A great number of field measurements with different methods and instruments were conducted in attempts to develop a method for an optimal combination of various geochemical and geophysical methods in archaeological prospecting. The research presented in this thesis focuses on a study of how different anthropogenic changes in the ground can be detected by geochemical and geophysical mapping and how the results can be presented. A six-year pilot project, Svealand in Vendel and Viking periods (SIV), was the beginning of this work in which EM- measurements, gradiometer and GPR surveys together with phosphate mapping succeeded in detecting settlements, mainly from the Iron Age. During the project, a new field kit for soil phosphate analysis was also developed and patented. Another major project was the examination of the Kings’ Mounds in Old Uppsala where a multi method survey including two different slingrams, three different types of GPR equipments and two different gradiometers was used for detecting structures inside the mounds. The Thing Mound was interpreted not to be a burial mound. The layers indicated by the GPR survey are most probably natural glaciofluvial layers. At the Eastern Mound the measurements detected an excavation tunnel from 1846-47, some known old brick furnaces from the time of building of the church, the original esker surface and the central cairn. The survey also detected two linear structures from the mounds base to the top and a depression under the mound in the old esker. The linear structures were interpreted as possible boulder rows and the depression as a possible older burial preceding the construction of the mound. Other surveys with slingram and GPR were used to detect subsurface features at historical gardens and historical glass works. A number of surveys to detect older church remnants were also carried out. In a project at Arethousa, Greek Macedonia, slingram measurements pointed out possible subsurface stonewalls and a possible hearth, which were confirmed later by excavations. At Old Uppsala, Sweden a GPR survey was successfully used for detecting the older cathedral under the present church. The overall results led to a recommended concept of combined methods for archaeological prospecting, especially in northern Europe. Slingram measurements of both electrical and magnetic components combined with phosphate mapping and GPR surveys proved to be useful methods for such prospecting.

<p>A great number of field measurements with different methods and instruments were conducted in attempts to develop a method for an optimal combination of various geochemical and geophysical methods in archaeological prospecting. The research presented in this thesis focuses on a study of how different anthropogenic changes in the ground can be detected by geochemical and geophysical mapping and how the results can be presented.</p><p>A six-year pilot project, Svealand in Vendel and Viking periods (SIV), was the beginning of this work in which EM- measurements, gradiometer and GPR surveys together with phosphate mapping succeeded in detecting settlements, mainly from the Iron Age. During the project, a new field kit for soil phosphate analysis was also developed and patented.</p><p>Another major project was the examination of the Kings’ Mounds in Old Uppsala where a multi method survey including two different slingrams, three different types of GPR equipments and two different gradiometers was used for detecting structures inside the mounds. The Thing Mound was interpreted not to be a burial mound. The layers indicated by the GPR survey are most probably natural glaciofluvial layers. At the Eastern Mound the measurements detected an excavation tunnel from 1846-47, some known old brick furnaces from the time of building of the church, the original esker surface and the central cairn. The survey also detected two linear structures from the mounds base to the top and a depression under the mound in the old esker. The linear structures were interpreted as possible boulder rows and the depression as a possible older burial preceding the construction of the mound.</p><p>Other surveys with slingram and GPR were used to detect subsurface features at historical gardens and historical glass works. A number of surveys to detect older church remnants were also carried out. In a project at Arethousa, Greek Macedonia, slingram measurements pointed out possible subsurface stonewalls and a possible hearth, which were confirmed later by excavations. At Old Uppsala, Sweden a GPR survey was successfully used for detecting the older cathedral under the present church.</p><p>The overall results led to a recommended concept of combined methods for archaeological prospecting, especially in northern Europe. Slingram measurements of both electrical and magnetic components combined with phosphate mapping and GPR surveys proved to be useful methods for such prospecting.</p>

Data storage in current hard disk drives is limited by three factors. These are thermal stability of recorded data, the ability to store data, and the ability to read back the stored data. An attempt to alleviate one factor can affect others. This ultimately limits magnetic recording densities that can be achieved using traditional forms of data storage. In order to advance magnetic recording and postpone these inhibiting factors, new approaches are required. One approach is recording on Bit Patterned Media (BPM) where the medium is patterned into nanometer-sized magnetic islands where each stores a binary digit.This thesis presents a statistical model of write errors in BPM composed of single domain islands. The model includes thermal activation in a calculation of write errors without resorting to time consuming micromagnetic simulations of huge populations of islands. The model incorporates distributions of position, magnetic and geometric properties of islands. In order to study the impact of island geometry variations on the recording performance of BPM systems, the magnetometric demagnetising factors for a truncated elliptic cone, a generalised geometry that reasonably describe most proposed island shapes, were derived analytically.The inclusion of thermal activation was enabled by an analytic derivation of the energy barrier for a single domain island. The energy barrier is used in a calculation of transition rates that enable the calculation of error rates. The model has been used to study write-error performance of BPM systems having distributions of position, geometric and magnetic property variations. Results showed that island intrinsic anisotropy and position variations have a larger impact on write-error performance than geometric variations.The model was also used to study thermally activated Adjacent Track Erasure (ATE) for a specific write head. The write head had a rectangular main pole of 13 by 40 nm (cross-track x down-track) with pole trailing shield gap of 5 nm and pole side shield gap of 10 nm. The distance from the pole to the top surface of the medium was 5 nm, the medium was 10 nm thick and there was a 2 nm interlayer between the soft underlayer (SUL) and the medium, making a total SUL to pole spacing of 17 nm. The results showed that ATE would be a major problem and that cross-track head field gradients need to be more tightly controlled than down-track. With the write head used, recording at 1 Tb/in² would be possible on single domain islands.

Este trabalho apresenta um método de inversão de perfis de dados magnetométricos em enxames de diques, utilizando os módulos de um programa desenvolvido no contexto do Mestrado. Os enxames de diques produzem padrões complexos de anomalia, dependendo da densidade de diques ao longo do perfil avaliado, das propriedades magnéticas de cada unidade e da existência de fontes mais rasas e profundas. Poucas técnicas se mostram eficazes em inverter dados em tal cenário, seja para recuperar parâmetros confiáveis para cada dique ou valores médios em casos mais complexos. O método inclui uma abordagem de inversão por etapas para modelos compostos por múltiplos prismas finos, identificados interativamente de acordo com a qualidade do ajuste aos dados. Na abordagem proposta, a intensidade do campo vetorial anômalo é inicialmente invertida para fornecer parâmetros geométricos (posição ao longo do perfil e profundidade do topo) e o produto da intensidade de magnetização pela espessura para as unidades do modelo. O modelo obtido é usado para inverter os dados de anomalia de campo total para se obter a inclinação de magnetização para cada prisma do modelo. Para perfis com poucos prismas (diques), essa abordagem revela-se eficaz na recuperação dos parâmetros verdadeiros para cada unidades do modelo. Para perfis com maior densidade de prismas, apenas valores médios de diferentes populações de diques podem ser recuperados. Isso é obtido aplicando uma abordagem por análise de grupo usando o algoritmo k-means, para soluções alternativas obtidas na inversão de dados. O método é testado com dados sintéticos gerados por configurações simples e complexas de prismas e interferências. Uma vez testado com simulações numéricas, o método é aplicado a um perfil do Enxame de Diques do Arco de Ponta Grossa. A análise de cluster de soluções alternativas identificou pelo menos três gerações para os diques neste perfil, de acordo com os parâmetros médios dos grupos. Os valores obtidos com a análise de grupos também foram utilizados para calcular a expansão crustal ao longo do perfil, chegando a valores entre 12 e 23%. Além disso, resultados de inversão foram analisados com poços da base de dados do Sistema de Informação de Águas Subterrâneas (SIAGAS) para avaliar a produtividade de poços com respeito à sua proximidade a unidades específicas de diques. Este estudo mostra que poços mais produtivos estão situados próximos de uma classe de diques mais rasos, conforme identificado pela análise k-means. Para poços perfurados em zona de influência dessa classe de diques em rochas cristalinas de alto grau metamórfico (tufos, meta-tufos), a produtividade é cerca de 14,5 vezes maior do que aqueles perfurados nas encaixantes. Para poços em zona de influência dessa classe de diques em rochas cristalinas de baixo grau metamórfico, a produtividade é cerca de 4,3 maior do que nas encaixantes. Um modelo conceitual para exploração de águas subterrâneas é apresentado levando-se em consideração a distribuição de diques mais rasos na região estudada. / This work presents a method of inversion of magnetometric data profiles in dyke swarms, using the modules of a program developed in the context of the Master. Dyke swarms produce complex patterns of anomalies, depending on the density of dikes along the evaluated profile, the magnetic properties of each unit and the existence of shallower and deeper sources. Few techniques prove effective in inverting data in such a scenario, either to retrieve reliable parameters for each dyke or average values in more complex cases. The method includes a stepwise inversion approach for multi-prism models that are interactively identified according to the quality of fit to the data. In the proposed approach, the intensity of the anomalous vector field is initially inverted to provide geometric parameters (position along the profile and depth of the top) and the product of the magnetization intensity by the thickness for the model units. The obtained model is used to invert the total field anomaly data to obtain the magnetization inclination for each prism of the model. For profiles with few prisms (dykes), this approach proves to be effective in recovering the true parameters for each model unit. For profiles with a higher density of prisms, only mean values of different dyke populations can be recovered. This is achieved by applying a group analysis approach using the k-means algorithm, for alternative solutions obtained in the inversion of data. The method is tested with synthetic data generated by simple and complex configurations of prisms and interferences. Once tested with numerical simulations, the method is applied to a profile of the Dike Swarm of the Ponta Grossa Arch. The cluster analysis of alternative solutions identified at least three generations for the dikes in this profile, according to the average parameters of the groups. The mean values obtained with the cluster analysis were also used to calculate the crustal expansion along the profile, reaching values between 12 and 23%. In addition, inversion results were analyzed with wells from the Groundwater Information System (SIAGAS) database to evaluate the productivity of wells with respect to their proximity to specific dyke units. This study shows that more productive wells are located near a class of shallower dikes, as identified by the k-means analysis. For wells drilled in a zone of influence of this class of dykes in crystalline rocks of high metamorphic degree (tufts, meta-tufts), the productivity is about 14.5 times greater than those drilled in the hosting rocks. For wells in the zone of influence of this class of dykes in crystalline rocks of low metamorphic degree, the productivity is about 4.3 higher than the ones in the hosting rocks. A conceptual model for groundwater exploration is presented considering the distribution of shallow dikes in the studied region.

The Limeira Intrusion is an occurrence related to the Mesozoic continental flood basalts of Paraná Magmatic Province, cropping out at the eastern São Paulo state. It is made up of basic- intermediate rocks with a great diversity of structures, textures, and modal compositions, related to the specific evolutionary process in a magma chamber. 2D forward modeling of magnetometric data, based on available aerial and newly obtained ground data integrated with in situ rock magnetic susceptibility measurements, were used to establish its geometry. The results, even considering intrinsic drawbacks of magnetometric theoretical models, are compatible with the geologic-based presumed intrusion geometry. In addition, the stratigraphic analysis of compositional and textural variations, coupled with the structural and geometric features, allowed the interpretation of its emplacement mechanism and thermal evolution. Quantitative textural analysis through crystal size distribution (CSD) of plagioclase crystals, the spatial distribution pattern of structures, microtextures, granulation, and rock-types, evidenced the internal heterogeneities of this occurrence. An approximately 110 m top-to-floor exposure section reveals that its internal heterogeneity was caused by non-instantaneous successive emplacement of three different magma injections. The textural analysis also reveals fine-grained crystals formed under different cooling paths, present in medium- to coarse- grained rocks within the intrusion, next to sharp contacts between different rock compositions. The contacts between different rocks are characterized by hybridization textures and by significant amounts of plumose granophyre-type and plumose plagioclase. The time lapse between consecutive pulses is responsible for a stepwise cooling-path, preservation of hybridization textures, and the development of almost rigid surfaces providing crystals alignment during magma flow. High-resolution Sr-isotopy data demonstrates a complex assembly history, possibly involving filter pressing of residual liquids, and pre-existent crystals before magma installation in coarse-grained rocks. It is also possible to recognize fewer amounts of country-rocks assimilation, which decreases towards the intrusion\'s core and can be associated with magma migration due to filter pressing processes. In the feeder zone, the evolution of emplacement was marked by an almost continuous decrease in wall-rock assimilation by the consecutive magma batches. / A intrusão de Limeira é uma ocorrência associada aos basaltos continentais Mesozoicos da Província Magmática do Paraná, aflorando na região leste do estado de São Paulo. Esta intrusão é composta por rochas básico-intermediárias que ocorrem com grande diversidade de estruturas, texturas e composições modais, relacionados aos mecanismos evolutivos específicos desta câmara. A modelagem magnetométrica bidimensional, baseado em aerolevantamentos disponíveis e dados recentes obtidos em campo e integrados às medidas de suscetibilidade magnética em rocha, foram utilizados para estabelecer sua geometria. Os resultados, mesmo considerando as desvantagens intrínsecas teóricas do método, são compatíveis com o modelo geológico presumido para esta intrusão. Adicionalmente, a análise das variações estratigráficas de composição e texturas, associados aos parâmetros estruturais e geológicos, permitiram a interpretação dos mecanismos de colocação e evolução térmica desta intrusão. Análises texturais quantitativas através da análise de distribuição de tamanho de cristais (DTC), a distribuição espacial de padrões estruturais, microtexturas, granulação e litotipos, evidenciam a heterogeneidade interna desta ocorrência. A seção de aproximadamente 110 metros de topo- a-base revela que sua heterogeneidade interna foi causada pela injeção sucessiva de pelo menos três pulsos magmáticos. Através da análise textural foram reconhecidos cristais de plagioclásio de granulação muito fina a fina presentes em rochas de granulação média a grossa, formados em diferentes razões de resfriamento e próximo ao contato abrupto entre rochas de diferentes composições. Estes contatos caracterizam zonas onde são reconhecidas texturas híbridas e são marcados pela presença e abundância de intercrescimentos granofíricos do tipo plumoso e plagioclásios plumosos. O espaço de tempo entre pulsos magmáticos consecutivos é responsável pela evolução térmica em etapas nesta intrusão, preservando as texturas de hibridização, e desenvolvendo superfícies com rigidez suficiente para promover o alinhamento de cristais de plagioclásio por fluxo magmático. Análises isotópicas demonstram um processo de colocação complexo para este corpo, possivelmente envolvendo a filtragem por pressão dos líquidos residuais da cristalização dos pulsos iniciais, além da existência de ante-cristais formados antes da instalação das rochas de granulação grossa. Também é possível reconhecer o processo de assimilação de uma pequena parcela das rochas encaixantes, principalmente pelas rochas das bordas, que decai para o centro da intrusão e é marcado pela migração dos líquidos residuais. Na zona de alimentação, a evolução da colocação é marcada pela diminuição do processo de assimilação pelos pulsos seguintes.

The Limeira Intrusion is an occurrence related to the Mesozoic continental flood basalts of Paraná Magmatic Province, cropping out at the eastern São Paulo state. It is made up of basic- intermediate rocks with a great diversity of structures, textures, and modal compositions, related to the specific evolutionary process in a magma chamber. 2D forward modeling of magnetometric data, based on available aerial and newly obtained ground data integrated with in situ rock magnetic susceptibility measurements, were used to establish its geometry. The results, even considering intrinsic drawbacks of magnetometric theoretical models, are compatible with the geologic-based presumed intrusion geometry. In addition, the stratigraphic analysis of compositional and textural variations, coupled with the structural and geometric features, allowed the interpretation of its emplacement mechanism and thermal evolution. Quantitative textural analysis through crystal size distribution (CSD) of plagioclase crystals, the spatial distribution pattern of structures, microtextures, granulation, and rock-types, evidenced the internal heterogeneities of this occurrence. An approximately 110 m top-to-floor exposure section reveals that its internal heterogeneity was caused by non-instantaneous successive emplacement of three different magma injections. The textural analysis also reveals fine-grained crystals formed under different cooling paths, present in medium- to coarse- grained rocks within the intrusion, next to sharp contacts between different rock compositions. The contacts between different rocks are characterized by hybridization textures and by significant amounts of plumose granophyre-type and plumose plagioclase. The time lapse between consecutive pulses is responsible for a stepwise cooling-path, preservation of hybridization textures, and the development of almost rigid surfaces providing crystals alignment during magma flow. High-resolution Sr-isotopy data demonstrates a complex assembly history, possibly involving filter pressing of residual liquids, and pre-existent crystals before magma installation in coarse-grained rocks. It is also possible to recognize fewer amounts of country-rocks assimilation, which decreases towards the intrusion\'s core and can be associated with magma migration due to filter pressing processes. In the feeder zone, the evolution of emplacement was marked by an almost continuous decrease in wall-rock assimilation by the consecutive magma batches. / A intrusão de Limeira é uma ocorrência associada aos basaltos continentais Mesozoicos da Província Magmática do Paraná, aflorando na região leste do estado de São Paulo. Esta intrusão é composta por rochas básico-intermediárias que ocorrem com grande diversidade de estruturas, texturas e composições modais, relacionados aos mecanismos evolutivos específicos desta câmara. A modelagem magnetométrica bidimensional, baseado em aerolevantamentos disponíveis e dados recentes obtidos em campo e integrados às medidas de suscetibilidade magnética em rocha, foram utilizados para estabelecer sua geometria. Os resultados, mesmo considerando as desvantagens intrínsecas teóricas do método, são compatíveis com o modelo geológico presumido para esta intrusão. Adicionalmente, a análise das variações estratigráficas de composição e texturas, associados aos parâmetros estruturais e geológicos, permitiram a interpretação dos mecanismos de colocação e evolução térmica desta intrusão. Análises texturais quantitativas através da análise de distribuição de tamanho de cristais (DTC), a distribuição espacial de padrões estruturais, microtexturas, granulação e litotipos, evidenciam a heterogeneidade interna desta ocorrência. A seção de aproximadamente 110 metros de topo- a-base revela que sua heterogeneidade interna foi causada pela injeção sucessiva de pelo menos três pulsos magmáticos. Através da análise textural foram reconhecidos cristais de plagioclásio de granulação muito fina a fina presentes em rochas de granulação média a grossa, formados em diferentes razões de resfriamento e próximo ao contato abrupto entre rochas de diferentes composições. Estes contatos caracterizam zonas onde são reconhecidas texturas híbridas e são marcados pela presença e abundância de intercrescimentos granofíricos do tipo plumoso e plagioclásios plumosos. O espaço de tempo entre pulsos magmáticos consecutivos é responsável pela evolução térmica em etapas nesta intrusão, preservando as texturas de hibridização, e desenvolvendo superfícies com rigidez suficiente para promover o alinhamento de cristais de plagioclásio por fluxo magmático. Análises isotópicas demonstram um processo de colocação complexo para este corpo, possivelmente envolvendo a filtragem por pressão dos líquidos residuais da cristalização dos pulsos iniciais, além da existência de ante-cristais formados antes da instalação das rochas de granulação grossa. Também é possível reconhecer o processo de assimilação de uma pequena parcela das rochas encaixantes, principalmente pelas rochas das bordas, que decai para o centro da intrusão e é marcado pela migração dos líquidos residuais. Na zona de alimentação, a evolução da colocação é marcada pela diminuição do processo de assimilação pelos pulsos seguintes.