http://rid.unrn.edu.ar:8080/handle/20.500.12049/526 2026-04-13T09:28:44Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/8736 Título: Generación de energía a través del aprovechamiento del gradiente geotérmico de la corteza terrestre: posibilidades de la Geotermia de bajas temperaturas Autor(es): Zanellato, Gabriel Luciano Abstract: No posee 2022-04-11T00:00:00Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/7066 Título: Los depósitos continentales del cretácico inferior tardío-superior en el norte de la cuenca neuquina (34-35°S) y su relación con el inicio del levantamiento andino Autor(es): Gómez, Ricardo E. Abstract: A multi-proxy provenance approach of the Early Cretaceous-Late Cretaceous succession in the northern Neuquén Basin using sedimentology, petrology, detrital zircon U–Pb geochronology and detrital low-temperature thermochronology provides new constrains for the evolution of the Southern Central Andes. The stratigraphic interval studied represents the transition of the Neuquén Basin between the back-arc and foreland stage as the result of acceleration in the absolute movement of South American tectonic plate after the opening of Atlantic Ocean. This resulted in a compressive tectonic regime in the Andean sector and the eastward migration of the orogenic front. The Upper Cretaceous non-marine deposits of the Neuquén Basin have an important regional exposure and characterized as the first foreland basin associated with the early uplift of the Andean orogen at ca. 100 Ma. These deposits are included in the Neuquén Group, a well-studied unit in both the south and central part of the basin and associated with an important paleontological content and as reservoir rock in some depocenters of the basin. However, the northernmost exposed between the Laguna del Diamante and the Atuel River (34°-35°S)-assigned to the Diamante Formationhad not been studied in detail before this work. In the studied area, the Diamante Formation corresponds to a braided fluvial system evolving through time towards a meandering fluvial system possibly as a part of fluvial fan o Distributive Fluvial System (DFS). Petrographic analyses show a predominance of feldspathic litharenite, lithic feldarenite and litharenite, while the source areas are mainly recycled orogen (QFL diagram), mixed and dissected arc (QmFLt diagram). The presence of limestone clasts and fragments of ammonites in the middle part of the stratigraphic sections together with changes in paleocurrents suggest a regional source shift and provenance from the west of the studied area associated with the onset of an important stage of deformation on the west. Detrital zircons from the base of the Diamante Formation were supplied sources from Upper Jurassic and Lower Cretaceous that were exposed during Late Cretaceous times, whereas in the top, a high content of Permo-Triassic detrital zircons indicates exhumation of the surrounding Permo-Triassic crystalline basement. Two maximum depositional ages were obtained, 107.2 ± 1.4 Ma (1σ; n = 4) from the base and 91.1 ± 2.2 Ma (1σ; n = 3) to the top of the Diamante Formation. In particular, the age of 107.2 Mawould indicate that the sedimentation of the Upper Cretaceous non-marine deposits occurred in the Albian at these latitudes (34°-35°S). The comparison between U-Pb maximum depositional ages documented for nonmarine Upper Cretaceous deposits throughout the Neuquén Basin allowed a re-evaluation of the diachronism between the first foreland deposits of the basin. An apatite fission track analysis (AFT) of a sample from the lower part of the Diamante Formation indicated an Albian central cooling age. The sample also showed a notable presence of angular apatite crystals (21%) and a predominance of rounded and sub-angular grains (56% and 23%, respectively). Likewise, it indicates a predominance of sub-angular zircon crystals (28%), with a significant percentage of angular crystals (23%) and to a lesser extent rounded (19%). A zircon fissiontrack analysis (ZFT) of a sample from the upper part of the Diamante Formation yielded two discrete populations of cooling ages, both reflecting source-cooling during the Late Jurassic (~161 Ma) and the Permian (~265 Ma). Finally, comparisons between the AFT and the U-Pb maximum depositional zircon-ages of the same sample revealed a short lag time (ca. 3 ma), likely related to the rapid magmatic cooling of a coeval volcanic source at ~110 Ma (Albian). The results presented in this work suggest coeval volcanic activity during the Diamante Formation deposition. The new data provided indicates a need to re-evaluate the role of the volcanic arc in the Southern Andes during the late Early-Late Cretaceous and its influence over the foreland deposits; as well as a re-evaluation of the timing of the onset of the foreland basin. 2021-01-01T00:00:00Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/6976 Título: Tomografía sísmica 2D en atenuación de la isla Decepción, Antártida. Autor(es): Guardo, Roberto A. Abstract: Deception Island is the most active and documented volcano in the South Shetland Islands (Antarctica). Since its last eruption (1970) several experiments have targeted an improved reconstruction of its magmatic systems. Geophysical imaging has provided new insight into Deception’s interior, particularly when using space-weighted seismic attenuation tomography for coda waves. Here, we apply sensitivity kernels and a novel inversion strategy to obtain a frequency-dependent model of the magmatic systems at Deception Island using active data, where particular care has been put on data selection and model optimisation. The results have been framed in the extensive knowledge of the geology and the geomorphology of the volcano with a Geographic Information System. This inter- and multi-disciplinary analysis will become a tool to improve the interpretation of the dynamics of Deception Island and its related hazards 2020-01-01T00:00:00Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/4880 Título: Tafonomía de restos óseos humanos del norte patagónico en diferentes contextos ambientales y sedimentológicos Autor(es): Vazquez, Romina C. 2020-04-30T00:00:00Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/4478 Título: Estimación y evaluación de los procesos de inestabilidad de laderas mediante el uso de técnicas en sensoramiento remoto en el Brazo Norte del lago Argentino (Patagonia Austral, Argentina) Autor(es): Moragues, Silvana N. Abstract: The present study aims at estimating and evaluating the hazards related to the slope instability processes following the retreat of the ice masses into the glacier valleys located at the Northern Branch of Argentino Lake (49º45´S-50º15´S, 73º24´O-73º0´O), in Los Glaciares National Park, Santa Cruz, Argentina. During the end of the 20th and the beginning of the 21st centuries, glaciers from all over the world have undergone a decrease in thickness and area, as well as a recession of the frontal position, covering the valley slopes with morainic deposits. With the passing of time and the combination of conditioning and triggering factors, this material becomes potentially unstable, contributing to the generation of paraglacial processes, related to slope instability. Also, the natural landscape has a great tourist attraction, especially in the summer season when thousands of tourists visit the area to go on the lake tourist circuits. The presence of people and infrastructure generates greater exposure and vulnerability to the occurrence of threats associated with slope instability. These events are a potential threat not only to tourism activities but also to the conservation of Los Glaciares National Park. Based on the motivation described above, the main objective of this research is to identify, analyze and evaluate the slope instability processes through the implementation and combination of techniques based on remote sensing and statistical methods, and Geographic Information Systems. The methods used were optimal for obtaining estimates of glacier surface velocities, identifying and analyzing the paraglacial geomorphology associated with the processes of instability, analyzing the space-time evolution of slope surface changes, zoning of the susceptibility resulting from the processes of instability, and finally, for characterizing the potential vulnerability of the area that includes the Agassiz subaerial landslide (Upsala Channel), which occurred in February 2013. In the first place, we consider the recent glacial activity that has favored the slope destabilization of the Upsala glacier catchment. In addition, the relationship between the frontal positions and the variations of the surface velocities of the Upsala Glacier was analyzed, where two episodes with increased velocities were detected, coinciding with a greater recession rate of the glacier. Thus, glacial activity has contributed to the generation of paraglacial processes, making the slopes of the Upsala glacier catchment notoriously unstable. Surface velocities estimated on the Upsala Glacier and its tributary glaciers ranged from 0.22 to 2.93 md-1 on average for the period between January and March 2013, and from 0.12 to 0.12 md-1 on average for the period between March and April 2014, respectively. When analyzing the fluctuations and velocities, two moments with maximum values were detected, the first episode occurred during the period between 1993 and 2002, and the second episode occurred between 2009 and 2010. The year 2008 is of great importance in this analysis, since the velocity values increased significantly that year, simultaneously with the fast retreat of the frontal position of Upsala Glacier during the present century. However, knowing the characteristics of the paraglacial geomorphology of the area completes the integral vision of the present thesis. The paraglacial geomorphology is influenced by the combination of several terrain morphometric factors; among them, it considers ground elevations greater than 700 m ASL, average slopes ranging from 25º to 45º, the orientation of the eastern-nor-western slopes with higher sunlight exposure, the concave curvature of the slopes, and slope thickness ranging from low to moderate. Among the conditioning factors, the morainic material deposited by the glaciers, rocky outcrops, and vegetation cover are considered in the area. Finally, triggering factors affect the area in general through the provision of subterranean water by means of infiltrating water from proglacial lakes, and of superficial water by rainfall, ice melting, and runoff; the fluctuation of air and soil temperature; the variation of the lake water level and the seismic activity. In order to detect instability processes, techniques based on statistical, mutivariate, and bivariate methods were applied, dividing the zone in testing areas (TASn) that showed destabilization features. The principal components (PC1 and PC2) explained 76% of the total variability, a percentage that represents the reliability of the relationships between the cases (TASn) and the applied variables. The TASn showed a dissimilar behavior; the distribution of data occurrence is different during those years when instability events represented through Gaussian distributions were recorded. Susceptibility zoning for slope instability processes in the area was carried out implementing weight weighting techniques, contributing to the knowledge of slopes prone to destabilization. The slopes showing high and very high susceptibility degrees are: (i) the western slope of the Upsala Channel, (ii) the slopes of Bertacchi and Cono tributary glaciers, (iii) and the slope of the Moyano and Norte valleys. These susceptibility degrees match the geographical location of the inventory of slope instability processes in the area. Finally, the description, characterization and analysis of the Agassiz subaerial landslide that occurred in February 2013 are further developed. The western slope of the Upsala Channel has shown signs of activity according to records for approximately two decades. The event displaced a large volume of water that generated a tsunami, impacting downstream on various sites and infrastructure present in the area. The valleys surrounding the slopes of the Uppsala channel have a higher degree of susceptibility that is associated with the risk of the area. This reveals the importance of further studies as the basis for future vulnerability and risk research, decision making, and as mechanisms for prevention and mitigation of a potential geological hazard associated with this type of natural process. 2020-04-06T00:00:00Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/4386 Título: Caracterización de las amenazas geo-climáticas en los Andes centrales y semi-áridos de Chile y Argentina (30-33 °S) Autor(es): Vergara Dal Pont, Iván P. Abstract: The extreme geo-climatic events constitute an important hazard in the Central and Semi-Arid Andes of Argentina and Chile, assiduously generating fatalities and significant economic losses. Due to this situation, it was worked on the aspects that were considered more urgent for the quantification of their current and future hazard. Due to the scarcity of meteorological information and recorded extreme geo-climatic events, these topics were developed in areas of the region where the necessary base information is densified and therefore the probability of finding novel results is greater. First, the probabilities for the triggering of hyper-concentrated flows, and debris and mud flows in the middle basin of the Elqui River (Chile) were determined. The objective was achieved collecting, for a period of fourteen years, the precipitation events generating high-discharge flows, as well as the larger precipitation events that did not generate this process. For each of these events, data of peak one-hour storm precipitation, temperature (representing the zero-isotherm altitude) and antecedent precipitation of one, five and ten days were collected from three meteorological stations. Initially, an ordinal logistic regression model for each antecedent precipitation was fitted, but all were discarded due to the low significance of these variables in the generation of the models. This result allowed to hypothesize that the high discharge flows of the region would be triggered by in-channel entrainment and shallow failure planes, and not by deep failure planes. Subsequently a new model with the remaining variables, peak precipitation and temperature, was performed, which was statistically validated. From this, it was considered prudent to take as thresholds for the occurrence of hyper-concentrated flows, and debris and mud flows, their respective probabilities of 50 %. For these thresholds, the model had an efficiency in the prediction of high-discharge flows of 90 %. Finally, the partial correlation coefficients of each predictor variable of the final model with respect to the dependent were calculated, establishing that the temperature has greater influence than the peak one-hour storm precipitation. Through the Difunta Correa watershed, representative of periglacial area of the Semi-Arid Andes, were investigated the thermo-radiative characteristics, the possible water sources, and the current and future frequency of debris flows triggered from rapid melt of seasonal snow, and / or ice within the active layer. Information was collected on three temporal clusters of debris flows during which no rains and major earthquakes occurred. The thermo-radiative conditions of each cluster were analysed through nearby stations that cover the entire watershed altitudinal range Snow covers were calculated using the closest satellite images before and after each cluster in order to evaluate the snowmelt contribution for each. The frequency of melting-driven debris flows, for the remainder of the 21st century was evaluated by calculating the trends of climatic variables that control them. The results indicate that debris flows present several patterns such as: lag of some hours between the warmest daily hours and their triggering, occurrence in clusters of three to five days during the early summer, and accelerated increase of temperature during the previous days to the clusters beginnings. In addition, it was inferred that the water of debris flows can come from the melt of seasonal snow as well as of shallow ice within the active layer. Lastly, due to the positive trend of the maximum temperature of warmer trimester and the high inter-annual variability of precipitation, a frequency increase is expected, followed by a possible decrease due to the negative and positive trends of precipitation and mean annual temperature, respectively. Finally, meteorological information and locations and dates of 569 landslides and snow avalanches were analysed, in order to advance in the detection and compression of temporary changes in the extreme geo-climatic events of the Eastern Central Andes. Initially, a characterization was carried out, that allowed to divide the extreme geo-climatic events in zones and seasons with different climates. Then, the trends of these events were calculated taking precautions for their non-systematic monitoring (selection of the series type, year of beginning and type of trend made). The frequencies of the extreme geo-climatic events triggered by precipitation for the different zones and seasons of the annual cycle were stationary or presented low positive trends. The positive changes were related to changes in precipitation, since both variables showed significant correlations, and greater increases in the Atlantic climate dominance sector than in the Pacific dominance. From these trends it was known that the increase in the record of extreme geo-climatic events triggered by precipitation since the second half of the 20th century was mainly due to increases in monitoring. In addition, from the study it was deduced that despite the warming that the region suffers, the decrease in the extreme geo-climatic events triggered by snowfall since the end of the 1990s was due solely to a reduction in precipitation. This is because the winter warming occurred exclusively on the days without precipitation; on days with precipitation an oceanic air mass usually enters which has not had significant thermal changes since at least 1974. Based on the results and conclusions obtained throughout the Thesis, it was deduced that although the relationship between the extreme geo-climatic activity and the climate is clear, it varies considerably depending on the type of landslide or snow avalanche, the type of triggering causal factor, the climate and the land properties. Understanding this relationship in its entirety implies knowing the interaction between atmospheric dynamics and the geotechnical, physical and morphometric properties of the terrain, so it can be considered a multidisciplinary study. 2020-03-16T00:00:00Z http://rid.unrn.edu.ar:8080/handle/20.500.12049/527 Título: Diseño, implementación y evaluación de una unidad didáctica para la enseñanza de modelos de membrana celular en la formación biológica del profesorado, con aportes de ideas metacientíficas provenientes del eje naturaleza de la ciencia Autor(es): Lozano, Eduardo Enrique Abstract: In the context of the university Biology teaching degree, we maintain that it is necessary that training spaces in didactic models begin to permeate ideas and work strategies towards disciplinary training spaces in biology; The integration of these areas will make more stable and meaningful the learnings linked to the scientific disciplinary models of biology as well as to the didactic models constructed by the students. The modeling and treatment of metascientific ideas are guidelines from current theoretical perspectives in the field of natural science teaching, and this thesis enhaces the value of such guidelines within a disciplinary training space. Within this framework, the didactic research developed was contextualized in the subject of Cell Biology, and had the general objective of interpreting processes of modeling of cell membrane biological phenomena and meta-scientific ideas constructed by students. The research had a qualitative approach and, oriented from the perspective of the design studies, involved the elaboration, implementation and evaluation of a didactic unit. The setting in which the empirical corpus was constructed was the natural environment of the classes of the research teacher. It was verified that students learned, involved in what we call "scientific school activity", cell membrane contents through modeling processes and also meta-scientific content of the nature axis of science and that could apply them to new situations. Descripción: Situados en el Profesorado en Biología en el ámbito de la Universidad, sostenemos que es necesario que los espacios de formación en modelos didácticos comiencen a permear ideas y estrategias de trabajo hacia los espacios de formación disciplinar en biología; la integración de estos ámbitos redundará en hacer más estables y significativos los aprendizajes vinculados tanto a los modelos científicos disciplinares de la biología como a los modelos didácticos que construyan los estudiantes. La modelización y el tratamiento de ideas metacientíficas son directrices provenientes de perspectivas teóricas actuales del campo de la didáctica de las ciencias naturales, y esta tesis pone en valor tales directrices al interior de un espacio de formación disciplinar. En ese marco, la investigación didáctica desarrollada se contextualizó en el ámbito de la materia Biología Celular, y tuvo el objetivo general de interpretar procesos de modelización de fenómenos biológicos de membrana celular y de ideas metacientíficas construidas por los estudiantes. La investigación tuvo un enfoque cualitativo y, orientada desde la perspectiva de los estudios de diseño, implicó la elaboración, implementación y evaluación de una unidad didáctica. El escenario en el cual se construyó el corpus empírico fue el ámbito natural de las clases del docente investigador. Se pudo constatar que los alumnos aprendieron, involucrándose en lo que llamamos “actividad científica escolar”, contenidos de membrana celular mediante procesos de modelización y también contenidos metacientíficos del eje naturaleza de la ciencia y que pudieron aplicarlos ante nuevas situaciones. 2016-01-01T00:00:00Z