Дисертації з теми "Tibetan and Himalayan Orography"

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.

The characteristic remanent magnetization (ChRM) isolated from Paleogene carbonate rocks of the Zongpu Formation in Gamba (28.3 degrees N, 88.5 degrees(E) of southern Tibet has previously been interpreted to be primary. These data are pertinent for estimating the width of Greater India and dating the initiation of India-Asia collision. We have reanalyzed the published ChRM directions and completed thorough rock magnetic tests and petrographic observations on specimens collected throughout the previously investigated sections. Negative nonparametric fold tests demonstrate that the ChRM has a synfolding or postfolding origin. Rock magnetic analyses reveal that the dominant magnetic carrier is magnetite. "Wasp-waisted" hysteresis loops, suppressed Verwey transitions, high frequency-dependent in-phase magnetic susceptibility, and evidence that > 70% of the ferrimagnetic material is superparamagnetic at room temperature are consistent with the rock-magnetic fingerprint of remagnetized carbonate rocks. Scanning electron microscopy observations and energy-dispersive X-ray spectrometry analysis confirm that magnetite grains are authigenic. In summary, the carbonate rocks of the Zongpu Formation in Gamba have been chemically remagnetized. Thus, the early Paleogene latitude of the Tibetan Himalaya and size of Greater India have yet to be determined and the initiation of collision cannot yet be precisely dated by paleomagnetism. If collision began at 59 +/- 1 Ma at similar to 19 degrees N, as suggested by sedimentary records and paleomagnetic data from the Lhasa terrane, then a huge Greater India, as large as similar to 3500-3800 km, is required in the early Paleogene. This size, in sharp contrast to the few hundred kilometers estimated for the Early Cretaceous, implies an ever greater need for extension within Greater India during the Cretaceous.

The Himalayan orogen provides an incredible natural laboratory to test models for continent-continent collision. The highest peaks of the Himalayas are composed of the Greater Himalayan Sequence (GHS), which is bound by a north-dipping low angle detachment fault above (South Tibetan detachment; STD) and by a thrust fault below (Main Central thrust; MCT). Assuming simultaneous movement on these features, the GHS can be modeled as a southward extruding wedge or channel. Channel flow models describe the coupling between mid-crustal flow, driven by gradients in lithostatic pressure between the Tibetan Plateau and the Indian plate, and focused denudation on the range front. Although the general geometry and shear sense criteria for these bounding shear zones has been documented, prior to this investigation, relatively few attempts had been made to quantify the spatial and temporal variation in flow path history for rocks from an exhumed section of the proposed mid-crustal channel. Results from this investigation demonstrate that mid-crustal flow at high deformation temperatures was distributed throughout the proposed channel. As these rocks began to exhume to shallower crustal conditions and therefore lower temperatures, deformation began to become partitioned away from the core of the channel and into the bounding shear zones. Based on these results a new method (Rigid Grain Net) to measure the relative contributions of pure and simple shear (vorticity) is proposed. Detailed thermobarometric analysis was conducted on rocks from the highest structural level in the Khumbu region, Nepal to construct pressure-temperature-time-deformation paths during the tectonic evolution of the GHS between ~32-16 Ma. Another aspect of the project suggests that the most active feature of the region is the N-S trending Ama Drime Massif (ADM). By combining new structural interpretation with existing remote sensing data this investigation proposes that the ADM is being exhumed during extension that is coupled with denudation in the trans-Himalayan Arun River gorge. Together these data provide important insights into the dynamic links between regional-scale climate and crustal-scale tectonics.
Ph. D.

This thesis presents and analyses Chinese, Tibetan, and British sources relating to the British Mission to Tibet of 1904. It balances accounts provided by the British officers and men with modern Chinese sources. It analyses both polarised sides of the history, whilst remaining critical of all sources. British historical accounts analysed in chapter one are balanced with Chinese narratives that present the Mission as an invasion of the Motherland and its unity. Chapter two examines the role of propaganda in modern China, and how different media are used to guide the Tibetan and Chinese populations’ understanding of their history and nation. Chapters three and four provide an original translation of Bod kyi rig gnas lo rgyus dpyad gzhi’i rgyu cha bdams bsgrigs, a textbook written from a Chinese nationalistic perspective. The introductory chapter providing the Chinese narrative of the build-up to the Mission is studied in chapter three, and chapter four analyses the bloody advance into Tibet. The translation and analysis in chapter five of the letters of the Dalai Lama to the King of Nepal, the Tongsa Pönlop, and the Chögyal of Sikkim place the Mission in pan-Himalayan context, and show how the Tibetan Government sought to counter the Mission. It is the first study to provide a historical Tibetan perspective of events. Chapter six analyses the divisive issue of looting during the Mission. It examines the psychology of those who looted Tibet, and the role the items taken play in shaping the image of Tibet in the West. Modern Chinese propaganda sources from the new media are analysed in chapter seven, and demonstrate how they have been used to compliment and propagate the established narrative. The conclusions analyse the impact of the Mission, and the lessons that may be learnt for those that play the ‘New Great Game.’

U rgyan pa Rin chen dpal (1230-1309) was a great adept of the bKa' brgyud school of Tibetan Buddhism, particularly renowned for his knowledge of the Kālacakra tantra and the unique teaching known as the Approach and Attainment of the Three Vajras (rDo rje gsum gyi bsnyen sgrub), said to have been given to him in his vision by Vajrayoginī (rDo rje rnal 'byor ma) in the Miraculous Land (sprul pa'i zhing) of U rgyan. He was the student of the 2nd Karma pa, who entrusted him with the Black Hat, which he passed to the 3rd Karma pa. He was also a great traveller who journeyed widely across and beyond Tibet. He met Qubilai Khan in the capital of Yuan China and visited sacred Buddhist sites in South India. He has been aptly described by van der Kuijp as "the great Tibetan yogi, thaumaturge, scholar, alchemist, and traveler". Thanks to the availability of a large amount of hitherto unknown materials from eleven biographies, the thesis has put considerable weight on the bibliographical comparison and analysis of the different works in an attempt to establish the possible relationship between them. This is supplemented by summaries of the biographies, to give an overview of the protagonist's life in Part One of the thesis. Part Two consists of a critical study of the different phases and aspects of U rgyan pa's life in the unique historical, political and religious context of each phase, drawing materials from the corpus of biographies and in the light of other primary and secondary sources in Tibetan, Chinese and Western languages. In Chapter I, U rgyan pa's family lineage, childhood and early studies are discussed in order to find out how his innate propensities and early studies are represented as having influenced his character. In Chapter II, the account of U rgyan pa's journey to West Tibet and U rgyan is studied. A sixteen-stanza song in his own words epitomising this journey, supplemented by route maps, will be used as a framework to illustrate and reconstruct his journey to the Land of the Ḍākinīs. In Chapter III, the teachings he received and the subsequent transformation of his character and status, are explored. In Chapter IV, his career as a tantric master, his other pilgrimages and benediction trips, and his conflicts with various religious and political authorities, are examined. The materials will be scrutinised in the hope of separating as far as possible fact from fiction.

The dominant discourse surrounding academic research libraries today is one of change and scholarship in the humanities has seen a similar revolution in practice. Yet, most of the documented changes in either have been ascribed to the availability of online journal materials. Despite the accessibility of millions of rare, digitized primary resources freely available on the web, little has been done to understand the impact of these materials on either the practice of scholarship or on libraries. The research described in this proposal is an investigation into digitization projects involving rare and closely guarded materials and the effects of these projects on humanities scholarship. This thesis uses both qualitative and quantitative measures to: Assess the impact of digitized primary resources on the work of humanities scholars; To construct a model based on the findings that explains current use of digitized primary sources; and, To discuss the implications of these findings for academic research libraries. The research questions are answered through a detailed analysis of the role of digitization in the field of Tibetan and Himalayan studies. The author presents detailed evidence of how digitization is changing the inputs, practice, and outputs of scholarship in this field, as well as the characteristics of digitization that have led to these changes. Importantly, these findings separate out the success of individual projects from the success of digitization across the field as a whole. Support for community and innovation as well as the presence of critical mass across the field are stressed as the three most significant factors. Finally, the implications of these findings are assessed within a newly proposed model of academic libraries. This “scholar-centric” model is intended to provide both a theoretical framework for the research findings as well as a normative provocation for structuring future research and discussions about the role of academic libraries and their presence online.

The Tibetan literary corpus offers a wide array of (auto)biographical accounts; Tibetans have been recollecting - and narrating - life stories in earnest since the "later diffusion" (Tib. phyi dar) of Buddhism in the 11^th century. The hybrid essence of life writing, suspended between fact and fiction, finds a perfect expression in the text at the core of the present dissertation, i.e. the journal (Tib. nyin deb) of a 20th century Khams pa trader, Kha stag 'Dzam yag. The text records the events, travels, and impressions experienced by the author between 1944 and 1956; structured like a diary, this autodiegetic text, originally written in a scroll-paper format, was later edited and finally published in India in 1997. Two different heuristic devices, i.e. narratology and socio-economic analysis, are used in the present dissertation to analyse the structure and content of the nyin deb, as well as the author's idiosyncrasies emerging from the process of narrativisation. Whereas the narratological approach allows the identification of the interplay of memory, self, and culture in the socio-historical context of mid-20th century Tibet, the socio-economic analysis reflects on the nyin deb as a form of social history rather than personal narrative. The identification of "true", historical facts confirms the author's claims to factuality, thus providing unique information and insight regarding the political and economic role of Khams pa traders in 1940s-1950s Tibet, as well as the development of new pilgrimage rituals and the emergence of forms of "spiritual tourism" in modern India.

The Himalayan fold-thrust belt and Tibetan Plateau are the result of the collision between the Indian and Eurasian continents. This dissertation documents the kinematics and tectonic history of the Himalayan fold-thrust belt of western Nepal and the northern Tibetan Plateau. In the Himalayan fold-thrust belt, the Main Central thrust emplaced a hanging wall flat of Greater Himalayan rock over a footwall flat of Lesser Himalayan rock in Early Miocene time. Subsequent growth of the Lesser Himalayan duplex (LHD) uplifted and rotated the Ramgarh thrust sheet, Main Central thrust, and overlying Greater Himalayan rock to the surface. Thus, growth of the LHD is responsible for the northward dips in the Greater Himalaya. New Nd isotopic data from throughout Nepal indicate that Lesser Himalayan rocks consistently have more negative epsilonNd values than Greater and Tibetan Himalayan rocks. Growth of the LHD is documented in the syntectonic sediments of the Neogene Siwalik Group. At ∼10-11 Ma in central and western Nepal, the epsilonNd values of the Siwalik Group shift toward more negative values which indicate detrital input from rocks in the LHD. Regional mapping in western Nepal and three balanced cross sections provide a three-dimensional view of the fold-thrust belt. These cross sections suggest over 900 km of shortening in upper crustal rock from the Indus suture to the Main Frontal thrust. This suggests a corresponding ∼900 km long wedge of lower crustal rock was consumed by the Himalayan-Tibetan orogen. This wedge may have been inserted under the Tibetan Plateau, helping it obtain its anomalously thick crust. If lower crustal rocks have been inserted under the Tibetan Plateau, the Himalayan collision can account for ∼70% of the overthickened crust. This leaves ∼30% to be accounted for by other mechanisms. The Tula uplift documents shortening along the northern edge of the Tibetan Plateau. The lithic composition of its sandstone, deformation, and erosion of strata suggests that significant regional uplift and thickening occurred since Late Jurassic time and is still occurring. These relationships suggest that the northern Tibetan Plateau region was tectonically active, and undergoing shortening, long before the early Tertiary India-Eurasian collision.

Dynamically recrystallized quartz microstructure and grainsize evolution along mid-crustal shear zones allows for the estimation of tectonic driving stresses and strain rates acting in the mid-crust. Quartz-rich tectonites from three exhumed mid-crustal shear zones, the Main Central Thrust (MCT; Sutlej valley, NW India), South Tibetan Detachment System (STDS; Rongbuk valley, S Tibet), and Moine thrust (NW Scotland), were analyzed. Deformation temperatures estimated from quartz microstructural and petrofabric thermometers indicate steep apparent thermal gradients (80â 420 °C/km) across 0.5â 2.3 km thick sample transects across each shear zone. Quartz recrystallization microstructures evolve from transitional bulging/sub-grain rotation to dominant grain boundary migration at ~ 200 m structural distance as traced away from each shear zone. Optically measured quartz grainsizes increase from ~ 30 μm nearest the shear zones to 120+ μm at the largest structural distances. First-order Zener space analysis across the Moine nappe suggests strong phyllosilicate control on recrystallized quartz grainsize. Recrystallized quartz grainsize piezometry indicates that differential stress levels sharply decrease away from the shear zones from ~ 35 MPa to 10 MPa at ~ 200 m structural distance. Strain rates estimated with quartz dislocation creep flow laws are tectonically reasonable, between 10^-12—10^-14 s^-1. Traced towards each shear zone strain rate estimates first decrease one order of magnitude before rapidly increasing one to two orders of magnitude at structural distances of ~ 200 m. This kinked strain rate profile is likely due to the steep apparent thermal gradients and relatively constant differential stress levels at large structural distances.
Master of Science

Le khroskyabs de Wobzi (rgyalronguique, sino-tibétain), avec environ 350 locuteurs, est parlé au canton de Wobzi, comté de Chuchen, préfecture tibétaine et qiang de Rngaba, au Sichuan, en Chine. Notre thèse, une description linguistique du khroskyabs de Wobzi, est la première grammaire de référence du khroskyabs basée sur un corpus de textes recueillis au cours de neuf terrains depuis 2010. Elle comporte cinq parties principales.D’abord, un chapitre introductif, le chapitre 1, présente la situation sociolinguistique du khroskyabs, et le chapitre 2 la phonétique et la phonologique. Parmi toutes les langues de la famille sino-tibétaine décrites jusqu’à maintenant, le khroskyabs est celle qui a le plus grand nombre de groupes de consonnes initiaux, avec 715 groupes distincts ; par ailleurs, c’est également une langue à deux tons (haut et descendant), qui ne s’assigne qu’à l’une des syllabes dans une unité prosodique. Au chapitre 3, une introduction aux différentes parties de discours en khroskyabs de Wobzi est proposée, suivie de trois chapitres sur la morphologie nominale (le chapitre 4), les adverbes (le chapitre 5) et les autres parties de discours fermées (le chapitre 6).Ensuite, nous consacrons sept chapitres, du chapitre 7 au chapitre 13, aux constructions verbales, qui forment la partie centrale de la langue khroskyabs. Manifestant une morphologie verbale gabaritique, le wobzi est principalement préfixant, avec 11 positions préfixales et 2 positions suffixales. De plus, les affixes, surtout le préfixe causatif s-, subissent des processus morphophonologiques complexes : assimilation, dissimilation et métathèse, etc. Les propriétés de TAME se réalisent avec des opérations morphologiques, des auxiliaires ou des constructions phrastiques spécifiques.Ensuite, nous présentons les constructions phrastiques à travers quatre chapitres, du chapitre 14 au chapitre 17 : les phrases simples, la complémentation propositionnelle, la relativisation et les constructions comparatives, respectivement. Ces constructions présentent des propriétés distinctes des langues rgyalrong, en faisant usage des enclitiques nominalisateurs pour les complétives et les relatives, et possédant une formation du discours semi-direct unique et innovée, impliquant des changements de point de vue spécifiques. Enfin, dans l’annexe de la thèse, nous fournissons deux textes glosés, un index du vocabulaire et un dictionnaire
Wobzi Khroskyabs (Rgyalrongic, Sino-tibetan), with around 350 speakers, is spoken in the Commune of Wobzi, Chuchen County, Rgnaba Tibetan and Qiang Autonomous Prefecture. This dissertation, a linguistic description of Wobzi Khroskyabs, is the first reference grammar of the Khroskyabs language, based on text corpora collected from nine fieldworks since 2010. It consists of five major parts.Firstly, an introductive chapter (Chapter 1) presents the socio-linguistic situation of Khroskyabs, and secondly, in Chapter 2, the phonetics and the phonology are treated. Khroskyabs is so far the language exhibiting the largest number of initial consonant clusters amongst all Sino-Tibetan languages, with 715 distinctive clusters ; it is also a two-tone language (high and falling) that assigns one single tone to each prosodic unit.In the third place, Chapter 3 is an introduction to different parts of speech in Wobzi khroskyabs, followed by three chapters on nominal morphology (Chapter 4), adverbs (Chapter 5) and other closed parts of speech (Chapter 6).Then, seven chapters, from Chapter 7 to Chapter 13, are dedicated to verbal constructions, forming the main part of the dissertation. Exhibiting a templatic morphology, Wobzi is mainly prefixing, with 11 prefix slots and 2 suffix slots. Moreover, the affixes, especially the causative prefix -s, undergoes complex morphophonological processes: assimilation, dissimilation, metathesis, etc. Wobzi also presents TAME phenomena related to morphological operations, auxiliaries and specific sentential constructions.The chapters on verbs are followed by four chapters on sentential constructions, from Chapter 14 to Chapter 17, in which we will discuss simple sentences, complementation, relativisation and comparative constructions. These constructions present different properties compared to Rgyalrong languages, on the one hand, making use of nominalising enclitics for complementation and relativisation, and on the other, exhibiting a unique and innovated formation of semi-direct speech, with specific point of view changes.In the end, in the appendices, two glossed texts, a vocabulary index and a dictionary are provided

Monsoon Low-Pressure Systems (LPS) are synoptic-scale tropical disturbances that periodically form over the Indian subcontinent during the summer monsoon season (June-September). Apart from being a lifeline to agriculture, the LPS-triggered precipitation could cause catastrophic floods. This thesis investigates the large-scale factors that influence LPS characteristics under the current and future climate change scenarios. In the early part of the thesis, a new approach is developed to track the formation and propagation of LPS over the Indian subcontinent. A detailed statistical and visual comparison is made between LPS tracks generated using our approach applied to ERA-Interim reanalysis data and tracks obtained in previous studies. Furthermore, extreme rainfall at locations in the vicinity of LPS is analyzed which could be valuable for flood risk assessment during the monsoon season in central India.       In the latter part of the thesis, a fully coupled version of the Community Earth System Model (CESM 1.2.2) is run at 0.9°×1.25° spatial resolution, and 6-hourly output is generated for track analysis. The model’s ability to simulate the characteristics of LPS is first assessed by performing a present-day control simulation. Simulations to study the sensitivity of LPS statistics to topographical features in the south Asian region (presence or absence of southeast Asian mountains and the height of Tibetan and Himalayan Orography (THO)) and the change in LPS characteristics under climate change are also performed. Simulations without the southeast Asian mountains enable determining the influence of these mountains on the downstream amplified systems (remnants of Pacific tropical cyclones) over the Bay of Bengal. The sensitivity analysis on the influence of the height of THO shows an interesting result: while a decrease in monsoon precipitation with a reduction in the height of THO is simulated, the number of LPS increases. A detailed analysis of the dynamic factors leading to this counter-intuitive result is performed. Finally, the change in LPS characteristics and the associated large-scale SST and circulation anomalies in the Indian Ocean and south Asian region are assessed for the RCP8.5 emissions scenario. It is found that the monsoon circulation is weakened, summer monsoon precipitation over India is enhanced, and the number of LPS remains nearly unchanged in a warmer world.