Inaug.-diss.--Munich. / Lebenslauf. "Literaturverzeichnis": p. 59-61.

The Karakoram Axial Batholith in N. Pakistan records the magmatic development of the Eurasian continental margin since the late Jurassic. Magmatism prior to the collision of India with Eurasia at c.45Ma is represented by subduction-related, calc-alkaline granodiorite plutonism. The chemical variation within these plutons is caused by high-level fractionation processes. However, heterogeneous isotope data suggests that the source of these magmas was the mantle wedge, enriched by87 a subducted slab component, with the melts being contaminated by a Sr-rich crustal component. There are two types of post-collisional leucogranite. The Sumayar pluton is related to restricted partial melting of sillimanite-grade metapelites triggered by fluxing of fluids from the underthrust Indian crust. This water-saturated, minimum melt is considered to be an analogue of the High Himalayan leucogranites. The other Karakoram leucogranites are related by fractionation to a more basic monzogranitic parent, whose geochemistry indicates a lower crustal source. However, melting of typical crust cannot explain the anomalously high large ion lithophile element (LILE) content of the monzogranites. Associated with the granites are ultra- potassic, LILE-enriched lamprophyres. This LILE-enrichment is attributed to alteration of the mantle wedge by fluids and/or siliceous melts from the slab. Amphibole in the resulting metasomatic assemblage acts as a sink for the otherwise incompatible LILE. As a result of heating and thermal relaxation beneath the thickened continental crust, enriched amphibole, stable in the pre-collisional mantle wedge beneath the Karakoram, dehydrated or melted some 20Ma after collision to give the lamprophyres. Fluid precursors to this melting contaminated the source region of the granites selectively enriching it in LILE and triggering/promoting melting. The identification of the above magma-types, which have different generative processes and magmatic triggers, in other collisional environments will lead to information about the evolution of similar orogenic belts.

Thesis (MA)--University of Montana, 2008. / Title from author supplied metadata. Contents viewed on February 11, 2010. Includes bibliographical references.

Les glaciers de montagne ont un impact sociétal important que ce soit à l'échelle locale où ils influencent les ressources en eau et l'attractivité touristique d'une région, ou à l'échelle mondiale en contribuant au niveau des océans. Par ailleurs, les glaciers de montagne sont extrêmement sensibles aux variations climatiques et sont donc des indicateurs pertinents des évolutions climatiques passées et présentes, en particulier du réchauffement global.Une meilleure compréhension de la réponse des glaciers à ces changements, ou dynamique, est nécessaire afin d'estimer leur contribution au système Terre et leur évolution future. Les satellites d'observation de la Terre, par leur couverture globale et des acquisitions régulières, représentent un atout formidable pour suivre l'évolution des glaciers. L'archive à disposition est considérable et celle à venir promet d'être encore plus importante. Il est donc indispensable de développer des méthodes pour traiter cette masse de données.L'objectif de cette thèse est de mieux comprendre la réponse dynamique des glaciers du Pamir-Karakoram-Himalaya (PKH) et des Alpes aux changements climatiques actuels en mettant à profit les 40 années de données satellitaires disponibles. Dans un premier temps, nous avons développé une chaine de traitement semi-automatique qui permet de mesurer les vitesses annuelles de surface d'écoulement des glaciers par corrélation d'images à partir d'une archive satellitaire. Grâce à la redondance des acquisitions, il est possible d'obtenir des champs de vitesse plus complets, plus robustes et d'estimer statistiquement l'incertitude. L’application de ce traitement à l’archive Landsat a permis d’obtenirdes champs de vitesse pour l’ensemble de la région du PKH (~92 000 km2) sur la période 1998-2014et sur les Alpes (~2 000 km2, période 1999-2014) avec une couverture de 60-80 % et une incertituded’environ 4 m/an. Des champs de vitesse ont également été obtenus de manière moins systématique sur la période 1972-1998 pour le PKH. Dans un second temps, l'analyse des variations de vitesse sur ces périodes a montré un ralentissement des glaciers sur l'ensemble des deux chaines de montagne, en lien avec un amincissement des glaciers sur la même période. Les variations de vitesse sont très contrastées spatialement et sont cohérentes avec les motifs observés pour les variations d'épaisseur. En particulier, les glaciers du Karakoram et du Kunlun qui sont stables ou gagnent de la masse sur cette période montrent également des signes d'accélération, alors que les zones d'amincissement le plus important (Himalaya occidental, Nyenchen Tangla, Alpes) sont celles ou le ralentissement observé est le plus fort. Il semble donc que les variations de vitesse observées soient conditionnées au premier ordre par un signal climatique. / Mountain glaciers have a high societal impact, first at a local scale since they influence the water ressources and the touristic attractivity of a region, but also at a global scale, being major contributors to the present sea-level rise. Moreover, mountain glaciers are sensitive to climate forcing and are thus relevant indicators of past and present climate change and particularly present global warming. It is thus important to analyse the dynamic of these glaciers and quantify the changes that are affecting them so that their contribution to the Earth system and their future evolution can be better estimated. Satellite Earth Observation imagery, with its global coverage and repeated acquisition, represents a unique tool to quantify temporal changes affecting glaciers. The available archive is huge and the flux of new data will increase it even more.It is thus necessary to develop new methods to process this large archive.The objective of this thesis is to quantify the dynamic response of mountain glaciers in the Pamir-Karakoram-Himalaya (PKH) and in the Alps to a changing climate, with the use of the 40-year long satellite archive. We first developped a semi-automated processing chain to derive annual ice flow velocities from feature-tracking of satellite images. The chain takes advantage of the redundancy in the archive to obtain more spatially complete and robust velocity fields and to statistically estimate the uncertainty. Application to the Landsat archive leads to the determination of an unprecedented velocity field for the entire PKH region (~92 000 km2) for the period 1998-2014 and over the Alps (2 000 km2, period 1999-2014) with a coverage of 60-80 % and a mean uncertainty of 4 m/yr.. Flow velocities have been derived less systematically for the period 1972-1998 over the PKH. Secondly, the analysis of velocity changes show a slow-down of the glaciers for most of the 2 regions. The velocity changes are spatially contrasted and coherent with the patterns of elevation changes. In particular, glaciers in the Karakoram and West Kunlun that are stable or advancing show also a clear speed-up, whereas regions where thinning is the most important (Western Himalaya, Nyenchen Tangla, Alps) show the most important slow-down. The observed velocity changes is thus primarily determined by a climatic signal.

L'économie du Pakistan, fondée sur l'agriculture, est hautement dépendante de l'approvisionnement en eau issu de la fonte de la neige et des glaciers du Haut Bassin de l'Indus (UIB) qui s'étend sur les chaînes de l'Himalaya, du Karakoram et de l'Hindukush. Il est par conséquent essentiel pour la gestion des ressources en eau d'appréhender la dynamique de la cryosphère (neige et glace), ainsi que les régimes hydrologiques de cette région dans le contexte de scénarios de changement climatique. La base de données satellitaire du produit de couverture neigeuse MODIS MOD10A2 a été utilisée de mars 2000 à décembre 2009 pour analyser la dynamique du couvert neigeux de l'UIB. Les données journalières de débits à 13 stations hydrométriques et de précipitation et température à 18 postes météorologiques ont été exploitées sur des périodes variables selon les stations pour étudier le régime hydro-climatique de la région. Les analyses satellitaires de la couverture neigeuse et glaciaire suggèrent une très légère extension de la cryosphère au cours de la dernière décade (2000‒2009) en contradiction avec la rapide fonte des glaciers observée dans la plupart des régions du monde. Le modèle « Snowmelt Runoff » (SRM), associé aux produits neige du capteur MODIS a été utilisé avec succès pour simuler les débits journaliers et étudier les impacts du changement climatique sur ces débits dans les sous-bassins à contribution nivo-glaciaire de l'UIB. L'application de SRM pour différents scénarios futurs de changement climatique indique un doublement des débits pour le milieu du siècle actuel. La variation des écoulement de l'UIB, la capacité décroissante des réservoirs existants (barrage de Tarbela) à cause de la sédimentation, ainsi que la demande croissante pour les différents usages de l'eau, laissent penser que de nouveaux réservoirs sont à envisager pour stocker les écoulements d'été et répondre aux nécessités de l'irrigation, de la production hydro-électrique, de la prévention des crues et de l'alimentation en eau domestique. / Agriculture based economy of Pakistan is highly dependent on the snow and glacier melt water supplies from the Upper Indus River Basin (UIB), situated in the Himalaya, Karakoram and Hindukush ranges. It is therefore essential to understand the cryosphere (snow and ice) dynamics and hydrological regime of this area under changed climate scenarios, for water resource management. The MODIS MOD10A2 remote-sensing database of snow cover products from March 2000 to December 2009 was selected to analyse the snow cover dynamics in the UIB. A database of daily flows from 13 hydrometric stations and climate data (precipitation and temperature) from 18 gauging stations, over different time periods for different stations, was made available to investigate the hydro-climatological regime in the area. Analysis of remotely sensed cryosphere (snow and ice cover) data during the last decade (2000‒2009) suggest a rather slight expansion of cryosphere in the area in contrast to most of the regions in the world where glaciers are melting rapidly. The Snowmelt Runoff Model (SRM) integrated with MODIS remote-sensing snow cover products was successfully used to simulate the daily discharges and to study the climate change impact on these discharges in the snow and glacier fed sub-catchments of UIB. The application of the SRM under future climate change scenarios indicates a doubling of summer runoff until the middle of this century. This variation in the Upper Indus River flow, decreasing capacity of existing reservoirs (Tarbela Dam) by sedimentation and the increasing demand of water uses suggests that new reservoirs shall be planned for summer flow storage to meet with the needs of irrigation supply, increasing power generation demand, flood control and water supply.

Metamorphic rocks constitute a vast volumetric proportion of the Earth’s continental lithosphere and are invaluable recorders of the mechanisms and rates of deformation and metamorphism that occur at the micro-, meso- and macro-scale. As such, they have the potential to provide detailed insight into important tectonic processes such as the subductive transport of material into, and back from, mantle depths and also folding, faulting and thickening of crust that occurs during collisional orogeny. The Himalayan-Karakoram-Tibetan orogen is the youngest and most prominent example of a continent-continent collisional mountain belt on Earth today and is a product of the on-going convergence of the Indian and Asian plates that initiated in the Early Eocene. Thus, it provides an exceptional natural laboratory for the investigation of such processes. Recent advances in the computational ability to replicate natural mineral assemblages through a variety of metamorphic modelling techniques have led to improvements in the amount (and quality) of petrographic data that may be obtained from a typical metamorphic rock. In this study, phase equilibria modelling (pseudosection construction) using THERMOCALC, amongst other techniques, has been integrated with in-situ U–Pb and Th–Pb geochronology of accessory monazite in order to constrain the tectonothermal evolution of four regions intimately associated with the Himalayan-Karakoram-Tibetan orogen. These regions comprise the Karakoram metamorphic complex (north Pakistan), the Tso Morari massif (north-west India), the eastern Himalayan syntaxis (south-east Tibet) and the Day Nui Con Voi metamorphic core complex of the Red River shear zone (North Vietnam). Each case study documents previously unreported metamorphic, magmatic or deformational events that are associated with the India-Asia collision. These data have allowed original interpretations to be made regarding the tectonic evolution of each individual region as well as the large-scale evolution of the Himalayan-Karakoram-Tibetan orogenic system as a whole.

High rates of soil loss and high sediment loads in rivers necessitate efficient monitoring and quantification methodologies so that effective land management strategies can be designed. Constructing a sediment budget is a useful approach to address these issues. Quantifying a sediment budget using classical field-based techniques, however, is labour intensive and expensive for poorly gauged, large drainage basins. The availability of global environmental datasets in combination with GIS techniques provides an opportunity for studying large basins. Following this approach, a framework is presented for constructing sediment budgets for large, data-sparse drainage basins, which is applied to the mountainous upper Indus River basin in northern Pakistan. The methodological framework consists of five steps: (1) analyzing hydro-climatological data for dividing the drainage basin into characteristic regions, and calculating sediment yields; (2) investigation of major controls on sediment yields; (3) identification and mapping of sediment source areas by spatially distributed modelling of erosional processes; (4) spatially distributed modelling of sediment yields; and (5) carrying out the sediment budget balance calculation at the basin outlet. Further analysis carried out on the Indus data has enabled a better understanding of sediment dynamics in the basin.<p> Analysis of the available hydro-climatological data indicates that the basin can be subdivided into three characteristic regions based on whether runoff production and subsequent sediment generation is controlled by temperature (Region 1, upper, glacierized sub-basins), precipitation caused by the monsoon and western disturbances (Region 3, lower sub-basins), or a combination of the two (Region 2, middle reach sub-basins). It is also demonstrated that contrary to the conventional model, the specific sediment yield increases markedly with drainage area along the Indus River. An investigation of major controls on specific sediment yield in the basin indicates that percent snow/ice cover is a major land cover control for specific sediment yield. Spatially distributed erosion modelling predictions indicate that 87% of the annual gross erosion takes place in the three summer months with greatest erosion potential concentrated in sub-basins with high relief and a substantial proportion of glacierized area. Lower erosion rates can be explained by the arid climate and low relief on the Tibetan Plateau, and by the dense vegetation and lower relief in the lower monsoon sub-region. The model predicts an average annual erosion rate of 3.2 mm/a or 868 Mt/a. Spatially distributed sediment yield predictions made with coupled models of erosion and sediment delivery indicate that the Indus sub-basins generally show an increase of sediment delivery ratio with basin area. The predicted annual basin sediment yield is 244 Mt/a and the overall sediment delivery ratio in the basin is calculated as 0.28. The long-term mean annual sediment budget, based on mass balance, is characterized by a gross erosion of 762.9, 96.7 and 8.4 Mt, and a gross storage of 551.4, 66.1, and 6.5 Mt in the upper, middle, and lower regions of the basin, respectively. The sediment budget indicates that the major sources of eroded sediment are located in the Karakoram, in particular in the Hunza basin. Substantial sediment storage occurs on the relatively flat Tibetan Plateau and the Indus River valley reach between Partab Bridge and Shatial. The presented framework for sediment budget construction requires relatively few data, mostly derived from global datasets. It therefore can be utilized for other ungauged or poorly gauged drainage basins of the world.

High rates of soil loss and high sediment loads in rivers necessitate efficient monitoring and quantification methodologies so that effective land management strategies can be designed. Constructing a sediment budget is a useful approach to address these issues. Quantifying a sediment budget using classical field-based techniques, however, is labour intensive and expensive for poorly gauged, large drainage basins. The availability of global environmental datasets in combination with GIS techniques provides an opportunity for studying large basins. Following this approach, a framework is presented for constructing sediment budgets for large, data-sparse drainage basins, which is applied to the mountainous upper Indus River basin in northern Pakistan. The methodological framework consists of five steps: (1) analyzing hydro-climatological data for dividing the drainage basin into characteristic regions, and calculating sediment yields; (2) investigation of major controls on sediment yields; (3) identification and mapping of sediment source areas by spatially distributed modelling of erosional processes; (4) spatially distributed modelling of sediment yields; and (5) carrying out the sediment budget balance calculation at the basin outlet. Further analysis carried out on the Indus data has enabled a better understanding of sediment dynamics in the basin.<p> Analysis of the available hydro-climatological data indicates that the basin can be subdivided into three characteristic regions based on whether runoff production and subsequent sediment generation is controlled by temperature (Region 1, upper, glacierized sub-basins), precipitation caused by the monsoon and western disturbances (Region 3, lower sub-basins), or a combination of the two (Region 2, middle reach sub-basins). It is also demonstrated that contrary to the conventional model, the specific sediment yield increases markedly with drainage area along the Indus River. An investigation of major controls on specific sediment yield in the basin indicates that percent snow/ice cover is a major land cover control for specific sediment yield. Spatially distributed erosion modelling predictions indicate that 87% of the annual gross erosion takes place in the three summer months with greatest erosion potential concentrated in sub-basins with high relief and a substantial proportion of glacierized area. Lower erosion rates can be explained by the arid climate and low relief on the Tibetan Plateau, and by the dense vegetation and lower relief in the lower monsoon sub-region. The model predicts an average annual erosion rate of 3.2 mm/a or 868 Mt/a. Spatially distributed sediment yield predictions made with coupled models of erosion and sediment delivery indicate that the Indus sub-basins generally show an increase of sediment delivery ratio with basin area. The predicted annual basin sediment yield is 244 Mt/a and the overall sediment delivery ratio in the basin is calculated as 0.28. The long-term mean annual sediment budget, based on mass balance, is characterized by a gross erosion of 762.9, 96.7 and 8.4 Mt, and a gross storage of 551.4, 66.1, and 6.5 Mt in the upper, middle, and lower regions of the basin, respectively. The sediment budget indicates that the major sources of eroded sediment are located in the Karakoram, in particular in the Hunza basin. Substantial sediment storage occurs on the relatively flat Tibetan Plateau and the Indus River valley reach between Partab Bridge and Shatial. The presented framework for sediment budget construction requires relatively few data, mostly derived from global datasets. It therefore can be utilized for other ungauged or poorly gauged drainage basins of the world.

abstract: The Himalayan orogenic system is one of the youngest and most spectacular examples of a continent-continent collision on earth. Although the collision zone has been the subject of extensive research, fundamental questions remain concerning the architecture and evolution of the orogen. Of particular interest are the structures surrounding the 5 km high Tibetan Plateau, as these features record both the collisional and post-collisional evolution of the orogen. In this study we examine structures along the southwestern margin of the Tibetan Plateau, including the Karakoram (KFS) and Longmu Co (LCF) faults, and the Ladakh, Pangong and Karakoram Ranges. New low-temperature thermochronology data collected from across the Ladakh, Pangong and Karakoram Ranges improved the spatial resolution of exhumation patterns adjacent to the edge of the plateau. These data show a southwest to northeast decrease in cooling ages, which is the trailing end of a wave of decreased exhumation related to changes in the overall amount of north-south shortening accommodated across the region. We also posit that north-south shortening is responsible for the orientation of the LCF in India. Previously, the southern end of the LCF was unmapped. We used ASTER remotely sensed images to create a comprehensive lithologic map of the region, which allowed us to map the LCF into India. This mapping shows that this fault has been rotated into parallelism with the Karakoram fault system as a result of N-S shortening and dextral shear on the KFS. Additionally, the orientation and sense of motion along these two systems implies that they are acting as a conjugate fault pair, allowing the eastward extrusion of the Tibet. Finally, we identify and quantify late Quaternary slip on the Tangtse strand of the KFS, which was previously believed to be inactive. Our study found that this fault strand accommodated ca. 6 mm/yr of slip over the last ca. 33-6 ka. Additionally, we speculate that slip is temporally partitioned between the two fault strands, implying that this part of the fault system is more complex than previously believed. / Dissertation/Thesis / Ph.D. Geological Sciences 2014

Lofty Hindukush, Karakoram and Himalayan (HKH) mountain ranges centered in the Northern Pakistan are host to some of the world’s largest glaciers outside the Polar Regions and are a source of water for drinking and irrigation to the millions of people living downstream. With the increase in the global temperatures, glaciers are reported as retreating globally. However, some of the glaciers in the Karakoram mountain ranges are reported as surging with positive mass balance, especially since the 1990s. This phenomenon is described as "The Karakoram Anomaly". Various efforts have been made to explain the state and fate of the HKH glaciers in the recent past. However, they are limited to quantification of the change in temperature, precipitation and river runoff, or through their impact on future climate projections. For the HKH region, temperature fluctuations have been out of the phase with hemispheric trends for past several centuries. Therefore, climate change in this region is not solely the temperature effect on melting as compared to other glaciated regions. To identify the reasons for the establishment of the Karakoram Anomaly, monthly mean climatic variables for last five decades, reported from meteorological observatories at the valley floors in HKH region, are analyzed. In addition to the climatic variables of temperature and precipitation, monthly mean synoptic observations reported by meteorological observatories in both morning and afternoon, along with monthly mean radiosonde data are used. From these data the role of different near-surface and upper atmospheric meteorological variables in maintaining the positive mass balance of the glaciers and the development of the Karakoram Anomaly can be explained. An overall warming in the region is observed. The trends in the summer temperatures, which were reported as decreasing a decade ago, are now found as increasing in updated time series. However, the overall gradient is still negative. The winter mean and maximum temperatures are increasing with accelerated trends. Both maximum and minimum temperatures in summer are not diverging anymore and the diurnal temperature range is decreasing in the most recent decade. The afternoon cloudiness is found as increasing throughout the year except for spring, which is indicative of an increase in convective uplifting. Moreover, humidity is increasing all over the region; due to evaporation in the spring, from monsoon moisture advection in summer, and due to the recycling of monsoon moisture in autumn. Furthermore, near-surface wind speed and net radiation in the region are decreasing, explaining the decrease in the summer minimum temperature and the presence of the cloudy skies. The decrease in near-surface wind speed, and net radiation, and increase in water vapor pressure put a limit on the evapotranspiration process. In addition, winter and summer precipitation is increasing. The aridity index, which is based on the ratio of precipitation and reference evaporation, indicates that region is turning moisture surplus and energy deficient. Surface atmospheric pressure and 700 hPa geopotential height is increasing due to warming in the bottom layers of the troposphere. Nighttime inversion in the lower tropospheric layers is decreasing due to warming. Analysis of gridded observed and reanalysis datasets indicates that they are not presenting a signal of change in accordance with the instrumental record. Furthermore, it is found that meteorological conditions during the summer season are still favorable for the sustenance of glaciers whereas more melting may occur in the spring season that may increase the early season river flows and may affect lower lying portions of the debris-free glaciers.