En tant qu'événement parmi les plus puissants de l'histoire éruptive récente de Lombok, les matériaux volcaniques expulsés par le volcan Samalas en 1257 couvrent toute l'île de Lombok et sont largement répandus dans sa partie est. Près de 800 ans après l'éruption, l'impact géomorphologique de cette éruption sur l'île reste inconnu, alors que ses conséquences climatiques et sociétales globales sont désomais mieux comprises. Une combinaison des informations stratigraphiques, des topographies actuelles, des mesures géophysiques, des sources écrites locales, analyse de laboratoire et informatique ont été utilisées pour obtenir des informations détaillées sur les impacts géomorphologiques de l'éruption du volcan Samalas sur la zone côtière le long du détroit d' Alas, Nusa Tenggara Ouest, Indonésie. Cette étude fournit de nouvelles informations relatives à l'impact géomorphologique d'une éruption volcanique majeure dans des zones côtières, dans ce cas-ci, dans la partie est de Lombok, ainsi que sur la côte ouest de Sumbawa. En premier lieu, les résultats de l'étude montrent que le paysage de la partie est de Lombok est encore évolué jusqu'à présent. Le volume de matière volcanique de l'éruption des Samalas reste à environ 14% du volume initial. Deuxièmement, la découverte de Babad Suwung fournit une description supplémentaire de l'éruption des Samalas sur l'île de Sumbawa et pourraient être la plus ancienne observation visuelle de déferlantes pyroclastiques après celles de Pline Ie Jeune en 79 pour le Vésuve. Enfin, l'éruption du volcan Samalas en 1257 a prouvé avoir déclenché un tsunami mineur qui a frappé l'île de Belang, sur la côte ouest de Sumbawa. / As the most powerful event in Lombok’s recent eruptive history, volcanic materials thatwere expelled by the Samalas volcano in 1257 CE covered the entire of Lombok Islandand are widespread in its eastern part. Almost 800 years after the eruption, the geomorphological impact of this eruption on the island of Lombok remains unknown,whereas its overall climatic and societal consequences are now better understood. Acombination of stratigraphic information, present-day topography, geophysical measurement with two-dimensional resistivity profiling technique, local written sources,as well as laboratory and computational analysis, were used to obtain detailed information concerning geomorphic impacts of the 1257 CE eruption of Samalas volcano on the coastal area along the Alas Strait in West Nusa Tenggara Province, Indonesia. This study provides new information related to the geomorphic impact of amajor eruption volcanic in coastal areas, in this case, on the eastern part of Lombok and the western coast of Sumbawa. In the first place, the study result shows that since the 1257 CE eruption, the landscape on the eastern part of Lombok is still evolved untilthe present time. The volume of the 1257 CE volcanic material remains about 14% from the initial volume. Secondly, the discovery of Babad Suwung provides additional explanation of Samalas eruption and may become the oldest visual observation of pyroclastic surges and volcanic fallout, following those by Pliny the Younger in 79 CE. Finally, the 1257 CE eruption of Samalas volcano has proven triggered a minor tsunami that hit Belang Island, on the west coast of Sumbawa.

<div><div><div><p>The radionuclide 10Be is produced in the atmosphere and is delivered to Earth’s surface in meteoric rain and aerosols. The stable nuclide 9Be is present in trace concentrations within rocks in Earth’s crust and is released via chemical weathering. Together, these two isotopes have been employed to study a wide range of Earth processes. Here I explore new terrestrial archives of Be isotopes: cave speleothems and terrestrial Mn-oxides. Until this point, these archives have barely been studied. Only one published dataset of Be isotopes in cave speleothems exists (Lundblad, 2006), and to my knowledge, terrestrial manganese oxides are yet to be explored. However, since speleothems and Mn-oxides precipitate from groundwater, they have the potential to encode temporal variations in the 10Be/9Be ratio of water and colloids in the vadose zone.</p><p>I develop a framework for using the 10Be/9Be ratio in the dissolved phase and/or secondary weathering products as a metric of chemical weathering rate. I am motivated by several over-arching questions:</p><ol><li><p>1) Which factor, or factors, is/are dominant in controlling Be isotopes in speleothems and terrestrial Mn-oxides?</p></li><li><p>2) Can Be isotopes in speleothems be used as a metric of weathering rate over time, particularly across glacial/interglacial cycles?</p></li><li><p>3) Can Be isotopes be used to date the formation of terrestrial Mn-oxides?</p></li></ol><p>I measure Be-isotope concentrations in speleothems from Soreq Cave, Israel. By applying an equation that I derive in this thesis, I use the temporal variation in the speleothem10Be/9Be ratio to calculate chemical weathering rates over the last 168 ka. Chemical weathering varies with independent proxies for temperature. The weathering-temperature relationship can be fit to an Arrhenius relationship, and the calculated activation energy (Ea) matches other field-based estimates for feldspar, an abundant mineral in the soil above the cave. In the Appendices I present additional results of Be-isotope measurements in a flowstone from Buffalo Cave in South Africa, as well as Mn-oxides from the Appalachians.</p></div></div></div>

The post-orogenic history of the Appalachian Mountains, particularly the persistence of rough topography and the degree of river incision throughout the region, has been a longstanding focus of geomorphology studies. Numerous models have been developed to explain the evolution of this landscape, variously invoking episodic or continuous processes of uplift and erosion to drive the generation or reduction of topographic relief. Recently, late Cenozoic uplift has found favor as a mechanism for rejuvenating the topography of the southern and central Appalachians. This hypothesis has drawn on longitudinal river profiles, seismic tomography, and offshore sediment records as evidence of Neogene uplift.<div><br></div><div>Radiometric dating of surficial deposits provides a means to directly test models of episodic and continuous landscape evolution, as well as the Neogene uplift hypothesis. The research described in this thesis dates surficial sediments (river terraces, alluvial fans, and a filled sinkhole) and supergene manganese oxides using 26Al/10Be burial dating and 40Ar/39Ar geochronology, respectively. Our cosmogenic 26Al/10Be dating provides detailed histories of aggradation and incision along the Shenandoah and Tennessee Rivers since the early Pliocene. 40Ar/39Ar dating of manganese oxides permits estimates of surface preservation and denudation in the Shenandoah Valley and nearby watersheds throughout the Cenozoic.<br></div><div><br></div><div>The results of our work in the Shenandoah Valley, Tennessee River basin, and intervening areas indicate that the Appalachians experienced no significant pulse of uplift during the Cenozoic. Long-term preservation of supergene manganese oxides dates as far back as the Eocene, demonstrating minimal denudation and discontinuous formation that lend evidence to episodic landscape evolution models. Cosmogenic26Al/10Be burial ages along the Shenandoah and Tennessee Rivers reveal Pliocene aggradation, with enhanced deposition in the Shenandoah Valley during the mid-Piacenzian Warm Period. Both rivers likely experienced incision during the Pleistocene, likely due to climatic fluctuations. These results demonstrate that while the Appalachian landscape has remained largely unchanged for tens of millions of years, rapid Pleistocene changes in base level recently triggered significant incision of major drainages.<br></div>

[pt] O processo de voçorocamento é apontado em muitas pesquisas como consequência do uso do solo, sobretudo da ação antrópica. Entretanto, no médio vale do rio Paraíba do Sul (RJ/SP), tem se observado que áreas sob o mesmo tipo de cobertura e uso do solo apresentam comportamentos diferentes quanto a ocorrência de voçorocas, indicando que existem outros fatores que determinam, de forma mais intensa, a ocorrência desse processo. Desta forma, esse trabalho se propôs a investigar os fatores que podem influenciar a distribuição diferencial do processo de voçorocamento nesta paisagem. Foram selecionadas as bacias mais próximas à calha principal do rio Paraíba do Sul e foram plotadas (em imagem de satélite, com método de fotointerpretação) todas as voçorocas identificadas nesta área. A distribuição espacial de voçorocas foi comparada com outros dados da região (unidades litológicas, cobertura e uso e aspectos morfométricos do relevo). Ao todo foram plotadas 671 voçorocas. Destas 671, 99 (14,7 por cento) foram identificadas como resultado de cortes de estrada e 572 (85,3 por cento) sem apararente relação direta com os cortes de estrada. O resultado da análise evidenciou a predominância deste processo sobre a unidade metassedimentar do gnaisse Paraíba do Sul, caracterizado por um material bastante friável quando decomposto. Além disso, a proximidade da calha principal do rio Paraíba do sul também exerce influência como nível de base regional, determinando o limite do processo erosivo. / [en] Gully erosion have been indicated in many researches as a consequence of the use of land use and land cover. However, it has been observed, in middle Paraíba do Sul river valley, that areas on the same type of current and past land use cover presents different behaviors regarding the occurence of gullies. This indicates that there are other factors that determine the occurenc of this process. The factors that may influence the diferencial distribution of the gully erosion process in this landscape were investigated. Initially, the watersheds closest to the main waterway of the Paraíba do Sul river were selected and all gullies were identified in this área. The spatial distribution of gullies was compared with other data of the region (lithologic units structure, land use cover and morphometric aspects of relief). In all, 671 gullies were plotted. Of these 671, 99 (14,7 percent) were identified as resulto f roads, and 572 (85,3 percent) with no apparent direct relation to this. The result of the analysis evidenced that the predominance of gully erosion is on the metassedimentary lithologic unit of the Paraiba do Sul gneiss. This lithologic unit is characterized by a very friable material when decomposed. In addition, the proximity of the main channel of the Paraiba do Sul river also exerts influences as a regional base level, determining the limit of the erosive process.

This dissertation combines studies of aeolian bedforms and aeolian dune-field patterns to create a comprehensive set of tools that can be used in tandem (or separately) to extract information about climate change and landscape evolution, and to identify the controls on formation for specific modern dune fields or ancient aeolian sequences. The spatial distribution of surface processes, erosion/deposition rates, and lee face sorting on aeolian dunes are each a function of the incident angle. This correlation between stratification style and incidence angle can be used to develop a “toolbox” of methods based on measurements of key suites of parameters found in ancient aeolian deposits. Information obtained from the rock record can be used as input data for different kinds of numerical models. Regional-scale paleowind conditions can be used to validate paleoclimate and global circulation models. Understanding the natural variability in the Earth’s climate throughout its history can help predict future climate change. Reconstructed wind regimes and bedform morphologies can be used in numerical models of aeolian dune-field pattern evolution to simulate patterns analogous to those reconstructed from ancient aeolian systems. Much of the diversity of aeolian dune-field patterns seen in the real world is a function of the sediment supply and transport capacity, which in turn determine the sediment availability of the system. Knowledge of the sediment supply, availability, and transport capacity of aeolian systems can be used to predict the amount of sand in the system and where it might have migrated. This information can be extremely useful for development and production of oil and gas accumulations, where a discovery has been made but the spatial extent of the aeolian reservoir is unknown. / text

[pt] A superfície da terra é formada por processos geológicos que geram as rochas, assim como por processos naturais de degradação e de erosão. A erosão destrói as estruturas que compõem o solo e seu transporte é feito pela ação da água da chuva, do vento, da gravidade e até do gelo. A origem e evolução das bacias sedimentares, dentre outros fenômenos, é estudada pela geologia sedimentar, a qual trata do estudo dos processos físicos, químicos e biológicos atuantes na superfície da terra desde o seu início até os dias atuais. Na atualidade, o uso de modelos que permitem analisar processos de escoamento superficial, desprendimento de partículas e de transporte e deposição de sedimentos em bacias hidrográficas é cada vez mais frequente. O uso e análise desses modelos demonstra que, para escalas relativamente pequenas e áreas não muito extensas, o rebaixamento do perfil dos rios está diretamente ligado aos processos de deformação tectônica. Por outro lado, modelos de previsão de evolução do relevo associados com intemperismo, erosão e deposição de sedimentos, considerando escalas espaciais do tipo regional ou continental e escalas de tempo relativamente grandes (maior que 10(5) anos) devem ser desenvolvidos acoplando tanto efeitos tectônicos como morfológicos. Neste trabalho é apresentado um modelo computacional que permite analisar a evolução na mudança do relevo de bacias hidrográficas, em pequena e grande escala, assim como estimar a produção de sedimento resultante do processo erosivo. O algoritmo de análise é escrito na linguagem de programação Cmais mais e considera a simulação de diferentes cenários, que incluem deformação tectônica, processos de encosta (difusão e movimentos de massa) e processos de incisão fluvial, dando-se particular atenção à formação e evolução da rede fluvial de drenagem. Para a análise de resultados, o programa oferece a visualização 3D de diferentes superfícies: distribuição dos sedimentos, evolução da rede fluvial, mudanças topográficas do relevo, etc. / [en] The surface of the earth is formed by geological processes that originate the rocks, as well as for natural processes of degradation and erosion. The erosion destroys the soil structures and the transport of sediments is made by the action of the rain water, wind, gravity and, in some cases, ice. The origin and evolution of sedimentary basins, amongst other phenomena, are studied by the sedimentary geology, which deals with the analysis of physical, chemical and biological processes that act directly on earth surface since its origin until the current days. Nowadays, the use of runoff - erosion models that analyze processes such as detachment of particles and transport and deposition of sediment in drainage basins is every time more frequent. The use of these models demonstrates that, for relatively small scales and not very extensive areas, relief changes are directly related to tectonic processes. On the other hand, landscape evolution models and associated weathering, erosion and deposition with parameterization for regional or continental spatial scales and large time scales (more than 10(5) years), must be developed to adequately couple tectonics and geomorphology. Is presented in this work a computational model to analyze the landscape evolution in hydrographic basins, considering small and large scales, as well as evaluate the production of sediment resultant of the erosive process. The algorithm is written in the programming language C++ and considers the simulation of different scenes, that include tectonics, hillslope processes (diffusion and landslides) and bedrock incision, giving particular attention to the channel network evolution. For the analysis process the program offers the visualization of different 3D surfaces: sediment distribution, drainage network, topographical relieves etc.

Made available in DSpace on 2015-02-24T19:48:44Z (GMT). No. of bitstreams: 1 SilvanaPPG_TESE_pag119_final.pdf: 4384081 bytes, checksum: f4e3889e03bd2b77ef4e8f1b271723a8 (MD5) Previous issue date: 2012-08-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The Northeast relief was described by the Pediplanation Model. This action discards the theoretical basis of post-Cretaceous tectonic evolution of the landscape. Through this model the Massif Pereiro - MP, Borborema Province, was established as part of the Tablelands Area Residual Sertanejos. The present work aims to establish the post- Cretaceous morphotectonic evolution of the MP by geomorphological and geological mapping using Geographic Information System, Remote Sensing and dating of sediments by Single Aliquot Regenerative-dose (SAR). The MP is contained in the core semi-arid, annual precipitation of 600-800 mm / year. The MP is NE-SW, is limited by Shear Zone Jaguaribe (ZCJ) and Portalegre Shear Zone (ZCPa), the same attitude, and crossed by several other shear zones. These shear zones show evidence of brittle Cenozoic reactivation, mostly as normal faults and shallow crustal level. The Quaternary sedimentation around the MP focuses on fault escarpments in a general pattern cascade, where ages decrease from the summits of the steep foothills. The ages of 51 sediment samples indicate a correlation with global climate following pulses: Last Interestadial-UI, the Last Glacial Maximum - LGM and the transition Pleistocene / Holocene, while the latter focus on 18 of 51 samples dated. This study also finds evidence of a new quaternary basin, here called Merejo Basin. Through these results it is concluded that no evidence of post-Cretaceous tectonic evolution of morphological MP, as their retreat along the fault scarps, invariably following the trend of the shear zones. The erosion of cliffs in large time scale is controlled by weakness zones generated by faults on the other hand the erosion of cliffs in short time, with the formation of deposits and colluvial horizons pedogenizados, has climate control. It was also found that in the study area there is a preponderance of past and current tectonic erosion processes on the morphological evolution / O relevo do Nordeste foi descrito por meio do modelo de pediplana??o. Esta base te?rica descarta a atua??o da tect?nica p?s-cret?cea na evolu??o da paisagem. Atrav?s deste modelo o Maci?o do Pereiro MP, Prov?ncia Borborema, foi definido como parte do Dom?nio dos Planaltos Residuais Sertanejos. O presente trabalho tem por objetivo estabelecer a evolu??o morfotect?nica p?s-cret?cea do MP, atrav?s da cartografia geol?gica e geomorfol?gica com uso de Sistema de Informa??o Geogr?fica, Sensoriamento Remoto e data??o de sedimentos por Single Aliquot Regenerative-dose (SAR). O MP est? contido no n?cleo semi?rido, de precipita??o anual entre 600 a 800 mm/ano. O MP tem dire??o NE-SW, ? limitado pela Zona de Cisalhamento de Jaguaribe (ZCJ) e Zona de Cisalhamento Portalegre (ZCPa), de mesma atitude, e atravessado por v?rias outras zonas de cisalhamento. Estas zonas de cisalhamento apresentam evid?ncias de reativa??o fr?gil cenozoica, na sua maioria como falhas normais e de n?vel crustal raso. A sedimenta??o quatern?ria em torno do MP se concentra em escarpas de falhas, em um padr?o geral em cascata, onde as idades diminuem das cimeiras aos sop?s das escarpas. As idades de 51 amostras de sedimentos indicam correla??o com seguintes pulsos clim?ticos globais: ?ltimo Interestadial- UI, o ?ltimo M?ximo Glacial - UMG e a transi??o Pleistoceno/Holoceno, sendo que nesta ?ltima concentram-se 18 das 51 amostras datadas. O presente trabalho tamb?m encontra evid?ncias de uma nova bacia quatern?ria, aqui denominada de Bacia Merejo. Atrav?s destes resultados conclui-se que h? evidencia de tect?nica p?s-cret?cea na evolu??o morfol?gica do MP, pois as suas escarpas recuam paralelamente ?s falhas, seguindo invariavelmente o trend das zonas de cisalhamento. A eros?o das escarpas em grande escala de tempo ? controlada pelas zonas de fraqueza geradas pelos falhamentos, por outro lado ? eros?o das escarpas em curtos espa?os de tempos, com a forma??o dos dep?sitos coluvionares e horizontes pedogenizados, possui controle clim?tico. Concluise ainda que na ?rea de estudo haja a preponder?ncia da tect?nica pret?rita e atual sobre os processos erosivos na evolu??o morfol?gica

<p>Understanding climate-driven changes in global land-based ice volume is a critical component in our capability to predict how global sea level will rise as a consequence of the current human-driven climate change. At the last glacial maximum (LGM, which peaked around 20 ka), ephemeral ice sheets covered vast regions of the northern hemisphere while both the Greenland and Antarctic ice sheets were more extensive than at present. As global temperatures rose at the transition into the Holocene, driving the LGM deglaciation, eustatic sea level rose by approximately 125 m. The east Antarctic ice sheet (EAIS) is the largest ice sheet on Earth today, holding an ice volume equivalent to ca. 53 m rise in global sea level. Considering current trends in global climate, specifically rapidly increasing atmospheric CO₂ levels and global temperature, it is important to improve our understanding of how the EAIS will respond to global warming so that we can make better predictions of future sea level changes to guide community adaptation and planning efforts. Numerical ice sheet models which inform projections of future ice volume changes, and can, therefore, yield projections of sea level rise, rely on empirical data to test their ability to accurately represent former and present ice configurations. However, there is a general lack of data on the paleoglaciology of the EAIS along the western Dronning Maud Land (DML) margin. In order to address this situation, the paleoglaciology of western DML forms the focus of the work presented in this thesis.</p><p><b> </b></p><p>Together with collaborators within the MAGIC-DML consortium (Mapping, Measuring and Modelling Antarctic Geomorphology and Ice Change in Dronning Maud Land) that provides the funding for this MS project, the author has performed geomorphological mapping across western DML; an area of approximately 200,000 km². The results of the mapping presented in this thesis will provide the basis for a detailed glacial reconstruction of the region. The geomorphological mapping was completed almost entirely by remote sensing using very high-resolution (sub-meter in the panchromatic) WordView-2 and WorldView-3 (WV) satellite imagery, combined with ground validation studies during field work. Compared to Landsat products, the improved spatial resolution provided by WV imagery has fundamentally changed the scale and detail at which remote sensing based geomorphological mapping can be completed. The mapping presented here is focused on the glacial geomorphology of mountain summits and flanks that protrude through the ice sheet’s surface (nunataks). In our study area of western DML these nunatak surfaces make up <0.2 % of the total surface area, and the landforms mapped here are generally smaller than can be identified from Landsat products (30 m spatial resolution). The detail achieved in our mapping, across such a vast, remote area that presents numerous obstacles to accessibility highlights the benefits of utilizing the new VHR WV data. As such an evaluation of the WV data, as applied to geomorphological mapping is presented here together with our mapping of the glacial geomorphology of western DML. The results of which provides evidence of ice having overridden sites at all elevations across the entire study area; from the highest elevation inland nunataks that form the coast-parallel escarpment, to low-elevation emerging nunataks close to the coast. Hence from our studies of the glacial geomorphology of this region we can ascertain that, at some point in the glacial history of western DML, ice covered all of the mountain summits that are exposed today, indicating an ice sheet surface lowering of up to 700 m in some places.</p>

The Western Mediterranean realm is considered as a region highly sensitive with regard to climate changes and landscape transformations. Within its semi arid and semi humid areas, even slight climatic changes but also human interventions may result in far-reaching consequences in respect of environment and ecological systems. Thus, research on landscape development has a high relevance in geosciences, especially in the light of current climate change research. It is a major concern to reveal regularities and patterns in past landscape evolution in order to provide a basis for the assessment of future developments. For the reconstruction of late Quaternary environmental conditions fluvial sediments play an important role as they almost uniquely reflect landscapes and landscape changes on a regional scale. This is due to the fact that fluvial dynamics and all enclosed processes are based on multi-causal relationships and a variety of factors like climatic conditions, vegetation development, human impact, or tectonic activity finds expression in fluvial dynamics. About 70 % of the Iberian Peninsula is influenced by moist Atlantic air masses, but in the whole area there is a considerable research gap concerning the exploration of fluvial archives. Taking this into account, this dissertation aims to systematically work out fluvial sediment successions of two river systems, namely the Jarama River in central Spain and the Guadalete River in southwestern Spain. For complementary considerations, first stratigraphic results from the middle to lower Guadalquivir River in southern Spain will be consulted. In a first step, the objective is to intensively study and document sediment profiles for the purpose of deriving a valuable composite profile for each river system. In a second step, the significance of these composite profiles regarding palaeoenvironmental conditions as well as changes will be examined. Beside the reaction of fluvial systems towards climatic changes, relationships with other influencing factors are a main issue. On the basis of a supra-regional comparison a possible coupling of fluvial geomorphic systems and large-scale climate fluctuations shall be analyzed. Furthermore, it is intended to address issues like system connectivity or varying response times and response durations. The bases for these considerations are abundant sedimentary profile records supported by electrical resistivity tomography and percussion drillings. Stratigraphic work includes the differentiation of sediment units, the identification of soil horizons, and the correlation of specific layers and horizons across different profile sections based on sedimentologic and pedogenetic characteristics. Subsequent soil-chemical and sedimentological laboratory analyses on certain key-profiles imply grain-size analyses, the measurement of organic carbon content, calcium carbonate content, pedogenic and total iron contents, as well as magnetic susceptibility. Laboratory analyses are used to strengthen results of field work and to differentiate between soils and soil sediments in ambiguous cases. The chronological resolution of the sediment successions will be provided by radiocarbon dating. The final aim is to work out a detailed fluvial sedimentation history for the late Quaternary. The precise characterization of the catchment areas, together with a comparison of the stratigraphic findings and secondary archive information from the literature, will enable the identification of relationships between fluvial dynamics and different influencing factors. In this dissertation, 36 profile sections have been worked out intensively. Furthermore, 13 percussion drillings were conducted in floodplain positions with insufficient exposure conditions. For the chronological frame 70 radiocarbon samples have been dated. The obtained results show a significant pattern of sedimentation periods and phases of stability associated with soil formation for each river system. The sedimentation history of the Guadalete and Guadalquivir Rivers could be reconstructed for the last 15 ka, while conclusions with regard to sedimentation dynamics of the Jarama River could be drawn for a period of 43 ka. Thanks to an abundance of available studies on other terrestrial archives with climatic or environmental relevance, it was possible to assess the influence of different parameters such as climate, vegetation, humankind, tectonics, and base-level changes on fluvial sedimentation dynamics. It emerged that, first and foremost, rapid climate changes had significant impact on the mobilization of sediments in the catchment area as well as their deposition in floodplain positions. On the other hand prolonged periods of climatic amelioration caused floodplain stability along with soil formation, as documented for the time spans between 13.3 and 12.7 ka, 7 and 5.1 ka, 2.8 and 2.3 ka, 1.4 and 1.2 ka, as well as 0.8 and 0.5 ka cal. BP in several river systems. Periods of increased sedimentation were initiated by phases of climatic aridification that affected fluvial systems through the weakening of the vegetation cover and the accentuation of the hydrological discharge regime. Corresponding patterns have been found for the time intervals between 8 and 7 ka, 5 and 3.8 ka, 2.2 and 1.5 ka, as well as around 1 ka and 0.4 ka cal. BP. The supra-regional effectiveness of the factor climate is contrasted by a strong regional individuality of the river catchments that is expressed by further, regionally limited phases of fluvial activity. Crucial to this development – apart from regional climate differences – are, inter alia, tectonic movements as evidenced for the Jarama River system in central Spain, or late Pleistocene and Holocene sea-level fluctuations that primarily affected fluvial dynamics along the lower course of the Guadalete River in southwestern Spain. Furthermore, it can be shown that variations in time and duration of fluvial system response are attributable to differing buffer capacities of river catchments towards external influences. The increase of human impact during the late Holocene apparently provoked a reinforcement of the effects of climatic impulses. There are clear evidences for the participation of humans in the mobilization of sediments; however, concerning the degree of influence it is hardly possible to differentiate between the factors humans and climate. / Der westliche Mediterranraum gilt als landschaftlich und klimatisch hochsensible Region, für deren semiaride bis semihumide Gebiete bereits kleinere klimatische Änderungen, aber auch Eingriffe des Menschen, mit weitreichenden Folgen für Umwelt und ökologische Systeme verbunden sein können. Forschungen zum Landschaftswandel nehmen hier vor allem vor dem Hintergrund des derzeitigen Klimawandels einen hohen Stellenwert in den Geowissenschaften ein. Ein wichtiges Anliegen ist dabei, in früheren Landschaftswandeln Muster zu entdecken, welche als Grundlage für Bewertungen zukünftiger Veränderungen dienen können. Für die Rekonstruktion spätquartärer Umweltbedingungen kommt fluvialen Sedimenten eine besondere Rolle zu. Wie kein anderes Archiv spiegeln fluviale Sedimentabfolgen Landschaftszustände und -entwicklung auf regionaler Ebene wieder. Dies ist dem Umstand geschuldet, dass fluviale Dynamik mit allen inbegriffenen Prozessen auf polykausalen Zusammenhängen beruht und somit eine Vielzahl an Faktoren, wie klimatische Verhältnisse und Vegetationsentwicklung, menschliche Einflussnahme oder tektonische Aktivität Ausdruck in fluvialer Dynamik finden. Von feuchten atlantischen Luftmassen geprägte Gebiete nehmen etwa 70 % der Fläche der Iberischen Halbinsel ein, allerdings besteht hier eine erhebliche Forschungslücke im Bereich der Analyse fluvialer Archive. Diesem Umstand soll in vorliegender Dissertation in Form einer systematischen Aufarbeitung der fluvialen Sedimentabfolgen zweier Flusssysteme in Zentralspanien (Rio Jarama), sowie in SW-Spanien (Rio Guadalete) Rechnung getragen werden. Für ergänzende Betrachtungen werden dabei erste Befunde zur stratigraphischen Gliederung des Guadalquivir-Mittellaufes in S-Spanien herangezogen. Ziel der Arbeiten ist es zunächst über umfangreiche Aufnahmen und Dokumentationen von Sedimentprofilen ein belastbares Standardprofil für jedes Flusssystem zu erarbeiten und dieses hinsichtlich der Aussagekraft in Bezug auf Paläoumweltbedingungen und vor allem -wandeln zu prüfen. Neben der möglichen Reaktion fluvialer Systeme auf klimatische Änderungen, stehen dabei vor allem auch Beziehungsgeflechte zu anderen Einflussfaktoren im Vordergrund. Anhand eines überregionalen Vergleichs soll eine mögliche Kopplung fluvialmorphologischer Systeme an großräumige Klimafluktuationen untersucht werden, zudem soll weiteren Themenkomplexen, wie der Konnektivität verschiedener Systeme oder unterschiedlichen Reaktionszeiten und -geschwindigkeiten nachgegangen werden. Grundlage für diese Betrachtungen bilden dabei aus zahlreichen Geländeaufnahmen resultierende Profilaufnahmen, sowie Ergebnisse geoelektrischer Messungen und Bohrsondierungen. Stratigraphische Arbeiten belaufen sich zunächst auf die Untergliederung verschiedener Sedimenteinheiten, die Ausweisung von Bodenhorizonten, sowie die Korrelation einzelner Schichten und Horizonte über unterschiedliche Profile hinweg anhand charakteristischer sedimentologischer und pedogenetischer Merkmale. Nachfolgende bodenchemische und sedimentologische Laboruntersuchungen an ausgewählten Profilen sollen über die Bestimmung von Korngrößenverhältnissen, Gehalten an organischem Kohlenstoff, Kalk- und Eisengehalten, sowie der magnetischen Suszeptibilität die Geländebefunde stützen und in unklaren Fällen eine Unterscheidung von Böden und Bodensedimenten erleichtern. Die zeitliche Auflösung der Sedimentabfolgen soll über Radiokarbondatierungen realisiert werden, mit dem letztendlichen Ziel, eine detaillierte fluviale Sedimentationsgeschichte für das Spätquartär zu erarbeiten. In einem weiteren Schritt werden begleitend zu einer detaillierten Einzugsgebietscharakteristik die chronostratigraphischen Befunde einem intensiven Vergleich mit in der Literatur verfügbaren Studien an Sekundärarchiven zugeführt, um Beziehungsgeflechte zwischen fluvialer Dynamik und verschiedenen Einflussfaktoren aufzudecken. Im Rahmen dieser Dissertation konnten zunächst 36 Profilaufschlüsse detailliert bearbeitet und zudem 13 Rammkernsondierungen in Flussauenpositionen abgeteuft werden. Für den chronologischen Rahmen wurden 70 Radiokohlenstoffproben datiert. Die Ergebnisse zeigen ein deutliches Muster von Sedimentationsphasen und Zeiten der Stabilität mit einhergehender Bodenbildung für jedes Flusseinzugsgebiet. Dabei konnte die Sedimentationsgeschichte der Flusssysteme Rio Guadalete und Rio Guadalquivir für die letzten 15.000 Jahre und des Rio Jarama für die letzten 43 ka rekonstruiert werden. Dank der Fülle an verfügbaren Studien an terrestrischen Vergleichsarchiven mit klima- und umweltrelevantem Bezug war es möglich, den Einfluss der unterschiedlichen Parameter Klima, Vegetation, Mensch und Tektonik, bzw. Erosionsbasis auf die fluviale Sedimentationsdynamik zu prüfen. So zeigte sich, dass vor allem rasche Klimaänderungen in der Lage waren die Mobilisierung von Sedimenten im Einzugsgebiet und deren Ablagerung in den Flussauen zu initiieren. Dahingegen bewirkten anhaltende klimatische Gunstphasen eine Stabilisierung mit einhergehender Bodenbildung, wie für die Zeiträume zwischen 13.3 und 12.7 ka, 7 und 5.1 ka, 2.8 und 2.3 ka, 1.4 und 1.2 ka, sowie 0.8 und 0.5 ka cal. BP für sämtliche Flusssysteme zu verzeichnen ist. Perioden verstärkter Sedimentation folgten in der Regel Phasen klimatischer Aridifizierung, welche über eine Schwächung der Vegetationsbedeckung und Akzentuierung des hydrologischen Abflussregimes in der Lage waren auf das fluviale System Einfluss zu nehmen. Entsprechende Muster konnten für die Zeiträume zwischen 8 und 7 ka, 5 und 3.8 ka, 2.2 und 1.5 ka, sowie um 1 ka als auch 0.4 ka cal. BP dokumentiert werden. Dem überregional wirksamen Einfluss des Faktors Klima steht jedoch eine starke landschaftsgeschichtliche Individualität der verschiedenen Regionen gegenüber, welche in weiteren, regional begrenzten Phasen fluvialer Aktivität zum Ausdruck kommt. Ausschlaggebend sind hier neben der Ausbildung regionaler Klimaunterschiede unter Anderem tektonische Verstellungen, welche für das in Zentralspanien gelegene System des Rio Jarama belegt werden konnten, oder spätpleistozäne und holozäne Meeresspiegelschwankungen, welche sich vor allem auf die fluviale Dynamik im Unterlauf des in SW-Spanien gelegenen Rio Guadalete auswirkten. Desweiteren können Unterschiede in Reaktionsdauer und -geschwindigkeit fluvialer Systeme mit variierendem Puffervermögen der Flusseinzugsgebiete gegenüber äußeren Einflüssen erklärt werden. Das intensivierte Wirken des Menschen im Spätholozän führte allem Anschein nach zu einer Verstärkung der Wirkung klimatischer Impulse, wobei sich klare Evidenzen für eine Beteiligung des Menschen an der Sedimentmobilisierung erkennen lassen, der Umfang des Einflusses des Menschen aber in der Regel nicht klar von dem des Klimas zu trennen ist.

The Western Mediterranean realm is considered as a region highly sensitive with regard to climate changes and landscape transformations. Within its semi arid and semi humid areas, even slight climatic changes but also human interventions may result in far-reaching consequences in respect of environment and ecological systems. Thus, research on landscape development has a high relevance in geosciences, especially in the light of current climate change research. It is a major concern to reveal regularities and patterns in past landscape evolution in order to provide a basis for the assessment of future developments. For the reconstruction of late Quaternary environmental conditions fluvial sediments play an important role as they almost uniquely reflect landscapes and landscape changes on a regional scale. This is due to the fact that fluvial dynamics and all enclosed processes are based on multi-causal relationships and a variety of factors like climatic conditions, vegetation development, human impact, or tectonic activity finds expression in fluvial dynamics. About 70 % of the Iberian Peninsula is influenced by moist Atlantic air masses, but in the whole area there is a considerable research gap concerning the exploration of fluvial archives. Taking this into account, this dissertation aims to systematically work out fluvial sediment successions of two river systems, namely the Jarama River in central Spain and the Guadalete River in southwestern Spain. For complementary considerations, first stratigraphic results from the middle to lower Guadalquivir River in southern Spain will be consulted. In a first step, the objective is to intensively study and document sediment profiles for the purpose of deriving a valuable composite profile for each river system. In a second step, the significance of these composite profiles regarding palaeoenvironmental conditions as well as changes will be examined. Beside the reaction of fluvial systems towards climatic changes, relationships with other influencing factors are a main issue. On the basis of a supra-regional comparison a possible coupling of fluvial geomorphic systems and large-scale climate fluctuations shall be analyzed. Furthermore, it is intended to address issues like system connectivity or varying response times and response durations. The bases for these considerations are abundant sedimentary profile records supported by electrical resistivity tomography and percussion drillings. Stratigraphic work includes the differentiation of sediment units, the identification of soil horizons, and the correlation of specific layers and horizons across different profile sections based on sedimentologic and pedogenetic characteristics. Subsequent soil-chemical and sedimentological laboratory analyses on certain key-profiles imply grain-size analyses, the measurement of organic carbon content, calcium carbonate content, pedogenic and total iron contents, as well as magnetic susceptibility. Laboratory analyses are used to strengthen results of field work and to differentiate between soils and soil sediments in ambiguous cases. The chronological resolution of the sediment successions will be provided by radiocarbon dating. The final aim is to work out a detailed fluvial sedimentation history for the late Quaternary. The precise characterization of the catchment areas, together with a comparison of the stratigraphic findings and secondary archive information from the literature, will enable the identification of relationships between fluvial dynamics and different influencing factors. In this dissertation, 36 profile sections have been worked out intensively. Furthermore, 13 percussion drillings were conducted in floodplain positions with insufficient exposure conditions. For the chronological frame 70 radiocarbon samples have been dated. The obtained results show a significant pattern of sedimentation periods and phases of stability associated with soil formation for each river system. The sedimentation history of the Guadalete and Guadalquivir Rivers could be reconstructed for the last 15 ka, while conclusions with regard to sedimentation dynamics of the Jarama River could be drawn for a period of 43 ka. Thanks to an abundance of available studies on other terrestrial archives with climatic or environmental relevance, it was possible to assess the influence of different parameters such as climate, vegetation, humankind, tectonics, and base-level changes on fluvial sedimentation dynamics. It emerged that, first and foremost, rapid climate changes had significant impact on the mobilization of sediments in the catchment area as well as their deposition in floodplain positions. On the other hand prolonged periods of climatic amelioration caused floodplain stability along with soil formation, as documented for the time spans between 13.3 and 12.7 ka, 7 and 5.1 ka, 2.8 and 2.3 ka, 1.4 and 1.2 ka, as well as 0.8 and 0.5 ka cal. BP in several river systems. Periods of increased sedimentation were initiated by phases of climatic aridification that affected fluvial systems through the weakening of the vegetation cover and the accentuation of the hydrological discharge regime. Corresponding patterns have been found for the time intervals between 8 and 7 ka, 5 and 3.8 ka, 2.2 and 1.5 ka, as well as around 1 ka and 0.4 ka cal. BP. The supra-regional effectiveness of the factor climate is contrasted by a strong regional individuality of the river catchments that is expressed by further, regionally limited phases of fluvial activity. Crucial to this development – apart from regional climate differences – are, inter alia, tectonic movements as evidenced for the Jarama River system in central Spain, or late Pleistocene and Holocene sea-level fluctuations that primarily affected fluvial dynamics along the lower course of the Guadalete River in southwestern Spain. Furthermore, it can be shown that variations in time and duration of fluvial system response are attributable to differing buffer capacities of river catchments towards external influences. The increase of human impact during the late Holocene apparently provoked a reinforcement of the effects of climatic impulses. There are clear evidences for the participation of humans in the mobilization of sediments; however, concerning the degree of influence it is hardly possible to differentiate between the factors humans and climate.:1 Introduction 1.1 Relevance of fluvial records in the context of climate change and landscape evolution in the Western Mediterranean 1.2 Environmental significance of fluvial deposits 1.3 Objectives and methodological approach 2 Late Quaternary fluvial dynamics of the Jarama River 2.1 Introduction 2.2 Study area 2.2.1 Geological and tectonic background 2.2.2 Geomorphological setting of the Jarama valley 2.3 Methods 2.4 Fluvial architecture and characteristics of the sedimentary units 2.4.1 Sequence 1 – Late Pleistocene 2.4.2 Sequence 2 – Early to Mid-Holocene 2.4.3 Sequence 3 – Mid-Holocene to Roman period 2.4.4 Sequence 4 – Little Ice Age 2.5 Interpretation - Stages of floodplain development 2.5.1 Extensive aggradations during Marine Isotope Stage (MIS) 3 2.5.2 Increased fluvial activity in the course of the Last Glacial Maximum (LGM) 2.5.3 Sand deposits (Unit 3) at the end of MIS 2 2.5.4 Younger Dryas and Early to Mid-Holocene sedimentation 2.5.5 Mid-Holocene warm period and climatic collapse 2.5.6 Highly dynamic floodplain aggradations and 3.0 ka-aridity crisis 2.5.7 Extensive sand deposition at 2.8 ka BP and following floodplain stability 2.5.8 Flood loam accumulation during the Roman epoch 2.5.9 Alternating flood loam accumulation and soil formation during the Medieval period 2.5.10 Accentuated fluvial dynamics during the Little Ice Age and recent flooding 2.6 Human influence versus climatic control factors 2.7 Significance of fluvial records in a spatial context 2.8 Conclusion 3 Late Pleistocene and Holocene fluvial dynamics of the lower Guadalete River 3.1 Introduction 3.2 Study area 3.3 Methods 3.4 Stratigraphic findings and sedimentation patterns within the Guadalete valley 3.4.1 Upper downstream section 3.4.1.1 Late Pleistocene sediments 3.4.1.2 Mid-Holocene sediments (5000 - 2000 cal. a BP) 3.4.1.3 Late Holocene sediments (<2000 cal. a BP) 3.4.1.4 Composite profile 3.4.2 Lower downstream section close to the estuary 3.4.2.1 Early Holocene sediments (~10000 - 8000 cal. a BP) 3.4.2.2 Mid- to late-Holocene sediments (<8000 cal. a BP) 3.5 Interpretation – Floodplain evolution and the influencing factors 3.5.1 Stages of floodplain evolution 3.5.1.1 Late Pleistocene dynamics (SU-1 to SU-3) 3.5.1.2 Early Holocene dynamics (SU-4 to SU-7) 3.5.1.3 Mid-Holocene dynamics (SU-8) 3.5.1.4 Mid-Holocene aridity collapse (SU-9a to SU-9c) 3.5.1.5 Late Holocene dynamics (SU-10 to SU-12) 3.5.1.6 Increased dynamics during the Little Ice Age (LIA) (SU-13a to SU-14) 3.6 Conclusion 4 Western Mediterranean environmental changes 4.1 Introduction 4.2 Study area 4.2.1 Jarama River 4.2.2 Guadalete River 4.2.3 Guadalquivir River 4.3 Methods 4.4 Results 4.4.1 Stratigraphic findings of the Jarama River 4.4.1.1 Fluvial architecture 4.4.1.2 Sedimentation patterns 4.4.1.3 Periods of soil formation 4.4.2 Stratigraphic findings of the Guadalete River 4.4.2.1 Fluvial architecture 4.4.2.2 Sedimentation patterns 4.4.2.3 Periods of soil formation 4.4.3 Stratigraphic findings of the Guadalquivir River 4.4.3.1 Fluvial architecture 4.4.3.2 Sedimentation patterns 4.4.3.3 Periods of soil formation 4.5 Discussion 4.5.1 General view of fluvial architectural patterns as basis for interpretations 4.5.2 Fluvial dynamic patterns and possible forcing mechanisms 4.5.3 The role of climate in triggering fluvial dynamics 4.5.4 Supra regional comparison of examined floodplain records 4.5.5 Variability of fluvial dynamics: A matter of sensitivity? 4.5.6 Large-scale consideration of Western Mediterranean fluvial records 4.5.7 Interrelations between North Atlantic sea surface temperature and landscape dynamics on the Iberian Peninsula 4.5.8 Landscape dynamics and corresponding atmospheric conditions 4.6 Conclusion Acknowledgements References 5 Synthesis 5.1 General architectural patterns of examined river floodplains in Spain 5.2 Assessment of influencing factors and their relevance for fluvial dynamics 5.3 Interpretations in terms of palaeo-environmental conditions 5.4 Comparative consideration of the various study areas 5.5 Climate change and implications for fluvial system behavior 5.6 Outlook References / Der westliche Mediterranraum gilt als landschaftlich und klimatisch hochsensible Region, für deren semiaride bis semihumide Gebiete bereits kleinere klimatische Änderungen, aber auch Eingriffe des Menschen, mit weitreichenden Folgen für Umwelt und ökologische Systeme verbunden sein können. Forschungen zum Landschaftswandel nehmen hier vor allem vor dem Hintergrund des derzeitigen Klimawandels einen hohen Stellenwert in den Geowissenschaften ein. Ein wichtiges Anliegen ist dabei, in früheren Landschaftswandeln Muster zu entdecken, welche als Grundlage für Bewertungen zukünftiger Veränderungen dienen können. Für die Rekonstruktion spätquartärer Umweltbedingungen kommt fluvialen Sedimenten eine besondere Rolle zu. Wie kein anderes Archiv spiegeln fluviale Sedimentabfolgen Landschaftszustände und -entwicklung auf regionaler Ebene wieder. Dies ist dem Umstand geschuldet, dass fluviale Dynamik mit allen inbegriffenen Prozessen auf polykausalen Zusammenhängen beruht und somit eine Vielzahl an Faktoren, wie klimatische Verhältnisse und Vegetationsentwicklung, menschliche Einflussnahme oder tektonische Aktivität Ausdruck in fluvialer Dynamik finden. Von feuchten atlantischen Luftmassen geprägte Gebiete nehmen etwa 70 % der Fläche der Iberischen Halbinsel ein, allerdings besteht hier eine erhebliche Forschungslücke im Bereich der Analyse fluvialer Archive. Diesem Umstand soll in vorliegender Dissertation in Form einer systematischen Aufarbeitung der fluvialen Sedimentabfolgen zweier Flusssysteme in Zentralspanien (Rio Jarama), sowie in SW-Spanien (Rio Guadalete) Rechnung getragen werden. Für ergänzende Betrachtungen werden dabei erste Befunde zur stratigraphischen Gliederung des Guadalquivir-Mittellaufes in S-Spanien herangezogen. Ziel der Arbeiten ist es zunächst über umfangreiche Aufnahmen und Dokumentationen von Sedimentprofilen ein belastbares Standardprofil für jedes Flusssystem zu erarbeiten und dieses hinsichtlich der Aussagekraft in Bezug auf Paläoumweltbedingungen und vor allem -wandeln zu prüfen. Neben der möglichen Reaktion fluvialer Systeme auf klimatische Änderungen, stehen dabei vor allem auch Beziehungsgeflechte zu anderen Einflussfaktoren im Vordergrund. Anhand eines überregionalen Vergleichs soll eine mögliche Kopplung fluvialmorphologischer Systeme an großräumige Klimafluktuationen untersucht werden, zudem soll weiteren Themenkomplexen, wie der Konnektivität verschiedener Systeme oder unterschiedlichen Reaktionszeiten und -geschwindigkeiten nachgegangen werden. Grundlage für diese Betrachtungen bilden dabei aus zahlreichen Geländeaufnahmen resultierende Profilaufnahmen, sowie Ergebnisse geoelektrischer Messungen und Bohrsondierungen. Stratigraphische Arbeiten belaufen sich zunächst auf die Untergliederung verschiedener Sedimenteinheiten, die Ausweisung von Bodenhorizonten, sowie die Korrelation einzelner Schichten und Horizonte über unterschiedliche Profile hinweg anhand charakteristischer sedimentologischer und pedogenetischer Merkmale. Nachfolgende bodenchemische und sedimentologische Laboruntersuchungen an ausgewählten Profilen sollen über die Bestimmung von Korngrößenverhältnissen, Gehalten an organischem Kohlenstoff, Kalk- und Eisengehalten, sowie der magnetischen Suszeptibilität die Geländebefunde stützen und in unklaren Fällen eine Unterscheidung von Böden und Bodensedimenten erleichtern. Die zeitliche Auflösung der Sedimentabfolgen soll über Radiokarbondatierungen realisiert werden, mit dem letztendlichen Ziel, eine detaillierte fluviale Sedimentationsgeschichte für das Spätquartär zu erarbeiten. In einem weiteren Schritt werden begleitend zu einer detaillierten Einzugsgebietscharakteristik die chronostratigraphischen Befunde einem intensiven Vergleich mit in der Literatur verfügbaren Studien an Sekundärarchiven zugeführt, um Beziehungsgeflechte zwischen fluvialer Dynamik und verschiedenen Einflussfaktoren aufzudecken. Im Rahmen dieser Dissertation konnten zunächst 36 Profilaufschlüsse detailliert bearbeitet und zudem 13 Rammkernsondierungen in Flussauenpositionen abgeteuft werden. Für den chronologischen Rahmen wurden 70 Radiokohlenstoffproben datiert. Die Ergebnisse zeigen ein deutliches Muster von Sedimentationsphasen und Zeiten der Stabilität mit einhergehender Bodenbildung für jedes Flusseinzugsgebiet. Dabei konnte die Sedimentationsgeschichte der Flusssysteme Rio Guadalete und Rio Guadalquivir für die letzten 15.000 Jahre und des Rio Jarama für die letzten 43 ka rekonstruiert werden. Dank der Fülle an verfügbaren Studien an terrestrischen Vergleichsarchiven mit klima- und umweltrelevantem Bezug war es möglich, den Einfluss der unterschiedlichen Parameter Klima, Vegetation, Mensch und Tektonik, bzw. Erosionsbasis auf die fluviale Sedimentationsdynamik zu prüfen. So zeigte sich, dass vor allem rasche Klimaänderungen in der Lage waren die Mobilisierung von Sedimenten im Einzugsgebiet und deren Ablagerung in den Flussauen zu initiieren. Dahingegen bewirkten anhaltende klimatische Gunstphasen eine Stabilisierung mit einhergehender Bodenbildung, wie für die Zeiträume zwischen 13.3 und 12.7 ka, 7 und 5.1 ka, 2.8 und 2.3 ka, 1.4 und 1.2 ka, sowie 0.8 und 0.5 ka cal. BP für sämtliche Flusssysteme zu verzeichnen ist. Perioden verstärkter Sedimentation folgten in der Regel Phasen klimatischer Aridifizierung, welche über eine Schwächung der Vegetationsbedeckung und Akzentuierung des hydrologischen Abflussregimes in der Lage waren auf das fluviale System Einfluss zu nehmen. Entsprechende Muster konnten für die Zeiträume zwischen 8 und 7 ka, 5 und 3.8 ka, 2.2 und 1.5 ka, sowie um 1 ka als auch 0.4 ka cal. BP dokumentiert werden. Dem überregional wirksamen Einfluss des Faktors Klima steht jedoch eine starke landschaftsgeschichtliche Individualität der verschiedenen Regionen gegenüber, welche in weiteren, regional begrenzten Phasen fluvialer Aktivität zum Ausdruck kommt. Ausschlaggebend sind hier neben der Ausbildung regionaler Klimaunterschiede unter Anderem tektonische Verstellungen, welche für das in Zentralspanien gelegene System des Rio Jarama belegt werden konnten, oder spätpleistozäne und holozäne Meeresspiegelschwankungen, welche sich vor allem auf die fluviale Dynamik im Unterlauf des in SW-Spanien gelegenen Rio Guadalete auswirkten. Desweiteren können Unterschiede in Reaktionsdauer und -geschwindigkeit fluvialer Systeme mit variierendem Puffervermögen der Flusseinzugsgebiete gegenüber äußeren Einflüssen erklärt werden. Das intensivierte Wirken des Menschen im Spätholozän führte allem Anschein nach zu einer Verstärkung der Wirkung klimatischer Impulse, wobei sich klare Evidenzen für eine Beteiligung des Menschen an der Sedimentmobilisierung erkennen lassen, der Umfang des Einflusses des Menschen aber in der Regel nicht klar von dem des Klimas zu trennen ist.:1 Introduction 1.1 Relevance of fluvial records in the context of climate change and landscape evolution in the Western Mediterranean 1.2 Environmental significance of fluvial deposits 1.3 Objectives and methodological approach 2 Late Quaternary fluvial dynamics of the Jarama River 2.1 Introduction 2.2 Study area 2.2.1 Geological and tectonic background 2.2.2 Geomorphological setting of the Jarama valley 2.3 Methods 2.4 Fluvial architecture and characteristics of the sedimentary units 2.4.1 Sequence 1 – Late Pleistocene 2.4.2 Sequence 2 – Early to Mid-Holocene 2.4.3 Sequence 3 – Mid-Holocene to Roman period 2.4.4 Sequence 4 – Little Ice Age 2.5 Interpretation - Stages of floodplain development 2.5.1 Extensive aggradations during Marine Isotope Stage (MIS) 3 2.5.2 Increased fluvial activity in the course of the Last Glacial Maximum (LGM) 2.5.3 Sand deposits (Unit 3) at the end of MIS 2 2.5.4 Younger Dryas and Early to Mid-Holocene sedimentation 2.5.5 Mid-Holocene warm period and climatic collapse 2.5.6 Highly dynamic floodplain aggradations and 3.0 ka-aridity crisis 2.5.7 Extensive sand deposition at 2.8 ka BP and following floodplain stability 2.5.8 Flood loam accumulation during the Roman epoch 2.5.9 Alternating flood loam accumulation and soil formation during the Medieval period 2.5.10 Accentuated fluvial dynamics during the Little Ice Age and recent flooding 2.6 Human influence versus climatic control factors 2.7 Significance of fluvial records in a spatial context 2.8 Conclusion 3 Late Pleistocene and Holocene fluvial dynamics of the lower Guadalete River 3.1 Introduction 3.2 Study area 3.3 Methods 3.4 Stratigraphic findings and sedimentation patterns within the Guadalete valley 3.4.1 Upper downstream section 3.4.1.1 Late Pleistocene sediments 3.4.1.2 Mid-Holocene sediments (5000 - 2000 cal. a BP) 3.4.1.3 Late Holocene sediments (<2000 cal. a BP) 3.4.1.4 Composite profile 3.4.2 Lower downstream section close to the estuary 3.4.2.1 Early Holocene sediments (~10000 - 8000 cal. a BP) 3.4.2.2 Mid- to late-Holocene sediments (<8000 cal. a BP) 3.5 Interpretation – Floodplain evolution and the influencing factors 3.5.1 Stages of floodplain evolution 3.5.1.1 Late Pleistocene dynamics (SU-1 to SU-3) 3.5.1.2 Early Holocene dynamics (SU-4 to SU-7) 3.5.1.3 Mid-Holocene dynamics (SU-8) 3.5.1.4 Mid-Holocene aridity collapse (SU-9a to SU-9c) 3.5.1.5 Late Holocene dynamics (SU-10 to SU-12) 3.5.1.6 Increased dynamics during the Little Ice Age (LIA) (SU-13a to SU-14) 3.6 Conclusion 4 Western Mediterranean environmental changes 4.1 Introduction 4.2 Study area 4.2.1 Jarama River 4.2.2 Guadalete River 4.2.3 Guadalquivir River 4.3 Methods 4.4 Results 4.4.1 Stratigraphic findings of the Jarama River 4.4.1.1 Fluvial architecture 4.4.1.2 Sedimentation patterns 4.4.1.3 Periods of soil formation 4.4.2 Stratigraphic findings of the Guadalete River 4.4.2.1 Fluvial architecture 4.4.2.2 Sedimentation patterns 4.4.2.3 Periods of soil formation 4.4.3 Stratigraphic findings of the Guadalquivir River 4.4.3.1 Fluvial architecture 4.4.3.2 Sedimentation patterns 4.4.3.3 Periods of soil formation 4.5 Discussion 4.5.1 General view of fluvial architectural patterns as basis for interpretations 4.5.2 Fluvial dynamic patterns and possible forcing mechanisms 4.5.3 The role of climate in triggering fluvial dynamics 4.5.4 Supra regional comparison of examined floodplain records 4.5.5 Variability of fluvial dynamics: A matter of sensitivity? 4.5.6 Large-scale consideration of Western Mediterranean fluvial records 4.5.7 Interrelations between North Atlantic sea surface temperature and landscape dynamics on the Iberian Peninsula 4.5.8 Landscape dynamics and corresponding atmospheric conditions 4.6 Conclusion Acknowledgements References 5 Synthesis 5.1 General architectural patterns of examined river floodplains in Spain 5.2 Assessment of influencing factors and their relevance for fluvial dynamics 5.3 Interpretations in terms of palaeo-environmental conditions 5.4 Comparative consideration of the various study areas 5.5 Climate change and implications for fluvial system behavior 5.6 Outlook References