Chemical weathering of silicate rock consumes atmospheric CO2 and supplies the oceans with cations, thereby controlling both seawater chemistry and climate. The rate of CO2 consumption is closely linked to the rate of CO2 outgassing from the planetary interior, providing a negative feedback loop essential to maintaining an equable climate on Earth. Reconstruction of past global temperatures indicates that a pronounced episode of global cooling began ~50 million years ago, coincident with the collision of India and Asia, and the subsequent exhumation of the Himalayas and Tibet. This has drawn attention to the possible links between exhumation, erosion, changes in silicate weathering rates, and climate. However, many of the present-day weathering processes operating on the continents remain debated and poorly constrained, hampering our interpretations of marine geochemical archives and past climatic shifts. To constrain the controls on silicate weathering, this thesis investigates the lithium (Li) isotopic composition of river waters, suspended sediments and bed load sediments in the Alaknanda river basin, forming the headwaters of the Ganges. Due to the large fractionation of Li isotopes in the Earth’s surface environment, Li is sensitive to small changes in silicate weathering processes. As a consequence of the pronounced gradients in climate (rainfall and temperature) and erosion across the basin, the river waters show large variations in their Li isotopic composition (δ7Li), ranging from +7.4 to +35.4‰, covering much of the observed global variation. This allows a detailed investigation of the controls on Li isotope fractionation, and by extension silicate weathering. The Li isotopic composition is modelled using a one-dimensional reactive transport model. The model incorporates the continuous input of Li from rock dissolution, removal due to secondary mineral formation, and hydrology along subsurface flow paths. Modelling shows that the Li isotopic variations can be described by two dimensionless variables; (1) the Damköhler number, ND, which relates the silicate dissolution rate to the fluid transit time, and (2) the net partition coefficient of Li during weathering, kp, describing the partitioning of Li between secondary clay minerals and water, which is primarily controlled by the stoichiometry of the weathering reactions. The derived values of the controlling parameters ND and kp, are investigated over a range of climatic conditions and on a seasonal basis, shedding light onto variations in the silicate weathering cycle. In a kinetically limited weathering regime such as the Himalayan Mountains, both climate and erosion exert critical controls the weathering intensity (the fraction of eroded rock which is dissolved) and the weathering progression (which minerals that are being weathered), and consequently the fractionation of Li isotopes and silicate weathering in general. Modelling of the Li isotopic composition provides an independent estimate of the parameters which control silicate weathering. These estimates are then used to constrain variables such as subsurface fluid flux, silicate dissolution rates, fluid transit times and the fraction of rock which is weathered to form secondary clay minerals. The simple one-dimensional reactive transport model therefore provides a powerful tool to investigate the minimum controls on silicate weathering on the continents.

Das Miandam-Untersuchungsgebiet (35° 1′- 5′ N, 72° 30′-37′ E) liegt in der Swat-Region der Provinz Khyber Pakhtunkhwa (ehemals North West Frontier Province) im nördlichen Pakistan. Die vorliegende Arbeit berücksichtigt sowohl ethnobotanische und pflanzensoziologische Aspekte als auch die Pflanzenartendiversität innerhalb des Gebietes. Aufgrund der hohen Habitatvielfalt weist das Miandam-Gebiet einen großen Reichtum von Medizinalpflanzen auf. Die im Rahmen der Arbeit durchgeführte ethnobotanische Studie dokumentiert das Vorkommen der Medizinalpflanzen sowie deren Nutzung in der Region. Weiterhin wurden die durch Sammlerpräferierten Lebensräume bestimmt und evaluiert inwiefern die Heilpflanzen durch Sammlung und Habitatzerstörung bedroht werden. Insgesamt wurden 106 traditionelle Heilpflanzen aus 54 Pflanzenfamilien verzeichnet. Zu den am häufigsten gefundenen Wuchsformen zählten mehrjährige (43%) und kurzlebige Kräuter (23%), Sträucher (16%) und Bäume (15%). Ein Großteil der untersuchten Heilpflanzen und ihrer Produkte wird zur Behandlung von Magen-Darm-Erkrankungen eingesetzt. Die Produkte werden vorrangig als Sud oder Pulver zubereitet und oral angewendet. Achtzig der 106 traditionellen Heilpflanzen gehören der Gruppe der einheimischen Arten an. Fast 50% der Pflanzenarten treten dabei in synanthroper Vegetation auf, während der Rest in naturnaher Umgebung (z.B. extensiv beweidete Wald- und Graslandbereiche) vorgefunden werden kann. Wälder sind der Ursprung der meisten nicht synanthropen einheimischen Medizinalpflanzen. Drei Arten (Aconitum violaceum, Colchicum luteum, Jasminum humile) können als Folge intensiven Sammelns als bedroht eingestuft werden. Um die pflanzensoziologischen und phytogeografischen Aspekte des Projektes abzudecken wurde die Vegetation des Miandam-Gebietes mit einem Fokus auf Wäldern, Gebüschen und anderen Formationen untersucht. Die Ergebnisse der Vegetationserhebungen wurden mit denen anderer Studien in der weiteren Umgebung des Hindukush-Himalayas verglichen. Weiterhin wurde untersucht inwiefern die Waldökosysteme durch anthropogene Aktivitäten im Untersuchungsgebiet bedroht sind. Die im Gebiet verzeichneten Gefäßpflanzenarten umfassen insgesamt 33 Bäume, 52 Sträucher, 305 Kräuter und 11 Lianen. Basierend auf einer multivariaten Analyse konnten 12 Pflanzengesellschaften identifiziert werden. Die Spanne dieser Gesellschaften reichte von subtropischen semiariden Wäldern mit Ailanthus altissima im Tiefland zu alpinen Rasen von Sibbaldia cuneata durchsetzt mit Juniperus. Die dominierende Vegetation des Untersuchungsgebietes besteht aus von Abies pindrow und Viburnum grandiflorum Wäldern. Eine georeferenzierte Karte der Vegetation erleichtert die Lokalisierung der ökologisch interessanten Vegetation. Artenreichtum und –diversität wurden entlang eines Höhengradienten untersucht. Dazu wurde die Alpha- sowie Beta-Diversität verschiedener Wuchsformtypen bestimmt. Der Artenreichtum aller Gefäßpflanzenarten erreichte sein Maximum zwischen 2200-2500 m. Dagegen zeigte der Artenreichtum der Sträucher einen glockenkurvenartigen Verlauf mit einem Maximum zwischen 2000 und 2200 m. Die höchste Alpha-Diversität der Gefäßpflanzenarten wurde in den tieferen Lagen des Untersuchungsgebietes verzeichnet. Die Beta-Diversität aller Wuchsformtypen zeigte entlang des gesamten Höhengradienten hohe Werte und somit einen starken Artenwechsel. Die Beta-Diversität der Straucharten fluktuiert entlang des Höhengradienten und zeigt damit ein einzigartiges Muster.

This dissertation analyses movements from and to a contemporary 21st century Indian multi-caste village in the Kumaun Himalayas, where movements have traditionally involved transhumance and border trade with western Tibet. With the closure of the Indo-Tibetan borders after the Indo-China war in 1962, the economy and livelihoods of the people of the region have fundamentally changed and movements now take place in the form of migration for work to the plains of India, both in the private sector and in government services. The dissertation is based on an ethnographic village study and explores all contemporary forms of movement visible in the village: out-migration; return-migration; and in-migration. It examines how these different types of movement tie in with the changing socio-economic lives of the villagers. This explorative study focuses on the patterns, causes and effects of migration on rural lives past and present, and on the multiple interrelated social changes, which are part of these migratory processes. The author uses mixed qualitative-quantitative methods, including a census survey of all 148 households, 45 semi-structured interviews, follow-up in-depth interviews, and innovative methods such as arts-based visual methods. The framework applied is interdisciplinary and multi-theoretical and contributes to the existing empirical body of literature on migration, development and change. The author chooses to employ the framework of the rural left behind when examining the lives of the wives and elderly parents of migrants. However, she argues that those in the village who are in the truest sense ‘left behind’ are not the family members of migrants, but the unemployed men who lack the capabilities to migrate for work and who reside in the village without any gainful economic activity. The thesis structure includes eight chapters in addition to the introduction and conclusion. Chapter 1 reviews the relevant literature on migration and development and is followed by the methodology chapter (chapter 2), a village background chapter (chapter 3) and a chapter covering the historical context (chapter 4). The structure of the main analysis (chapters 5-8) is along the lines of patterns and reasons for out-migration (chapter 6), out-migration types and their impact (chapter 6), return migration types, reasons and impact (chapter 7) and in-migration types, reasons and impact (chapter 8). Each analysis chapter ends with brief conclusions; these are expanded in the final conclusions (chapter 9).

La vitesse de surrection du l’Himalaya et du plateau tibétain tout au long du Cénozoïque reste encore aujourd’hui largement débattue. L’analyse des isotopes stables de l’oxygène pour reconstruire les paléo-altitudes est considérée comme une technique très efficace et a été largement utilisée. Néanmoins, cette méthode a deux limites principales: 1) les relations entre δ18O et climat ne sont pas bien établies et 2) le climat Cénozoïque en Asie est mal contraint. Dans le cadre de cette thèse, nous avons étudié le lien entre la surrection des montagnes, les changements climatiques associés et le δ18O dans la paléo-précipitation. Nous utilisons le modèle de circulation générale atmosphérique isotopique LMDZ-iso. Nos simulations climatiques montrent que le retrait de la Paratéthys, le déplacement latitudinal de l’Inde et l’altitude du plateau tibétain contrôlent les précipitations et la variabilité de la mousson en Asie. Afin de comprendre où et comment ces changements climatiques liés à la surrection des montagnes affectent le δ18O, nous avons proposé une expression théorique de la composition isotopique des précipitations fondée sur la distillation de Rayleigh. Nous avons montré que seulement 40 % des sites échantillonnés de l’Himalaya et du plateau tibétain contiennent une signature isotopique représentant la topographie. Les résultats obtenus dans cette étude montrent que l’Himalaya pourrait avoir atteint son altitude actuelle plus tardivement que précédemment proposé. Des conditions aux limites réalistes nous permettent de reconstruire le δ18O des paléo-précipitations pour quatre époques du Cénozoïque (55, 42, 30 et 15 Ma). Dans la mesure où les reconstructions des paléo-altitudes sont particulièrement controversées pour les premières étapes de l’évolution du plateau tibétain, nous avons ensuite approfondi notre étude en nous focalisant sur l’Eocène (en utilisant une paléogéographie qui correspond à 42 Ma). Pour ce cas, nous montrons que le δ18O des précipitations est insensible à l’altitude en Asie, tandis que le δ18O dans les archives naturelles (carbonates) enregistre le signal de la paléo-élévation puisque le fractionnement entre la calcite et l’eau est sensible à la température, qui elle-même dépend en partie de l’altitude. La comparaison du δ18O simulé pour l’Eocène avec les données du δ18O mesuré dans les carbonates suggère que, pendant l’Eocène, l’Himalaya et le plateau tibétain n’avaient pas encore atteint leur élévation actuelle (> 3000 m). / The timing and rate of surface elevations of the Himalayas and the Tibetan Plateau remain controversial and their impact on Asian climate and the onset of monsoon systems in this area is highly debated. Stable oxygen paleoaltimetry is considered to be a very efficient and widely applied technique, but has limitations from two sides: 1) the link between stable oxygen composition of precipitation and climate is not well established, 2) Cenozoic climate over Asia is poorly reconstructed. With a purpose of filling the gap in our knowledge of climate variability over Asia during the Cenozoic, we use the isotope-enabled atmospheric general circulation model LMDZ-iso to understand the links between the growth of mountains, associated climate changes and δ18O in paleo-precipitation. Our results show a significant influence of the Paratethys retreat, the latitudinal displacement of India and the height of the Tibetan Plateau on Asian hydrological cycle. For the purpose of understanding where and how the climatic changes linked with the growth of mountains affect δ18O in precipitation, we develop a theoretical expression for the precipitation composition based on the Rayleigh distillation and show that only 40% of sampled sites for paleoaltimetry depict signal attributed to topography changes. We conclude that the Himalayas may have attained their current elevation later than expected. Realistic Cenozoic boundary conditions allow us reconstructing δ18O in paleoprecipitation for several periods during the Cenozoic (for 55 Ma, 42 Ma, 30 Ma and 15 Ma). The focus has been put on the Eocene (42 Ma), since paleoelevation reconstructions are particularly controversial for this time. We show that Eocene precipitation δ18O is rather insensitive to topographic height in Asia. However, carbonate δ18O still records paleo-elevation because the fractionation between calcite and water is sensitive to temperature, which partly depends on altitude. Comparison of simulated Eocene δ18O patterns with data from the carbonate archives suggest that the Himalayas and the Tibetan Plateau did not reach present-day (> 3000 m) elevations during the Eocene.

No description available.

This study contributes to the understanding of major river evolution in Southeast Asia during the Cenozoic. In order to trace the evolution of a hypothesized palaeo-Yarlung Tsangpo-Irrawaddy River, this work undertakes the first systematic provenance study of detrital minerals from Cenozoic synorogenic fluvial and deltaic sedimentary rocks of the Central Burma Basin, employing a combination of high precision geochronology, thermochronology, and geochemistry analytical techniques on single grain detrital zircon and white mica. The dataset is compared to published isotopic data from potential source terranes in order to determine source provenance and exhumation history from source to sink. A Yarlung Tsangpo-Irrawaddy connection existed as far back as ca. 42 Ma and disconnection occurred at 18–20 Ma, based on provenance changes detected using a combination of U-Pb ages and εHf(t) values on detrital zircons, and ⁴ºAr/³⁹Ar dating on detrital micas. During the Eocene and Oligocene, units are dominated by U-Pb age and high positive εHf(t) values, characteristic of a southern Lhasa Gangdese magmatic arc source. An antecedent Yarlung Tsangpo-Irrawaddy River system formed the major river draining the eastern Himalaya at this time. A significant change in provenance is seen in the early Miocene, where detritus is predominantly derived from bedrock of the eastern Himalayan syntaxis, western Yunnan and Burma, a region drained by the modern Irrawaddy-Chindwin river system characterized by Cenozoic U-Pb ages and negative εHf(t) values. This is attributed to the disconnection of the Yarlung-Irrawaddy River and capture by the proto-Brahmaputra River, re-routing Tibetan Transhimalayan detritus to the eastern Himalayan foreland basin. Re-set zircon fission track ages of 14-8 Ma present in all units is used to infer post-depositional basin evolution related to changes in the stress regime accommodating the continued northward migration of India. The early Miocene initiation of the Jiali-Parlung-Gaoligong-Sagaing dextral shear zone and the continued northward movement of the coupled India-Burma plate aided in focusing deformation inside the syntaxis contributing to the disconnection of the Yarlung Tsangpo-Irrawaddy system, linking surface deformation and denudation with processes occurring at deeper crustal levels.

Ce travail étudie l’affirmation de la « culture des droits » dans le contexte népalais, en explorant le rapport triangulaire qui relie les associations locales, le discours international sur les droits humains et la morphologie des transformations – sociales, normatives, institutionnelles – qui ont caractérisé l’histoire récente du Népal.L’enquête se fonde sur une ethnographie transversale des associations urbaines, qui traverse les différentes échelles territoriales où ces associations se mobilisent et les multiples registres sur lesquels elles opèrent (le social, le politique, le juridique). La première partie est axée sur le niveau micro-local du quartier et de la ville et concerne trois réseaux associatifs: les collectifs de mères, les associations pour le développement du quartier et les organisations des Dalit, les basses castes ; la deuxième porte sur les associations des minorités ethniques (ou « nationalités indigènes ») et sur celles des groupes parbatiya, les hautes castes des collines népalaises ; la troisième est consacrée à l'interaction entre justice et société civile au Népal, telle qu’elle émerge de l’analyse d’actions en justice introduites à la Cour suprême par des associations spécialisées dans la défense des droits humains.A partir de cette analyse, on cherche à dégager 1) les mécanismes à travers lesquels le discours sur les droits est devenu un langage hégémonique de formulation des revendications collectives et d’articulation des conflits sociaux ; 2) le rôle des associations de la société civile dans ce processus ; 3) l’impact de la culture de droits sur l’expression de l’éthique, des identités et des politiques locales, ainsi que sur le cadre normatif et constitutionnel du pays. / This dissertation examines the emergence of a culture of human rights in Nepal, by focusing on the triangular relationship between civil society organizations (CSOs), the international discourse on human rights, and the social, legal and institutional changes that have characterized the country’s recent history.The research is based on ethnographic work in the field of urban associations, at the various levels and across the various fields (social, political and legal) where they operate. My first part looks at the micro-local level of the neighborhood and city, through a study of three specific networks of associations: mothers’ groups, neighborhood development associations and Dalit (low-caste) associations. In a second stage, I focus on ethnic minority (or “indigenous nationality”) associations and on parbatiya (Nepali high caste of hill origin) groups. The third and final section of the dissertation is dedicated to the interaction between the judiciary and civil society in Nepal, as it emerges from an analysis of cases filed at the Supreme Court by associations specialized in the defense of human rights.The overall aim of this research is to identify: 1) the mechanisms through which the human rights discourse has asserted its hegemony, becoming the dominant medium through which collective demands and social conflicts can be articulated; 2) the role played by CSOs in this process, and 3) the impact of the culture of human rights on the expression of local ethics, identities and politics, as well as on Nepal’s legal and constitutional framework.

The hand has the highest surface area-to-volume ratio of any body part. This property offers the potential for the hand to serve an important function in thermoregulation through radiative heat loss. Theoretically, the capacity for heat loss may be influenced by hand and digit proportions, but the extent to which these proportions influence the hand's radiative properties remains under-investigated. Although hand morphology is highly constrained by both integration and functional dexterity, phenotypic variation in hand and digit proportions across human populations shows broad ecogeographic patterns. These patterns have been associated with climate adaptation. However, the theory linking climate adaptation to such ecogeographic patterns is based on underlying assumptions relating to thermodynamic principles, which have not been tested in vivo. This study sought to determine the influence of hand and digit proportions on heat loss from the hands directly, the additional anthropometric factors that may affect this relationship, and the impact of variation in hand proportions on dexterity in the cold. The relationship between hand proportions and thermoregulation was tested through both laboratory-based investigation and a field study. The laboratory investigation assessed the relationship between hand proportions and heat loss, the influence of body size and composition on this relationship, and the effect of morphological variation on manual dexterity. Participants (N=114; 18-50 years of age), underwent a 3-minute ice-water hand-immersion. Thermal imaging analysis was used to quantify heat loss. Hand and digit proportions were quantified using 2D and 3D scanning techniques; body size and composition were measured using established anthropometric methods and bio-impedance analysis. After accounting for body size, hand width, digit-to-palm length ratio, and skeletal muscle mass were significant predictors of heat loss from the hand, whilsthand length and fat mass were not. A separate set of participants (N=40) performed a Purdue pegboard dexterity test before and after the immersion test, which demonstrated that digit width alone negatively correlated with dexterity. The field study tested whether phenotypic variation in upper limb proportions could be attributed to cold adaptation or selection for dexterity in living populations exposed to significant energetic stress. Upper limb segment lengths were obtained from participants (N=254; 18-59 years of age), from highland and lowland regions of the Nepalese Himalayas using established anthropometric methods, and relative hand proportions were assessed in relation to severe energetic stress associated with life at high altitude. Relative to height, hand length and hand width were not reduced with altitude stress, whilst ulna length was. This indicates that cold adaptation is not shaping hand proportions in this case, although phenotypic variation in other limb segments may be attributed to cold adaptation or a thrifty phenotype mechanism. The current study provides empirical evidence to support the link between surface area-to-volume ratio, thermodynamic principles and ecogeographical patterns in human hand morphology. However, this research also demonstrates the complexity of the hand's role in thermoregulation; not only do other factors such as muscularity affect heat loss from the hand, but hand morphology is also highly constrained by integration and dexterity.

This thesis deals with the role of precipitation on erosion and landscape formation in the Nepal Himalayas. I investigate all successive steps involved in the erosion process: 1) Starting from the evaluation of precipitation datasets, 2) the transfer of precipitation to river discharge, 3) the mobilization and transport of material out of the mountain range, 4) and finally, erosion constrains over longer time-scales. I show that the dataset derived from the interpolation of rain gauge data performs best in the Himalayas. I demonstrate the importance of an until now unconsidered, major compartment of the Himalayan discharge cycle, which I identify as a fractured basement aquifer, and estimate the snow and ice melt contribution to the Himalayan rivers. Erosion rates calculated from suspended sediment fluxes and cosmogenic nuclide analysis range between 0.1 and 4 mm/yr. The rivers in the Nepal Himalayas are supply limited and the hillslopes as contributing source are transport limited. Last I show that over several thousand years erosion is not related with precipitation, but with relief. / Cette thèse porte sur le rôle des précipitations sur l’érosion et la formation des reliefs dans l’Himalaya Népalais. J’étudie chaque étape du processus d’érosion : 1) Evaluation des bases de données de précipitations, 2) Transfert des précipitations au débit fluvial, 3) Mobilisation et transport du matériel dans le bassin versant, et enfin 4) Mécanismes d’érosion sur de longues échelles de temps. Je montre que la base de données de précipitations obtenue par interpolation de données pluviométriques est la plus performante pour la région de l\'Himalaya. Je démontre l’importance d’une composante majeure, jusqu’alors ignorée, du cycle de débit de l’Himalaya que j’identifie comme étant les aquifères de sous-sol fracturé, et j’évalue la contribution de la fonte des neiges et glaces aux rivières Himalayennes. Les taux d’érosion calculés à partir des flux de sédiments en suspension et des analyses de nucléides cosmogéniques varient de 0.1 à 4 mm/a. Les rivières au Népal sont limitées par l’apport sédimentaire alors que les versants, en tant que source de sédiments, sont limités par le transport. Enfin, je montre que l’érosion sur des milliers d’années ne dépend des précipitations mais du relief. / Die vorliegende Arbeit beschäftigt sich mit der Rolle des Niederschlag bei Erosions- und Oberflächenprozessen im nepalesischen Himalaja. Ich untersuche die Abfolge der Erosionspsozesse im Himalaja: 1) Ausgehend von der Bewertung von Niederschlagsdatensätzen, 2) die Prozesse der Abflussbildung in Flüssen, 3) die Mobilisierung und Transport von Material, 4) und Erosionsraten über längere Zeiträume. Ich zeige, dass interpolierte Niederschlagsdaten die beste Qualität im Himalaya haben. Ich zeige auf, wie wichtig der bislang unberücksichtigt Grundwasserzwischenspeicher für die Abflussbildung im Himalaya ist und schätze den Anteil der Schnee-und Eisschmelze an dem Gesamtabfluss der Flüssen im Himalaja. Erosionsraten die mittels Schwebestofffracht und der Analyse kosmogener Nukluide berechnet wurden, liegen zwischen 0,1 und 4 mm pro Jahr. Der Sedimenttransport in den Flüssen in Nepal ist limitiert durch die Verfügbarkeit von transportierbarem Material, während der Transport und die Mobilisierung auf den Hängen durch die Verfügbarkeit von Wasser limitiert ist. Zudem sind die Erosionsraten über mehrere Jahrhundert nicht von der Niederschlagsverteilung abhängig sondern vom Relief.

No description available.