, and 2014. For the training and validation of the classifier, a randomly sampled reference dataset was generated from Google Earth images based on expert knowledge of the region. The overall classification accuracies of 92% (2001), 91% (2007), and 91% (2014) indicate the well-functioning of the developed methodology. The resulting maps show an expansion of agricultural area of 91% from about 61,000 km² in 2001 to 116,900 km² in 2014. While rainfed agricultural areas account for the major part of this increase, irrigated areas and plantations also spread considerably. Especially the expansion of irrigation systems and plantation area can be explained by the promotion through various national and international development projects. The increase of agricultural areas goes in line with the rapid population growth in most of Burkina Faso’s provinces which still had available land resources for an expansion of agricultural area. An analysis of the development of agricultural areas in the vicinity of protected areas highlighted the increased human pressure on these reserves. The protection of the remnant habitats for flora and fauna while at the same time improving food security for a rapidly growing population, are the major challenges for the region in the future.
The developed ESTARFM framework showed great potential beyond its utilization for the mapping of agricultural area. Other large-scale research that requires a sufficiently high temporal and spatial resolution such as the monitoring of land degradation or the investigation of land surface phenology could greatly benefit from the application of this framework.
The urban micro climate has been increasingly recognised as an important aspect for urban planning. Therefore, urban planners need reliable information on the micro climatic characteristics of the urban environment. A suitable spatial scale and large spatial coverage are important requirements for such information. This thesis presents a conceptual framework for the use of airborne hyperspectral data to support urban micro climate characterisation, taking into account the information needs of urban planning. The potential of hyperspectral remote sensing in characterising the micro climate is demonstrated and evaluated by applying HyMap airborne hyperspectral and height data to a case study of the German city of Munich. The developed conceptual framework consists of three parts. The first is concerned with the capabilities of airborne hyperspectral remote sensing to map physical urban characteristics. The high spatial resolution of the sensor allows to separate the relatively small urban objects. The high spectral resolution enables the identification of the large range of surface materials that are used in an urban area at up to sub-pixel level. The surface materials are representative for the urban objects of which the urban landscape is composed. These spatial urban characteristics strongly influence the urban micro climate. The second part of the conceptual framework provides an approach to use the hyperspectral surface information for the characterisation of the urban micro climate. This can be achieved by integrating the remote sensing material map into a micro climate model. Also spatial indicators were found to provide useful information on the micro climate for urban planners. They are commonly used in urban planning to describe building blocks and are related to several micro climatic parameters such as temperature and humidity. The third part of the conceptual framework addresses the combination and presentation of the derived indicators and simulation results under consideration of the planning requirements. Building blocks and urban structural types were found to be an adequate means to group and present the derived information for micro climate related questions to urban planners. The conceptual framework was successfully applied to a case study in Munich. Airborne hyperspectral HyMap data has been used to derive a material map at sub-pixel level by multiple endmember linear spectral unmixing. This technique was developed by the German Research Centre for Geosciences (GFZ) for applications in Dresden and Potsdam. A priori information on building locations was used to support the separation between spectrally similar materials used both on building roofs and non-built surfaces. In addition, surface albedo and leaf area index are derived from the HyMap data. The sub-pixel material map supported by object height data is then used to derive spatial indicators, such as imperviousness or building density. To provide a more detailed micro climate characterisation at building block level, the surface materials, albedo, leaf area index (LAI) and object height are used as input for simulations with the micro climate model ENVI-met. Concluding, this thesis demonstrated the potential of hyperspectral remote sensing to support urban micro climate characterisation. A detailed mapping of surface materials at sub-pixel level could be performed. This provides valuable, detailed information on a large range of spatial characteristics relevant to the assessment of the urban micro climate. The developed conceptual framework has been proven to be applicable to the case study, providing a means to characterise the urban micro climate. The remote sensing products and subsequent micro climatic information are presented at a suitable spatial scale and in understandable maps and graphics. The use of well-known spatial indicators and the framework of urban structural types can simplify the communication with urban planners on the findings on the micro climate. Further research is needed primarily on the sensitivity of the micro climate model towards the remote sensing based input parameters and on the general relation between climate parameters and spatial indicators by comparison with other cities.
U.S. and German Approaches to Regulating Retail Development: Urban Planning Tools and Local Policies
(2012)
This dissertation examines retail development regulation in the U.S. and in Germany, comparing the various urban planning tools and policies in use by municipal governments. These similarities and differences are explored through research into three case study cities in each country, with special attention paid to how these governments regulate large-scale or "big box" retail.
Processes of the Earth’s surface occur at different scales of time and intensity. Climate in particular determines the activity and seasonal development of vegetation. These dynamics are predominantly driven by temperature in the humid mid-latitudes and by the availability of water in semi-arid regions. Human activities are a modifying parameter for many ecosystems and can become the prime force in well-developed regions with an intensively managed environment. Accounting for these dynamics, i.e. seasonal dynamics of ecosystems and short- to long-term changes in land-cover composition, requires multiple measurements in time. With respect to the characterization of the Earth surface and its transformation due to global warming and human-induced global change, there is a need for appropriate data and methods to determine the activity of vegetation and the change of land cover. Space-borne remote sensing is capable of monitoring the activity and development of vegetation as well as changes of the land surface. In many instances, satellite images are the only means to comprehensively assess the surface characteristics of large areas. A high temporal frequency of image acquisition, forming a time series of satellite data, can be employed for mapping the development of vegetation in space and time. Time series allow for detecting and assessing changes and multi-year transformation processes of high and low intensity, or even abrupt events such as fire and flooding. The operational processing of satellite data and automated information-extraction techniques are the basis for consistent and continuous long-term product generation. This provides the potential for directly using remote-sensing data and products for analyzing the land surface in relation to global warming and global change, including deforestation and land transformation. This study aims at the development of an advanced approach to time-series generation using data-quality indicators. A second goal focuses on the application of time series for automated land-cover classification and update, using fractional cover estimates to accommodate for the comparatively coarse spatial resolution. Requirements of this study are the robustness and high accuracy of the approaches as well as the full transferability to other regions and datasets. In this respect, the developments of this study form a methodological framework, which can be filled with appropriate modules for a specific sensor and application. In order to attain the first goal, time-series compilation, a stand-alone software application called TiSeG (Time Series Generator) has been developed. TiSeG evaluates the pixel-level quality indicators provided with each MODIS land product. It computes two important data-availability indicators, the number of invalid pixels and the maximum gap length. Both indices are visualized in time and space, indicating the feasibility of temporal interpolation. The level of desired data quality can be modified spatially and temporally to account for distinct environments in a larger study area and for seasonal differences. Pixels regarded as invalid are either masked or interpolated with spatial or temporal techniques.
Diese Studie entwickelt und testet ein Ausbildungskonzept für die Lehrerausbildung im Fach Geographie am Beispiel der Bildungseinrichtung Studienhaus Geographie des Schullandheims Bauersberg bei Bischofsheim a.d. Rhön. Die theoretischen Überlegungen beinhalten einen Überblick über die bestehenden pädagogischen Zielsetzungen, die administrativen Grundlagen, die aufgezeigten Defizite der universitären Lehrerausbildung wie die daraus resultierenden Reformansätze und Forderungen an eine qualifizierte Lehrerausbildung. Für das fallbeispielhaft entwickelte Konzept einer Lehrerausbildung im Fach Geographie stellen die professionstheoretischen Ansätze zu einer kompetenzorientierte Lehrerausbildung die Basis dar, auf der die pädagogischen Zielsetzungen einer auf Professionalität ausgerichteten Lehrerausbildung formuliert werden. Schwerpunktmäßig basiert das Ausbildungskonzept auf dem bildungstheoretischen Dreieck zur Neustrukturierung der Lehrerbildung von BAYER/CARLE/WILDT, welches die Vernetzungsmöglichkeiten der die Lehrerausbildung kennzeichnenden Bezugssysteme Wissenschaft (im Sinne von Theorie), Praxis (im Sinne von Berufsfeldbezug) und Person (im Sinne von Professionalität) beschreibt. Grundlage des Ausbildungskonzeptes stellen ebenfalls die administrativen Vorgaben der bayerischen Lehrerausbildung dar. Eine wesentliche Rolle für die Konzeption dieser Form der Ausbildung am Standort Studienhaus Geographie spielen neben den strukturellen Voraussetzungen dieser Einrichtung die geäußerten Defizite der universitären Lehrerausbildung, die jeweils in der Aussage einer zu wenig an der Praxis orientierten Ausbildung gipfeln. Untersuchungen zur Qualität der universitären Geographielehrerausbildung geben Hinweise zu einer intensiveren Vermittlung von Methodenkompetenz bezüglich des Unterrichtsprinzips Handlungsorientierung und des Einsatz von geographischen Arbeitstechniken wie Experimente, Exkursionen/Arbeiten im Gelände etc.. Unterstützt werden die sich daraus ableitenden Optimierungsvorschläge durch die Realisierung verschiedener Reformansätze im Fach Geographie wie fächerübergreifendes, projektorientiertes, in der Zusammenarbeit mit der Schulpraxis stattfindendes Arbeiten an außerschulischen Lernorten und durch die von den jeweiligen Fachvertretern formulierten Richtlinien zur Optimierung der Lehrerausbildung. Das Ausbildungskonzept basiert auf interdisziplinär angelegten Lehrveranstaltungen, die in Kooperation der Geographiedidaktik mit der Physischen Geographie, der Humangeographie, der Geologie, der Mineralogie und der Schulpraxis und zur Erarbeitung unterrichtsrelevanter geographischer Ausbildungsinhalte stattfinden. Kennzeichnend ist die Veranstaltungsstruktur Blockveranstaltung, welche handlungs- und projektorientierte, auf Teamarbeit ausgerichtete Arbeitsformen fördert und die gemeinsame Erarbeitung von Ausbildungsinhalten aus fachdidaktischer und fachwissenschaftlicher Perspektive in der Theorie mit anschließender Anwendung bei Geländearbeiten. Eine Umsetzung der theoretischen Kenntnisse in fachadäquates, didaktisch-methodisches Unterrichtsmaterial/-vorhaben wie deren Erprobung mit Schülern schließt sich an. Den Abschluss dieser Ausbildungsform bildet eine gemeinsame Evaluation und Reflexion der gesetzten fachdidaktischen, fachwissenschaftlichen und hochschuldidaktischen Zielsetzungen bezüglich der Ausbildungsinhalte und -methode. In der qualitativen Studie wurde die Eignung des Standortes Studienhaus Geographie für Lehrveranstaltungen, die gemäß dem Konzept der theoriegeleiteten praxisorientierten Lehrerausbildung stattfinden, evaluiert. Lehrende der Geographie/Geologie/Mineralogie, Studierende und Lehrkräfte wurden in Leitfadeninterviews befragt. In der quantitativen Studie evaluierten alle teilgenommenen Studierende mittels eines Fragebogens dieses Ausbildungskonzept. Sowohl aus der Perspektive der Lehrenden der Fachwissenschaft als auch aus derjenigen der Geographiedidaktik und der Studierenden stellt diese Einrichtung aufgrund ihrer Lage und räumlichen wie materiellen Ausstattung einen geeigneten Ausbildungsort für eine universitäre Lehrerausbildung, die nach pädagogischen, fach- und hochschuldidaktischen Kriterien organisiert ist, dar.
As a cradle of ancient Chinese civilization, the Yellow River Basin has a very long human-environment interrelationship, where early anthropogenic activities re- sulted in large scale landscape modifications. Today, the impact of this relationship
has intensified further as the basin plays a vital role for China’s continued economic
development. It is one of the most densely-populated, fastest growing, and most dynamic
regions of China with abundant natural and environmental resources providing a livelihood for almost 190 million people. Triggered by fundamental economic reforms, the
basin has witnessed a spectacular economic boom during the last decades and can be
considered as an exemplary blueprint region for contemporary dynamic Global Change
processes occurring throughout the country, which is currently transitioning from an
agrarian-dominated economy into a modern urbanized society. However, this resourcesdemanding growth has led to profound land use changes with adverse effects on the Yellow
River social-ecological systems, where complex challenges arise threatening a long-term
sustainable development.
Consistent and continuous remote sensing-based monitoring of recent and past land
cover and land use change is a fundamental requirement to mitigate the adverse impacts
of Global Change processes. Nowadays, technical advancement and the multitude of
available satellite sensors, in combination with the opening of data archives, allow the
creation of new research perspectives in regional land cover applications over heterogeneous landscapes at large spatial scales. Despite the urgent need to better understand the
prevailing dynamics and underlying factors influencing the current processes, detailed
regional specific land cover data and change information are surprisingly absent for this
region.
In view of the noted research gaps and contemporary developments, three major objectives are defined in this thesis. First (i), the current and most pressing social-ecological
challenges are elaborated and policy and management instruments towards more sustainability are discussed. Second (ii), this thesis provides new and improved insights on
the current land cover state and dynamics of the entire Yellow River Basin. Finally (iii),
the most dominant processes related to mining, agriculture, forest, and urban dynamics
are determined on finer spatial and temporal scales.
The complex and manifold problems and challenges that result from long-term abuse
of the water and land resources in the basin have been underpinned by policy choices,
cultural attitude, and institutions that have evolved over centuries in China. The tremendous economic growth that has been mainly achieved by extracting water and exploiting
land resources in a rigorous, but unsustainable manner, might not only offset the economic benefits, but could also foster social unrest. Since the early emergence of the first Chinese dynasties, flooding was considered historically as a primary issue in river management and major achievements have been made to tame the wild nature of the Yellow
River. Whereas flooding is therefore largely now under control, new environmental and
social problems have evolved, including soil and water pollution, ecological degradation,
biodiversity decline, and food security, all being further aggravated by anthropogenic
climate change. To resolve the contemporary and complex challenges, many individual
environmental laws and regulations have been enacted by various Chinese ministries.
However, these policies often pursue different, often contradictory goals, are too general
to tackle specific problems and are usually implemented by a strong top-down approach.
Recently, more flexible economic and market-based incentives (pricing, tradable permits,
investments) have been successfully adopted, which are specifically tailored to the respective needs, shifting now away from the pure command and regulating instruments.
One way towards a more holistic and integrated river basin management could be the
establishment of a common platform (e.g. a Geographical Information System) for data
handling and sharing, possibly operated by the Yellow River Basin Conservancy Commission (YRCC), where available spatial data, statistical information and in-situ measures
are coalesced, on which sustainable decision-making could be based. So far, the collected
data is hardly accessible, fragmented, inconsistent, or outdated.
The first step to address the absence and lack of consistent and spatially up-to-date
information for the entire basin capturing the heterogeneous landscape conditions was
taken up in this thesis. Land cover characteristics and dynamics were derived from
the last decade for the years 2003 and 2013, based on optical medium-resolution hightemporal MODIS Normalized Differenced Vegetation Index (NDVI) time series at 250 m.
To minimize the inherent influence of atmospheric and geometric interferences found in
raw high temporal data, the applied adaptive Savitzky-Golay filter successfully smoothed
the time series and substantially reduced noise. Based on the smoothed time series
data, a large variety of intra-annual phenology metrics as well as spectral and multispectral annual statistics were derived, which served as input variables for random
forest (RF) classifiers. High quality reference data sets were derived from very high
resolution imagery for each year independently of which 70 % trained the RF models. The
accuracy assessments for all regionally specific defined thematic classes were based on the
remaining 30 % reference data split and yielded overall accuracies of 87 % and 84 % for
2003 and 2013, respectively. The first regional adapted Yellow River Land Cover Products
(YRB LC) depict the detail spatial extent and distribution of the current land cover status
and dynamics. The novel products overall differentiate overall 18 land cover and use
classes, including classes of natural vegetation (terrestrial and aquatic), cultivated classes,
mosaic classes, non-vegetated, and artificial classes, which are not presented in previous
land cover studies so far.
Building on this, an extended multi-faceted land cover analysis on the most prominent
land cover change types at finer spatial and temporal scales provides a better and more
detailed picture of the Yellow River Basin dynamics. Precise spatio-temporal products
about mining, agriculture, forest, and urban areas were examined from long-trem Landsat
satellite time series monitored at annual scales to capture the rapid rate of change in four
selected focus regions. All archived Landsat images between 2000 and 2015 were used to
derive spatially continuous spectral-temporal, multi-spectral, and textural metrics. For
each thematic region and year RF models were built, trained and tested based on a stablepixels reference data set. The automated adaptive signature (AASG) algorithm identifies those pixels that did not change between the investigated time periods to generate a
mono-temporal reference stable-pixels data set to keep manual sampling requirements
to a minimum level. Derived results gained high accuracies ranging from 88 % to 98 %.
Throughout the basin, afforestation on the Central Loess Plateau and urban sprawl are
identified as most prominent drivers of land cover change, whereas agricultural land
remained stable, only showing local small-scale dynamics. Mining operations started in
2004 on the Qinghai-Tibet Plateau, which resulted in a substantial loss of pristine alpine
meadows and wetlands.
In this thesis, a novel and unique regional specific view of current and past land cover
characteristics in a complex and heterogeneous landscape was presented by using a
multi-source remote sensing approach. The delineated products hold great potential for
various model and management applications. They could serve as valuable components
for effective and sustainable land and water management to adapt and mitigate the
predicted consequences of Global Change processes.
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 Paraná 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.
The area northeast of Sudbury, Ontario, is known for one of the largest unexplained geophysical anomalies on the Canadian Shield, the 1,200 km2 Temagami Anomaly. The geological cause of this regional magnetic, conductive and gravity feature has previously been modelled to be a mafic-ultramafic body at relatively great depth (2–15 km) of unknown age and origin, which may or may not be related to the meteorite impact-generated Sudbury Igneous Complex in its immediate vicinity. However, with a profound lack of outcrops and drill holes, the geological cause of the anomaly remains elusive, a genetic link to the 1.85 Ga Sudbury impact event purely speculative.
In search for any potential surface expression of the deep-seated cause of the Temagami Anomaly, this study provides a first, yet comprehensive petrological and geochemical assessment of exotic igneous dykes recently discovered in outcrops above, and drill cores into, the Temagami Anomaly. Based on cross-cutting field relations, petrographic studies, lithogeochemistry, whole-rock Nd-Sr-Pb isotope systematics, and U-Pb geochronology, it was possible to identify, and distinguish between, at least six different groups of igneous dykes: (i) Calc-alkaline quartz diorite dykes related to the 1.85 Ga Sudbury Igneous Complex (locally termed Offset Dykes); (ii) tholeiitic quartz diabase of the regional 2.22 Ga Nipissing Suite/Senneterre Dyke Swarm; (iii) calc-alkaline quartz diabase of the regional 2.17 Ga Biscotasing Dyke Swarm; (iv) alkaline ultrabasic dykes correlated with the 1.88–1.86 Ga Circum-Superior Large Igneous Province (LIP); and (v) aplitic dykes as well as (vi) a hornblende syenite, the latter two of more ambiguous age and stratigraphic position.
The findings presented in this study – the discovery of three new Offset Dykes in particular – offer some unexpected insights into the geology and economic potential of one of the least explored areas of the world-class Sudbury Mining Camp as well as into the nature and distribution of both allochthonous and autochthonous impactites within one of the oldest and largest impact structures known on Earth. Not only do the geometric patterns of dyke (and breccia) distribution reaffirm previous notions of the existence of discrete ring structures in the sense of a ~200-km multi-ring basin, but they provide critical constraints as to the pre-erosional thickness and extent of the impact melt sheet, thus helping to identity new areas for Ni-Cu-PGE exploration. Furthermore, this study provides important insights into the pre-impact stratigraphy and the magmatic evolution of the region in general, which reveals to be much more complex, compositionally divers, and protracted than initially assumed. Of note is the discovery of rocks related to the 2.17 Ga Biscotasing and the 1.88–1.86 Ga Circum-Superior magmatic events, as these were not previously known to occur on the southeast margin of the Superior Craton. Shortly predating the Sudbury impact and being contemporaneous with ore-forming events at Thompson (Manitoba) and Raglan (Cape Smith), these magmatic rocks could provide the missing link between unusual mafic, pre-enriched, crustal target rocks, and the unique metal endowment of the Sudbury Impact Structure.
The actual geological cause of the Temagami Anomaly remains open to debate and requires the downward extension of existing bore holes as well as more detailed geophysical investigations. The hypothesis of a genetic relationship between Sudbury impact event and Temagami Anomaly is neither borne out by any evidence nor particularly realistic, even in case of an oblique impact, and should thus be abandoned. It is instead proposed, based on circumstantial evidence, that the anomaly might be explained by an ultramafic complex of the 1.88–1.86 Ga Circum-Superior LIP.
This study presents new petrological results obtained from high-grade metamorphic rocks of the Beit Bridge, Mahalapye and Phikwe Complexes, which constitute the Central Zone of the Limpopo Belt in southern Africa. These results provide detailed information about the prograde and retrograde pressure-temperature (P-T) evolution of the three investigated complexes and, in concert with geochronological data, form the basis for the development of a coherent geodynamic model for the evolution of the Limpopo’s Central Zone. The P-T paths were inferred by the thorough investigation of silica-saturated and silica- undersaturated metapelitic and metabasic rocks, comprising six sillimanite-garnet-cordierite gneisses, four (garnet)-biotite-plagioclase gneisses, two garnet-orthopyroxene-biotite-Kfeldspar-plagioclase gneisses, one garnet- cordierite-orthoamphibole fels, one garnet-biotite amphibolite, and one garnet-clinopyroxene amphibolite. P-T points and P-T evolutions were derived by the application of conventional geothermobarometers, and quantitative phase diagrams in the systems Na2O - CaO - K2O - FeO - MgO - Al2O3 - SiO2 - H2O - TiO2 - O (NCKFMASHTiO), and MnO - TiO2 - Na2O - CaO - K2O - FeO - MgO - Al2O3 - SiO2 - H2O (MnTiNCKFMASH) - using the computer software THERMOCALC and THERIAK-DOMINO. The petrological information, in particular those obtained by comparison between observed and thermodynamically calculated mineral assemblages, zonations and modes, in combination with new and existing geochronological data provide evidence that rocks from the three investigated complexes underwent slightly different P-T evolutions at different times. The samples from the Bulai Pluton area (Beit Bridge Complex) provide evidence for a Neoarchean high-grade metamorphic event at ~2.64 Ga (M2), with peak P-T conditions of ~850°C at 8-9 kbar, and a decompression-cooling path to ~750°C at 5-6 kbar. This metamorphic evolution perhaps took place in a magmatic arc setting. In contrast, samples from the Mahalapye and Phikwe Complex document a Palaeoproterozoic event at ~2.03-2.05 Ga (M3), and were subject to different styles of prograde metamorphism. Metamorphic rocks from the Mahalapye Complex experienced a high-temperature low-pressure (HT-LP) metamorphic overprint, accompanied by the emplacement of voluminous granite bodies between 2.06 and 2.02 Ga, and provide evidence for a slightly prograde decompression from ~650°C/7 kbar to ~800°C/5.5 kbar. In contrast, the metamorphic rocks from the Phikwe Complex provide evidence for a simultaneous pressure and temperature increase from ~600°C/6 kbar to ~750°C/8 kbar, in the absence of significant Palaeoproterozoic magmatism. The HT-LP metamorphic evolution of the Mahalapye Complex is interpreted to be initiated by the underplating of hot mafic melts, either formed in response to SE-subduction during the Kheis-Magondi orogeny, and/or by contemporaneous mantle plume activities related to the formation of the Bushveld Complex. In contrast, the prograde pressure and temperature increase reflected by the rocks from the Phikwe Complex rather reflects successive crustal stacking at ~2.03 Ga. This stacking, which is also reported from many other units throughout the Limpopo Belt, is interpreted to result from the final convergence between the Kaapvaal and Zimbabwe Cratons, perhaps caused by SE-directed compression in response to the Kheis-Magondi orogeny between ~2.06 and 1.90 Ga.
Periglacial environments are facing dramatic changes. Warming air temperatures and strong snow cover variations fundamentally affect landforming processes in this hotspot region of Climate Change. But before we can assess the response of landform development to a changing climate, we need to enhance our understanding of the internal structure of those landforms. Within this study, a broad scope of landform types from alpine and subarctic regions is investigated: rock glaciers, solifluction lobes, palsas and patterned ground. By using the geophysical methods 2-D and 3-D ERI, as well as GPR surveying, structural differences and similarities between landform units of different or the same landform types are highlighted. This enables a reconstruction of their past and a projection of their future development.
This study explores and examines the geomorphology of a large endorheic basin, approximately twice the size of Luxemburg, situated in the Etosha National Park, Namibia. The main focus is directed on how and when this depression, known as Etosha Pan, came into being. Geomorphological investigation was complemented and guided primarily by the application and interpretation of satellite-derived information. Etosha Pan has attracted scientific investigations for nearly a century. Unfortunately, their efforts resulted into two diverging and mutually exclusive views with respect to its development. The first and oldest view dates back to the 1920s. It hypothesized Etosha Pan as a desiccated palaeolake which was abandoned following the river capture of its major fluvial system, the Kunene River. The river capture was assumed to have taken place in the Pliocene/Early Pleistocene. In spite of the absence of fluvial input that the Kunene contributed, the original lake was thought to have persisted until some 35 ka ago, long after the Kunene severed its ties with the basin. The current size of the basin and its playa status was interpreted to have resulted from deteriorating climatic conditions. The opposing view emerged in the 1980s and gained prominence in the 1990s. This view assumed that there were an innumerable number of small pans on the then surface of what later to become Etosha Pan. Since the turn of the Pliocene to Early Pleistocene, these individual pans started to experience a combined effect of fluvial erosion during the rainy season and wind deflation during the dry period. The climatic regime during that entire period was postulated to be semi-arid as today. This climatic status was used to rule out any existence of a perennial lake within the boundary of Etosha since the Quaternary. Ultimately, these denudational processes, taking place in a seasonal rhythm, caused the individual pans to deepen and widen laterally into each other and formed a super-pan that we call Etosha today. Thus the Kunene River had no role to play in the development of the Etosha Pan according to this model. However, proponents of this model acknowledged that the Kunene once fed into the Owambo Basin and assigned the end of the Tertiary to the terminal phase of that inflow. Findings of this study included field evidence endorsing the postulation that the Kunene River had once flowed into the Owambo Basin. Its infilled valley, bounding with the contemporary valley of the Kunene near Calueque, was identified and points towards the Etosha Pan. It is deliberated that a large lake, called Lake Kunene, existed in the basin during the time. Following the deflection of the Kunene River to the coast under the influence of river incision and neo-tectonic during the Late Pliocene, new dynamics were introduced over the Owambo Basin surface. After the basin was deprived of its major water and sediment budget that the Kunene River contributed, it was left with only smaller rivers, most notably the Cuvelai System, as the only remaining supplier. This resulted in the Cuvelai System concentrating and limiting its collective load deposition to a lobe of Lake Kunene basin floor. The accident of that lobe is unclear, but it is likely that it constituted the deepest part of the basin at the time or it was influenced by neo-tectonic that helped divert the Kunene River or both. Against the backdrop of fluvial action that was initiating the new lake, most parts of the rest of the basin, then denied of lacustrine activity, were intermittently riddled with a veneer of sediment, especially during phases of intensified aeolian activity. In the mean time, the area that was regularly receiving fluvial input started to shape up as a distinct lake with the depositions of sediments around the water-body, primarily via littoral action, serving as embankment. Gradually, a shoreline is formed and assisted in fixing and delineating the spatial extent of the new and much smaller lake, called Lake Etosha. That Lake Etosha is the predecessor of the modern day Etosha Pan. Indicators for a perennial lake found in this study at Etosha include fossil fragments of Clariidae species comparable to modern species measuring some 90 cm, and those of sitatunga dated to approximately 5 ka. None of these creatures exist today at Etosha because of their ecological requirements, which among others, include permanent water. The sitatunga, in addition, is known as the only truly amphibious antelope in the world. Since its inception, the new lake underwent a number of geomorphological modifications. A prominent character amongst these modifications is the orientation of the lake, which has its long-axis oriented in the ENE-WSW direction. It resulted from wave action affected by the prevailing dominant northeasterly wind, which is believed to have been in force since the Middle Pleistocene. Lake Etosha has also witnessed phases of waning and waxing under the influence of the prevailing climatic regime. Over the last 150 ka, the available data intercepted about seven phases of high lake levels. These data are generally in agreement with regional palaeoclimatic data, particularly when compared with those obtained from neighbouring Makgadikgadi Pans in Botswana. The last recorded episode of the wet phase at Etosha was some 2,400 years before the present.
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.
Taxonomy and palaeoecology of the Cenomanian-Turonian macro-invertebrate from eastern Sinai, Egypt
(2010)
The present study concerened with taxonomy and palaeoecology of the Cenomanian-Turonian macrobenthic fauna which includes bivalves, gastropods, echinoids, and coral. In addtion, cephalopods are also taken in consideration. 144 taxa are identified and systematically described. Palaeoecological and taphonomic anylsis of the statistically sampled macrobenthos are also discussed. The biostratigraphic sequences along the Cenomanian-Turonian rocks were carried out on the basis of ammonites and other macrobenthic fauna such as corals and bivalves. In order to reconstruct benthic association, 41 statistically sampled were subjected to cluster ananlysis by using Past Programm (Hammer et al., 2001). 10 association and three assemblages were described in order to reconstruct the different depositional enviroments.