Dissertations / Theses: 'Phytolithes'

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Novello, Alice. "Les phytolithes, marqueurs des environnements mio-pliocènes du Tchad. Reconstitution à partir du signal environnemental des phytolithes dans l'Afrique subsaharienne actuelle." Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2303/document.

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Ce mémoire présente l'étude du signal phytolithique de sédiments mio-pliocènes du Tchad(Afrique Centrale) datés entre 7-2 Ma, et contemporains des Homininés anciens Sahelanthropustchadensis et Australopithecus bahrelghazali. Une calibration de la relation plantes-phytolithes-solspour l'Afrique tropicale subsaharienne actuelle a d'abord été réalisée pour apprécier la signatureenvironnementale des phytolithes dans le registre fossile. L'analyse des assemblages phytolithiques de98 espèces de graminées (Poaceae) a permis d'élaborer trois nouveaux indices phytolithiques à partirde 43 types propres aux Poaceae. Testés sur une base de 57 sols/sédiments modernes du Tchad, cesindices permettent de tracer les associations graminéennes aquatiques du Lac Tchad, les associationsmésophytiques des milieux humides soudaniens, et les associations xérophytiques des milieux secssahéliens. L'analyse des assemblages phytolithiques des sols/sédiments actuels considérés dans leurensemble a permis d'évaluer le potentiel de ce proxy à caractériser la physionomie des formationssoudano-sahéliennes modernes. La calibration a été appliquée à l'étude d'un enregistrementsédimentaire discontinu du Lac Tchad (6-2 Ma) (forage de Bol, 13°N/14°E) et à celle de 18 niveauxpaléontologiques du Djourab (7-3.5 Ma) (16°N/17°E). Les résultats indiquent la présence de savanesintermédiaires à fermées et de zones de végétation aquatique dominantes à 7 Ma dans le Djourab, puisde savanes plus ouvertes et sèches à 3.5 Ma. Une phase de bas niveau lacustre est enregistrée entre3.6-2.8 Ma à Bol, et un pic d'aridité à 3.2 Ma. Enfin, les résultats montrent l'existence de graminéesen C4 au Tchad depuis 7 Ma This thesis dissertation is dedicated to the study of the phytolith signal of Mio-Pliocenesediments from Chad (Central Africa) dated between 7-2 Ma, and contemporary to the early Homininspecies Sahelanthropus tchadensis and Australopithecus bahrelghazali. A calibration work studyingthe relationship plants-phytoliths-soils in modern sub-Saharan tropical Africa was carried out in orderto assess the environmental significance of the phytolith signal in the fossil record. Phytolithassemblages produced by 98 sub-Saharan grass species (Poaceae) were analyzed and the results led tothe development of three new phytolith indices defined from 43 types specific to Poaceae. Tested on adatabase of 57 modern soil/sediment samples from Chad, these indices allow drawing aquatic grassassociations of Lake Chad, mesophytic grass associations of wetlands from the Sudanian domain, andxerophytic grass associations of drylands from the Sahelian domain. The analysis of modern soilphytolith assemblages (total assemblages) was used to assess the potential of this proxy to characterizethe physiognomy of the Sudano-Sahelian vegetation types. The calibration had been applied to thestudy of a discontinuous sedimentary record from Lake Chad (6-2 Ma) (Bol core, 13°N/14°E) and of18 paleontological levels from the Djourab (7-3.5 Ma) (16°N/17°E). The results indicate thedominance of intermediate to closed savannas and areas of aquatic vegetation at 7 Ma in the Djourab,and more open and dry savannas at 3.5 Ma. A limited lacustrine stage is recorded between 3.6-2.8 Maat Bol, and a shift of aridity at 3.2 Ma. Finally, the results show the existence of C4 grasses in Chadsince 7 Ma

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Alexandre, Anne. "Phytolithes, interactions sol-plante et paléoenvironnements." Aix-Marseille 3, 1996. http://www.theses.fr/1996AIX30122.

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Les phytolithes sont des particules d'opale-a (sio#2 nh#2o) micrometriques qui precipitent dans et entre les cellules des tissus vegetaux vivants. Le but de ce travail a ete de developper l'etude des phytolithes afin de mieux contraindre la dynamique des sols et les reconstitutions paleoenvironnementales dans la zone intertropicale. Trois etudes sont presentees: 1) le cycle biogeochimique du silicium en foret dense (dimonika, congo) est estime. On montre que entre 2 et 7. 5% de l'apport au sol en silicium biogenique alimentent un pole phytolithique stable. Pour que le systeme soit maintenu a l'equilibre, la vegetation doit absorber du silicium dissous provenant de l'alteration, autrement disponible pour des neoformations ou une exportation hors du systeme, dans les eaux de lessivage. La vegetation augmente donc le taux d'alteration sans augmenter le taux de denudation dans cet environnement. 2) l'analyse morphologique d'assemblages phytolithiques issus de sediments lacustres (lac sinnda, congo et lac de guiers, senegal), montre que les phytolithes sont des traceurs precis de la dynamique des differentes formations herbacees en c4 qui ne sont discriminables ni par analyse pollinique ni par analyse isotopique du carbone. Ce resultat est de premiere importance pour l'etude de la dynamique des zones biogeographiques intertropicales et des phases climatiques ou anthropiques associees. 3) les etudes morphologique, quantitative et en microspectroscopie infrarouge de phytolithes de sol permettent de tracer les processus de translocation, de dissolution et de melange particulaire au sein du profil. On montre que malgre ces perturbations, les assemblages phytolithiques du sol peuvent etre interpretes en terme paleoenvironnemental

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Testé, Marc. "Histoire naturelle des phytolithes des basses-terres mayas : implication pour la reconstitution des Paléoenvironnements et des interactions sociétés-environnements." Thesis, Paris 1, 2020. http://www.theses.fr/2020PA01H023.

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Sous les latitudes tropicales, les phytolithes représentent un indicateur clé dans la reconstitution des paléoenvironnements. Pourtant, ils sont encore modestement utilisés dans les études sur les environnements passés des basses-terres mayas, et ce, en dépit du faible potentiel des autres bioindicateurs de la végétation. C’est dans ce contexte et au travers des riches archives sédimentaires du site archéologique de Naachtun et de ses alentours, que nous proposons une nouvelle approche permettant d’exploiter les avantages inhérents à ces microfossiles siliceux, pour l’étude des environnements passés. Situé à l’extrême nord du Guatemala dans la forêt subtropicale du Petén, le territoire de Naachtun fait l’objet de recherches archéologiques et géoarchéologiques depuis 2010. Par sa localisation géographique au sein des basses-terres et sa proximité aux grands centres politiques mayas, ce site représente un espace clé dans l’évaluation des interactions entre les sociétés mayas et l’environnement au cours des 4 derniers millénaires, problématique principale de ce travail doctoral. Afin d’y répondre, deux axes méthodologiques ont été privilégiés. Le premier axe concerne une démarche actualiste et a pour but de calibrer les assemblages modernes de phytolithes par rapport aux écosystèmes actuels, ‘’naturels’’ et anthropiques, de Naachtun et de sa région. Le second axe, paléoenvironnemental, vise à utiliser les assemblages de phytolithes fossiles, enregistrés en contextes hors-site, dans les sédiments palustres de bajo, et intrasite, afin de proposer une reconstitution de l’histoire socioenvironnementale de Naachtun. Ce travail de thèse démontre le potentiel de ce nouvel outil pour l’approche des paléoenvironnements dans les basses-terres mayas mais il apporte aussi de nouvelles connaissances sur l’utilisation des zones humides par les populations mayas. Plus largement, ce travail s’insère dans la construction actuelle d’un imaginaire des sociétés mayas conscientes de leur environnement et adaptées à ses changements, contre-exemple de nos problématiques et crises modernes In tropical latitudes, phytoliths represent an important indicator of the paleoenvironmental reconstitutions. Yet, they are still modestly used in past environments studies of Mayan Lowlands, despite the low potential of other vegetation bioindicators. It is in this context, and through the rich sedimentary archives of the Naachtun archaeological site and its surroundings, that we propose a new approach to exploit the inherent advantages of these siliceous microfossils for the study of past environments. Located in the extreme north of Guatemala in the subtropical Petén forest, the territory of Naachtun has been the subject of archaeological and geoarchaeological research since 2010. With its geographical location in the middle of the major Mayan political centers, this site represents a crucial space in the evaluation of the interactions between Mayan societies and the environment over the last 4 millennia, the main issue of this doctoral dissertation. To answer this question, two methodological axes have been privileged. The first axis concerns an actualist approach and aims to calibrate modern phytolith assemblages about the current natural and anthropogenic ecosystems of Naachtun and its region. The second axis, palaeoenvironmental, aims to use fossil phytolith assemblages recorded in off-site contexts, in the bajo palustrine sediments, and intra-site, to propose a reconstruction of the socio-environmental history of Naachtun. This thesis research demonstrates the potential of this new tool for the approach of palaeoenvironments in the Mayan lowlands, but it also provides new knowledge on the use of wetlands by Mayan populations. More broadly, this work is part of the current construction of an imaginary of Mayan societies conscious of their environment and adapted to its changes, a counter-example to our modern problems and crises En las latitudes tropicales, los fitolitos representan un indicador esencial en la reconstitución de paleoambientes. Sin embargo, todavía se utilizan modestamente en estudios de ambientes pasados en las Tierras Bajas Mayas, a pesar del bajo potencial de otros bioindicadores de vegetación. Es en este contexto, y a través de los ricos archivos sedimentarios del sitio arqueológico de Naachtun y sus alrededores, que proponemos un nuevo enfoque para explotar las ventajas inherentes de estos microfósiles silíceos para el estudio de los ambientes del pasado. Ubicado en el extremo norte de Guatemala en el bosque subtropical del Petén, el territorio de Naachtun ha sido objeto de investigaciones arqueológicas y geoarqueológicas desde 2010. Por su situación geográfica en las tierras bajas y su proximidad a los principales centros políticos mayas, este sitio representa un espacio crucial en la evaluación de las interacciones entre las sociedades mayas y el medio ambiente durante los últimos 4 milenios, el tema principal de este trabajo de doctorado. Para responder a esta pregunta se han privilegiado dos ejes metodológicos. El primer eje se refiere a un enfoque de actualismo y tiene como objetivo calibrar los ensamblajes de fitolitos modernos en relación con los actuales ecosistemas naturales y antropogénicos de Naachtun y su región. El segundo eje, paleoambiental, tiene como objetivo utilizar los ensamblajes de fitolitos fósiles registrados en contextos fuera del sitio, en los sedimentos palustres de bajo, y dentro del sitio, para proponer una reconstrucción de la historia socio-ambiental de Naachtun. Este trabajo de tesis demuestra el potencial de esta nueva herramienta para el abordaje de paleoambientes en las tierras bajas mayas, pero también aporta nuevos conocimientos sobre el uso de los humedales por parte de las poblaciones mayas. En términos más generales, este trabajo se inscribe en la construcción actual de un imaginario de sociedades mayas conscientes de su entorno y adaptadas a sus cambios, un contraejemplo a nuestros problemas y crisis actuales

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Guntzer, Flore. "Impact de la culture intensive de céréales sur les stocks de silice biodisponible dans les sols européens." Aix-Marseille 3, 2010. http://www.theses.fr/2010AIX30064.

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Le silicium est présent dans les mêmes proportions que la plupart des macronutriments dans les végétaux, et est reconnu pour être un élément bénéfique pour leur croissance. Le silicium a beau être abondant dans le sol, les formes solides sous lesquelles on le trouve ne sont pas disponibles pour les plantes. Dans des écosystèmes naturels, les phytolithes (particules de silice amorphe d'origine végétale) sont l'une des sources de silicium les plus importantes pour les plantes car à pH > 4, leur cinétique de dissolution est plus rapide que celles des minéraux silicates. Or dans les sols cultivés où l'on exporte les végétaux, les phytolithes ne reviennent pas au sol. Nous avons étudié des sols cultivés sous céréales pour mesurer l'impact de l'exportation des récoltes sur le stock de silice amorphe. Il en résulte que tous les sols étudiés sont appauvris. Dans un deuxième temps, nous avons étudié différents amendements en silice. Il en ressort que la restitution de pailles, même sur un laps de temps court, a un réel impact sur les stocks de silice amorphe et pourrait être une méthode simple pour atténuer l'appauvrissement des stocks de silice biodisponible dans les sols cultivés Silicon is found in the same proportions as most macronutrients in plants and is known to be beneficial for their growth. Although silicon is one of the main constituents of soil, most of the forms under which it is found are not available for plants. In natural ecosystems, phytoliths (amorphous silica particle recycled by plants) are one of the main sources of silicon for plants as their dissolution cinetic is way faster than that of other silicate minerals at pH > 4. However in cultuvated soils where the crops are exported, phytoliths do not come back to the soil. We studied soils cultivated with cereals to asses the impact of the exportation of crops on the amorphous silica stock. All studied soils were poor in amorphous silica. We also studied the effect of different Si fertilization. Restoration of straw to the soil, even for a short period of time, has a real impact on the stock of amorphous silica. This means the restitution of straw could be a simple remediation for the decrease of the bioavailable silica stock of cultivated soils

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Pasturel, Marine. "Pour une meilleure représentation de la diversité des biomes herbacés africains dans les modèles de végétation : apports des traits physionomiques, de l’indice de surface foliaire et des phytolithes de graminées." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4316.

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Les biomes herbacés africains intertropicaux devraient faire face, dans un proche futur, à des changements drastiques. Les modèles dynamiques de végétation (DGVM) ont des difficultés à simuler les limites actuelles de ces biomes, notamment parce qu’ils ne prennent pas en compte la diversité des couverts herbacés en C4. Il est donc nécessaire de caractériser cette diversité floristique et physionomique afin qu’elle puisse être facilement prise en compte dans les DGVMs, et que les comparaisons modèle/données (phytolithes) soient possibles.Dans cet objectif, les traits physionomiques des graminées en C4 dominantes au Sénégal et en Afrique du Sud ont été répertoriés. Quatre groupes physionomiques ont été statistiquement discriminés. Ils varient avec la distribution spatiale des biomes et les précipitations régionales. Deux groupes sont fortement corrélés à l’indice de surface foliaire (LAI) et à la biomasse herbacée. Au Sénégal ces deux groupes sont bien différenciés par l’indice phytolithique Iph qui est un proxy des couverts herbacés intertropicaux. En Afrique du Sud, les phytolithes n’ont pas permis de tracer l’ensemble de la transition savane/steppe. Ces deux groupes physionomiques remplissent les critères nécessaires à la caractérisation de types fonctionnels de plantes (PFT). L’intégration de ces PFTs dans le modèle LPJ-GUESS améliore la simulation des biomes herbacés actuels et permet de proposer des simulations pour l’horizon 2100. Ces simulations montrent que l’augmentation de la durée de la saison sèche et de la concentration en CO2 atmosphérique devraient favoriser l’expansion simultanée des steppes et des savanes fermées aux dépens des savanes ouvertes Intertropical african herbaceous biomes are expected to face drastic changes in a near future. However Dynamic Global Vegetation Models (DGVMs) simulate their modern boundaries with poor accuracy, especially at the regional scale. DGVMs fail to consider the diversity of their C4 grass cover. Efforts are thus needed to characterize this floristic and physiognomic diversity in a way that can be used for enhancing DGVMs simulations, and enabling model/data (phytoliths) comparisons. For that purpose, physiognomic traits of dominant C4 grass species settled in Senegal and South Africa were listed. Four grass physiognomic groups were statistically identified. The abundance of four of them significantly varied with biome distributions and regional precipitation. Two grass physiognomic groups were additionally strongly correlated with leaf area index (LAI) and grass biomass. In Senegal, those two groups were also well traced by the Iph phytolith index which is a tropical grass cover proxy. In South Africa the limited set of phytolith data did not allow to observe the full savanna/steppe transition. The two physiognomic groups finally fulfilled the criteria required for creating Plant Functional Types (PFTs). Those new PFTs, parameterized in the LPJ-GUESS DGVM, enhanced the simulation of modern herbaceous biomes distribution in Senegal and South Africa. Simulations were additionally performed for the 2100 horizon. They evidence that the increase of both length of the dry season and atmospheric CO2 concentration should favor the simultaneous spread of steppes and closed savannas at the expense of open savannas

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Crespin, Julien. "Analyse de la composition isotopique en oxygène ([delta][18]O) des phytolithes de bois et des diatomées lacustres pour la mise au point de nouveaux traceurs paléoclimatiques continentaux." Aix-Marseille 3, 2008. http://www.theses.fr/2008AIX30065.

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Ce travail a permis d'appliquer avec succès la technique d'extraction de l'oxygène par. Afin de palier au manque de marqueurs quantitatifs des paléoclimats continentaux, ce travail s'attache à définir de nouvelles relations entre [delta][18]O"silice biogenique", [delta][18]O"eau de formation" et température. Pour ce faire, la technique d'extraction de l'oxygène par fluorination-laser IR a été appliqué avec succès à l'analyse [delta][18]O de très petits échantillons de silice biogénique. Pour la première fois, une relation thermo-dépendante entre [delta][18]O"phytolithes de bois" et [delta][18]O"précipitation" est mise en évidence, pour des assemblages phytolithiques de forêts tropicales humides (Queensland, Australie). Une relation thermo-dépendante entre [delta][18]O"diatomees", et [delta][18]O"eau du lac" obtenue pour le lac d'Annecy confirme les relations mises en évidence pour les diatomées. Ces relations pourront servir de bases à l'interprétation d'enregistrements quaternaires[delta][18]O"phytolithes" (e. G. Région Australo-Pacifique) et [delta][18]O"diatomées" (lacs) In order to compensate for the scarcity of quantitative terrestrial paleoclimate proxies, this PhD thesis aim to define new thermo-dependant relationships between [delta][18]O"biogenic silica" and [delta][18]O"forming water". The IR Laser-Fluorination technique for extracting oxygen was successfully used for analyzing [delta][18]O composition of small to minute samples of biogenic silica. For the first time a thermo-dependant relationship between [delta][18]O"wood phytoliths" and [delta][18]O"rainfall" is evidenced, for phytolith assemblages from rainforests (Queensland, Australia). The thermo-dependant relationships between [delta][18]O"lake diatoms" and [delta][18]O"lake water" obtained from the lake ofAnnecy (France) supports the previous calibration obtained for lacustrine diatoms. These relationships will be used as references for interpreting [delta][18]O"phyitoliths" (e. G. From the Australo-Pacific area) and S^Odiaioms (from lakes) quaternary records

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Fraysse, Fabrice. "Cycle biogéochimique du silicium dans les environnements superficiels continentaux : Impact des plantes terrestres." Phd thesis, Université Paul Sabatier - Toulouse III, 2007. http://tel.archives-ouvertes.fr/tel-00179740.

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Cette étude expérimentale a consisté dans un premier temps en la caractérisation de la réactivité et des propriétés physico-chimiques de microparticules d'opales biogènes appelées phytolithes, pour plusieurs espèces de plantes terrestres provenant de milieux différents. Pour ce faire, une approche combinant plusieurs techniques complémentaires telles que, mesures de solubilité, cinétiques de dissolution, mesures électrophorétiques et titrages acido-basiques, a été menée sur ces phytolithes ce qui a permis de mieux quantifier le cycle biogéochimique du silicium (Si) à travers les plantes terrestres. Dans un second temps et afin de mieux contraindre ce cycle biogéochimique, cette étude a aussi porté sur les interactions de litières de plantes terrestres avec les solutions aqueuses en combinant cette fois des expériences de dégradation de litières dans des réacteurs fermés et dans des réacteurs à circulation. Les résultats démontrent une très forte réactivité des phytolithes et des litières de plantes vis-à-vis du relargage de Si, qui sont au minimum de un à deux ordres de grandeur plus élevés que les minéraux. La quantification du contrôle des phytolithes et des litières de plantes sur le relargage de Si à partir de ces réservoirs solides, démontre la possibilité d'un fort impact des plantes sur le cycle biogéochimique du silicium dans la plupart des environnements terrestres.

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Bremond, Laurent. "Calibration des fonctions de transfert entre assemblages phytolithiques, structure des végétations et variables bioclimatiques actuelles, pour l'intégration de la dynamique des biomes herbacés dans les modèles de végétation." Phd thesis, Aix-Marseille 3, 2003. http://tel.archives-ouvertes.fr/tel-00008000.

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Les formations herbacées actuellement dominantes en zone intertropicale sont mal discriminées par les marqueurs de végétation courants. Ainsi, la modélisation de la végétation et les reconstitutions des climats passés dans ces zones sont limitées. Les phytolithes sont des particules d'opale formées par précipitation de silice amorphe entre et/ou dans les cellules de nombreuses plantes vivantes, couramment utilisés pour tracer la dynamique des formations herbacées. Cependant, les calibrations entre assemblages phytolithiques, végétation et climat sont rares. Cette thèse établit des fonctions de transfert entre indices phytolithiques, caractéristiques des formations herbacées intertropicales actuelles, et contraintes bio-climatiques, en vue de pouvoir intégrer les données phytolithiques à la méthode de biomisation pollinique permettant des reconstitutions de végétation. Ceci permettra d'améliorer et de valider certains modèles prédictifs de végétation. En Afrique de l'Ouest, l'indice Iph permet de différencier les savanes à graminées basses des savanes à graminées hautes. Une fonction de transfert, établie pour estimer l'évapotranspiration (AET/PET), offre de bons résultats, comparables et complémentaires aux estimations fournies par la biomisation pollinique. L'indice Ic étudié sur un gradient altitudinal en Afrique de l'Est estime correctement la proportion des sous-familles graminéennes Pooideae et Panicoideae en zone intertropicale soit, potentiellement, la domination des Poaceae en C4/C3, jusqu'alors difficilement enregistrée. Pour la première fois un marqueur de végétation, l'indice D/P, est calibré de façon quantitative en terme de LAI le long d'un transect forêt-savane. Finalement, une analyse discriminante utilisant la totalité des assemblages permet de définir six biomes phytolithiques. Ces biomes intégrés à la méthode de biomisation pollinique, offriront des reconstructions paléo-environnementales plus précises, notamment les transitions désert/savane/forêt.

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Delhon, Claire. "Anthropisation et paléoclimats du tardiglaciaire à l'Holocène en moyenne vallée du Rhône : études pluridisciplinaires des spectres phytolithiques et pédo-anthracologiques de séquences naturelles et de sites archéologiques." Paris 1, 2005. http://www.theses.fr/2005PA010511.

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L'analyse phytolithique et la pédo-anthracologie sont appliquées à grande échelle en contexte "hors site", en moyenne vallée du Rhône. L'information paléoenvironnementale est déduite des courbes de phytolithes de dicotylédones, de pins et de graminées, d'un nouvel indice phytolithique, le BI (Bulliform Index), qui permet de chiffrer l'évapotranspiration et donc les conditions climatiques, et des listes floristiques obtenues par détermination taxinomique des charbons. A la lumière des résultats obtenus, l'évolution de la végétation de la moyenne vallée du Rhône est divisée en 19 phases (Tardiglaciaire - période actuelle), la relation entre les sociétés et leur environnement naturel est discutée, et des modes de gestion du milieu sont proposés pour certaines périodes clefs (Néolithique moyen, Antiquité, Moyen Âge. . . ). Sur le plan de la biogéographie, certains acquis sont remis en question et de nouveaux éléments sont avancés pour une révision des modèles de peuplement postglaciaires par certaines espèces (hêtre, Rhamnus/Phillyrea), ce qui amène à s'interroger sur la composition de la végétation climacique des étages méso- à supraméditerrannéens dans la vallée du Rhône.

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Garnier, Aline. "La dynamique d’un système fluvial et des zones humides associées en Afrique soudano-sahélienne au cours de l'Holocène : Approches géomorphologique et biogéographique. L'exemple du Yamé au Mali." Caen, 2013. https://tel.archives-ouvertes.fr/tel-01084539.

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Le système fluvial est façonné par des flux hydrologiques et de matières dont la dynamique dépend essentiellement des conditions environnementales au sein du bassin versant. Les enregistrements sédimentaires du fond de vallée représentent alors un indicateur clé de l’évolution des relations Nature/Société. Pourtant, en Afrique de l’Ouest, la recherche s’est souvent concentrée sur d’autres milieux, en particulier lacustres. Dans ce contexte, nous proposons un modèle d’évolution sur le temps long d'un système fluvial afin de s’interroger sur les variables de contrôle (naturelles et/ou anthropiques) ayant pu intervenir. Cette recherche s’appuie sur l’étude du bassin versant du Yamé, un affluent de rive droite du Niger (Pays Dogon, Mali). Deux approches ont été développées : (1) une approche géomorphologique qui permet de reconstituer les dynamiques hydro-sédimentaires de la vallée du Yamé et (2) une approche biogéographique qui, au travers de l’analyse des phytolithes contenus dans les dépôts, nous renseigne sur l’évolution de la végétation au cours de l’Holocène. Ce travail de thèse permet de mieux comprendre les transformations du système fluvial en réponse aux crises climatiques. Enfin, il questionne aussi les conséquences environnementales des transitions économiques, sociétales et techniques des derniers millénaires, telles que l’émergence de l'agriculture, de l’élevage, de la métallurgie et plus récemment l’accroissement de la population. Nous proposons ainsi d’apporter de nouvelles connaissances sur l’évolution climatique et anthropique de l’Afrique de l’Ouest et plus généralement sur l’impact de l’anthropisation sur les systèmes fluviaux soudano-sahéliens The fluvial system is shaped by water discharge and sediment supply which dynamics are depending on the watershed environmental conditions. Valley bottom sedimentary records are also a crucial indicator of the relationships between nature and societies. However, in West Africa, researches were mostly focused on other environments, principally lacustrine environments. In this context, a long term evolution model of the fluvial system is proposed in order to question the acting controlling factors (natural and/or anthropogenic). This research is focused on the study of the Yamé watershed, a right bank tributary of the Niger River (Pays Dogon, Mali). Two approaches were developed to answer the research questions: (1) a geomorphological approach permitting reconstructing the hydro-sedimentary dynamics of the valley and (2) a biogeographical approach informing on the Holocene vegetation dynamics, by means of phytoliths analysis. This work permits better understanding the transformations of the fluvial system as a response to climatic crises. Finally, it questions the environmental consequences of the economic, societal and technical transitions which marked the last centuries such as the emergence of agro-pastoral activities and metal industry or more recently the population growth. This work finally proposes to highlight new knowledge about the climatic and anthropogenic evolution of western Africa, and more globally on the human impact on sudano-sahelian environments

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Hart, Thomas Chesley. "A stroll through the park evaluating the usefulness of phytolith and starch remains found on medieval sherds from Wicken, Northamptonshire, England /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5058.

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Thesis (M.A.)--University of Missouri-Columbia, 2007. The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 3, 2008) Includes bibliographical references.

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Tubb, Helen J. "Anatomical, developmental and physiological aspects of silica in wheat." Thesis, Oxford Brookes University, 1995. https://radar.brookes.ac.uk/radar/items/197165a2-c303-4a80-a9d2-93b8954f4e92/1.

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The major aims of this thesis were to study silica deposits in cereal inflorescences and wheat roots and investigate soluble/deposited silica partitioning and uptake of silica by wheat. The morphology of a particular phytolith (the papilla) from inflorescence bracts of 70 species from Triticum (wheat). Hordeum, Aegilops families and Secale cereale was analyzed. Using papilla pit number and/or diameter it is possible to distinguish between Hordeum sp. and Triticum sp., and between wheats of different ploidy levels. The root growth of T. aestivum was reduced by silica in the nutrient solution (Si+) during the first six days of growth, compared to plants grown in solution not supplemented by silica (Si-), After a further four days Si+ plants had significantly longer roots than Si- plants. At the light microscope level, a time course for silicification of the inner tangential wall of the root endodermis of T. aestivum was elucidated over ten days. Very few walls were silicified after 24 hours exposure to Si+ solution, but by day 10 up to 80% of endodermal cells in the basal area of the root were silicified. The percentage of silicified cells increased from the apex to the base of the root. Silica in T. aestivum was measured quantitatively using a molybdate blue detection method. Typically, 99% of the total silica in the seedlings was in the deposited form. The average concentration of soluble silica within the xylem exudate was 3.6 mM. The uptake of silica was affected by the silica concentration and pH of the nutrient solution. By measuring transpirational water loss and the silica content of the plants, it was concluded that silica uptake was active in T. aestivum. Uptake mechanisms were investigated by growing seedlings in nutrient solutions containing 2 mM Si and an inhibitor for 24 hours. The inhibitors used were ATPase inhibitors ( sodium orthovanadate, diethylstilbestrol, erythrosin B) and ionophores (nigericin, FCCP). The data suggests that functional ATPases and a proton gradient are required for silica uptake. Transport into the xylem and uptake at the root surface may be differentially affected by the inhibitors.

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Blinnikov, Mikhail S. "Late-Pleistocene history of the Columbia Basin grassland based on phytolith records in loess /." view abstract or download file of text, 1999. http://wwwlib.umi.com/cr/uoregon/fullcit?p9948017.

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Thesis (Ph. D.)--University of Oregon, 1999. Typescript. Includes vita and abstract. Includes bibliographical references (leaves 202-211). Also available for download from the Internet; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9948017.

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Gallaher, Kirsten S. L. "Reconstruction of late Holocene vegetation and climate of Hluhluwe Mfolozi area using phytoliths." Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/26585.

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This study presents a phytolith record from a late Holocene sedimentary core from the Hluhluwe-iMfolozi area in northeastern KwaZulu-Natal. Radiocarbon dating showed the oldest sediments to be from 23 80 ± 40 BP. Phytoliths are present throughout the record. There was a high degree of unclassifiable phytoliths (>79% per sub-sample), but preliminary trends identified include a dominance of C₄ grasses throughout (Chloridoideae and Panicoideae; adapted to higher temperatures and greater insolation), and slightly more C₃ grasses (Pooideae; adapted to cooler temperatures and/or winter rainfall) towards the base. The tree cover density index (D/P) does not reflect increased bush encroachment at this site, but appears to show a closed forest at 36cm depth and relatively densely-wooded savannas throughout, while the humidity-aridity index (lph) and water stress index (Fs) suggest a move towards a xerophytic short grass savanna, and increased water stress at the top of the sequence, which could reflect the climate becoming hotter and drier due to global warming. Future studies should be done to identify phytoliths specific to the vegetation of the study site and to calibrate the indices used to confirm their utility for this area.

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Duncan, Neil Andrew. "At the edge of the Puna : archaeological test excavation and sampling for phytolith signatures of ancient corrals at Antibal, Peru /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418014.

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Logan, Amanda Lee. "The application of phytolith and starch grain analysis to understanding formative period subsistence, ritual, and trade on the Taraco Pennisula, Highland Bolivia." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4596.

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Thesis (M.A.)--University of Missouri-Columbia, 2006. The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 21, 2009) Includes bibliographical references.

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Pomerantz, Solomon. "The prehistory of Madagascar : microbotanical and archaeological evidence from coastal and highland sites." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:a0f536e8-9f1f-451b-b02d-cc9365ed3aba.

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Despite nearly one hundred years of archaeological and palaeoecological research in Madagascar, the human colonisation of the island remains poorly understood. Long- standing narratives of this colonisation described the arrival of Austronesian- speaking peoples by AD 400, eventually reaching the Central Highlands by the 12th century. The recent discovery of microlithic tools at the rockshelter of Lakaton'i Anja has radically disrupted conventional narratives for this colonisation by more than doubling the known period of Madagascar's human history, and questioning the presumed Austronesian origins of these first Malagasy peoples. This discovery also challenges existing models for the late Holocene extinction of the island's megafauna. This thesis constitutes the first systematic review in the last thirty years of literature relating to the colonisation of the island, as well as the first to approach this multidisciplinary material in light of new archaeological evidence from Lakaton'i Anja. This study also represents the first comprehensive and comparative phytolith analysis conducted on Madagascar. Despite the wide application of phytolith analysis across regional archaeological and palaeoecological contexts, it has never before been applied here. This thesis explores the botanical impact of these early colonists in and around sites of occupation, as well as tracing the introduction of Asian rice (Oryza sativa) and domesticated bananas (Musa acuminata). New methods of phytolith analysis were developed, adapted, and applied to sediments collected from two seasons of excavations in 2012 and 2013. The sites of Lakaton'i Anja, Mahilaka, and Ankadivory D'Ralambo were re-excavated, as well as the new site of Ampasimahavelona, near Vohémar. This thesis presents and discusses these excavations as well as the earliest evidence for the cultivation of both Musa acuminata and Oryza sativa on Madagascar, and an ultra-high resolution botanical perspective on the last four millennia of Madagascar's prehistory.

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Watling, Jennifer Georgina. "Environmental impact of the pre-Columbian geoglyph builders of Western Amazonia." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/16386.

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A debate that has received much attention in recent years is the nature and scale of pre-Columbian impact in the Amazon lowlands. While the notion that Amazonia is a “pristine wilderness" has long been debunked, several papers have proposed that human impact in western regions was more sporadic and on a smaller scale than impacts in central and eastern regions, and that western Amazonia supported sparse pre-Columbian populations. The discovery of over 400 geometrically-patterned earthworks (geoglyphs) in the western Brazilian Amazon, which until recently lay under in-tact tropical forest, has raised important questions about the kind of societies that built them and the impact that they had on the terra firme upland landscapes. This study represents the very first investigations into human-environment interactions in the geoglyph region. By analysing phytoliths, charcoal and stable carbon isotopes from a series of soil profiles in the vicinities of two well-dated and excavated geoglyph sites, this study aims to discern the nature of the environment before, during and after the construction and use of the sites, and the spatial and temporal scales of landscape transformations that were effected by the geoglyph cultures. The data call for a re-appraisal of what is meant by “scales" of human impact in Amazonia, and propose that an understanding of the diversity of human-environment interactions must be considered through studies that closely combine regionally-sensitive archaeological and palaeoecological data.

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Simone, Yves Claude. "Le Géosystème Dunaire Anthropisé d'Essaouira-Est (Maroc atlantique) : Dynamique et Paléoenvironnements." Phd thesis, Université de Provence - Aix-Marseille I, 2000. http://tel.archives-ouvertes.fr/tel-00171576.

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Le système holocène de la région d'Essaouira connaît une dynamique éolienne très active représentée par un géosystème dunaire littoral dont je recherche la signification en étudiant les interactions entre éléments biotiques, abiotiques et anthropiques, qui définissent ses propres caractères. Leur description forme un premier volet ; une deuxième partie porte sur la dynamique spatiale du géosystème et le troisième volet retrace sa dynamique temporelle à l'échelle de Holocène supérieur, à partir d'analyses sédimentologiques et géo-historiques. Je mets en relief deux géofaciès structurants : un géofaciès dunaire et un géofaciès lagunaire présent dans la partie ouest au contact géosystème / espace urbain. Horizontalement, leur organisation spatiale prend la forme d'une mosaïque où ils s'interpénètrent. Et verticalement, le premier se superpose au second dont la lithomasse limono-argileuse constitue le substratum. Aussi, la partie supérieure de ce dernier forme une surface d'érosion décapée par l'alizé notamment dans le couloir de déflation principal. Cette déflation est mesurée et indique une ablation cumulée de sables et limons de 3 cm/an en moyenne depuis 50 ans. Mais l'efficacité de la dynamique éolienne est aussi démontrée par l'analyse diachronique de photographies aériennes, soulignant l'évolution considérable de la forme et de la répartition des dunes à la périphérie de la ville entre 1953 et 1984. De façon cohérente, l'index de mobilité de Lancaster M = 160 marque une instabilité élevée des versants et des sommets. La réalisation des assemblages de phytolithes actuels calibrés sur la végétation, permet de calculer les index du couvert arboré, de l'aridité édaphique et du climat (d/P = 0,5 ; Iph = 91 % et Ic = 27 %). Ces quantifications montrent le positionnement actuel vers l'aride et le chaud contraignant le géosystème à une mutation accélérée, d'autant plus que l'anthropisation récente exerce une pression élevée et crée des couloirs de déflation hiérarchisés. Ma réflexion porte aussi sur l'étude du passé et des relations à l'environnement naturel. La présence humaine marque le site dès la fin du Néolithique et les rapports mutuels entre nature et sociétés sont jalonnés de crises depuis au moins cinq siècles. Alors que sur le plan morphoclimatique, j'observe un assèchement du climat à partir de 4 350 +/- 120 ans cal BP sur un carottage effectué dans le substratum limono-argileux dont les dépôts paléo-synsédimentaires continentaux sont liés à la régression océanique post-mellahienne. Il apparaît clairement qu'une mutation si rapide du paysage autour d'Essaouira est principalement contrôlée ou incontrôlée par les activités humaines. Un petit « Sahara » s'est formé fonctionnant comme un désert brumeux particulier, unique dans le domaine macaronésien. J'en déduit, d'une part que des boucles de rétroaction (pouvant être récursives) liées au mode d'anthropisation et aux activités humaines se forment dans le géo-système et accroissent sa complexité ; d'autre part, que le paysage en transformation permanente n'est que la partie émergée du géo-système qui tend à assurer son autoconservation.

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Chabot, Yohan. "Approche géomorphologique de la vallée de Deli et étude géoarchéologique du site historique de Kota Cina (Sumatra Nord, Indonésie)." Thesis, Paris 1, 2017. http://www.theses.fr/2017PA01H058/document.

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La reconstitution des paléoenvironnements et la compréhension des dynamiques géomorphologiques sont de plus en plus appréhendées au regard des recherches archéologiques. Toutefois, en Indonésie, cette approche est encore peu usitée. L’étude du site de Kota Cina (Sumatra Nord, Indonésie) entreprise dans le cadre de cette thèse, est un travail pionnier qui vise à comprendre les changements environnementaux à l’interface Homme/Nature, dans le but d’une reconstitution paléogéographique. Cet ancien comptoir commercial portuaire du Détroit de Malacca, actif entre les XIème et XIVème siècles AD, se trouve aujourd’hui à 7 km du rivage. Afin de s’interroger sur les variables de contrôle naturelles et anthropiques de l’évolution paysagère de la région, des investigations ont été menées à Kota Cina et dans la vallée de Deli. Deux approches ont été privilégiées : (1) une approche géomorphologique qui permet de reconstituer les dynamiques hydro-sédimentaires du site et de sa vallée ; (2) une approche biogéographique à travers une analyse du contenu phytolithiques des dépôts de Kota Cina, afin de renseigner l’évolution de la végétation du site. Cette étude met en exergue des évolutions paléoenvironnementales notables, en réponse à des forçages singuliers. Le volcanisme pré-holocène de la région a engendré par son détritisme un remplissage majeur de la vallée. La réponse hydro-sédimentaire holocène a modifié la géomorphologie de la région par une forte incision et un important transfert sédimentaire. Enfin, à l’époque historique, une nouvelle transformation paysagère a eu lieu avec l’anthropisation du milieu, notamment à partir du XIXème siècle avec l’essor des plantations coloniales Paleoenvironment reconstructions and geomorphological dynamics understanding are increasingly being considered with regards to archaeological research. However, in Indonesia, this approach remains unusual. The present study of Kota Cina site (North Sumatra, Indonesia) is a pioneering work that aims to understand environmental changes dynamics at the human/nature interface for the purpose of paleogeographic reconstruction. Kota Cina is an ancient trade harbour of the Strait of Malacca. It was active between the XIth and the XIVth centuries AD. Nowadays, the site is located at 7 km from the coast. In order to examine the implication of natural and anthropogenic factors in the landscape changes of the region, investigations were carried out at Kota Cina and the Deli Valley. Two approaches were developed: (1) a geomorphological approach to reconstitute the hydro-sedimentary dynamics of Kota Cina site and its valley; (2) a biogeographical approach to reconstruct the vegetation changes at Kota Cina from a phytolith analysis of the site deposits. This work highlights important paleoenvironment changes as response to unique forcings. The pre-Holocene volcanism of the region generated a major filling of the valley by its detritism. The Holocene hydro-sedimentary response has altered the geomorphology of the region through a strong incision and significant sediment transfer. Finally, during the historical period, new landscape changes took place with the environment anthropisation, especially from the XIXth century with the development of colonial plantations

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Taylor, Sam. "Reconstructing Historical Vegetation Cover in Otago, New Zealand, Using Multi-proxy Analysis of Peat Cores." Thesis, University of Canterbury. Geological Sciences, 2010. http://hdl.handle.net/10092/4206.

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This research has examined the historical vegetation of two Eastern Otago sites below the regional treeline, with the aim of addressing questions about the distribution and spread of native tussock grasslands prior to human arrival in New Zealand c. 800 yr BP. Pollen and phytolith (plant opaline silicate) proxies have been extracted from peat cores at Swampy Summit and Clarks Junction to provide a record of vegetation spanning the Holocene. Using multiple proxies and two sample sites has allowed for comparisons of the record of vegetation from within sites and between sites. A record of the modern pollen rain was also gathered from localised moss polsters at Swampy Summit in order to reconcile modern pollen assemblages and transport patterns with historical findings. It became clear from the research that the record of vegetation inferred from phytoliths was not analogous to the pollen-based records, which supported the hypothesis that vegetation reconstructions based solely on pollen may be unreliable. Good pollen preservation in the sediments allowed for the identification of over 50 taxa, although only Chionochloid forms were identifiable to a family level in the phytolith records. Poaceae pollen was abundant throughout the Clarks Junction record, suggesting grassland had persisted at this site during the Holocene, while Poaceae pollen at Swampy Summit was minimal and sporadic. Phytoliths at Swampy Summit show grasses have persisted at the site thoughout the Holocene, at times in much greater proportions than the pollen record would suggest, while Chionochloid phytoliths only become common near the top of the record, possibly reflecting increasing dominance of this taxa after human disturbance. In contrast to Swampy Summit, the Clarks Junction phytolith record reflects a more stable presence of grasses throughout the Holocene, with Chionochloid forms present throughout. Phytoliths appear to be a more reliable proxy for local vegetation, with both sites indicating a Holocene presence of grasses below the regional treeline prior to human arrival in New Zealand. In comparison, the pollen record appears to indicate a more regional pattern of vegetation, with the grassland pollen record complicated by pollen dispersal and deposition factors.

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Iriarte, José. "MID-HOLOCENE EMERGENT COMPLEXITY AND LANDSCAPE TRANSFORMATION: THE SOCIAL CONSTRUCTION OF EARLY FORMATIVE COMMUNITIES IN URUGUAY, LA PLATA BASIN." UKnowledge, 2003. http://uknowledge.uky.edu/gradschool_diss/243.

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This dissertation is a multidisciplinary study combining both archaeological andpaleoecological data to examine the rise of early Formative societies in Uruguay, La Plata Basin.It is contextualized within broader anthropological concerns related to the emergence of culturalcomplexity, the significance of ritual and public architecture in intermediate-level societies, andthe role of human-environment interactions during the mid-Holocene. This investigationgenerated the first Late Quaternary paleoclimatic record, based on pollen and phytolith analyses,documenting that the mid-Holocene (ca. 6,620 to ca. 4,040 bp) was a period of environmentalflux and increased aridity. It describes the occupational history of the Los Ajos site from thecreation of a household-based community integrating a centralized communal space during thePreceramic Mound Component (ca. 4,120 – 3,000- 2,500 bp) to the Ceramic Mound Component(ca. 3,000 2,500 bp to the Contact Period), where Los Ajos acquired a strong public ritualcharacter through the formatilization and spatial segregation of its mounded architecture. Duringthe Ceramic Mound Period, the site exhibited both internal stratification (inner versus outerprecincts) and dual asymmetrical architecture in its central sector, which suggest the emergenceof incipient social differentiation. This study also marks the earliest occurrence of at least twodomesticated crops in the region: corn (Zea mays) and squash (Cucurbita spp.), showing that theearly Formative societies adopted a mixed economy shortly after 4,120 bp. Collectively, theseresults challenge the long-standing view that the La Plata Basin was a marginal area byevidencing an early and idiosyncratic emergence of social complexity never before registered inthis region of South America.

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Rocheford, MaryKathryn. "An early to middle Holocene carbon isotope and phytolith record from the Sac Valley Archaeological District, southwest Missouri." Thesis, University of Iowa, 2009. https://ir.uiowa.edu/etd/425.

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New pedologic, carbon isotope and phytolith analyses along with stratigraphic correlations to nearby archaeological sites record the spatial and temporal distribution of past vegetation patterns in the Sac Valley Archaeological District of southwest Missouri. Radiocarbon ages obtained from a soil core along Bear Creek, CB5, are related to those from Hajic et al. (1998, 2000) indicating that the CB5 location contains correlative middle Rodgers Shelter submember deposits. This relationship also indicates that sedimentation was approximately two times greater at the CB5 locality than at the Big Eddy (23CE426) archaeological site providing much higher temporal resolution for the alluvial history as well as the vegetation proxies during the early to middle Holocene. Most midcontinent climate proxy records include indications of an early Holocene warm period when prairie replaced forests, then a cooler period in which trees dominated the landscape, followed by a warmer middle Holocene period when prairie vegetation was dominant. However, the CB5 δ13C profile of mixed C3/C4 vegetation indicates either that the vegetation at this location was not as sensitive to climate change or that this location was buffered from other influences, e.g. fires, which were critical to the expansion of prairie vegetation. On the other hand, the phytolith assemblages at CB5 indicate that there were periods with abundant C4 grasses even though the δ13C values indicate a dominance of C3 vegetation. This indicates that in the mixed forest/prairie ecotone interpretations of past vegetation from either carbon isotopes or phytolith assemblages alone may not accurately reflect patterns of vegetation. A new core, DDY-KR2, was obtained from the Big Eddy (23CE426) archaeological site and a finer resolution of δ13C values at Big Eddy increased the detail about alluvial activity and revealed subtle changes in the vegetation. The vegetation types suggested by the δ13C values for DDY-KR2 are reflected in the phytolith assemblages validating their usefulness in reconstructing local vegetation history.

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Weisskopf, A. R. "Vegetation, agriculture and social change in late Neolithic China : a phytolith study." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/20313/.

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Late Neolithic and Early Bronze Age Central China was the scene of important cultural developments, which impacted on agricultural practices and local vegetation. Using phytolith data from 4 archaeological -sites and a survey of a further 11 sites in Henan this project investigates changing crop choices, developments in crop processing and, to a lesser extent, differing local environments both temporally and spatially. Comparisons of relative levels of phytoliths from crop husks, Panicum, Setaria and Oryza, from each site and period were compared to provide evidence of changes in crop repertoire. Results from these investigations show crop variation both over time and in different parts of the region. Millet farming predominated in the more Northern sites in the Yellow River Valley, while rice was clearly the main crop at Baligang, the southernmost site within the Yangtze catchment. However, rice became more important in the Yellow River valley during the late Neolithic and interestingly despite a changing climate making rice farming more challenging in the Early Bronze Age farmers continued rice cultivation. Crop processing stages were interpreted by examination of differing proportions of phytoliths from crop husks, weed husks and crop and weed leaves which can illustrate differing cultivation systems, harvesting and processing practices. These can be seen especially clearly in the rice data from Baligang suggesting more successful agricultural practices and possible change in social organisation in the Late Neolithic. Evidence of local environmental variation was more challenging to unpick as all the phytolith samples available were from cultural contexts. However, the results of the investigation into the changing local environment reflect other proxy data. Differences in occurrence of specific key phytolith short cell morphotypes and changes in the levels of bulliforms, and cone shaped phytolith morphotypes from Cyperaceae indicating wetland were used to interpret local vegetational change, again both spatially and temporally. Rondel and bilobe shaped short cells represent Pooid and Panicoid grasses respectively and short cell morphotypes, such as rondels, bilobes, saddles, can also be used to track variation in levels of C3 and C4 grasses, so changes in proportions of these morphotypes can indicate larger vegetational change. A comparison between the dataset from Neolithic Central China and one from Neolithic India highlighted possible variations in arable systems with millet and wet rice farming in China contrasting with dry rice in India.

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Webb, Elizabeth A. "Stable isotopic compositions of silica phytoliths and plant water in grasses, implications for the study of paleoclimate." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0021/NQ58164.pdf.

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Madella, Marco. "Morphological analysis of phytoliths : a botanical tool for the interpretation of archaeological and geological sediments from Eurasia." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421361.

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Rocheford, Mary Kathryn Bettis Elmer A. "An early to middle Holocene carbon isotope and phytolith record from the Sac Valley Archaeological District, southwest Missouri." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/425.

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Hilbert, Lautaro Maximilian. "Investigating plant management in the Monte Castelo (Rondônia-Brazil) and Tucumã (Pará-Brazil) shell mound using phytoliths analysis." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/30060.

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Shell mound or sambaqui, as commonly named in Brazil, are anthropic intentional mound constructions made by complex hunter-gatherer fishing communities. Typically distributed along shorelines and inland regions of Brazil, these sites are arguably one of the earliest evidence of human presence in South America, with dates ranging from 910-660 to 10,179-9,708 cal. yr. B.P. As archaeobotanical investigations reported the presence of various plant resources in these sites, a debate that has received much attention in recent years is regarding the scale of which the shell mound builders managed these resources. The Monte Castelo (9,495-9,137 cal. yr. B.P - state of Rondônia) and the Tucumã shell mound (4,425-4245 cal. yr. B.P. - state of Pará) will be the case studies of this research. The aim of this thesis is to use phytolith data from archaeological contexts in order to evaluate and discern the extent to which these mound builders managed plant resources. The outcome of this study provides novel evidence revealing the management and consumption of wild and domesticated plants through the mid-Holocene. The data calls for an evaluation on the potential scale of horticulture practices by Amazonian shell mound builders as well as the relative contribution of each domesticated resources to the indigenous diet.

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Sjöström, Jenny. "Late Holocene palaeoenvironmental reconstruction on a peat sequence from northeastern South Africa, using grass phytoliths as main proxy." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-91882.

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Contemporary a geographical imbalance of where palaeoclimatological studies have been undertaken exists, where the majority of palaeodata is based on studies from the northernhemisphere. Multiproxy analysis was performed on a peat core from Lydenburg, north-eastern Mpumalanga, covering the last 1.600 years. Proxy focus was put on fossil grassphytoliths. A general drying trend can be noted from AD 400 to 1000, followed by moremesic conditions around AD 1200. The increasingly mesic conditions were interrupted by asignificantly drier period between c. AD 1250 to 1350. This part of the Lydenburg sequenceoccurs in the end of a climate event termed “Medieval warm period” (MWP), suggested tohave been warmer and variable but mostly wetter in southern Africa. The results are in lineregarding the increased temperature and suggested variability. However, in contrast withearlier findings, significantly drier conditions seem to have prevailed at the Lydenburg fenat the end of “MWP” as interpreted by multiple proxies. Following AD 1400 increasinglymesic conditions was recorded as interpreted by several of the analysed proxies. Morepalaeoenvironmental studies needs to be performed in the area in order to elaborate on thedriving factors of palaeoenvironmental change in the region, as well as to establish if thesignals from the Lydenburg fen record local or regional changes. The results support earlierphytolith studies suggesting that small rondels should be excluded from phytolithassemblages in tropical and sub-tropical areas in Africa. People, Land, and Time in Africa (PLATINA) Bokoni project. This MA thesis is part of a transdisciplinary project involving scholars from Sweden and South Africa aiming to understand traces of pre-colonial terraces found in north-easter Mpumalanga, South Africa.

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Zhao, Zhijun. "Rice domestication in the middle Yangtze Region, China : an application of phytolith analysis /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9823337.

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Buffington, Abigail Francesca. "Using Phytolith Assemblages to Detect a Pastoral Landscape in Neolithic Wādī Sanā, Yemen." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1566227843382311.

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Walshaw, Sarah Catherine. "Reconstruction of environment in early Bronze Age Syria through phytolith analysis on human dental calculus." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ46995.pdf.

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Ryan, P. L. "Diversity of plant and land use during the Near Eastern Neolithic : phytolith perspectives from Çatalhöyük." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/645476/.

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Based in the Konya Basin of Central Anatolia, the Neolithic site of Çatalhöyük (East Mound) is important to our understanding of the development of early agricultural societies. Occupied between 7400-7100 cal BC to 6200-5900 cal BC, the site is notable for its extended period of occupation, large size and densely packed architecture. Research into Neolithic plant and land use has generally focused upon agricultural crops and the environments in which they are grown, and less is known about the role of wild plants and the non-food use of plants in the later Neolithic. This project used phytolith analysis, a micro-botanical technique, as a way of exploring patterns of plant and land use. Phytoliths present in sediments collected from middens and buildings were analysed to investigate plants exploited for food, fuel, craft activities, and construction. Unusually abundant macroscopically visible silicified (phytolith) remains, including from plant artifacts, also offered direct evidence for certain types and locations of plant-use. A wide range of plant-uses and pathways has highlighted how phytolith assemblages relate to different kinds of ‘input sources’, and how certain environmental habitats may be reflected in the different types of original materials found in archaeological contexts. Quantified analysis of sediments has detected temporal changes in plants present throughout the site occupation, including a dramatic increase in amounts of Phragmites australis. This increase probably reflects the invasive potential of that particular wetland reed, and may be the result of anthropogenic impact. Whilst the use of cereals, in particular wheat, is emphasised, wild plants were also stored for food and used for a wide range of other purposes. The role of wild plants in diversification strategies, together with the sustainability of their exploitation, should be further considered at other Neolithic sites and may have varied in relation to the diversity of Near Eastern environments.

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Boyadjian, Célia Helena Cezar. "Microfósseis contidos no cálculo dentário como evidência do uso de recursos vegetais nos sambaquis de Jabuticabeira II (SC) e Moraes (SP)." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/41/41131/tde-31012008-161121/.

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A análise de microfósseis vegetais é extremamente útil para a recuperação de informações acerca da utilização de plantas por grupo humanos do passado, especialmente em sítios arqueológicos em que os macro-restos botânicos são raros, como é o caso dos sambaquis. Estes micro-restos podem ser obtidos a partir de sedimento, coprólitos, utensílios de pedra ou cerâmica, assim como de cálculo dentário (tártaro). Durante a mastigação e a utilização dos dentes como ferramentas, micro partículas provenientes do alimento ou da matéria prima utilizada, como grãos de amido, fitólitos, fibras, ficam retidas na matriz do cálculo, podendo ali permanecer protegidas por milhares de anos. O tratamento químico do cálculo permite a recuperação destes microfósseis, que, uma vez quantificados e identificados, fornecem dados valiosos para a reconstrução de hábitos e dieta. Entretanto, existem sítios em que, além da má preservação dos macro-restos vegetais, restam apenas escassas marcas de cálculo dentário aderidos aos dentes, impedindo a obtenção de fragmentos de cálculo e conseqüentemente a recuperação dos microfósseis. A utilização de recursos vegetais pelos grupos construtores de sambaquis constitui uma área do conhecimento ainda pouco explorada. Dentre os sambaquieiros há aqueles com depósitos fartos de cálculo dentário, como é o caso em Jabuticabeira II (SC), mas também há aqueles que apresentam somente reduzidos depósitos de cálculo, como é o caso em Moraes (SP). Assim, os objetivos deste trabalho foram: processar e analisar quantitativamente o conteúdo do cálculo dentário de indivíduos de Jabuticabeira II; desenvolver e testar um método alternativo que permitisse a recuperação de microfósseis a partir de marcas de cálculo dentário (.dental wash.); aplicar este método alternativo nos indivíduos de Moraes e comparar os resultados obtidos entre os dois sítios. Através dos resultados obtidos concluiu-se que: - O método .dental wash. é eficiente para a recuperação de micro partículas a partir de marcas exíguas de cálculo dentário, e seus resultados são comparáveis àqueles obtidos através da técnica tradicional. Contudo, o .dental wash. pode tornar os dentes mais friáveis, prejudicando análises morfológicas e de microdesgaste. - Foram observados grãos de amido em praticamente todas as amostras de Jabuticabeira II e Moraes, enquanto fitólitos somente foram encontrados em poucas delas. Isso indica um importante aporte de alimento amiláceo em ambos os sítios, enquanto que apenas 134 alguns indivíduos consumiam uma dieta mais diversificada, constituída em parte de vegetais ricos em fitólitos. - Grãos de amido modificados (em ambos os sítios) e fragmentos escuros de origem vegetal (somente em Jabuticabeira II) indicam o preparo de alimentos através de cocção, maceração, abrasão. - A concentração média dos grãos de amido significativamente maior nas amostras de Moraes em comparação com Jabuticabeira II sugere que o aporte amiláceo tivesse sido maior em Moraes, o que é confirmado indiretamente através da maior freqüência de cáries. -Não parece ter havido distinção no aporte vegetal da dieta entre os sexos, já que não houve diferença das concentrações de amido e fitólitos entre homens e mulheres de Jabuticabeira II e Moraes. The analysis of vegetal microfossils is paramount for the recovery of informations about plant use in past human groups, especially in archaeological contexts where macro remains are poorly preserved (as in shellmounds or sambaquis). Micro remains can be recovered from sediments, coprolites, stone artefacts, pottery, as well as from dental calculus. During the mastication and the use of the teeth as tools, micro particles like starch grains, phytoliths and fibers, become trapped in the dental calculus matrix. Chemical processing of dental calculus permits the extraction of microfossils. Quantification and identification allows reconstruction of habits and diet of past human groups. However, there are sites in which the calculus deposits do not preserve well enough to be processed using the traditional method. The plant use by Brazilian shellmound groups is still an underexplored matter. Among these there are groups like Jabuticabeira II (SC) with large deposits of dental calculus, where the traditional method can be applied, as well as others with just faint dental calculus marks, like Moraes (SP). Therefore, the aims of this work are to: process and analyse dental calculus contents from Jabuticabeira II individuals; develop and test a new method for the recovery of microfossils form cryptic dental calculus marks (dental wash); apply the dental wash in Moraes teeth; and, finally, to compare the results between both sites. The data obtained permit the following conclusions: -The dental wash technique is efficient for the recovery of microfossils from faint dental calculus marks and the results are comparable to those obtained by the traditional method. However, dental wash can preclude morphological and microwear analyses. - Starch grains were observed in almost all samples from both sites but the phytoliths were obtained only from few of them. This indicates that the vegetal diet in these sites was based mainly in storage organs of plants where only few individuals had a more diverse food intake, consuming also vegetal parts rich in phytoliths. - Modified starch grains found in both sites and dark plant fragments (charcoal) found only in Jabuticabeira II suggest food preparation. - The significant higher concentrations of starch grains in Moraes than in Jabuticabeira II, suggests that the intake of carbohydrate rich food was higher in Moraes. Indeed, this is corroborated by a much higher caries rates in the latter site. 136 -The absence of differences of starch and phytolith concentrations between men and women suggest that there was no distinction in the plant food consumed between the sexes.

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Pearce, Madison Natasha. "Laying the Foundation for a Fremont Phytolith Typology Using Select Plant Species Native to Utah County." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6648.

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Archaeobotanical evidences for the presence of wild plants at Fremont archaeological sites are numerous. However, little can be positively argued for why those plants are present, if they were used by site inhabitants, and how they were used. Additionally, there are likely several wild plants that were used but that do not appear in the archaeobotanical record as pollen or macrobotanicals, the two most commonly identified plant remains. I argue that it is possible to provide better interpretations for how and why the Fremont used plants by researching how their historic counterparts, the Goshute, Shoshone, Ute, and Southern Paiute, used the same plants that are identified at prehistoric sites. I further argue that a phytolith typology for Fremont archaeology can provide more insight into prehistoric plant use. I demonstrate its utility through a phytolith analysis of ground stone tools from Wolf Village, a Fremont site in Utah County.

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Albert, Cristóbal Rosa Maria. "Study of ash layers through phytolith analyses from the Middle Paleolithic levels of Kebara and Tabun caves." Doctoral thesis, Universitat de Barcelona, 1999. http://hdl.handle.net/10803/2606.

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The Levant, and Israel in particular, possesses a rich archaeological record of prehistoric caves from the Middle and Upper Paleolithic periods. Some of these caves have been subjected to intensive multidisciplinary studies, providing information not only on the archaeological record, but also on the diagenetic processes that have affected this archaeological record through time. One of the most interesting remains preserved in these caves is the ashy features or hearths. They are usually abundant and often visually well preserved. Ash accumulations are sometimes meters thick. Their presence has made it possible to use and develop new techniques in order to obtain more information about the fire related activities carried out in the cave, the functionality of these hearths and their significance in the social life of past cultures. One of the techniques used for the study of hearths involves the analysis of phytoliths. Phytolith analyses in prehistoric hearths can be used for a variety of purposes. These include the identification of ash remains, even in locations where they are not visible to the naked eye due to diagenetic alteration; the identification, in a specific hearth, of the use of wood/bark as opposed to other types of vegetation such as grasses, and the identification of different species of trees and/or other plants used as fuel in a specific hearth. It is also conceivable that the latter two sources of information could provide indications of possible uses of fire (cooking, warmth, technical purposes, etc.) based on the different fuels used. An interpretation of the phytolith data from an ashy feature or hearth needs to be based both, on the morphological characteristics and the quantitative analyses of the phytoliths. This provides information on the absolute number of phytoliths produced by the trees and other plant taxa present in the area, and on the number of phytoliths per unit weight of sediment. This in tum may indicate, for example, the extent of mixing of ash with other soils, the relative proportions of say wood ash and grasses in a hearth, or the use of fruits from trees or other parts of the trees. This study focuses on the ash layers frorn two prehistoric caves in Israel, Tabun and Kebara, both located on Mount Carmel, Israel (Figure 1). Tabun was occupied during the Lower and Middle Paleolithic periods and Kebara was occupied during the Middle and Upper Paleolithic periods. Both caves have visible hearths, with those in Kebara being particularly impressive. Alternative modes of occupation of Tabun Cave during the deposition of the Mousterian Levels B and C, have been proposed. Garrod & Bate (1937) interpreted the archaeological record of both levels as being indicative of domestic occupationaI activities. Jelinek et al. (1973) proposed that the presence of articulated limb bones of "Dama mesopotamica" in the Level B sediments below the cave chimney, indicated that the cave was used as a natural game trap. They also noted that the white ash layers in Level C extended across the whole cave, and proposed that this was due to the burning of natural vegetation in the cave. The study carried out in Tabun cave aims at clarifying the modes of occupation during these periods. Level B sediments closely resembles the terra rossa soil, that is common in this region. Burning activity is inferred from charcoal fragments observed in thin sections. A minor wood ash component is present based on the preponderance of phytoliths with a variable, irregular morphology, produced mostly in wood and bark as compared to those with a consistent or characteristic morphology, as well as phytoliths with shapes characteristics of those formed in wood and bark of local trees. Thus fires were produced in the cave during this period. The cave may also have been used as a game trap. Level C is composed of multiple layers of brown, black and white sediments. Micromorphology, mineralogy and phytolith analyses all show that these layers are mixtures of terra rossa soil and ash, with the latter being abundant in the white layers. The phytoliths in these layers are derived almost entirely from wood and bark, and not from grasses. These observations are consistent with a domestic occupational mode. Kebara cave is a well studied archaeological site. It contains abundant visible hearths and ash-derived minerals that are the major component of the Mousterian sediments. The latter are in varying states of preservation. Furthermore, archeobotanic information is available from charred remains. Kebara cave is thus an ideal location to study the potential of phytoliths to provide information on the mode of fire used in the cave, to assess the input of other plant materials, as well as to determine the effects of diagenesis on phytolith preservation. Sixteen samples were analyzed in terms of their mineralogy, phytolith contents per unit weight of acid insoluble fraction, and phytolith morphologies. In general the preservation of the phytoliths is good, except for the two samples in which the mineral component at present is largely ash-derived calcite. The cave sediments contain about ten times more phytoliths than those present in the four samples analyzed from outside the cave. The major source of plant material input into the cave is clearly from the wood and bark used for the fuel for fires. The grass phytoliths present in the samples are also thought to have been brought into the cave mainly associated with the wood/bark fuel. Sediments from the hearths, as well as those between the hearths, contain abundant wood/bark phytoliths. The two samples of the latter contain also appreciable amounts of phytoliths not known to be present in wood and bark, as do other hearth-derived samples. Plant materials other than those used as fuel, were thus also brought into the cave. The study about Kebara cave shows that phytoliths analysis, in conjunction with detailed mineralogical, stratigraphic, archaeobotanic and field information, can provide a more complete understanding of the use of plant materials in prehistoric caves for both fuel and other purposes.

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Alves, Daiana Travassos. "Dark Earth plant management in the Lower Tapajos." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/34077.

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The highly fertile Amazonian Dark Earths (ADE) results from landscape transformations found in association with archaeological sites throughout Amazonia. In the Lower Tapajos region, ADEs are found in ancient Tapajó settlements dated to the Late Pre-Columbian period (AD 1000-1600). This research focuses on plant management associated with the regional formation of ADE. Three ADE sites are analysed for microbotanical remains. Phytolith and microcharcoal (< 125μm) from test pits and excavation profiles reveal diverse plant-use including food and non-food plants. Geochemical data indicated a variety of formations processes intra-site. The inter-site comparison indicated a gradiente of vegetation change related with the formation of ADEs. Aditionally, small changes folloed the adoption of cultigens together with ADE formation. These data suggest the practice of polyculture agroforestry in the investigated sites.

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Braune, Caroline [Verfasser], and Thomas M. [Akademischer Betreuer] Kaiser. "Nanoindentation an Phytolithen ausgewählter Nahrungspflanzen herbivorer Säugetiere und der potentielle Einfluss der Härte auf die Usur der Dentition / Caroline Braune. Betreuer: Thomas M. Kaiser." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2015. http://d-nb.info/1068316829/34.

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McCune, Jenny Lyn. "The long-term history of plant communities on southeastern Vancouver Island based on vegetation resurveys and phytolith analysis." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45618.

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Terrestrial plant communities are complex systems, and major storehouses of global biodiversity. The composition of a plant community today is contingent on conditions that have occurred throughout its history. Therefore, an understanding of current plant community structure requires an understanding of its origin and its variability over time. In this thesis, I investigate the history of plant communities on southeastern Vancouver Island, Canada, at two time scales. These communities are now highly fragmented and threatened by human disturbance, but they also have a long history of management by indigenous peoples. To quantify changes due to recent urbanization, I resurveyed 184 vegetation plots originally surveyed in 1968. I documented striking increases in plot-level and total species richness, but a decline in the variation in plant community composition between plots, a phenomenon called ‘biotic homogenization’. Exotic species were more likely than natives to increase over time, but exotic colonizations were not correlated with biotic homogenization or native declines. Plant life history traits predicted colonizations based on landscape context within 500m of a plot, but extirpations were rare and much less predictable, suggesting time lags in plant community response to landscape disturbance and fragmentation, and a potential extinction debt. I used plant microfossils called phytoliths extracted from soil to investigate changes in plant communities prior to European settlement. I established that the ratio of asterosclereid phytoliths produced in the needles of Douglas-fir (Pseudotsuga menziesii) to the rondel phytoliths produced by most grasses can accurately distinguish between Douglas-fir dominated forests and Garry oak (Quercus garryana) savannah habitats today. I then examined changes in this ratio with depth at seven local sites, finding that infilling by Douglas-fir forest first began at different times, depending on the site. However, some savannah sites have supported grassy vegetation for at least two thousand years. Active management to maintain open conditions will be necessary to preserve rare species that evolved in these conditions. These investigations demonstrate that examining the history of plant communities can reveal surprises and challenge assumptions about how they respond to disturbance. This knowledge can improve ecological theory, and inform management and conservation strategies.

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Wilbur, Cricket C. "A History of Place: Using Phytolith Analysis to Discern Holocene Vegetation Change on Sanak Island, Western Gulf of Alaska." Antioch University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1395927847.

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Levin, Maureece. "Food Production, Environment, and Culture in the Tropical Pacific: Evidence for Prehistoric and Historic Plant Cultivation in Pohnpei, Federated States of Micronesia." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/19669.

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Food production, or the cultivation and processing of edible materials, is closely linked to both the physical environment and human social systems. This is especially true on the islands of Remote Oceania, where cultivation of plants introduced with colonization has always been a key component of survival. This project centers on the production systems of an island in the west central Pacific: Pohnpei, Micronesia. It addresses the fundamental question of how food production is related to changes in social and physical environments and also addresses the optimum ways to archaeologically study plant remains in tropical oceanic environments with poor preservation. In order to examine these questions, this project looks at human-environment interrelationships using historical ecology. A multi-pronged approach was used in this research. Archaeological survey was used to identify prehistoric and historic features on the landscape and to map the distribution of food production activities. Excavation of selected archaeological features, including breadfruit fermentation pits, yam enclosures, and cooking features, was conducted to examine formation patterns. Paleoethnobotanical analysis included collection and analysis of flotation samples for carbonized plant macroremain analysis and sediment samples for phytolith analysis. Finally, because a reference collection is key to all paleoethnobotanical research, plant specimens from multiple Pacific locations were collected and processed for phytolith reference. Botanical data show that phytolith analysis is very useful in the Pacific region, as many economically important taxa produce phytoliths. However, because of differential silica uptake, it should be used in conjunction with other methods. Archaeological phytolith analysis of the garden landscape shows disturbance caused by pigs, which were introduced historically, a change from the prehistoric phytolith record, which shows no major shifts. Combined analysis of plant macroremains and phytoliths from secure archaeological contexts shows the use of banana leaves in breadfruit cooking in the historic period, highlighting the importance of multi-method paleoethnobotanical study. These data point towards an anthropogenic environment and stable agricultural system that was present in late prehistoric Pohnpei. Major changes occurred in the historic period, although production of plant foods that were important for centuries continues to flourish today.

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Shillito, Lisa Marie. "Investigating traces of activities, diet and seasonality in middens at Neolithic catalhoyuk : An integration of microstratigraphic, phytolith and chemical analyses." Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529968.

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This research examines formation processes of middens and the associated activities at the site of Catalh6yuk, Turkey. Using this site as a case study, this research has wider significance for understanding the Neolithic of the region and for the study of middens in general. Middens are a unique deposit in that they contain traces of activities that may not be found in cleaner contexts such as floors, and contain materials such as ash, animal dung, phytoliths and coprolites which can inform on plant resource use, diet and subsistence strategies at a high temporal resolution. In this research thin section micromorphology is used, combined with phytolith analysis of individual layers, to examine both the composition and associations of finely stratified midden deposits in situ. Additional analyses of mineral components using FT-IR and SEM-EDX has been carried out, along with biomolecular analysis of organic residues in coprolites by GC-MS, to further characterise material that is difficult to analyse by thin section alone. This integrated analysis contributes to the understanding of midden formation processes and activities, as well as environment, agriculture, plant resource use, diet and fuel use. This analysis has developed a new method for classifying complex midden deposits based on their micro-inclusions and micro-structure, and has identified key deposits such as hackberry pericarps in coprolites, which can potentially be used as seasonal "markers". Examination of midden deposits has provided direct evidence for the use of dung as fuel through the presence of faecal spherulites and reed phytoliths in fuel ash layers, and FT-IR analysis of material embedded in ash indicates clay deposits which could be linked to large open-air firing of pottery. This has wider significance for understanding early pyrotechnology during the Neolithic, and the widespread use of wetland resources i.e. reeds. The dominance of reed phytoliths in the midden assemblage supports the idea of a local wetland environment during the Neolithic. However, thin section observations indicate that phytolith taphonomy at the site is currently poorly understood, and that phytolith size is not a reliable indicator of the growing environment. The samples analysed were found to contain surprisingly few cereals, which also raises questions about the taphonomy of the non-charred cereal remains, and the role of crop growing in the economy. Analysis of coprolites, a frequent deposit in middens, has indicated the presence of lithocholic acid and coprostanol which indicate a human origin for much of this material. This has raised interesting questions on the idea of cleanliness, and has allowed further analysis of diet through observing phytoliths and other inclusions, such as bone, embedded in coprolites, both in situ in thin section, and through examination of extracted phytoliths.

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Morris, Lesley. "Combining Environmental History and Soil Phytolith Analysis at the City of Rocks National Reserve: Developing New Methods in Historical Ecology." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/35.

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Historical ecology is an emerging and interdisciplinary field that seeks to explain the changes in ecosystems over time through a synthesis of information derived from human records and biological data. The methods in historical ecology cover a wide range of temporal and spatial scales. However, methods for the more recent past (about 200 years) are largely limited to the human archive and dendrochronological evidence which can be subject to human bias, limited in spatial extent or not appropriate for non-forested systems. There is a need to explore new methods by which biological data can be used to understand historic vegetation and disturbance regimes over the recent past especially in arid ecosystem types. Soil phytolith analysis has the potential to provide much needed information regarding historical conditions in both areas. Phytoliths are structures formed in plants through deposition and accumulation of silica within and around cell walls that are released from plants and preserved in sediments long after death and decay of plant material. The City of Rocks National Reserve in southern Idaho was an excellent place to develop new methods in historical ecology because the human records of historic environmental conditions were so rich. There were two overarching and interconnected objectives for this dissertation research. The first was to reconstruct an ecological history of the City of Rocks National Reserve from the period of overland emigration to present. The second objective was to explore the utility of soil phytolith analysis for inferring vegetation and disturbance regime change over the recent past by testing its sensitivity to record known changes. I employed modern analogue studies, a multi-core approach and detailed core analysis to test for known changes through analysis of extraction weights, relative abundance of phytolith assemblages, microscopic charcoal and burned (darkened) phytoliths. My results showed that this combination of history and soil phytolith analysis would be a useful approach for inferring vegetation changes (e.g. increases in introduced grasses) and disturbances (e.g. fire) in ecological histories.

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Mann, Nicole Jean. "A reconstruction of the mid-to late Pleistocene plant community along the southwestern coast of South Africa using phytolith evidence." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27237.

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The sites of Elandsfontein (EFT) and Duinefontein (DFT) preserve important records of mid-Pleistocene human occupation along South Africa's southwestern coast. In addition to human fossils in the case of EFT, both sites have produced extensive collections of artefacts and faunal remains. Analyses of the latter have provided the broad environmental contexts for mid-Pleistocene human occupation along this coast. Recently, research into landscape use by mid-Pleistocene human populations at EFT and DFT has highlighted the need for more precise palaeoenvironmental data for the region. In response to this need, I analysed plant phytoliths extracted from sediments sampled at EFT and DFT. The results of this analysis are reported and interpreted in this thesis. To assist with the interpretation of the EFT and DFT phytolith assemblages, I established a modern phytolith reference collection. In addition, pre-existing phytolith collections were examined and literature was consulted. Phytoliths extracted from modern and mid-Pleistocene aged sediments sampled at different localities at EFT and DFT were identified and tallied to determine vegetation composition during the middle Pleistocene. Distinctions were made between "grassier" and "more woody" samples. Analyses of modern plant samples confirmed that grass species produced abundant phytoliths, whereas the majority of dicotyledons did not produce diagnostic morphotypes. Phytoliths belonging to grass species currently growing in the region were identified in the modern sediment samples, as were non-grass phytoliths that included those from woody dicotyledonous and monocotyledon plants. The majority of the mid-Pleistocene sediment samples from EFT produced varying proportions of grass, woody dicotyledon, monocotyledon, sedge and palm type phytoliths which are characteristic of cool-season growing landscapes. In comparison to EFT, the late mid- Pleistocene sediment samples from DFT contained fewer phytoliths. These results suggest that the conditions at DFT were either not conducive to the preservation of phytoliths or that the vegetation was sparse and/or did not produce abundant phytoliths. Where sufficient phytoliths were preserved, assemblages suggested landscapes similar to that of EFT. In summary, analyses suggest that during the middle to late Pleistocene, a heterogeneous vegetation community, consisting primarily of C₃ grasses, woody dicotyledons and other monocotyledonous plants existed along South Africa's southwest coast. Furthermore, results support the longterm presence of the winter rainfall zone in the region. This study demonstrates the potential of phytolith analysis as an important proxy in determining the composition of palaeo-vegetation communities in South Africa. Although there were limitations that necessitated the broad classification of phytolith groups, the study nevertheless provided more precise information, particularly about mid-Pleistocene vegetation structure, that was not previously available.

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奥野, 充., Mitsuru OKUNO, 俊夫中村 та ін. "北部九州の樫原湿原におけるボーリング・コア試料 (KS0412-3)の分析結果(速報)(タンデトロン加速器質量分析計業績報告2004(平成16)年度)". 名古屋大学年代測定資料研究センター, 2005. http://hdl.handle.net/2237/13640.

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Rodríguez, Antón David. "Ocupación e impacto humano en la alta montaña durante la prehistoria. Un estudio arqueoambiental de Aigüestortes (8 – 4 ka cal BP) mediante el análisis de fitolitos." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/669526.

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Aquesta tesi doctoral investiga sobre el poblamiento prehistòric a l’alta muntanya dels Pirineus catalans occidentals, més concretament, al Parc Nacional d’Aigüestortes i Estany de Sant Maurici (Lleida). En particular, aquest treball de recerca es distingeix per presentar una proposta metodològica innovadora, que contribueix a l’estudi de l’ocupació humana de les muntanyes durant el Neolític. La metodologia arqueològica desenvolupada s’adreça a la detecció de les activitats productives realitzades per les comunitats agroramaderes prehistòriques, la seva gestió ambiental i el seu impacte en el medi. Amb aquest objetiu s’han analitzat els fitòlits procedents de diferents tipus de dipòsits sedimentaris. Aquestes microrestes són cossos silicis produïts per les plantes, que ens informen de la composició vegetal dels sediments. Els fitòlits son un bon indicador per a l’estudi de les activitats que les societats feien amb les plantes i la conseqüent generació de paisatges socials. L’anàlisi de fitòlits s’ha integrat en aquesta tesi com una eina per a l’estudi de les ocupacions prehistòriques en zones d’alta muntanya dels Pirineus per primer cop. A més, com a proposta d’investigació bioarqueològica integradora, els resultats obtinguts s’han interpretat tenint en compte altres restes biològiques presents als sediments analitzats, com ara els carbons, el pol·len, les diatomees o la matèria orgànica. Esta tesis doctoral investiga sobre el poblamiento prehistórico de la alta montaña en los Pirineos catalanes occidentales, concretamente, en el Parque Nacional de Aigüestortes i Estany de Sant Maurici (Lleida). En particular, este trabajo de investigación se distingue por presentar una propuesta metodológica innovadora, que contribuye al estudio de la ocupación humana de las montañas durante el Neolítico. La metodología arqueológica desarrollada se enfoca en la detección de las actividades productivas realizadas por las comunidades agropastorales prehistóricas, su gestión ambiental y su impacto en el medio. Para ello, se han analizado los fitolitos procedentes de diferentes tipos de depósitos sedimentarios. Estos microrestos son cuerpos silíceos producidos por las plantas, que nos informan de la composición vegetal de los sedimentos. Los fitolitos son un indicador de las actividades realizadas por las sociedades con las plantas y su impacto en el paisaje. El análisis de fitolitos se ha integrado como una herramienta para el estudio de las ocupaciones prehistóricas en la alta montaña de los Pirineos por primera vez. Además, como propuesta de investigación bioarqueológica integral, los resultados obtenidos en esta tesis se han interpretado en relación con otros restos biológicos documentados en los sedimentos analizados, como los carbones, el polen, las diatomeas o la materia orgánica. This Ph.D dissertation focuses on the prehistoric settlement at high mountain areas of the western Catalan Pyrenees, particularly, in Aigüestortes i Estany de Sant Maurici National Park (Lleida). More specifically, this research work distinguished by an innovative methodological approach, which contributes to the study on human mountain occupation during Neolithic. The archaeological method is focused to detect the activities carried out by these agropastoral populations, the natural resources exploited and the impact caused on environment. Different sedimentary deposits were studied, in order to analyse silica phytoliths. They are siliceous bodies produced by plants, used as a proxy for detecting human activities on plants and their impact on landscape. Phytolith analysis is integrated as a tool for studying the prehistoric occupations in the high-altitude areas at the Pyrenees for the first time. In addition, into an integrated bioarchaeological approach, the results obtained are interpreted taken into account other biological remains analysed in sediments, such as charcoal, pollen, diatoms and organic matter.

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Macedo, Rodrigo Santana. "Pedogênese e indicadores pedoarqueológicos em terra preta de índio no município de Iranduba - AM." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-14042014-164952/.

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Uma evidência contundente da ocupação pré-histórica na Amazônia são os solos de cor escura com material arqueológico, conhecidos regionalmente como Terra Preta de Índio (TPI). Apesar de amplamente estudados, alguns de seus atributos permanecem ainda pouco conhecidos, especialmente os micromorfológicos, mineralógicos e geoquímicos. Esses estudos podem identificar os processos envolvidos na gênese e evolução desses solos, e quando empregados em conjunto com estudos fitolíticos, podem auxiliar na elucidação das suas formas de uso pretéritas. O objetivo desse estudo foi obter uma aproximação da hierarquia dos processos envolvidos na gênese desses solos e as suas prováveis formas de uso em tempos pré-colombianos. A pesquisa foi conduzida no Campo Experimental do Caldeirão, Iranduba - AM. Foram estudados dois perfis com TPI (P1 e P2) e um solo adjacente com horizonte A moderado (P3). Em cada horizonte foram coletadas amostras deformadas para análises físico-químicas, mineralógicas e geoquímicas e a cada 5 cm de profundidade para análise fitolítica e isotópica. Lâminas delgadas de amostras indeformadas de horizontes selecionados foram confeccionadas e descritas em sua micromorfologia, com posterior exame em microscópio eletrônico de varredura com microanálise química. A idade dos solos foi estabelecida com base em datações 14C de carvões. A microestrutura granular das TPI é de origem zoogenética e geoquímica. A gênese dos horizontes antrópicos envolveu: i) a ação do homem descartando e queimando resíduos (antropização); ii) espessamento do horizonte A e escurecimento dos horizontes subsuperficiais por bioturbação (cumulização e melanização); iii) dispersão e translocação de colóides (argiluviação); iv) condições pedoambientais diferentes das atuais (pedorrelíquia - nódulos ferruginosos). Revestimentos de argila com extinção forte, contínua e estriada nas cerâmicas indica que o processo de argiluviação é atual. O processo de elutriação predomina no solo não antrópico. A degradação dos nódulos de ferro na TPI favorece a xantização e atua como fonte de argila (pedoplasmação). Arecaceae e Cyperaceae são mais abundantes nos horizontes antrópicos, notadamente nos níveis com maior quantidade de cerâmica. A ausência de fitólitos de plantas domesticadas indica que a formação das TPI não está relacionada com práticas agrícolas. As evidências fitolíticas demonstram que as atividades antrópicas ocorreram de forma mais intensa no P1. A rápida ciclagem de silício, evidenciada pela presença de fitólitos com silicificação incompleta, favorece a estabilidade da mineralogia caulínitica. VHE, ilita e variscita-estrengita ocorrem somente nos perfis com TPI. P2O5-CaO-K2O-NaO-Cs-Co-Zn-Cu-Ba-Rb-Ni representa a assinatura geoquímica das TPI. A presença de variscita-estrengita, tridimita e maghemita nas TPI, notadamente nas cerâmicas, confirma a formação de minerais em decorrência das práticas antrópicas. As cerâmicas apresentam predominantemente cauixi (Tubella reticulata e Parnula betesil) e cariapé (Licania utilis). A presença comum de micas primárias nesses artefatos sugere material alóctone em seu fabrico. As TPI resultam da adição de artefatos arqueológicos e melanização de horizontes pedogenéticos não antropizados. Tais atividades enriqueceram em nutrientes e alteraram a assinatura geoquímica do solo, assim como promoveram a formação de minerais. Essa antropização acelerou os processos de argiluviação e de degradação de petroplintitas. No decorrer de sua evolução, foram utilizados e adicionados resíduos de plantas, destacadamente de palmeiras e Cyperaceae. A remarkable evidence of human occupation in Amazonian region is the existence of soils with dark colors and presence of ceramic materials, known as Indigenous Dark Earth (IDE). Despite of widely studied some of their features are still poorly understood, mainly that related to micromorphology, mineralogy and geochemical aspects. Such approach, in combination to phytolytic studies, is able to identify soil genesis processes and unravel the comprehension of occupation mechanisms of human. The aim of this study was to establish the hierarchy of these processes and their association with ancient activities of pre-Columbian populations. The research was carried out in the experimental site of Caldeirão, Iranduba city (Amazon state, Brazil). Two pedons containing surface anthropogenic horizons (P1 and P2) were directly compared to a non-anthropogenic soil (P3). In each soil horizon disturbed soil samples were sampled in order to perform physical, chemical, mineralogical and geochemical analyses. For phytolitic analyses samples were taken each 5 cm of depth. Micromorphological samples were studied in thin sections in the optical microscope and further analyzed in Scanning Electron Microscopy (SEM). The chronology was accomplished after 14C dating. The microaggregates in anthropogenic horizon are related to geochemical and biological processes. The genesis of IDE implicates in the following mechanisms: i) disposal and burning of residues by humans (anthropization); ii) deepening A horizons and darkening subsurface horizons by bioturbation (cumulization and melanization processes); iii) dispersion and migration of colloidal particles leading to argiluviation process; iv) different condictions of environment that not occur nowdays (pedorelict - ferruginous nodules). Clay coatings with extinction bands and continuous orientation in the ceramic artifacts suggest a current argiluviation process. The degradation of Fe nodules enhances the xantization process also providing clay (source of clay). The prevalent soil genesis in non-anthropic soil is the elutriation. The degradation of Fe nodules in the IDE enhances the xantization process also providing clay (pedoplasmation). The number of phytoliths of Arecaceae and Cyperaceae is higher in IDE than non-IDE, mainly in the horizons with more ceramics. The phytolitic evidence demonstrate that activities anthropic was more intense in the P1. The rapid Si cycling, highlighted by the presence of phytoliths without complete silicification, contribute to stability of kaolinitic mineralogy. HIV, illite and variscite-strengite are constrained to IDE pedons. P2O5-CaO-K2O-NaO-Cs-Co-Zn-Cu-Ba-Rb-Ni represents the geochemical signature of IDE. The presence of maghemite, variscite-strengite and tridimite strengthen a mineral forming process linked to human activity. In ceramic materials there is a prevalence of phytoliths from cauixi (Tubella reticulata and Parnula betesil) and cariapé (Licania utilis). The presence of mica suggests an alloctone material for their manufacturing. Hence the anthropic horizons result from the addition of archeological artifacts and melanization of non-anthropic horizons. These activities chemically enriched and modify the geochemical signature of soil, as soon as promoted formation of minerals. The anthropic activities conducted the argiluviation and degradation of Fe nodules. During their evolution there was a clear addition of plant residues, notably related to palm trees and Cyperaceae species.

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Boyadjian, Célia Helena Cezar. "Análise e identificação de microvestígios vegetais de cálculo dentário para a reconstrução de dieta sambaquieira: estudo de caso de Jabuticabeira II, SC." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41131/tde-16102012-102717/.

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Embora os indivíduos construtores dos sambaquis constituam o grupo pré-histórico brasileiro melhor estudado, várias questões continuam em aberto. Algumas delas estão ligadas a estratégias de subsistência. Sabe-se que a economia desses indivíduos era baseada na pesca e que a coleta de moluscos teria papel complementar na alimentação. Mas, atualmente, estudos antracológicos e de cálculo dentário vêm demonstrando a grande importância da utilização de plantas pelos sambaquieiros. Entretanto, pouco se conhece sobre as espécies consumidas e o modo de preparo dos alimentos. O sambaqui Jabuticabeira II, localizado na região sul de Santa Catarina, apresenta indícios da utilização de plantas que incluem: artefatos líticos que se acredita que tenham sido usados para raspar, moer e quebrar vegetais; sementes de famílias de plantas que produzem frutos comestíveis; coquinhos; e restos carbonizados de lenho de uma grande diversidade de espécies. Além disso, notou-se grande número e variedade de grãos de amido no cálculo dentário dos indivíduos sepultados nesse sambaqui, sugerindo que o consumo de vegetais ricos em amido teria sido grande. O presente estudo trata, portanto, da análise de 119 microvestígios vegetais de cálculo dentário de 19 adultos de Jabuticabeira II, objetivando avaliar se ocorria, de fato, um consumo de grande variedade de vegetais amiláceos, bem como identificar quais plantas foram consumidas. Para possibilitar tal identificação, foi iniciada a elaboração de uma coleção de referência de grãos de amido de plantas nativas da região. A partir dos resultados obtidos sugere-se que os sambaquieiros de Jabuticabeira II consumiam uma grande variedade de plantas ricas em amido. Embora o número de microrrestos vegetais variasse bastante entre os indivíduos, aparentemente, não ocorria diferença quanto a dieta vegetal de acordo com sexo, classe etária ou lócus de enterramento. A presença de diatomáceas de ambientes de água salobra indicam que os recursos faunísticos consumidos eram obtidos a partir da paleolaguna. Eram consumidos órgãos de reserva subterrâneos de aráceas (inhames), Dioscorea sp. (carás), Calathea SP. (ariá) e Ipomoea batatas (batata-doce) e, possivelmente, frutos das famílias Myrtaceae (incluindo Eugenia uniflora - pitanga) e Arecaceae (palmeiras). Acredita-se que o milho (Zea mays) também fazia parte da dieta, embora não tenha sido possível discernir se era cultivado nesse sitio, ou se foi obtido através de troca com grupos cultivadores de outras regiões. Ainda que fitólitos de gramíneas possam ter sido acidentalmente incorporados ao cálculo dentário dos indivíduos de Jabuticabeira II, sugere-se que algumas gramíneas poderiam ter sido utilizadas, não somente como alimento, mas também com fins medicinais ou de higiene oral. O alimento de origem vegetal parece ter sido processado através de moagem ou maceração, assado em brasas ou cinzas ou, ainda, preparado em fornos escavados. As evidências obtidas neste trabalho não apontam para o cultivo intensivo das plantas que eram utilizadas na dieta desse grupo, mas não corroboram, nem descartam a hipótese de que o manejo ou horticultura de alguns taxa florísticos importantes tenha ocorrido The sambaqui (shellmound) builders are the best studied ancient human group from Brazil. However, much has still to be discovered about them. It is very well known that their subsistence was based on fishing and that molluscs\' gathering was a complement to their diet. Recently, anthracology and dental calculus studies have shown the importance of plants, but very little is known about the species eaten and the processes that were used for food preparation. The Jabuticabeira II sambaqui, located in southern Santa Catarina, shows evidences of plant use that include: lithic artifacts related to food processing; seeds from plant families that produce edible fruits; palm nuts; and remains from carbonized wood from a variety of species. Besides that, a high number and variety of starch grains were recovered from the dental calculus of some skeletons, suggesting that the consumption of starchy plants was important. For the present study, plant microfossils (n=119) recovered from the dental calculus from 19 adults exhumed from Jabuticabeira II shellmound were analysed, in order to identify the species consumed and to test if, in fact, their diet consisted of a high variety of starchy plants. To allow identification, the construction of a starch reference collection from plants from the studied region was initiated. The results suggest that the individuals buried at Jabuticabeira II indeed ate a high variety of starchy plants. Despite the inter- individual variation in the number of microfossils, there seems to be no difference in the plant intake according to sex, age class and burial site. The diatoms from brackish water that were also found indicate that the faunal resources consumed were obtained from the paleolagoon nearby. Underground storage organs from the Araceae family (arum family), Dioscorea sp. (yams), Calathea sp. (llerén), Ipomoea batatas (sweet potato), and possibly fruits from the Myrtaceae family, including Eugenia uniflora (pitanga), and Arecaceae family (palm trees) were eaten. Although corn starch (Zea mays) grains were also identified, it is not yet clear if it was cultivated in Jabuticabeira II, or if it was obtained through exchange with cultivators from other sites. The grass leaf phytoliths that were also recovered suggest that plants from the Poaceae family could have been used as medicine or for oral hygiene. Plant food seems to have been processed through grinding, toasting in ashes, and maybe in underground ovens. Finally, there is no evidence that suggests that plants were cultivated in Jabuticabeira II, but the management of some botanical taxa cannot be excluded

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King, Daniel James. "Reconstructing Prehistoric Human/Plant Relationships at Casas Grandes, Chihuahua, Mexico Through a Microfossil Analysis of Dental Calculus." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6367.

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As part of a multinational project and with the help of other professionals, I gathered and analyzed 110 samples of dental calculus (fossilized plaque) from human remains discovered at Paquimé and the Convento site in the Casas Grandes River valley to identify various microfossils still present in the silica matrix. Once identified, I used the results to reconstruct human/plant relationships present during the Viejo (700-1250 CE) and Medio (1250-1450 CE) periods in and around Paquimé. My data suggest that maize was used throughout both time periods, supplemented by wild plants, and possible marine resources. Further, evidence for cultural food modification methods such as fermentation, roasting, grinding, and nixtamalization (an alkaline treatment of the grain) was present. The data suggest prehistoric plant use went beyond simple subsistence, being modified for use as part of non-subsistence activities.

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Nakamura, Ryosuke. "Diversity of silicon uptake by tropical forest trees and its implication for biogenic silicon flux through leaf-litter." Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/253319.

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付記する学位プログラム名: グローバル生存学大学院連携プログラム 京都大学 0048 新制・課程博士 博士(農学) 甲第22483号 農博第2387号 新制||農||1075(附属図書館) 学位論文||R2||N5263(農学部図書室) 京都大学大学院農学研究科森林科学専攻 (主査)教授北島薫, 教授神﨑護, 教授北山兼弘 学位規則第4条第1項該当 Doctor of Agricultural Science Kyoto University DGAM

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Dissertations / Theses on the topic 'Phytolithes'

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