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Road Deposited Sediment (RDS) is an important pathway of pollution material in the urban environment. Traditional particulate matter (PM) monitoring methods are typically expensive and time consuming. To date, urban sediment studies have not fully explored the application of mineral magnetic technologies as an alternative to characterise RDS or, perhaps more importantly, their use as particle size proxy. Therefore, this study addresses these issues by determining the extent of any linkages between magnetic properties and the physio-chemical concentrations of RDS. Investigations have focussed on a spatial temporal study (2008-10) of RDS from the City of Wolverhampton (n = 546) and a similar ‘snap-shot’ study of eight selected town and cities across the UK (n = 306), plus a comparison investigation linked to regional monitoring of air sampling units (ASU) (n = 208). A suite of analytical approaches, namely mineral magnetism, laser diffraction, X-Ray Fluorescence spectroscopy (XRF), Scanning Electron Microscopy (SEM) and Loss on Ignition (LOI), were employed to characterize sample properties. Data interrogation identified mainly weak correlations exist between most mineral magnetic parameters and particle size classes (i.e. sand, silt and clay) and respiratory health-related size classes (i.e. PM10, PM2.5 and PM1.0). The few strongest correlations (p <0.001) were found between mineral magnetic concentration and <PM10 parameters. In Wolverhampton this occurred for samples collected during the spring months (March and May), indicating possible seasonal influences on RDS dynamics and sources. Elsewhere in the UK, and at ASU stations, results revealed mainly limited or insignificant (p >0.05) correlations exist between mineral magnetic parameters and particle size. However, for some locations (most notably, London and Scunthorpe), results exhibit signatures perceived to be associated with environmental factors. Detailed multivariate Factor Analysis plots and Geographical Information System (GIS) images have been used to explore these findings further. These illustrate RDS properties of road types (arterial and residential) display significantly different characteristics, with raised mineral magnetic concentrations for arterial roads, compared to lesser concentrations for residential roads, which corresponds to traffic flow data. This is supported by SEM analyses that reveal elevated concentrations of iron oxide spheres in samples collected from arterial roads, which are indicative of inputs from anthropogenic combustion sources. Contextualising these findings within the framework of existing knowledge, a conceptual approach has been presented that explores factors (i.e. sampling area, topography, land use, sediment source and potential mixing), which influence the reliability of using mineral magnetic techniques a particle size proxy. This demonstrates that any increase in the complexity of these factors (sampling area dynamics) can be used to predict the likelihood of being able to employ mineral magnetic measurements as a proxy. To surmise the work overall, despite mineral magnetic technologies offering an inexpensive and rapid means of analysing RDS, its use as a proxy measure for particulate matter appears to be limited by a series of site-related factors but the technique seems to offer valuable insights for pollution source studies.

NE Brazil is a semi-arid region influenced by the southward displacement of the Intertropical Convergence Zone (ITCZ), which is the main atmospheric system that modulates the seasonal increasing in precipitation over this region. It is well established that these wet periods correlate temporally with the Heinrich Events. However, the local oceanographic response to the fresh water pulses in North Atlantic and how it influences sediment transport along the margin off NE Brazil, is still a matter of discussion. This thesis presents a rock magnetic and element data along four marine cores collected in the south equatorial Atlantic Ocean, covering the last 85 ka BP. Moreover, it was performed an end-member analysis based on the IRM acquisition curves bringing better understanding about sediment sources. Magnetic characterization permitted us to investigate a possible relationship between river supply/longitudinal transport and precipitation enhancement caused by cold events over the North Atlantic. The results suggest a differential deposit of magnetic minerals along the coast, with highly coercive phases (hematite and goethite) further west, and gradually softer phases, like (titano)magnetite to the east. This difference is due mainly to differential oxidation over land, but secondarily we suggest a transport from W-E of coercive material, caused by weakness of NBC. / O NE do Brasil é uma região semiárida influenciada pela migração para sul da Zona de Convergência Intertropical (ITCZ), que é o principal sistema atmosférico que controla o aumento sazonal da precipitação nessa região. É bem estabelecido que esses períodos úmidos se correlacionam temporalmente com os Eventos Heinrich. Entretanto, a resposta oceanográfica local a esse input de água doce no Atlântico Norte e como isso influencia o transporte de sedimentos ao longo da margem adjacente ao NE do Brasil é ainda discutido. Este trabalho apresenta dados magnéticos e geoquímicos para quatro testemunhos coletados na parte sul do Oceano Atlântico equatorial, para os últimos 85 ka BP. Além disso, foi feito um estudo de end-members baseado nas curvas de aquisição de IRM, a partir do qual elucidamos sobre possíveis fontes de sedimento. O estudo magnético permitiu investigar uma possível relação entre input de rios/transporte longitudinal e aumento da precipitação causado pelos eventos frios do Atlântico Norte. Os resultados sugerem uma deposição diferencial de minerais magnéticos a longo da costa, com fases altamente coercivas (hematita e goethita) na parte oeste, e fases gradualmente menos coercivas, como titano(magnetita) para leste. Essa diferença é devida, principalmente, à oxidação diferencial no continente, mas secundariamente nós sugerimos um transporte W-E de material coercivo, causado pelo enfraquecimento da Corrente Norte do Brasil (NBC).

This thesis provides a detailed study of environmental magnetism in a speleothem. It focuses on a stalagmite from Pau DAlho cave (15°1220S, 56°4841W) located in Rosário dOeste, Mato Grosso State, Brazil. This speleothem grew during the past 1355 years, with average growth rate of ~168 mm/ka and encompasses two key events in the South American Summer Monsoon (SASM), the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA), major dry and wet, respectively. The rock magnetic experiments conducted, include isothermal remanent magnetization (IRM) and anhysteretic remanent magnetization (ARM) acquisition curves, thermal demagnetization of three-axis IRM acquisition, hysteresis loops, first order reversal curves (FORC) and low-temperature SQUID magnetometry experiments. The main magnetic remanence carriers in the stalagmite are magnetite and goethite, with a nearly constant relative proportion. Magnetite has remanent coercivities between 14-17 mT, and its magnetic properties are similar to those produced by pedogenic processes. Magnetic remanence is broadly correlated with carbon and oxygen isotope data throughout most of the speleothem, suggesting that precipitation and soil dynamics above the cave exert a strong control on the input of magnetic minerals into the Pau dAlho cave system. Dry periods like the MCA are associated with less stable soils that result in higher mineral fluxes carried into karst systems via groundwater, while conversely, colder and wetter periods like the LIA are associated with soils topped by denser vegetation that are more capable of retaining micrometer-scale pedogenic minerals, and thus reduce mineral fluxes into karst environments. / Esta tese fornece um estudo detalhado do magnetismo ambiental de espeleotemas. Este estudo é feito em uma estalagmite da caverna Pau D\'Alho (15 ° 12\'20 \"S, 56 ° 48\'41\" W), localizado em Rosário d\'Oeste, Mato Grosso, Brasil. Este espeleotema cresceu durante os últimos 1355 anos, com taxa média de crescimento de ~ 168 mm/ka e engloba dois eventos climáticos do Sistema de Monção Sul-americano (SMSA), a Anomalia Climática do Medieval (ACM) e a Pequena Idade do Gelo (PIG), eventos secos e molhados, respectivamente. Os experimentos de magnetismo de rocha incluem: magnetização remanecte isotermal (MRI), ciclos de histerese, magnetização remanente anisterética (MRA), desmagnetização térmica em três eixos, first order reversal curves (FORC) e experimentos de baixa temperatura. Os principais portadore magnéticos na estalagmite são magnetita e goethita, com uma proporção relativa quase constante. A magnetita tem coercividades entre 14-17 mT, e as suas propriedades magnéticas são semelhantes às produzidas por processos pedogênicos. As remanências magnéticas são amplamente correlacionadas com dados de isótopos de carbono e oxigênio durante o registro, sugerindo que a precipitação e a dinâmica do solo acima da caverna exerce um forte controle na entrada de minerais magnéticos no sistema de cavernas Pau d\'Alho. Períodos secos como o ACM estão associados a solos menos estáveis, que resultam em maiores fluxos de minerais detríticos carreados para o sistema de cavernas, ao passo que, inversamente, os períodos frios e chuvosos como a LIA estão associados a solos cobertos pela vegetação mais densa que são mais capazes de reter minerais pedogênicos de escala micrométrica, e, assim, diminuir os fluxos de minerais detríticos para o sistema de cavernas.

This thesis provides a detailed study of environmental magnetism in a speleothem. It focuses on a stalagmite from Pau DAlho cave (15°1220S, 56°4841W) located in Rosário dOeste, Mato Grosso State, Brazil. This speleothem grew during the past 1355 years, with average growth rate of ~168 mm/ka and encompasses two key events in the South American Summer Monsoon (SASM), the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA), major dry and wet, respectively. The rock magnetic experiments conducted, include isothermal remanent magnetization (IRM) and anhysteretic remanent magnetization (ARM) acquisition curves, thermal demagnetization of three-axis IRM acquisition, hysteresis loops, first order reversal curves (FORC) and low-temperature SQUID magnetometry experiments. The main magnetic remanence carriers in the stalagmite are magnetite and goethite, with a nearly constant relative proportion. Magnetite has remanent coercivities between 14-17 mT, and its magnetic properties are similar to those produced by pedogenic processes. Magnetic remanence is broadly correlated with carbon and oxygen isotope data throughout most of the speleothem, suggesting that precipitation and soil dynamics above the cave exert a strong control on the input of magnetic minerals into the Pau dAlho cave system. Dry periods like the MCA are associated with less stable soils that result in higher mineral fluxes carried into karst systems via groundwater, while conversely, colder and wetter periods like the LIA are associated with soils topped by denser vegetation that are more capable of retaining micrometer-scale pedogenic minerals, and thus reduce mineral fluxes into karst environments. / Esta tese fornece um estudo detalhado do magnetismo ambiental de espeleotemas. Este estudo é feito em uma estalagmite da caverna Pau D\'Alho (15 ° 12\'20 \"S, 56 ° 48\'41\" W), localizado em Rosário d\'Oeste, Mato Grosso, Brasil. Este espeleotema cresceu durante os últimos 1355 anos, com taxa média de crescimento de ~ 168 mm/ka e engloba dois eventos climáticos do Sistema de Monção Sul-americano (SMSA), a Anomalia Climática do Medieval (ACM) e a Pequena Idade do Gelo (PIG), eventos secos e molhados, respectivamente. Os experimentos de magnetismo de rocha incluem: magnetização remanecte isotermal (MRI), ciclos de histerese, magnetização remanente anisterética (MRA), desmagnetização térmica em três eixos, first order reversal curves (FORC) e experimentos de baixa temperatura. Os principais portadore magnéticos na estalagmite são magnetita e goethita, com uma proporção relativa quase constante. A magnetita tem coercividades entre 14-17 mT, e as suas propriedades magnéticas são semelhantes às produzidas por processos pedogênicos. As remanências magnéticas são amplamente correlacionadas com dados de isótopos de carbono e oxigênio durante o registro, sugerindo que a precipitação e a dinâmica do solo acima da caverna exerce um forte controle na entrada de minerais magnéticos no sistema de cavernas Pau d\'Alho. Períodos secos como o ACM estão associados a solos menos estáveis, que resultam em maiores fluxos de minerais detríticos carreados para o sistema de cavernas, ao passo que, inversamente, os períodos frios e chuvosos como a LIA estão associados a solos cobertos pela vegetação mais densa que são mais capazes de reter minerais pedogênicos de escala micrométrica, e, assim, diminuir os fluxos de minerais detríticos para o sistema de cavernas.

NE Brazil is a semi-arid region influenced by the southward displacement of the Intertropical Convergence Zone (ITCZ), which is the main atmospheric system that modulates the seasonal increasing in precipitation over this region. It is well established that these wet periods correlate temporally with the Heinrich Events. However, the local oceanographic response to the fresh water pulses in North Atlantic and how it influences sediment transport along the margin off NE Brazil, is still a matter of discussion. This thesis presents a rock magnetic and element data along four marine cores collected in the south equatorial Atlantic Ocean, covering the last 85 ka BP. Moreover, it was performed an end-member analysis based on the IRM acquisition curves bringing better understanding about sediment sources. Magnetic characterization permitted us to investigate a possible relationship between river supply/longitudinal transport and precipitation enhancement caused by cold events over the North Atlantic. The results suggest a differential deposit of magnetic minerals along the coast, with highly coercive phases (hematite and goethite) further west, and gradually softer phases, like (titano)magnetite to the east. This difference is due mainly to differential oxidation over land, but secondarily we suggest a transport from W-E of coercive material, caused by weakness of NBC. / O NE do Brasil é uma região semiárida influenciada pela migração para sul da Zona de Convergência Intertropical (ITCZ), que é o principal sistema atmosférico que controla o aumento sazonal da precipitação nessa região. É bem estabelecido que esses períodos úmidos se correlacionam temporalmente com os Eventos Heinrich. Entretanto, a resposta oceanográfica local a esse input de água doce no Atlântico Norte e como isso influencia o transporte de sedimentos ao longo da margem adjacente ao NE do Brasil é ainda discutido. Este trabalho apresenta dados magnéticos e geoquímicos para quatro testemunhos coletados na parte sul do Oceano Atlântico equatorial, para os últimos 85 ka BP. Além disso, foi feito um estudo de end-members baseado nas curvas de aquisição de IRM, a partir do qual elucidamos sobre possíveis fontes de sedimento. O estudo magnético permitiu investigar uma possível relação entre input de rios/transporte longitudinal e aumento da precipitação causado pelos eventos frios do Atlântico Norte. Os resultados sugerem uma deposição diferencial de minerais magnéticos a longo da costa, com fases altamente coercivas (hematita e goethita) na parte oeste, e fases gradualmente menos coercivas, como titano(magnetita) para leste. Essa diferença é devida, principalmente, à oxidação diferencial no continente, mas secundariamente nós sugerimos um transporte W-E de material coercivo, causado pelo enfraquecimento da Corrente Norte do Brasil (NBC).

No description available.

Die Magnetometerprospektion gilt mittlerweile als ein Standardverfahren der archäologischen Prospektion. Nicht selten jedoch werden Messergebnisse (Magnetogramme) dieser schnellen und oft ertragreichen Prospektionsmethode ohne eine notwendige Überprüfung im Labor interpretiert, was zu falschen Bewertungen der Magnetfeldanomalien in archäologischen und geoarchäologischen Kontexten führen kann. Die vorliegende Arbeit versucht diesem Problem entgegen zu treten und widmet sich dem Ziel Interpretationen von Magnetometermessungen zu verbessern und Verfahren weiter zu entwickeln, die zur schnellen und hinreichenden Klärung von Magnetfeldanomalien angewandt werden können. Hierfür werden in mehreren Untersuchungsgebieten magnetometrische und umweltmagnetische Messungen in Kombination mit bodenkundlich-sedimentologischen Kennwerten, ausgewertet. Als Untersuchungsgebiete und Umweltarchive stehen die braunen Plaggenesche am Übergang zwischen dem Unteren Weserbergland und der Dümmer-Geestniederung sowie die semiterrestrischen Sedimente des Karlsgrabens (Fossa Carolina) am Übergang zwischen dem fränkischen Keuper-Lias-Land und der fränkischen Alb im Fokus. Magnetometrisch prospektiert wird mit einem, sehr oft bei archäologischen Prospektionen eingesetzten, Vektor-Gradiometer (Bartington Grad601 dual). Als geophysikalische Leitgröße zur Identifizierung und ersten Charakterisierung magnetisch-auffälliger und Magnetfeldanomalien-erzeugender Bodenhorizonte und Sedimentschichten in betrachteten Umweltarchiven wird die magnetische Suszeptibilität herangezogen. Anhand der Curie-Temperatur-Messungen und Domänenstatusermittlungen werden die umweltmagnetischen Minerale und deren Korngrößen in magnetisch auffälligen Lagen und Horizonten charakterisiert. Ergebnisse aus der Kombination umweltmagnetischer Messungen mit Bodenkennwerten an brauen Plaggeneschen weisen darauf hin, dass die in den Plaggenauflagen detektierten, ferrimagnetischen Eisensulfide PSD-Greigite anthropogen induziert sein müssen. Außerdem deutet sich an, dass diese Greigite vom Sicker- und Grundwasser verändert und gegebenenfalls mobilisiert werden können. Ein Vergleich mit Greigiten aus der Literatur zeigt, dass die Plaggenesch-PSD-Greigite in einem Domänenstatus vorliegen, in dem bislang noch keine natürlichen Greigite gemessen wurden. Dieser Domänenstatus wird als ein Oxidationsstadium des ferrimagnetischen Eisensulfids zur Diskussion gestellt. In den Grabenverfüllungen bzw. Paläokanälen des Karlsgrabens wurden in Magnetfeldanomalien-erzeugenden Lagen authigene SD-Greigite nachgewiesen und damit die Annahme von Stanjek et al. (1994) bestätigt, dass die Greigite für die Magnetometerprospektion in semiterrestrischen Umgebungen von Bedeutung sein können. In flankierende Begleitstrukturen des Karlsgrabens wurden hingegen hocherhitzte, thermoremanente PSD-Titanomagnetite als Magnetfeldanomalien-Erzeuger ermittelt. Ihre Entstehung bleibt ungeklärt, jedoch wird eine natürliche Bildung dieser Magnetominerale vor Ort ausgeschlossen. Im Hinblick auf das Ziel der vorliegenden Arbeit hat sich die methodische Vorgehensweise am Karlsgraben als besonders effiziente und relativ kostengünstige Methode zur abgesicherten Klärung von Magnetfeldanomalien in den Magnetogrammen gezeigt.

Le fer et ses composés, notamment les (oxyhydr)oxydes, sont présents dans la nature et produits par les activités anthropiques. Ce caractère ubiquiste du fer et sa sensibilité aux conditions environnementales en fait un excellent traceur de sources et de processus.Cette thèse a pour objectif de tracer l’impact de l’Homme sur les matières en suspension (MES) de la Seine à partir des propriétés magnétiques de sa fraction ferrugineuse en utilisant les outils et méthodes du magnétisme environnemental.Un échantillonnage des MES a permis de couvrir le cours de la Seine et ses affluents durant différents contextes hydrologiques. Des analyses ont été conduites sur ces MES afin de caractériser les particules ferrugineuses magnétiques et d'examiner leurs relations avec les conditions environnementales dans lesquelles elles se sont formées et/ou ont évolué.La magnétite apparait comme l’oxyde dominant et montre une forte affinité avec la fraction fine des MES et ses propriétés magnétiques peuvent être utilisées pour décrire la charge sédimentaire de la Seine et les phénomènes de remise en suspension.Des augmentations de tailles et de concentration de magnétites sont associées à l’urbanisation et aux activités industrielles. Les variations spatiales entre amont et aval des confluences et les variations temporelles montrent que le cours d’eau joue un rôle dans les mécanismes d’accumulation, transport et dilution de ces particules. / Iron and its compounds, in particular iron (hoxyhydr)oxides are ubiquitous in both nature and human activity, and are sensitive to environmental conditions. They can hence be used as environmental source and process tracers.This thesis focuses on tracing the human activities impact in the ferruginous compound of the suspended particulate matter (SPM) in the Seine River (France) using environmental magnetism tools.SPM sampling was conducted along the Seine path and its tributaries during different hydrological contexts. Magnetic properties were measured to characterize the ferruginous magnetic particles and to examine their relationship with the environment in which they have been formed.The main magnetic carrier is magnetite. It is concentrated in the fine sediment fraction and its magnetic properties can be used to trace the sediment load and hydrodynamic processes of the Seine.Increases in concentration and grain size of magnetite particles are associated to urbanization and industrial activities which are sources of anthropogenic particles. Significant variations can be observed between upstream and downstream of confluences and in the temporal scale and can be associated to hydrodynamic processes such as dilution, accretion, transport and re-suspension of the ferruginous particles.