A presente pesquisa teve por objetivo demonstrar quais processos pedogenéticos ocorrem na gênese e evolução de solos no setor noroeste do Estado do Paraná, mais especificamente a evolução de horizontes B níticos sobre B latossólicos em uma área de basaltos inseridos na faixa de transição litológica arenitos-basaltos deste setor do estado. A área de estudos é a bacia hidrográfica do córrego Gurupá, no município de Floraí/PR. Utilizamos técnicas e procedimentos de fotointerpretação para levantamento geológico com o objetivo de elucidar a distribuição do substrato, formas de relevo e solos associados, elaborando como produto final um Mapa Morfolitológico. Para a análise multiescalar da organização e dinâmica da cobertura pedológica utilizamos procedimentos propostos pela Análise Estrutural da Cobertura Pedológica. O sistema pedológico estudado apresenta um volume superficial arenoso e volumes subsuperficiais mais argilosos, com organizações em blocos poliédricos ou microagregados, bem distinguíveis em campo; a análise dos parâmetros físicos e químicos demonstrou uma diferenciação morfológica dos grãos de quartzo em profundidade e concentração heterogênea de elementos e óxidos nos perfis estudados. Com o auxílio de conceitos, técnicas e procedimentos da micromorfologia de solos, demonstramos que na área de estudos ocorre uma intensa dissolução geoquímica de grãos de quartzo, sob a forma de golfos de dissolução, separações plásmicas mais abundantes no contato entre os volumes arenoso e argiloso, com evolução em profundidade, e intensa acumulação de argila iluviada em subsuperfície, provocando reorganizações de núcleos microagregados em blocos poliédricos, com evolução ascendente. Em síntese, este sistema evolui em decorrência do transporte de matéria que promove reorganizações no interior da cobertura pedológica (processo de eluviação-iluviação), indicando que a área passa por um período de desequilíbrio pedobioclimático. / The goal of the present research is to show which pedogenetic processes take place in the genesis and evolution of soils in the northwest of the state of Paraná, aiming specifically on the formation of nitic horizons on top of latosolic horizons in a basaltic area, inserted in a lithological transition zone, between basalts and sandstones. The study area is the Gurupá Creek hydrographical basin, located in Floraí - PR. In this process, photointerpretation techniques and procedures were used for the geological survey, in order to elucidate the substratum´s distribution, landforms and associated soils. The final cartographic product is a Morpholithological Map. The Structural Analysis of the Pedological Coverage supplied us with the procedures which allowed the multi-scalar analysis of the organization and dynamics of the soil coverage. The pedological system studied in this research presents a sandy superficial volume, and an increase in clay content in the subsuperficial volumes, organized in polyhedral blocks or microaggregated structure, clearly distinguishable during the field work; the analysis of the physical and chemical parameters revealed a morphological difference between the quartz grains in depth and heterogeneous concentration of elements and oxides in the studied profiles. With the support of different concepts, techniques and procedures of soil micromorphology, we demonstrated that an intense geochemical dissolution of the quartz grains is currently taking place, in the form of dissolution gulfs, abundant plasmic separations in the contact of the sandy and argilic volumes, with an evolution in depth and intense illuviated clay accumulation in the subsurface, causing the reorganization of the microaggregated structure in polyhedral blocks, with an ascending evolution. In synthesis, this system evolves through the transportation of matter, which promotes reorganizations within the pedological coverage (elluviation/illuviation), indicating that the area is going through a period of pedobioclimatic imbalance.

Charwell Basin is a 6 km-wide structural depression situated at the boundary between the axial ranges and faulted and folded Marlborough Fault Zone of north-eastern South Island, New Zealand. The basin contains the piedmont reach of the Charwell River, and a series of late Quaternary loess-mantled alluvial terraces and terrace remnants that have been uplifted and translocated from their sediment source due to strike-slip motion along the Hope Fault which bounds the basin to its immediate north. The aim of this study was to provide an interdisciplinary, integrated and holistic analysis of late Quaternary landscape evolution and environmental change in Charwell Basin using terrain analysis, loess stratigraphy, soil chemistry and paleoecological data. The study contributes new understanding of New Zealand landscape and ecosystem responses to regional and global climatic change extending to Marine Isotope Stage (MIS) 6, and shows that climatically-forced shifts in biogeomorphic processes play a significant role in lowland landscape evolution. Morphometric analysis of alluvial terraces and terrace remnants of increasing age demonstrated geomorphic evolution through time, with a decrease in extent of original planar terrace tread morphology and an increase in frequency of steeper slopes and convexo-concave land elements. Paleotopographic analysis of a &gt150 ka terrace mantled by up to three loess sheets revealed multiple episodes of alluvial aggradation and degradation and, subsequent to river abandonment, gully incision prior to and coeval with loess accumulation. Spatial heterogeneity in loess sheet preservation showed a complex history of loess accumulation and erosion. A critical profile curvature range of -0.005 to -0.014 (d2z/dx2, m-1) for loess erosion derived from a model parameterised in different ways successfully predicted loess occurrence on adjacent slope elements, but incorrectly predicted loess occurrence on an older terrace remnant from which all loess has been eroded. Future analyses incorporating planform curvature, regolith erosivity and other landform parameters may improve identification of thresholds controlling loess occurrence in Charwell Basin and in other South Island landscapes. A loess chronostratigraphic framework was developed for, and pedogenic phases identified in, the three loess sheets mantling the &gt150 ka terrace. Except for one age, infrared-stimulated luminescence dates from both an upbuilding interfluve loess exposure and colluvial gully infill underestimated loess age with respect to the widespread Kawakawa/Oruanui Tephra (KOT; 27,097 ± 957 cal. yr BP), highlighting the need for improvements in the methodology. Onset of loess sheet 1 accumulation started at ca. 50 ka, with a break at ca. 27 ka corresponding to the extended Last Glacial Maximum (eLGM) interstadial identified elsewhere in New Zealand. Loess accumulation through MIS 3 indicates a regional loess flux, and that glaciation was not a necessary condition for loess generation in South Island. Loess accumulation and local alluvial aggradation are decoupled: the youngest aggradation event only covers ~12 kyr of the period of loess sheet 1 accumulation. Older local aggradation episodes could not be the source because their associated terraces are mantled by loess sheet 1. In the absence of numerical ages, the timing of L2 and L3 accumulation is inferred on the basis of an offshore clastic sediment record. The upbuilding phase of loess sheet 2 occurred in late MIS 5a/MIS 4, and loess sheet 3 accumulated in two phases in MIS 5b and late MIS 6. Biogenic silica data were used to reconstruct broad shifts in vegetation and changes in gully soil saturation status. During interglacial/interstadial periods (MIS 1, early MIS 3, MIS 5) Nothofagus¬-dominated forest covered the area in association with Microlaena spp grasses. Lowering of treeline altitude during glacial/stadial periods (MIS 2, MIS 3, MIS 5b, late MIS 6) led to reduction in forest cover and a mosaic of shrubs and Chionochloa spp, Festuca spp and Poa spp tussock grasses. Comparison of interfluve and gully records showed spatial heterogeneity in vegetation cover possibly related to environmental gradients of exposure or soil moisture. A post-KOT peak in gully tree phytoliths corresponds to the eLGM interstadial, and a shift to grass-dominated vegetation occurred during the LGM sensu stricto. Diatoms indicated the site became considerably wetter from ca. 36 ka, with peak wetness at ca. 30, 25 and 21 ka, possibly due to reduced evapotranspiration and/or increased precipitation from a combination of strengthened westerly winds and increased cloudiness, or strengthened southerly flow and increased precipitation. Human influence after ca. 750 yr BP led to re-establishment of grassland in the area, which deposited phytoliths mixed to 30 cm depth in the soil. A coupled gully colluvial infilling/vegetation record showed that sediment flux during the late Pleistocene was ~0.0019 m3 m-1 yr-1 under a shrubland/grassland mosaic, and Holocene sediment flux was ~0.0034 m3 m-1 yr-1 under forest. This increase of 60% through the last glacial-interglacial transition resulted from increased bioturbation and down-slope soil transport via root growth and treethrow, which formed a biomantle as evidenced by slope redistribution of the KOT. These results contrast with sediment transport rates and processes hypothesised to occur contemporaneously in adjacent mountain catchments. This suggests that intraregional biogeomorphic processes can differ significantly depending on topography and geological substrate, with different landscapes responding in unique ways to the same climate shifts. Analysis of Quaternary terrestrial landscape evolution in non-glaciated mountainous and lowland areas must therefore consider spatial and temporal heterogeneity in sediment fluxes and underlying transport processes.

A presente pesquisa teve por objetivo demonstrar quais processos pedogenéticos ocorrem na gênese e evolução de solos no setor noroeste do Estado do Paraná, mais especificamente a evolução de horizontes B níticos sobre B latossólicos em uma área de basaltos inseridos na faixa de transição litológica arenitos-basaltos deste setor do estado. A área de estudos é a bacia hidrográfica do córrego Gurupá, no município de Floraí/PR. Utilizamos técnicas e procedimentos de fotointerpretação para levantamento geológico com o objetivo de elucidar a distribuição do substrato, formas de relevo e solos associados, elaborando como produto final um Mapa Morfolitológico. Para a análise multiescalar da organização e dinâmica da cobertura pedológica utilizamos procedimentos propostos pela Análise Estrutural da Cobertura Pedológica. O sistema pedológico estudado apresenta um volume superficial arenoso e volumes subsuperficiais mais argilosos, com organizações em blocos poliédricos ou microagregados, bem distinguíveis em campo; a análise dos parâmetros físicos e químicos demonstrou uma diferenciação morfológica dos grãos de quartzo em profundidade e concentração heterogênea de elementos e óxidos nos perfis estudados. Com o auxílio de conceitos, técnicas e procedimentos da micromorfologia de solos, demonstramos que na área de estudos ocorre uma intensa dissolução geoquímica de grãos de quartzo, sob a forma de golfos de dissolução, separações plásmicas mais abundantes no contato entre os volumes arenoso e argiloso, com evolução em profundidade, e intensa acumulação de argila iluviada em subsuperfície, provocando reorganizações de núcleos microagregados em blocos poliédricos, com evolução ascendente. Em síntese, este sistema evolui em decorrência do transporte de matéria que promove reorganizações no interior da cobertura pedológica (processo de eluviação-iluviação), indicando que a área passa por um período de desequilíbrio pedobioclimático. / The goal of the present research is to show which pedogenetic processes take place in the genesis and evolution of soils in the northwest of the state of Paraná, aiming specifically on the formation of nitic horizons on top of latosolic horizons in a basaltic area, inserted in a lithological transition zone, between basalts and sandstones. The study area is the Gurupá Creek hydrographical basin, located in Floraí - PR. In this process, photointerpretation techniques and procedures were used for the geological survey, in order to elucidate the substratum´s distribution, landforms and associated soils. The final cartographic product is a Morpholithological Map. The Structural Analysis of the Pedological Coverage supplied us with the procedures which allowed the multi-scalar analysis of the organization and dynamics of the soil coverage. The pedological system studied in this research presents a sandy superficial volume, and an increase in clay content in the subsuperficial volumes, organized in polyhedral blocks or microaggregated structure, clearly distinguishable during the field work; the analysis of the physical and chemical parameters revealed a morphological difference between the quartz grains in depth and heterogeneous concentration of elements and oxides in the studied profiles. With the support of different concepts, techniques and procedures of soil micromorphology, we demonstrated that an intense geochemical dissolution of the quartz grains is currently taking place, in the form of dissolution gulfs, abundant plasmic separations in the contact of the sandy and argilic volumes, with an evolution in depth and intense illuviated clay accumulation in the subsurface, causing the reorganization of the microaggregated structure in polyhedral blocks, with an ascending evolution. In synthesis, this system evolves through the transportation of matter, which promotes reorganizations within the pedological coverage (elluviation/illuviation), indicating that the area is going through a period of pedobioclimatic imbalance.

Made available in DSpace on 2016-04-26T19:39:32Z (GMT). No. of bitstreams: 1 2009 - Ademir Fontana.pdf: 2160169 bytes, checksum: fd6ae828d8a9c078041d2b180e5bd9b9 (MD5) Previous issue date: 2009-04-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The importance of soil organic matter in pedology and especially soil classification studies can be substantiated by the use of attributes such as organic carbon content, degree of organic matter decomposition from the fibers content. Recent studies in Brazil with humic substances report establishment of standards that could be used to differentiate soil horizons (diagnostic attributes), soil horizon classification and the relationship with properties that connote soil fertility. This study had as objectives: to characterize humic substances and humic acids of different diagnostic soil horizons of Brazilian soils; b) to propose the utilization of attributes related to humic substances in the characterization of the lower hierarchical levels (family and series) of the Brazilian System of Soil Classification (SiBCS). The soil material utilized material from 169 diagnostic horizons or epipedons, identified as: 13 O histic, 30 H histic, 42 A mollic, 39 A umbric, and 45 B spodic horizons. In these horizons there were evaluated the chemical properties: TOC, pH, H+, SB (sum of bases), CEC and V% (base saturation); physical properties: sand, silt and clay contents; quantitative fractionating of humic substances: fulvic acid fraction (C-FAF), humic acid fraction (C-HAF) and humin (C-HUM), C-HAF/C-FAF, C-AE/C-HUM, and C-AE/COT ratio (C-AE = C-FAF + C-HAF), and the %FAF, %HAF, %HUM and %AE. In the purified humic acid (HA) spectroscopic analyses were performed on visible and infrared regions, elemental composition and termogravimetric analyses; in addition to that the alkaline extract (AE) was analyzed by spectroscopy on visible region. The quantitative fractionating of humic substances showed differential distribution between the types of diagnostic soils horizons, highlighting the O and H histic horizons, where the predominance of humin showed average around 53% and 39%, respectively, and followed by humic acids. Also, for the H histic horizon there were high values of the C-HAF/C-FAF ratio (average of 5.6). On the mollic epipedon it was observed predominance of humin with average around 71%, and low values of C-AE/C-HUM ratio (average of 0.2), and on the umbric epipedon humin predominance averaging 47%, followed by humic acids. On the spodic horizon there was predominance of fulvic and humic acids with average around 30% and 44%, respectively. On this horizon, the values of the C-HAF/C-FAF ratio were high, with average around 9.9 (most of them higher than 1.0), and the C-AE/C-HUM ratio averaged 16.5 (majority higher than 2.0). The evaluation of variables related to visible and infrared spectroscopic, elemental composition and termogravimetric of HA, and visible region for AE, showed similar characteristics and absence of a pattern independent ly of soils genesis. According to the distribution of humic substances the following differential characteristics were proposed to the SiBCS: Stable Organic Matter (surface mineral horizons) C-AE/C-HUM = 0.5, Iluvial Organic Matter (subsurface mineral horizons) - C-AE/C-HUM = 2.0, and Leaching Potential (system or soil) - C-HAF/C-FAF and C-AE/C-HUM = 1.0. Also, the establishment of classes according to humic substances was efficient to identify distinct groups based on their chemical properties. This result validates the proposal of using these variables to classify these horizons on the family and series levels, and contribute to structure the SiBCS in the lower hierarchical levels (5th and 6th). / A import?ncia da mat?ria org?nica do solo nos estudos de pedologia e em especial na classifica??o de solos pode ser constatada pela utiliza??o de atributos como os teores de carbono org?nico e grau de decomposi??o da mat?ria org?nica a partir do teor de fibras. Alguns trabalhos desenvolvidos recentemente no Brasil com subst?ncias h?micas em solos buscaram estabelecer padr?es que poderiam ser utilizados na separa??o de horizontes (atributo diagn?stico), classifica??o dos horizontes ou mesmo rela??es com propriedades ed?ficas que conotam fertilidade dos solos. Este trabalho teve como objetivos: caracterizar diferentes horizontes diagn?sticos de solos por meio das subst?ncias h?micas e dos ?cidos h?micos; e propor o uso de atributos relacionados ?s subst?ncias h?micas na categoriza??o dos n?veis hier?rquicos inferiores (fam?lia e s?rie) do SiBCS. Foram utilizados materiais de solo de 169 horizontes diagn?sticos, sendo: 13 O h?stico, 30 H h?stico, 42 chernoz?mico, 39 A h?mico, 45 B esp?dico. Foram avaliadas as propriedades qu?micas: COT, pH, SB, H+, Al3+, CTC e V%; propriedades f?sicas: areia, silte e argila; fracionamento quantitativo das subst?ncias h?micas: fra??o ?cidos f?lvicos (C-FAF), fra??o ?cidos h?micos (C-FAH) e fra??o humina (C-HUM), rela??es C-FAH/C-FAF, C-EA/C-HUM e C-EA/COT (C-EA = C-FAF + C-FAH) e a %FAF, %FAH, %HUM, % EA. Em ?cidos h?micos (AH) purificados foram realizadas an?lises espectrosc?picas na regi?o do vis?vel e infravermelho, composi??o elementar e termogravim?trica; al?m de, no extrato alcalino (EA) an?lise espectrosc?pica na regi?o do vis?vel. O fracionamento quantitativo das subst?ncias h?micas apresentou distribui??es diferenciadas entre os tipos de horizontes diagn?sticos de solos, destacando-se no O h?stico e H h?stico o predom?nio da humina com m?dia de 53% e 39%, respectivamente, seguido dos ?cidos h?micos e ainda para o ?ltimo, altos valores da rela??o C-FAH/C-FAF (m?dia de 5,6). No A chernoz?mico observou-se o predom?nio absoluto da humina com m?dia de 71% e baixos valores da rela??o C-EA/C-HUM (m?dia de 0,2) enquanto no A h?mico houve predom?nio da humina (m?dia de 47%), seguida dos ?cidos h?micos. No B esp?dico o predom?nio dos ?cidos f?lvicos e h?micos com m?dia de 30% e 44%, respectivamente, e altos valores da rela??o C-FAH/C-FAF com m?dia de 9,9 (maioria superiores 1,0) e C-EA/C-HUM com m?dia de 16,5 (maioria superiores 2,0). Pela avalia??o das vari?veis relacionadas ? espectroscopia do vis?vel e infravermelho, composi??o elementar e termogravimetria dos AH, e na regi?o do vis?vel para o EA, observou-se caracter?sticas semelhantes e aus?ncia de padr?o diferencial independente da g?nese dos solos. Com base na distribui??o das subst?ncias h?micas foram feitas as seguintes propostas de caracter?sticas diferenciais no SiBCS: Mat?ria Org?nica Est?vel (horizontes minerais superficiais) - C-EA/C-HUM = 0,5, Mat?ria Org?nica Iluvial (horizontes minerais subsuperficiais) - C-EA/C-HUM = 2,0 e, Potencial de Lixivia??o (sistema ou solo) - C-FAH/C-FAF e C-EA/C-HUM = 1,0. O estabelecimento de classes com os valores das subst?ncias h?micas tamb?m foi eficiente para individualizar grupos pela compara??o das propriedades qu?micas, o que valida a proposta de utiliza??o dessas vari?veis para a classifica??o desses horizontes nos n?veis de fam?lia ou s?rie e podem contribuir para a estrutura??o do SiBCS nos n?veis hier?rquicos inferiores (5? e 6?).

Les Technosols comprennent les sols soumis à une forte pression anthropique et en particulier les sols influencés par les matériaux d'origine humaine. Dans ce contexte, les sites miniers abandonnés peuvent souvent contenir une grande quantité de déchets transformés enrichis en métaux et métalloïdes. En comparaison avec les sols naturels, la singularité des Technosols miniers correspond à leur matériel parental constitués de déchets minéraux de granulométrie fine. Contrairement à leurs homologues peu anthropisés, les Technosols sont encore assez mal connus. L'objectif global de cette étude est d'approfondir les connaissances des processus pédogénétiques des Technosols développés naturellement à partir de déchets miniers de façon à mieux anticiper la réhabilitation de ces sites. Ainsi, différents profils ont été échantillonnés correspondant respectivement à d’anciennes exploitations de W, Pb-Ag, Sn et Au. Leurs fonctionnements pédologiques ont dès lors été étudiés afin de déterminer les liens potentiels et les leviers guidant leur évolution. Cette étude préliminaire correspond à une image contemporaine de ce que peut donner une réhabilitation naturelle (par simple formation de solum après végétation spontanée) pour une durée d’environ 75 ans en moyenne. Dans un second temps plusieurs techniques de réhabilitation ont été étudiés respectivement: (i) la phytoremédiation par culture du Douglas ainsi que (ii) la revalorisation des déchets par synthèse de géopolymères enrichis en déchets miniers. / The Technosols include soils subject to strong anthropogenic pressure and particularly to the soil influenced by human-made materials. In this context, abandoned mine sites can contain a large amount of transformed waste materials often enriched with metals and metalloïds. Compared to natural soils, the singularity of mining Technosols naturally developed from mining waste corresponding to their parental material made by fine-grained mineral waste. Unlike their poorly anthropized homologous, Technosols are not enough well known. So, the overall objective of this study is to increase knowledge of soil processes of Technosols after spontaneous vegetation impact. Thus, different profiles were sampled respectively corresponding to different abandoned mine exploitation type: W, Pb-Ag, Sn and Au. Their pedogenic way have therefore been studied to determine potential linkages and levers guiding their evolution. This preliminary study is based on the contemporary picture of a natural rehabilitation (by simple solum formation) for a period of about 75 years on average. Secondly several rehabilitation techniques have been studied respectively: (i) the phytoremediation by growing Douglas plant and (ii) the reused of waste by mine sediment based geopolymer synthesis.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Neossolos Litólicos and Regolíticos (Leptosols and Regosols) cover at least 15% of the Rio Grande do Sul state (RS) area. Those soils have been classified as low potential soils for general use, and also have been inadequately described in the field, due to difficulties in interpreting soil-saprolite-rock contacts. Besides, the classes of Neossolos, in the Brazilian Soil Classification System (SiBCS), are those needing improvements. The aim of this research was to analyze different profiles of Neossolos derived from volcanic rocks of the Serra Geral formation, disposed in a lito-climosequence in the RS. The research was separated into three investigation lines: a) chemical and mineralogical characterization of soil and saprolite profile; b)contributions to the morphologic analysis of Neossolos, including their saprolites; c) contributions to the taxonomic classification of Neossolo regolith. The results allowed verifying that the chemical and mineralogical characteristics and, consequently, the degree of weathering of the profiles are affected by the local climatic and geological conditions. Contacts of soil-saprolite, different from those found in the SiBCS, were identified in the field, through morphologic analysis. Thus, suggestions for the taxonomic classification of Neossolos derived from volcanic rocks in the RS were presented, seeking to contribute with the improvement of SiBCS. / Os Neossolos Litólicos e Regolíticos compreendem pelo menos 15% da área do Rio Grande do Sul (RS). Esses solos têm sido classificados como materiais de baixo potencial de uso geral, ao mesmo tempo em que têm sido inadequadamente descritos no campo, devido à dificuldade em se interpretar os contatos solosaprolito- rocha. Além disso, as classes dos Neossolos Litólicos e Neossolos Regolíticos, no Sistema Brasileiro de Classificação de Solos (SiBCS), são consideradas as que mais necessitam de aprimoramentos. Nesse sentido, o objetivo deste trabalho foi analisar diferentes perfis de Neossolos Litólicos e Regolíticos derivados de rochas vulcânicas da Formação Serra Geral, dispostos em uma litoclimoseqüência no RS. O trabalho foi dividido em três linhas de investigação: a) caracterização química e mineralógica de Neossolos e saprolitos; b) contribuições à análise morfológica de Neossolos e saprolitos; c) contribuições à classificação taxonômica de Neossolos e saprolitos. Os resultados permitiram verificar que as características químicas e mineralógicas e, conseqüentemente, o grau de intemperismo dos perfis são afetados pelas condições climáticas e geológicas locais. Foram encontrados, através de análise morfológica no campo, diferentes contatos solo-saprolito, os quais não apresentam correspondência no SiBCS. Nesse caso, propostas à classificação taxonômica de Neossolos derivados de rochas vulcânicas no RS foram sugeridas, visando contribuir para a evolução do SiBCS.

Pour protéger la ressource sol, il est nécessaire de prévoir les conséquences des activités humaines et du changement global sur l'évolution des sols notamment en modélisant cette dernière. Dans cette étude, nous avons démontré la sensibilité de SoilGen2.24 au climat, à l’usage des terres et à la réduction du travail du sol et identifié trois de ses principales limites, à savoir, certains processus trop simplifiés, certains processus manquants et une hypothèse de volume constant du sol. Ainsi, nous avons 1) construit le premier modèle d'évolution du sol entièrement modulaire, OC-VGEN, en intégrant dans VSoil, les processus du modèle SoilGen2.24; 2) testé différents formalismes pour certains des processus clés responsables de la distribution verticale de Corg, à savoir la distribution verticale des racines, la bioturbation et l'évolution verticale du taux de décomposition de Corg; 3) proposé un module mécaniste du changement de volume pour la modélisation de l'évolution du sol à court et moyen terme. OC-VGEN a été utilisé pour reproduire et projeter l’évolution, à l’échelle du siècle, de la distribution verticale de Corg pour des Luvisols ayant connu des historiques d'utilisation des terres et de travail du sol différents. Nous avons montré que 1) l'impact des processus de rétroaction sur la distribution verticale de Corg n'est pas négligeable; 2) l'usage des terres et le travail du sol influencent les rétroactions internes entraînant un impact indirect sur la dynamique de Corg; 3) le manque de connaissances sur les processus a une plus grande influence sur les trajectoires d’évolution des sols que les incertitudes sur les scénarios climatiques ou d'usage des terres. / Soil is a critical natural resource that inherently changes through time. To preserve the soil and protect it, it is necessary to predict the consequences of human activities and global change on soil evolution. This can be achieved using soil evolution modelling. In this study, we demonstrated the sensitivity of SoilGen to climate, land use and tillage reduction and identified three of its main limitations, namely some over-simplified processes, some missing processes and a simplifying assumption of constant soil volume. To overcome these limitations, we 1) built up the first fully modular soil evolution model, OC-VGEN, by using the process of SoilGen2.24 model in a modelling platform, VSoil; 2) tested different formalisms for some of the key processes responsible for the OC depth distribution, namely the root depth distribution, bioturbation and the depth evolution of the OC decomposition rate; 3) proposed a first, mechanistic approach to account for soil volume change in a short to medium time scale soil evolution modelling. OC-VGEN was used to reproduce and project the depth distribution of OC at a century time scale for Luvisols having experienced different histories of land use and tillage. We demonstrated that, at this time scale, 1) the impact of feedback processes on OC depth distribution are not negligible; 2) land use and tillage, beside their direct impact on the input of organic matter to soil, influence the internal feedbacks leading to an indirect impact on OC dynamics; 3) when projecting soil evolution, the lack of knowledge on the process definition has a larger influence on the projected trajectories than uncertainties on climate or land use scenarios.

Les terrils du bassin minier de Provence sont implantés dans le paysage et demeurent à proximité des habitations de la métropole Aix-Marseille. Les terrils les plus anciens ont été naturellement colonisés par la végétation et des sols s’y sont développés avec une vitesse remarquable. Cette étude vise à comprendre les processus pédogénétiques en cours depuis 55 ans sur les terrils miniers. Nous avons étudié l’impact du lignite sur les caractéristiques physico-chimiques et microbiologiques d’un Rendosol naturel. Deux sols similaires, dont l’un est traversé par l’affleurement naturel d’une veine de lignite et l’autre pas, ont donc été comparés afin de caractériser les variables impactées par le lignite. L’étude du terril Armand a permis de comprendre les facteurs responsables de la formation et de la variabilité des caractéristiques des sols observés sur le terril. L’abondance de composés carbonés récalcitrants dans les sols enrichis en lignite affecte les niveaux d’activité des microorganismes responsables des processus biologiques dans les sols sans induire d’effets néfastes. Le lignite semble intervenir comme un facteur de dilution du carbone organique, diminuant ainsi la quantité de carbone disponible et donc la vitalité d’expression des fonctions microbiennes. Les activités biologiques sont diminuées en présence de lignite, mais les changements induits sur les propriétés physico-chimiques semblent améliorer la fertilité du sol. Les sols du terril Armand demeurent cependant encore à un stade d’évolution trop jeune pour préjuger de leur évolution future. / Spoil heaps are scattered over the coal basin of Provence: they are inserted in the landscape and often located close to urban areas of the Aix-Marseille Metropole. The oldest spoil heaps have been naturally colonized by local vegetation and soils have simultaneously quickly developed. This study aims at understanding the processes involved in soil forming on undisturbed lignite-rich spoil heaps since 55 years. We studied the impact of lignite on the physico-chemical and microbiological characteristics of an undisturbed soil: we compared two similar Rendosols, except that one was developed in a natural lignite outcrop. Then we studied on the 55-year-old Armand spoil heap the factors responsible for soil genesis and variability of soil characteristics. Recalcitrant carbon compounds found in soils enriched with lignite modify microbial activity but do not induce negative effects. It seems that lignite acts as a diluting factor of the organic carbon that decreases the available carbon pool and consequently on the vitality of the expression of the microbial functions. Enzymatic activities and basal respiration decrease while changes observed on physico-chemical properties tend to improve soil fertility. Some characteristics of the soils developed on the spoil heap are similar to those of the soil developed from the lignite outcrop, while others are more related to the way the spoil heap was set up. Although these results have shed light on some of the processes involved in soil formation on spoil heaps in a carbonated environment, soils on Armand spoil heap are still at an early stage of development that precludes conclusion on their future evolution.

Le lessivage du lutum (0-2 µm) est un de processus majeurs de la pédogenèse, qui a néanmoins été peu quantifié et modélisé. Ce processus ainsi que la bioturbation ont été quantifiés ici en couplant des différents systèmes isotopiques (137Cs, 210Pb (xs), 10Be atmosphérique, 206/207Pb, δ13C, 14C) à une modélisation numérique par une équation de diffusion-convection à paramètres variables avec la profondeur. Cette méthode originale a été appliquée sur des anthroposéquences de Luvisols développées sur du loess et différantes de par leur utilisation (culture, prairie ou forêt) et leurs pratiques agricoles (travail du sol, apport du fumier). Nos résultats montrent que 91 ± 9 % du 137Cs et 80 ± 9 % du 10Be sont associés au lutum et ainsi peuvent effectivement tracer des transferts verticaux de matière solide dans les sols à pH > 5 et à teneur en carbone organique faible. Le partage du plomb entre les différentes phases solides est plus complexe. En considérant deux compartiments pour les isotopes (macropores ou la matrice de sol), nous avons conçu un modèle multi-isotopique permettant de quantifier la contribution des transferts de matière solide à la distribution verticale de la fraction 0-2 µm actuelle. Le lessivage est responsable de 9 à 66 % de l'accumulation de lutum dans l'horizon Bt. Le coefficient de diffusion permet de quantifier le taux de mélange par la bioturbation. La modélisation multi-isotopique est une méthode de prédilection pour les études modernes de la pédogenèse et des processus de la zone critique. / Clay translocation is one of the major soil forming processes, howeverit is poorly quantified and modeled. We propose to quantify it togetherwith bioturbation by combining different isotopic systems (137Cs , 210Pb (xs),meteoric 10Be, 206/207Pb, δ13C, 14C) with numerical modeling based on a nonlineardiffusion-convection equation with depth dependent parameters. Thisnovel method has been applied on Luvisol anthroposequences developed onloess, differing by their land use (cropping versus grassland or forest) andtheir agricultural practices (reduced tillage, no tillage and manure input).Our results show that as much as 91 ± 9 % and 80 ± 9 % of 137Cs and10Be, respectively, are associated to the clay size fraction (0-2 µm) and canthus effectively trace vertical solid matter transfers in soils with pH > 5 andlow organic carbon. Lead partitioning between different solid phases is morecomplex. Considering two spatial distributions of isotopes (macropores or soilmatrix), we built up a multi-isotopic modelling approach that simulates theexperimental data with the common set of transfer parameters and allowedus to quantify the relative contributions of vertical solid matter transfers topresent-day 0-2 µm vertical distributions. Clay translocation is responsiblefor 9 to 66 % of the clay accumulations in the Bt-horizon. The diffusion coefficientalso quantifies the rate of soil mixing by bioturbation. Modeling of thekinetics of solid matter transfer at multiple spatio-temporal scales should becomea method of predilection in modern pedogenic and critical zone studies.

Charwell Basin is a 6 km-wide structural depression situated at the boundary between the axial ranges and faulted and folded Marlborough Fault Zone of north-eastern South Island, New Zealand. The basin contains the piedmont reach of the Charwell River, and a series of late Quaternary loess-mantled alluvial terraces and terrace remnants that have been uplifted and translocated from their sediment source due to strike-slip motion along the Hope Fault which bounds the basin to its immediate north. The aim of this study was to provide an interdisciplinary, integrated and holistic analysis of late Quaternary landscape evolution and environmental change in Charwell Basin using terrain analysis, loess stratigraphy, soil chemistry and paleoecological data. The study contributes new understanding of New Zealand landscape and ecosystem responses to regional and global climatic change extending to Marine Isotope Stage (MIS) 6, and shows that climatically-forced shifts in biogeomorphic processes play a significant role in lowland landscape evolution. Morphometric analysis of alluvial terraces and terrace remnants of increasing age demonstrated geomorphic evolution through time, with a decrease in extent of original planar terrace tread morphology and an increase in frequency of steeper slopes and convexo-concave land elements. Paleotopographic analysis of a >150 ka terrace mantled by up to three loess sheets revealed multiple episodes of alluvial aggradation and degradation and, subsequent to river abandonment, gully incision prior to and coeval with loess accumulation. Spatial heterogeneity in loess sheet preservation showed a complex history of loess accumulation and erosion. A critical profile curvature range of -0.005 to -0.014 (d²z/dx², m⁻¹) for loess erosion derived from a model parameterised in different ways successfully predicted loess occurrence on adjacent slope elements, but incorrectly predicted loess occurrence on an older terrace remnant from which all loess has been eroded. Future analyses incorporating planform curvature, regolith erosivity and other landform parameters may improve identification of thresholds controlling loess occurrence in Charwell Basin and in other South Island landscapes. A loess chronostratigraphic framework was developed for, and pedogenic phases identified in, the three loess sheets mantling the >150 ka terrace. Except for one age, infrared-stimulated luminescence dates from both an upbuilding interfluve loess exposure and colluvial gully infill underestimated loess age with respect to the widespread Kawakawa/Oruanui Tephra (KOT; 27,097 ± 957 cal. yr BP), highlighting the need for improvements in the methodology. Onset of loess sheet 1 accumulation started at ca. 50 ka, with a break at ca. 27 ka corresponding to the extended Last Glacial Maximum (eLGM) interstadial identified elsewhere in New Zealand. Loess accumulation through MIS 3 indicates a regional loess flux, and that glaciation was not a necessary condition for loess generation in South Island. Loess accumulation and local alluvial aggradation are decoupled: the youngest aggradation event only covers ~12 kyr of the period of loess sheet 1 accumulation. Older local aggradation episodes could not be the source because their associated terraces are mantled by loess sheet 1. In the absence of numerical ages, the timing of L2 and L3 accumulation is inferred on the basis of an offshore clastic sediment record. The upbuilding phase of loess sheet 2 occurred in late MIS 5a/MIS 4, and loess sheet 3 accumulated in two phases in MIS 5b and late MIS 6. Biogenic silica data were used to reconstruct broad shifts in vegetation and changes in gully soil saturation status. During interglacial/interstadial periods (MIS 1, early MIS 3, MIS 5) Nothofagus-dominated forest covered the area in association with Microlaena spp grasses. Lowering of treeline altitude during glacial/stadial periods (MIS 2, MIS 3, MIS 5b, late MIS 6) led to reduction in forest cover and a mosaic of shrubs and Chionochloa spp, Festuca spp and Poa spp tussock grasses. Comparison of interfluve and gully records showed spatial heterogeneity in vegetation cover possibly related to environmental gradients of exposure or soil moisture. A post-KOT peak in gully tree phytoliths corresponds to the eLGM interstadial, and a shift to grass-dominated vegetation occurred during the LGM sensu stricto. Diatoms indicated the site became considerably wetter from ca. 36 ka, with peak wetness at ca. 30, 25 and 21 ka, possibly due to reduced evapotranspiration and/or increased precipitation from a combination of strengthened westerly winds and increased cloudiness, or strengthened southerly flow and increased precipitation. Human influence after ca. 750 yr BP led to re-establishment of grassland in the area, which deposited phytoliths mixed to 30 cm depth in the soil. A coupled gully colluvial infilling/vegetation record showed that sediment flux during the late Pleistocene was ~0.0019 m³ m⁻¹ yr⁻¹ under a shrubland/grassland mosaic, and Holocene sediment flux was ~0.0034 m³ m⁻¹ yr⁻¹ under forest. This increase of 60% through the last glacial-interglacial transition resulted from increased bioturbation and down-slope soil transport via root growth and treethrow, which formed a biomantle as evidenced by slope redistribution of the KOT. These results contrast with sediment transport rates and processes hypothesised to occur contemporaneously in adjacent mountain catchments. This suggests that intraregional biogeomorphic processes can differ significantly depending on topography and geological substrate, with different landscapes responding in unique ways to the same climate shifts. Analysis of Quaternary terrestrial landscape evolution in non-glaciated mountainous and lowland areas must therefore consider spatial and temporal heterogeneity in sediment fluxes and underlying transport processes.