Thesis (M.A.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 16, 2008). Includes bibliographical references (p. 101-111).

Thesis (M. A.)--Memorial University of Newfoundland,1999. / Bibliography: leaves 115-127.

Thesis (Ph. D.)--University of California, Santa Barbara, 1988. / Typescript. Vita. Includes bibliographical references (leaves 411-440).

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Glen H. Doran, Florida State University, College of Arts and Sciences, Dept. of Anthropology. Title and description from dissertation home page (viewed June 13, 2006). Document formatted into pages; contains xii, 126 pages. Includes bibliographical references.

xxviii, 463 p. : ill., maps. A print copy of this title is available through the UO Libraries under the call number: KNIGHT F868.M65 J45 1991 / The environmental context and chronology of the transition from Early Holocene Lake Mojave to Middle Holocene Pinto cultural complexes of the southern California deserts has long been debated. This dissertation re-examines that debate, based on excavations at two major sites, and a rethinking of our most basic assumptions concerning culture change, cultural ecology, site formation processes, and dating techniques. Archaeological data recovered from two Lake Mojave/Pinto sites at Fort Irwin, in the Central Mojave Desert, were analyzed in order to track chronologically sensitive shifts in Lake Mojave-Pinto artifact assemblages through time. The archaeological assemblages recovered from Rogers Ridge and the Henwood sites were carefully analyzed into 36 depositional/analytical components for this task. Defining and chronologically ordering these assemblages required systematic consideration of artifact distributions and the development and application of 3 obsidian hydration rates based on associations with twelve 14C dates. The analysis shows that the Pinto Complex occurred in three phases. Phase I, ca. 8,200 to 7,500 BP, is marked by the addition of Pinto points to the Lake Mojave assemblage and a continuation of the basic Lake Mojave settlementsubsistence patterns. Phase II, 7,500 to 5,000 BP, is marked by the gradual disappearance of Lake Mojave points from the archaeological assemblages. Dramatic decreases in assemblage size and increases in assemblage diversity mark changing logistical strategies to infrequent and specialized site use. Phase III, 5,000 to 4,000 BP, is marked by a strong predominance of Pinto points and slightly larger assemblages. Patterns of variation among assemblages suggest that logistical strategies continued to emphasize infrequent and specialized site useage. The link between environmental change and shifting settlement-subsistence strategies was apparently relatively direct during the Pinto period, Environmental changes during the Early Holocene (11,000 to 8,000 BP) Mojave Desert led to subsistence stress among populations of the Pinto Complex. Cultural adjustments resulted in smaller human populations moving through larger home territories. It is suggested that critical thresholds in communication and mating networks were crossed which resulted in the collapse of social systems in the Mojave Desert about 7,000 BP. / Committee in charge: C. Melvin Aikens, Ann Simonds, Don E. Dumond, and William Loy

xvii, 205 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Fire is a fundamental, transformative, yet poorly understood process in the Earth system; it can radically reorganize ecosystems, alter regional carbon and energy balances, and change global climate. Short-term fire histories can be reconstructed from satellite (seasonal- to interannual-scales), historical (decadal scales), or dendrochronological records (for recent centuries), but only sedimentary charcoal records enable an analysis of the complex interactions between climate, vegetation and people that drive fire activity over longer temporal scales. This dissertation describes the compilation, synthesis and analysis of a global paleofire dataset and its application to understanding past, current, and future changes in fire activity. Specifically, I co-led efforts to compile charcoal records around the world into a single database, and to conduct three meta-analyses to understand the controls on fire at multiple spatial and temporal scales. The first meta-analysis reconstructed global biomass burning since the Last Glacial Maximum (LGM) 21,000 years ago. Results from this study demonstrated that global fire activity is low when conditions are cool and high when conditions are warm. This fundamental relationship between climate and fire is due in large part to associated changes in vegetation productivity. The second meta-analysis examined fire activity in North America during past abrupt climate changes and looked for evidence of continental-scale wildfires associated with a hypothesized comet impact ∼13,000 years ago. This analysis found a correlation between increased fire activity and abrupt climate change, but provided no evidence for continental-scale wildfires. A final meta-analysis disentangled the climate and human influences on global biomass burning during the past 2000 years; it found a close relationship between climate change and biomass burning until ∼1750 A.D., when human activities became a primary driver of global fire activity. Together, these three meta-analyses demonstrate that climate change is the primary control of global fire activity over long time scales. In general, global fire activity increases when the Earth's climate warms and decreases when climate cools. The paleofire data and analyses suggest that the rapid climate changes projected for coming decades will lead to widespread increases in fire frequency and biomass burning. This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Patrick Bartlein, Chairperson, Geography; Daniel Gavin, Member, Geography; W. Andrew Marcus, Member, Geography; Cathy Whitlock, Member, Geography; Ronald Mitchell, Outside Member, Political Science

La calotte polaire du Groenland retient dans ses glaces une contribution potentielle au niveau des mers de 7,3 mètres. Alors que des changements importants sont observés à l'heure actuelle, réaliser des projections sur son état futur à l'échelle pluri-centennal est devenu une priorité. La modélisation numérique 3D est l'un des outils pour effectuer ces projections. Ce travail incorpore largement l'utilisation des carottages profonds du Groenland, qui rassemblent une grande part d'information sur les états passés. Ainsi, l'accent est ici mis sur les validités des reconstructions effectuant constamment des aller-retour entre observations et simulations. La robustesse de ces reconstructions et des projections futures est largement questionnée au travers de nombreuses expériences de sensibilité. La calibration du modèle de glace en utilisant des contraintes sur les informations de la dernière déglaciation permet de proposer des scénarios sur l'état de la calotte au cours du précédent interglaciaire, l'Eémien, potentiel analogue pour le climat futur. / The Greenland ice sheet represents a potential sea level rise contribution of 7.3 meters. When drastic changes are recently observed, multi-centennal futur projections are urgently needed. 3D numerical modelling is one of the tools to realize these projections. This work intensively incorporates the use of Greenland deep ice core drillings, which represent an important amount of information of past states of the ice sheet. The validity of the reconstructions are thus assured by constant back and forth between observations and simulations. Robustness of these reconstructions and of future projections are largely questionned through wide sensitivity experiments. The ice sheet model calibration is performed during the last deglaciation considering the numerous constraints during this period. Given that, scenarios of ice sheet states during the whole last climatic cycle, in particular during the last interglacial, the Eemian, potential analogue for a future climate.

Made available in DSpace on 2014-06-11T19:24:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-29Bitstream added on 2014-06-13T20:51:43Z : No. of bitstreams: 1 cabrera_jia_me_prud.pdf: 4667317 bytes, checksum: 4a617550148d2b871f7300488be03210 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho é mostrar a contribuição que uma pesquisa arqueológica pode oferecer à compreensão da formação do espaço geográfico e suas transformações. Tanto para a Geografia quanto para a Arqueologia é fundamental o estudo das técnicas, pois é através delas que o homem pode medir seu nível cultural. Tentar entender e compreender que essas técnicas são a peça chave para saber quais eram os hábitos e costumes dos povos pré-históricos, pois através dessas técnicas é que podemos saber quais eram seu modo de vida e sua relação com o espaço ocupado. Com isso podemos ver que numa análise mais abrangente através do conhecimento de técnicas, podemos estar descrevendo os costumes dos povos que habitaram determinada região. Neste aspecto, o projeto tem por objetivo analisar o material arqueológico encontrado durante as escavações, procurando identificar, através de um sítio definido, que servirá como parâmetro, quais as técnicas utilizadas pelos povos pré-históricos que habitaram a região, bem como compreender e identificar qual a origem desses povos, e a que grupos pertenciam, bem como a forma pela qual eles se relacionavam com o meio natural para a construção do espaço geográfico no qual habitaram no passado. Identificando esses povos não apenas estaremos descobrindo uma parte de nossa própria história regional, bem como avançando na compreensão da evolução do homem enquanto agente transformador do espaço em que habitava e interagia. / This work is a contribution to archaeological research that can provide the understanding about the formation of geographical space and their transformations. Both for the Geography and the Archeology the study of techniques is fundamental, for it is through them that man can measure their cultural level. Trying to understand and realize that these techniques are the key to what the habits and customs of prehistoric people were, because through these techniques is that we can know what were their way of life and their relation to space. With this we can see that in a more comprehensive analysis of their techniques we can describe the customs of peoples who inhabited a region. Here, the project aims to analyze the material found during the archaeological excavations, seeking to identify, through a established site to serve as a parameter to which techniques were used by prehistoric peoples who inhabited the region, and understand and identify which origin of these peoples and groups that belonged, and the way in which they interact to the natural environment for the construction of the geographical area in which they inhabited in the past. By identifying these people, we will not only discover a part of our regional history, as well as advancing the understanding of the evolution of man as an agent of transformation of the space in which they lived and interacted.

L'évolution est le produit de deux grands facteurs: l'environnement et le développement. Il est donc important de déterminer l'impact de ces deux forces lorsque l'on s'intéresse à l'évolution morphologique d'un organe. Pour cela, il est utile d'étudier l'évolution en temps profond, seul moyen d'observer les mécanismes en action sur de longs intervalles de temps et les réponses à des variations environnementales majeures. Le but de ce travail de thèse est de mieux comprendre l'évolution d'une espèce fossile: le conodonte. Ce vertébré marin dépourvus de mâchoire possède un appareil buccal composé de structures minéralisées semblables à des dents, appelées éléments conodontes. Leur fort taux d’évolution, leur enregistrement fossile long et sub-continu, et la taille importante de leurs populations font de ces éléments conodontes un modèle de choix pour répondre aux questions évolutives en temps profond. Dans la littérature, peu d'études ont tentées de quantifier la forme de ces éléments, et aucune dans un cadre développemental. Grâce à la découverte de fossiles exceptionnellement préservés, ainsi qu'à l'établissement d'une méthodologie pour quantifier les patrons de variation morphologique et de covariation de ces éléments, plusieurs facettes de l'évolution de la forme chez ces éléments ont pu être étudiées. Nous avons entre autre établis l'existence de covariations entre certains traits morphologiques, illustrant les contraintes faisant pression sur ceux-ci. Certaines contraintes sont considérées comme développementales et d'autres potentiellement mécaniques. Des directions évolutives sont également mises en évidence, contraintes par le développement qui canalise ainsi l'évolution. A l'échelle inter-genre, nous avons démontré un lien entre les changements environnementaux (notamment des variations de température) et ces directions évolutives. Ces résultats démontrent un effet croisé des forces développementales (contraignant les morphologies possible) et les forces environnementales (sélectionnant les morphologies en fonction des changements de conditions) dans l'évolution des éléments conodontes. Nous proposons des évènements d'hétérochronie comme mécanisme sous-jacent à cette évolution, potentiellement contrôlés par la température océanique. La quantification de la forme est également utilisée pour tenter de clarifier la taxonomie des neogondolellides au Trias inférieur. Ces travaux démontrent le potentiel du conodonte en tant qu'organisme modèle pour étudier l'évolution en temps profond. / Evolution is the result of two main factors: the environment and the development. In this context, untangling the impact of these two forces on the morphological evolution of a structure is of major importance. To do so, studying evolution in deep time is useful, as it is the only way to observe the mechanisms in action over a long time interval and the responses to major environmental variations. In this thesis, we aim to better understand the evolution of a fossil species: the conodont. These marine jawless vertebrates possess a feeding apparatus composed of mineralized structures comparable to teeth, called conodont elements. Their high evolutionary rate, their long and sub-continuous fossil record, and their large populations made them a relevant model to conduct evolutionary studies in deep time. In the literature, only a few studies attempt to quantify the shape of conodont elements, and never in a developmental framework. With the discovery of new exceptionally preserved fossils, and the establishment of a methodology to quantify the patterns of morphological variation and covariations in these elements, the morphological evolution of conodont elements have been studied from different angles. We have established the existence of covariations between some morphological characters, illustrating the constraints on possible morphologies. Some constraints are considered developmental, while others are potentially mechanical. Evolutionary directions are highlighted, channelled by developmental constraints. At the inter-genera scale, we demonstrated a relationship between environmental changes (especially temperature variations) and these evolutionary directions. The results revealed a combined effect of the developmental forces (that constrain the initial possible morphologies) and the evolutionary forces (selecting the fittest morphologies depending on conditions) in the conodont elements evolution. We proposed heterochrony as underlying mechanism for these patterns, potentially driven by oceanic temperature. Shape quantification is also used in an attempt to clarify the neogondolellids taxonomy of the early Triassic. This work demonstrates the conodont's potential as model organism to study evolution in deep time.

In a warming world, glaciers and ice sheets have an increasingly large influence on the environment, particularly through their contribution to sea level rise. Their response to anthropogenic climate change, in addition to natural variability, has a critical impact on dependent populations and will be key to predict future climates. Understanding the past natural transitions is also important as if the natural variability of the climate system is not well understood, we stand little change of accurately predicting future climate changes, especially in the context of rapid global warming. Ice cores represent the best time capsules for the recovery of paleo-climate informations. For that, the recovery of a suitable 1.5 million-year-old ice core in Antarctica is fundamental to better understand the natural climate reorganisation which occurred between 0.9 and 1.2 Ma. Constraining the englacial and basal temperature evolution of glaciers and ice sheets through time is the first step in understanding their temporal stability and therefore potential impacts on climate. Furthermore, obtaining the best constraints on basal conditions is essential as such million-year-old ice will be located very near to the bedrock, where the thermal regime has the strongest impact. However, measurements of current englacial and basal temperature have only been obtained at a few drill sites for glaciers and ice sheets. We must therefore turn to thermodynamical models to provide theoretical and statistical constraints on governing thermal processes. Thermodynamical models rely on a suite of governing equations, which we describe in this thesis. Our first study area is the McCall glacier, in Alaska (USA), where we show that the glacier cooled down in the warming climate of the last 50 years using a 1D thermodynamical model. We calculate the present-day englacial temperature distribution using recently acquired data in the form of englacial temperature measurements and radio-echo sounding surveys of the glacier. We show the important of absence of latent heat release due to the refreezing of meltwater inside an active surface layer and reconstruct the last 50 years of equilibrium line altitude (ELA) elevation changes. In the context of Beyond Epica Oldest Ice, a European project aimed at recovering a 1.5 million year-old ice core, we propose for the first time a map of the location of adequate drilling sites for the entire Antarctic Ice Sheet. We use a 3D thermomechanical model to calculate a new basal temperature map of the Antarctic Ice Sheet, as well as a 1D thermodynamical model to constrain the poorly known geothermal heat flux (GHF). These combined model runs use the latest acquired data sets for the GHF, ice flow velocity, ice thickness and subglacial lakes. In order to take into account 2 Ma of Antarctic climate history, we use a transient 1D thermodynamical model to provide constraints on GHF by calculating the maximum value of GHF allowed to keep frozen basal conditions everywhere underneath the ice sheet. These values are then statistically compared to published GHF data sets to propose a probabilistic map of frozen and thawed bedrock locations. This transient model uses high spatial resolution radar data acquired over the Dome Fuji and Dome C regions to examine their likelihood of having preserved 1.5-million-year ice. We define a number of important criteria such as GHF, bedrock variability, ice thickness and other parameter values for Oldest Ice survival. We anticipate that our methods will be highly relevant for Oldest Ice prospection in other areas of the ice sheet that so far remain little or un-surveyed, as well as for the thermal modelling of other glaciers and ice sheets, and in particular, of the Greenland Ice Sheet. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished