The Llanos foreland basin of Colombia is located along the eastern margin of the northern Andes. The Llanos basin is bounded to the north by the Mérida Andes, to the east by the Guiana shield, to the south by the Serrania de la Macarena, and to the west by the frontal foothills thrust system of the Andes (the Cordillera Oriental). The Llanos foreland basin originated in the Maastrichtian, after a post-rift period during the Mesozoic, and recorded an abrupt pulse of middle Miocene subsidence possibly in response to subduction and collision events along the Pacific margin of northwestern South America. Regional east-west shortening, driven in part by collision of the Panama arc along the Pacific margin of Colombia, has built the widest part of the northern Andes. This wide area (~600 km) includes a prominent arcuate thrust salient, the Cordillera Oriental, which overthrusts the Llanos foreland along a broad V-shaped salient that projects 40 km over the northern Llanos foreland basin. In this study, I interpret 1200 km of 2D seismic data tied to 18 wells and regional potential fields (gravity and magnetic) data. Interpreted seismic data are organized into four regional (300 to 400-km-long) transects spanning the thrust salient area of the northern Llanos basin. I performed 2D flexural modeling on the four transects in order to understand the relative contributions of flexural subsidence due to tectonic and sedimentary loading. Sedimentary backstripping was applied to the observed structure maps of six Eocene to Pleistocene interpreted horizons in the foreland basin in order to remove the effects of sedimentary and water loading. Regional subsidence curves show an increase in the rate of tectonic subsidence in the thrust salient sector of the foreland basin during the middle to late Miocene. The flexural models predict changes in the middle Miocene to recent position of the eastern limit of foreland basin sediments as well as the changing location and vertical relief of the flexurally controlled forebulge. Production areas of light oil in the thrust belt and foreland basin are located either south of the thrust salient (Cusiana, Castilla, Rubiales oilfields) or north of the salient (Guafita-Caño Limon, Arauca oilfields) but not directly adjacent to the salient apex where subsidence, source rock thicknesses, and fracturing were predicted by a previous study to be most favorable for hydrocarbons. There are no reported light oil accumulations focused on the predicted present or past positions of the forebulge, but detailed comparisons of seismic reflection data with model predictions may reveal stratigraphic onlap and/or wedging relationships that could provide possible traps for hydrocarbons. / text

Recent climate changes show that the historical record is not an appropriate analog for future climate conditions. This understanding calls into question management decisions that assume climate stationarity and consequently the demand for climate information has increased in order to help frame climate risk more accurately. However, deficits in knowledge about climate impacts and weak connections between existing information and resource managers are two barriers to effective incorporation of climate information in resource management, development, risk management, and other climate-sensitive decisions. In research presented here, I showcase results that address knowledge gaps in the impact of climate on glacial resources in Bolivia, South America. I present a mixing model analysis using isotopic and anion tracers to estimate that glacial meltwater contributed about 50% of the water to streams and reservoirs in La Paz region of Bolivia during the 2011 wet and 2012 dry seasons. To assess how future warming may impact water supplies, I develop a temperature-driven empirical model to estimated changes in a future glacial area. Surface temperature changes were extracted from a multi-model ensemble of global climate models produced for the latest Intergovernmental Panel on Climate Change (IPCC) fifth assessment report and for two greenhouse gas emission scenarios. In both scenarios, declines in glacial area are substantial. For many small glaciers, temperatures at the toe of each glacier rise above the glacier's maximum elevation by 2050 suggesting that water resources will be substantially impacted with continued warming. While these results address a knowledge gap, the extent to which they inform resource management is unknown because the research was conducted without an explicit connection to resource management. Information produced in this fashion is generally acknowledged as being less immediately useful for decision-making because of access and comprehension barriers. These challenges may be mollified, however, with information management strategies. Therefore, I present results from an experiment to see if translating and contextualizing existing climate-related information - information produced similarly to the glacier results highlighted above - help facilitate its use. During a drought afflicted period in Arizona and New Mexico, a monthly synthesis of climate impacts information was disseminated to more than 1400 people. Survey responses from 117 people who consulted the information indicated that the majority of them made at least one drought-related decision and the information in the synthesis at least moderately influenced the majority of those decisions. In addition, more than 90% of the survey respondents indicated that the synthesis improved their understanding of climate and drought; it also helped the majority of them better prepare for drought. The results demonstrate that routine interpretation and synthesis of existing climate information can help enhance access to and understanding of climate information.

Los Andes ecuatorianos albergan ecosistemas con la más alta biodiversidad sobre la tierra. Información preliminar sobre la dinámica de los ecosistemas en el pasado es necesaria para entender, conservar y manejar los ecosistemas y su biodiversidad. Tres muestras de sedimentos fueron datadas, Rabadilla de Vaca (RV) a 3244 m de altura y Valle Pequeño (VP) a 3200 m de altura, ambas en la parte central del Parque Nacional Podocarpus (PNP), y Lagunas Natosas Bosque (LNB) a 3495 m de altura, al sur del PNP al sur del Ecuador en la región llamada Depresión Andina. Estas muestras fueron estudiadas con base en análisis de polen, esporas y partículas de carbón. Los resultados revelan cambios en la vegetación en la zona de LNB durante los últimos 16,000 años, y en RVM y VP desde hace 2100 años. Durante el Plestoceno tardío (15,930 – 11,660 cal yr BP), la vegetación de páramo dominó el área y la presencia de Plantago rigida sugiere condiciones ambientales frías y húmedas en el área de LNB. La población de P. rigida disminuyó drásticamente durante el último período glacial y especialmente durante el “Younger Dryas”, que es un corto período frío (hace 12,800 a 11,500 años), y el límite superior del bosque (UFL) muy probablemente fue mas bajo que en la actualidad. Entre 11,660 – 4280 cal yr BP, ocurrió una marcada reducción de cobertura de páramo, acompañada por una expansión de la vegetación de subpáramo (arbusto enano leñoso). En la región de LNB, al sur del PNP, se evidención un cambio altitudinal hacia arriba del UFL. En este sitio se evidencia por primera vez la presencia de grandes extensiones de Polylepis en la región de la Depresión Andina. Alrededro de 4200 cal yr BP el regreso a condiciones climáticas frías y húmedas favoreció la expansión de los páramos. El Holoceno tardío hasta el presente se caracteriza por la contínua fluctuación entre vegetación de páramo y subpáramo. Sin embargo, alrededor de los 1200 cal yr BP, vegetación de subpáramo (arbustos enanos) fueron precuentes, lo que sugiere un incremento moderado en temperatura y humedad. En el área de RVM desde los 2100 hasta los 1720 cal yr BP, la dominancia de subpáramo sugiere condiciones climáticas más húmedas y cálidas. En el área de LNB después de los 500 cal yr BP, el incremento de vegetación de páramo indica condiciones más húmedas. Esto también se registró en la zona de RVM y VP desde 800 a 310 cal yr BP, donde la vegetación de páramo se expandió ampliamente y redujo la posibilidad de crecimiento de bosque. Inlfuenciada por condiciones más húmedas y fuegos (incendios) frecuentes, en el área de LNB, Polylepis estuvo casi ausente durante el Holoceno tardío. Aunque, restos de partículas de carbón indican la presencia humana desde hace más de 4000 años. La máxima concentración de partículas de carbón indican alta frecuencia de fuegos desde 1800 hasta 1600 cal yr BP y desde 600 a 400 cal yr BP. Comparando la vegetación y los regsitros de carbón entre los tres sitios, es evidente que el fuego favoreció la expansión de vegetación de páramo en detrimento de la vegetación de subpáramo y bosque montano alto (UMF). El fuego probablemente tuvo un rol importante en el control de los cambios del límite del bosque durante el Holoceno tardío. Sin embargo, es difícil establecer si cambios en las condiciones del clima también tuvieron un rol importante durante este período. Los fuegos se presentaron a distintos momentos entre los diferentes sitios, esto sugiere que existió influencia antropogénica. Es posible inferir cambios a nivel regional ocasionados por la variabilidad de clima; sin embargo, condiciones locales como temperatura, precipitación, vientos, radiación solar y geomorfología, también tienen un impacto fuerte en los patrones de la vegetación, los mismos que pueden determinar la estructura, heterogeneidad y distribución de los ecosistemas.

Theories of writing are one of the fundamental ways by which Indigenous peoples have been labeled as "uncivilized." In these discussions, writing becomes synonymous with history, literacy, and often times Truth. As such, scholars studying Nahua codices and Andean khipu sometimes juxtapose the two because together they present a break in an evolutionary theory of writing systems that links alphabetic script with the construction of "complex civilizations." Contemporary scholars tend to offer an "inclusive" approach to the study of Latin American histories through challenging exclusive definitions of writing. These definitions are always informed and limited by language-the extent to which these "writing" systems represent language. However, recentering discussions of writing and language on what Gregory Cajete has called Native Science shifts the discussion to matters of ecology in a way that intersects with current scholarship in bicocultural diversity studies regarding the link between language, culture, and biodiversity. Because of the ways in which language configures rhetoric and writing studies, a shift in understanding how language emerges bears great impact on how we understand not only the histories tied to codices and khipu but also how they function as epistemologies. In my dissertation, I build a model of relationality using Indigenous and decolonial methodologies alongside the Nahua concept of in ixtli in yollotl (a wise face/a wise heart) and embodied rhetorics. The model I construct here offers a path for understanding "traditional" knowledges as fluid and mobile. I specifically look at the relationship between land, bodies, language, and Native Science functions on the reciprocal relationship between those three components in making meaning. I then extend this argument to show how the complex web of relations that we might call biocultural diversity produces and is produced by "things" like images from codices and khipu that in turn help to (re)produce biocultural diversity. Thing theory, in emerging material culture studies, argues for the agency of cultural artifacts in the making of various realities. These "things" always-already bear a relationship to bodies and "nature." Thing theory, then, can challenge us to see artifacts like khipu and Nahua images as language artifacts and help us connect Nahua images and khipu to language outside of a text-based model. Ultimately, I argue that Native Science asks us to see language as a practice connected to biocultural diversity.

This research investigate the geochemical environmental impact of ancient ash deposits erupted to hundreds of thousands to several million years ago in the southern Puna and neighbouring areas (Argentina), Uruguay and five historical eruptions occurred over a 20-year period in the Andes. In the latter case, pristine ash samples of Cophue, 2000, Lonquimay, 1988, Llaima, 2008, Chaiten, 2008, and Hudson, 1999 eruptions were studied. The main purpose of this research is to investigate the geochemical environmental hazard posed by different types of volcanic ashes in general, and from the Andes, in particular. The specifics aims of this research are:(1) to develop an analytical methodology for the physico-chemical characterisation of volcanic ash;(3) to propose a new ash leaching methodology that can be useful both for recent and ancient volcanic ashes (Single Batch Leaching Test, SBLT);(4) to recognize the geochemical impact occurring after the deposition of volcanic ash on the environment through leaching experiments (Batch leaching tests, Column leaching tests, and Sequential Extraction Scheme). The main conclusions extracted from this research can be summarised as follows:(1) The physico-chemical information of ashes (mainly the morphological features by SEM, grain-size distribution by laser diffraction and Potential toxic trace elements identification and quantification of the bulk ashes) highlights the main environmental concerns related to the studied ashes and it lays the foundation of the basic knowledge required to understand the ash leaching. (2) The main body of this research has been to propose a proved methodology for a single batch leaching test (SBLT) with deionised water in order to obtain information on short term leaching behaviour of volcanic ash identifying, qualitatively and quantitatively, the potentially hazardous elements being rapidly released from both recently erupted and ancient volcanic ashes. The proposed procedure is completed within few hours and its design is simple, concise and reliable.(3) The application of the SBLT (with deionised water) method developed in this research have allowed to define the potential geochemical impact of the volcanic ashes investigated on the environment. This study shows that major elements with high mobility are Ca, Mg, Na, Si, K, and Al. Puna and Uruguay ashes could release in the environment the same trace elements (i.e., P, Ti, Fe, Mn, Zn), however, in different concentrations. These are macro- and micronutrients evidencing the fertilizing potential of the ashes. Chaiten ashes showed high concentrations for As, Pb, Fe, and Zn, whilst the other samples (i.e., COP, LON, LLA, and HUD) could release principally P, Ti, Mn, Ni, Zn, and Pb. Most of these are potentially toxic trace elements (PTTE) even at very low concentration. They are included in the drinking water guidelines due to their potential toxicity and must be especially monitored in the environmental assessment of these ashfall deposits. (4) Dynamic leaching tests conducted on raw ashes and grain-size fractions allowed to define the element implied during glass and mineral dissolution. From the data nowadays available on the temporal leaching of Andean rhyolitic ashes (from CVZ to SVZ), the association between ash dissolution and some trace elements (As, Mo, V, B, and U) through laboratory experiments was demonstrated. This study represents a great advance on the knowledge of the geochemical environmental hazard posed by volcanic ashes, in general, and from the Andes, in particular. In terms of methodological approach, the developed method of SBLT is a very important contribution because there is a need to harmonize the batch tests applied to volcanic ash. In addition, column leaching test and sequential extraction scheme complement the information obtained by SBLT and facilitate decision making on management of geochemical hazard associated with the volcanic ash fall.

Esta tesis doctoral centra su interés en el estudio geográfico de la cuenca hidrográfica del estero Morales, afluente del río Volcán, en los Andes centrales chilenos. Para ello analiza el medio biofísico, describe, analiza y clasifica el paisaje, realiza una serie de propuestas para su mejor y adecuada gestión. Se trata de una investigación de base que aporta datos de interés relativo al funcionamiento del sistema natural del valle, catalogado como figura de protección por parte del Gobierno chileno, administrado por CONAF, tipo de paisaje que lo caracteriza y recomendaciones para su uso y salvaguarda de sus valores patrimoniales (medio natural y social-económico).Desde la perspectiva del medio biofísico hay que señalar el interés que posee la zona de estudio, pues se trata de un valle recientemente deglaciado en el que en cabecera aún persisten masas glaciares (glaciar de San Francisco). Ello lo convierte en un espacio montañoso donde el medio glaciar y periglaciar persisten y alternan según estacionalidad, lo que conduce la dinámica y evolución de sus ecosistemas. En tal sentido, destaca, ante todo, la proliferación de procesos morfogénicos de producción de clastos y movimientos de masas, que se traducen en una generalizada inestabilidad de laderas producto de las fuertes pendientes. Estas condiciones de clima frío se traducen en el desarrollo incipiente de suelos, mayoritariamente de acuerdo a su capacidad de uso Vlll y en la presencia de una cubierta vegetal en disposición abierta y de porte herbáceo o subarbustivo. Sin embargo, estas condiciones ecológicas no se cumplen en el sector mas bajo del valle, donde la presencia de la aldea Baños Morales -centro urbano incipiente, muestra un paisaje diferenciado debido a las más benignas condiciones climáticas y a la presencia de vegetación arbórea introducida.El valle en su conjunto es un medio de alto valor patrimonial, en particular en lo referente a su medio biofísico y social-cultural, a lo que se une el afloramiento de aguas termales, producto de la actividad volcánica presente en el área. Ello lo convierte en espacio protegido, pues existen ricos ecosistemas que albergan especies vegetales relictas y restos materiales de antigua colonización, además de ser enclave de alto significado científico para el estudio y seguimiento de la deglaciación actual de las masas glaciares de cabeceras (glaciar San Francisco).Estas circunstancias demandan actuaciones a favor del paisaje por lo que resulta necesario revisar la actual legislación emanada de CONAF, y al mismo tiempo asumir nuevos programas por parte de la Administración que tiendan a conservar y preservar los valores patrimoniales y belleza escénica del conjunto del valle. / "El Morado Natural Monument (Central Chilean Andes). Biophysical medium, landscape and behavior proposal."TEXT:This Phd thesis deals with the geographical study of the Morales stream basin, tributary of the Volcán River, in the Chilean central Andes. For that purpose it analyses the biophysical medium; describes, analyses and classifies the landscape, it puts forward a series of proposals for its better and adequate management. It is about a base research that provides interesting data related to the valley's natural system classified as protected figure by the Chilean government, managed by CONAF, type of landscape that characterizes it and recommendations for its use and safeguard of its patrimonial values. (Natural and socio economical medium).From the biophysical medium perspective it must be said that this region possesses a huge interest because it is a recent melted glacier where we still can see an ice cap (San Francisco glacier). This fact turns it into an specific mountainous area where glaciers and periglaciers endure and take turns according to the season, fact that guides the dynamism and evolution of their ecosystem. In that sense, what can be highlighted is the spread of morphogenic processes, clastos production and mass movements, all that results on a generalized instability of hillsides due to steep slopes.This cold weather conditions converge at the development of an incipient ground, mainly because of its capacity to use VIII and on the presence of a vegetation cover in an open position and herbaceous or shrub-like size. However these ecological conditions are not the same in the lowest sections of the valley where Baños Morales village can be found. It is an urban center which shows a diverse landscape due to nice weather conditions and an introduced wooded area.The valley itself is a high value patrimony medium, particularly in its biophysical and socio cultural context plus thermal water outbursts due to volcanic activity in the area. That fact gives the place the quality of "protected area" because there are vast ecosystems that house relic vegetal species and material form old colonization, besides the fact of being a significant high scientific enclave to do research and also to follow up the melting process of ice caps mass glaciers (San Francisco).These circumstances require actions towards the landscape and so, it is necessary to check former laws put forward by CONAF and, at the same time, to assume new programs by the administration that will lead towards the preserving of patrimonial values and beauty of the valley.

Thesis (Ph. D.)--Lehigh University, 1999. / Includes vita. Includes bibliographical references (leaves 163-175).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 400-428). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 400-428). Also available on the Internet.

Little is known about the evolution and ecology of crassulacean acid metabolism (CAM) in the genus Puya Molina. CAM is a photosynthetic pathway typified by nocturnal CO2 fixation and is regarded as a water-saving mechanism. Puya is one of the largest genera in the pineapple family (Bromeliaceae), with 226 species distributed across the Andes to Costa Rica and the Guiana Shield, and from sea level to 5000 m. About 21% of Puya species are CAM and at least 10 of these CAM species occur above 3000 m. The main aim of this thesis was to uncover new evidence to understand the ecophysiology and evolution of CAM in the montane genus Puya. The prevalence of CAM and C₃ species in Puya was estimated from carbon isotope values of 161 species. The climatic niche of constitutive CAM species and C₃ species of Puya was modelled using georeferenced herbarium records and climatic variables to evaluate the differences between their niches. The evolution of CAM in Puya was investigated by reconstructing the ancestral photosynthetic pathway on an AFLP phylogeny and by studying positive selection in the genes encoding the key enzyme phosphoenolpyruvate carboxylase (PEPC). The coldresistance and the thermal lability of PEPC was investigated for high- and low- elevation CAM species of Puya to explore the potential molecular adaptations of CAM plants in high-elevation environments. The present study concludes that the common ancestor of Puya was a cold-resistant plant. This is suggested to explain the prevalence of Puya at highelevations. The evolution of CAM was correlated with changes in the climatic niche, and occurred multiple times in Puya. These multiple origins were not independent because the common ancestor of Puya was likely to be a weak CAM plant (based on a diagnostic Arg679 residue in the PEPC sequence). It is likely that populations of P. chilensis gained CAM by introgression with P. alpestris ssp. zoellneri. Weak CAM photosynthesis and coldxv resistance allowed Puya to colonise the Andes from the south to the north; and, in the process, constitutive CAM and C₃ evolved. The later-evolving species in the genus are suggested to have lost their capacity for CAM as they radiated into more mesic habitats during their colonisation of the northern Andes.