Дисертації з теми "Glaciers – Tibet, Plateau of"
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Grigholm, Bjorn. "Climate Investigations Using Glaciochemical Records from a Tibetan Ice Core and a Fresh Snow Reconnaissance Study from Tierra del Fuego." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/GrigholmB2007.pdf.
Повний текст джерелаFujita, Koji, 耕史 藤田, Takeshi Ohta, and Yutaka Ageta. "Characteristics and climatic sensitivities of runoff from a cold-type glacier on the Tibetan Plateau." Wiley, 2007. http://hdl.handle.net/2237/11361.
Повний текст джерелаYang, Chao. "Geology, geochronology, stable isotope, and sulfides of the Tiegelongnan porphyry-epithermal Cu (Au) deposit, Tibet, China." Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/67954.
Повний текст джерелаShi, Chunming. "Paleoclimate information archived in tree-ring width and tree-ring stable isotopes on Tibetan Plateau." Versailles-St Quentin en Yvelines, 2011. http://www.theses.fr/2011VERS0023.
Повний текст джерелаThe Tibetan plateau, 4000m high, is called the earth’s third pole. No other area in the world is a water repository of such size, serving as a lifeline for much of a continent and millions of people in countries downstream. The water supply in this head water region accounts for instance for more than 60% of the total runoff to the Yellow River (Zhao et al. , 2008). Climate evolution in Tibet would potentially have serious impacts. The current climate change could thus cause a rapid retreat of the glaciers with significant consequences on water resources in the region. However, the glacier water balance is influenced not only by local temperature variations, but also by precipitation ones. In southern Tibet, precipitation events exhibit a strong interannual-to-decadal variability directly related to the variability of Indian monsoon rainfall. To decipher the causes and the driving forces of water supply variability in the ‘water tower’ of China, it is therefore crucial to understand how it is affected by local and global climate changes. The climate and river flow in the source region of the Yellow River are documented through instrumental records starting in the 20th century. The Tibetan Plateau can offer a variety of climate archives but high-resolution proxy data, which are needed to document long-term climate change impacts, are still scarce in this area. The width and the isotopic composition of tree-ring have shown to be very valuable proxies of climate parameters. However, the potential of these proxies for reconstructing parameters linked to the hydrological cycle (precipitation, relative humidity, cloud cover, river flow) in this area still needs to be investigated. This thesis aims at characterizing climate variability in the Southern Tibetan Plateau over the last centuries. The main goals are: a) to determine the relations between some key climate parameters and tree-ring parameters (ring-width and cellulose 13C and 18O) over the instrumental time-period, b) to reconstruct and interpret climate variability in the South-Eastern Plateau over the last centuries from new tree-ring chronologies
Wang, Baiqiu, and 王伯秋. "Magmatic and sedimentary constraints on the evolution of the triassic Yidun Arc, eastern Tibet." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B50605719.
Повний текст джерелаpublished_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
Wang, Yun Summer, and 王筠. "Love to the eternity : eco-tourism design along Qinghai-Tibet railway." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207151.
Повний текст джерелаpublished_or_final_version
Architecture
Master
Master of Landscape Architecture
Chen, Yiwei, and 陈怡伟. "Optical dating investigation into the slip rate of Altyn Tagh fault and evolution of Zhari Namco, Tibetan Plateau." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hdl.handle.net/10722/197127.
Повний текст джерелаpublished_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
Goussin, Fanny. "Subductions continentales au Tibet Central : héritages pétrologique, rhéologique et construction d'un plateau." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU007/document.
Повний текст джерелаHow and when the Tibetan Plateau was built remains a complicated issue, with many implications for our understanding of the behaviour of colliding continental lithospheres. Some models highlight the importance of the underthrusting of the Indian lithosphere and of localized thickening at the edges of rigid Asian microplates ; while others consider that the Asian lithosphere is weak and deforms in a distributed manner. The growing, high-quality database documenting deep and surface processes has now to be integrated in order to constrain the different evolution models of the Plateau.This thesis work focuses on the north-eastern Qiangtang block in Central Tibet : although it is a keystone for reconstructions and models, this region remains one of the least studied of the collision zone.In a first part, new 40Ar/39Ar dating of the Late Triassic (215-200 Ma) deformation on the Jinsha suture, along with a metamorphic study of Early Triassic (249 Ma) corundum-bearing crustal xenoliths sampled in Eocene magmatic rocks, shed light on the the major, but underestimated role played by the Mesozoic subductions in bulk crustal thickening. Our results suggest that prior to the Eocene, our study area had reached a crustal thickness of 45-55 km, i.e 80% of its present-day crustal thickness of 66 km. This Mesozoic crustal thickening was likely achieved by continental arc magmatism related to the 80 Ma of continuous oceanic subductions on both edges of the NE-Qiangtang terrane.These interpretations are consistent with the regional emersion and paleo-altitude data.In a second part, a petrological and geochemical study of Eocene magmatic rocksfrom the Nangqian and Xialaxiu basins suggests an intense metasomatism of the source lithospheric mantle by H2O- and CO2-rich fluids or melts. These results are used as a starting point for a series of rheological and thermo-mechanical models, to characterize the behaviour of such lithosphere in a continental convergence context. We show that the lithospheric mantle underlying our study area in the Eocene was particularly weak (logmin~2.3) and buoyant (~3310 kg/m3 à 2 GPa), and its solidus was deflected to low temperatures at medium mantle pressures (~930°C à 3 GPa). From these characteristics, thermo-mechanical models forecast an atypical deformational and partial melting regime, through the injection of metasomatized lithospheric mantle into the asthenosphere, whichadequately reproduces the timing and location of Xialaxiu and Nangqian magmatic events, and the magnitude of crustal thickening observed in our study area, without any delamination of the weakened lithospheric root.This eventually leads us to reconsider the available geophysical data for the Tibetan lithospheric mantle : the low-velocity zone imaged beneath Central Tibet could indeed represent a geochemical, rather than thermal anomaly
He, Siyuan. "Hydrological processes and meadow degradation in the Kobresia meadow of Northern Tibet." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648713.
Повний текст джерелаWang, Baolai. "Some aspects of plateau permafrost, Qinghai-Xizang (Tibet) Plateau, China, and a comparison with the Mackenzie Delta region, Canada." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6840.
Повний текст джерелаLi, Shenghui. "The indepth magnetotelluric experiment on the Tibetan Plateau and its implications /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/6817.
Повний текст джерелаXue, Zhenhua. "Mesozoic tectonic evolution of the Longmenshan thrust belt, East Tibet." Thesis, Orléans, 2017. http://www.theses.fr/2017ORLE2020/document.
Повний текст джерелаThe Longmenshan Thrust Belt (LMTB), constituting the eastern boundary of the Tibetan Plateau, is well known by its steep topography, intensive tectonic activities and the complicated structures. As a typical composite orogen, the LMTB experienced extensive intracontinental deformation during the Mesozoic. The knowledge on the Mesozoic tectonic evolution of the LMTB therefore is crucial to understand the intracontinental orogeny and uplifting of the Plateau. The vertical cleavage belt divides the LMTB into a Western Zone and an Eastern Zone. The Eastern Zone displays a top-to-the-SE shearing while the western zone a top-to-the-NW shearing. The Eastern Zone can be further divided into four subunits with foliations deepening from SE to NW. The syntectonic granite and published geochronologic data constrain this main deformation to the Early Mesozoic around 219 Ma. Structural analysis, AMS and microstructural study and gravity modeling on the Pengguan complex, one of the orogen-parallel Neoproterozoic complexes located in the middle segment of the LMTB, reveal a basement-slice imbricated structure of the LMTB and adjacent areas. Published ages, localized fast exhumation rate and flexural subsidence of the foreland basin suggest that the basement-slices imbricated southeastwards during Late Mesozoic (166-120 Ma). The LMTB is far away from the contemporaneous plate boundary and devoid of ophiolite-related material, therefore, it is supposed to be an intracontinental orogen. During the Early Mesozoic, the Yangtze basement underthrusted westwards due to the far-field effect of the Paleo-Tethys’ obliteration, and the materials in different structural levels have been exhumated to the surface by southeastward thrusting and contemporaneous backward thrusting. During the Late Mesozoic, the basement is further underthrusted due to the collision between the Lhasa and Eurasia blocks, which led to SE-ward imbrication of the basementslices that may thicken the crust
Gourbet, Loraine. "Évolution morphologique et sédimentologique des bordures ouest et sud-est du plateau du Tibet." Thesis, Lyon, École normale supérieure, 2015. http://www.theses.fr/2015ENSL0982/document.
Повний текст джерелаTibet is the widest and highest plateau on Earth. Tectonics, climate evolution and ante-surrection geomorphology are the main factors controlling the plateau formation. In order to assess the relative influence of these factors, we study the relief evolution on the plateau edges using geomorphic analysis, sedimentology and exhumation rates based on low-temperature thermochronometry.The results show that the western and eastern plateau edges were already at high elevation at ca 35 Ma, only 20 Ma after the India-Asia collision. This favors an “en bloc” uplift model for the plateau.In western Tibet, the hydrographic network was connected to the Indus river, allowing the early development of a >1000 m amplitude relief, probably before 35 Ma. The relief was preserved due to low erosion conditions. Western Tibet was then isolated from the Indus drainage network due to the Karakorum fault slip.The relief formation in Eastern Tibet is older than in western Tibet: at ca 35 Ma, in the Jianchuan area (northern Yunnan), which was already at high elevation, was a large braided river system. This implies a moderate regional slope. It also implies a local relief further north and significant precipitations
Cheung, Man-ching, and 張敏青. "Holocene paleo-environmental reconstruction in central Tibetan plateau inferred from a lacustrine sediment record." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/211563.
Повний текст джерелаpublished_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
Van, der Woerd Jérôme. "Couplage cinématique entre décrochements et chevauchements actifs dans le Nord du Tibet : croissance du plateau Tibétain." Paris 7, 1998. http://www.theses.fr/1998PA077159.
Повний текст джерелаPullen, Alexander. "The Nature of Continental Rocks During Collisional Orogenesis and Tectonic Implications: Tibet." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194378.
Повний текст джерелаCheng, Feng. "Source to sine relations between the Qaidam basin (Tibet) and the surrounding mountains." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S017/document.
Повний текст джерелаThe Qaidam basin, located within the northern Tibetan plateau, is the deepest intracontinental basin, yet located in the highest plateau with the thickest continental crust. Understanding how this peculiar basin developed has broad implications for the Tibetan geology in particular and for continental tectonics in general. Many approaches have been used to decipher the tectonic and topographic history of that region, however, the initial topography of the area now represented by the northern Tibetan plateau, as well as the early stages of development of the present day topography remain poorly constrained and highly debated. In order to better understand the Cenozoic evolution of the Qaidam basin and its surrounding regions (including Eastern Kunlun Range to the south, Altyn Tagh Range to the northwest, and Qilian Shan to the northeast), four critical issues are addressed in this thesis: 1) the Cenozoic joint tectonic evolution of the Qaidam basin and the Eastern Kunlun Range; 2) the interplay between the sedimentation within the Qaidam basin and the active tectonics within the Altyn Tagh Range; 3) a quantitative estimate of the lateral extrusion along the Altyn Tagh Fault-Qilian Shan tectonic system; 4) the nature and classification of the Qaidam basin. I suggest that the SW Qaidam basin has been bordered by a series of strike-slip faults to the south since the Early Miocene, rather than, as previously suggested by a continuous northward or southward thrusting system. Based on U-Pb dating (LA-ICP-MS) of detrital zircons collected from 4 sections (Paleocene to Holocene) within the southwestern Qaidam basin combined with provenance analysis and new seismic profile interpretation, I demonstrated that the Eastern Kunlun Range was already exhumed prior to the Paleocene. I show that the Qaidam basin was widening southward during thet early Cenozoic period (Paleocene to Oligocene). From Oligocene the relief of the Eastern Kunlun and Altyn Tagh ranges increased, leading to isolation and narrowing of the Qaidam basin from Miocene to the present. Along the northern edge of the basin, I identified the Tula-Huatugou and Anxi-Eboliang regions as residual parts of the original Qaidam basin. I suggest that the Altyn Tagh Fault has experienced a total of ~360 km of displacement since its Early Eocene initiation. Based on this ~360 km northeastward migration of the relatively rigid Qaidam block along the Altyn Tagh Fault and 3D isovolumetric balance of the crustal deformation within the Altyn Tagh Fault – Qilian Shan system, I demonstrate that 250 ± 28 km (43.8~49.4 %) of N20E directed crustal shortening and an additional ~250 to ~370 km of eastward motion of the Qilian Shan crust must be accounted for by strike-slip faulting in the Qilian Shan and crustal thickening in the Qinling area, as well as extension in the adjoining North China block graben systems
Saylor, Joel Edward. "The Late Miocene through Modern Evolution of the Zhada Basin, South-Western Tibet." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194652.
Повний текст джерелаAichner, Bernhard. "Aquatic macrophyte-derived biomarkers as palaeolimnological proxies on the Tibetan Plateau." Phd thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4209/.
Повний текст джерелаDas tibetische Hochplateau ist die größte gehobene Landmasse der Erde und beeinflusst maßgeblich atmosphärische Zirkulationsmuster wie den Asiatischen Monsun. Um die Auswirkungen zukünftiger Schwankungen der Monsundynamik auf das regionale Klima besser einschätzen zu können, ist es wichtig, ein fundiertes Verständnis vergangener Klimaänderungen zu entwickeln. Daher ist das Tibetplateau in den letzten Jahren mehr und mehr in den Fokus paläoklimatischer Studien gerückt. Die große Anzahl an Seen in der Region bietet ein unerschöpfliches Klimaarchiv und viele Studien haben sich bereits mit Seesedimenten zur Klimarekonstruktion befasst. Dabei wurde in erster Linie auf biologische, sedimentologische und geochemische Parameter zurückgegriffen, wohingegen organische Biomarker bisher recht selten benutzt wurden. Die vorliegende Arbeit untersucht die Anwendbarkeit dieser potentiellen Klimaindikatoren auf dem Tibetplateau. Hierbei wurde ein Schwerpunkt auf die Analyse kutikularer Blattwachse von Wasserpflanzen gelegt, da diese wegen ihres starken Auftretens in tibetischen Seen einen erheblichen Beitrag zur organischen Substanz im Sediment leisten. Um den Einfluss von Wasserpflanzen auf das Sediment über einen weiten klimatischen Gradienten zu untersuchen, wurden Oberflächensedimente und Wasserpflanzen vom zentralen und östlichen Tibetplateau auf ihre Biomarkerzusammensetzung sowie auf ihre Kohlen- und Wasserstoffisotopensignatur untersucht. Dadurch wurde das Verständnis über beeinflussende Faktoren auf diese Parameter in Sedimenten vertieft. In einem Sedimentbohrkern des Koucha-Sees (östliches Tibetplateau) konnten diese Parameter dann im Hinblick auf Änderungen der Produktivität im See sowie der hydrologischen und klimatischen Bedingungen der letzten 15000 Jahre interpretiert werden. Es zeigte sich, dass der See bis 8000 Jahre vor Heute stark mit Wasserpflanzen bewachsen war, während die letzten 6000 Jahre Algen dominierten. Mit Hilfe von Wasserstoffisotopen wurden eine Zunahme des Monsuns und steigende Niederschläge zwischen 15000 und 10000 Jahren vor Heute sowie eine relativ trockene Periode zwischen 10000 und 7000 Jahren vor Heute rekonstruiert. Durch Kombination von Biomarkerkonzentrationen sowie deren Kohlenstoffisotopensignal wurden außerdem kurzzeitige Kälteperioden um ca. 6000, 3100 und 1800 Jahren vor Heute nachgewiesen, die vorher bereits in anderen Klimaarchiven in Tibet sowie auf der nördlichen Hemisphäre belegt wurden. Mit Hilfe von organischen Biomarkern konnte so ein detailliertes Bild über die Entwicklung des Koucha-Sees seit dem letzten Glazial gewonnen werden. Organische Biomarker haben sich somit als geeignet erwiesen, einen Beitrag zur Klimarekonstruktion auf dem Tibetplateau zu leisten.
Perrineau, Aude. "Evolution morphologique et tectonique récente des marges NE et SE du plateau tibétain : lien avec la dynamique des grands fleuves." Paris, Institut de physique du globe, 2010. http://www.theses.fr/2010GLOB0007.
Повний текст джерелаCyr, Andrew J. "GEOCHEMICAL AND STABLE ISOTOPIC EVALUATION OF FENGHUOSHAN GROUP LACUSTRINE CARBONATES, NORTH-CENTRAL TIBET: IMPLICATIONS FOR THE PALEOALTIMETRY OF THE MID-TERTIARY TIBETAN PLATEAU." Connect to this document online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1080329128.
Повний текст джерелаTitle from first page of PDF document. Document formatted into pages; contains [1], v, 76 p. : ill. Includes bibliographical references (p. 42-50).
Wischnewski, Juliane. "Reconstructing climate variability on the Tibetan Plateau : comparing aquatic and terrestrial signals." Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5245/.
Повний текст джерелаDie räumlichen und zeitlichen Temperatur- und Feuchtigkeitsmuster auf dem Tibet-Plateau sind sehr komplex. Im Einzugsbereich der asiatischen Monsune sind insbesondere der Beginn und das Ausmaß des Klimaoptimums während des Holozäns von wissenschaftlichem Interesse, da diese Periode oft als Analogie für die derzeitige globale Klimaerwärmung herangezogen wird. In Hinblick auf sich teilweise widersprechende Paläoklima- und Umweltrekonstruktionen für das Tibet-Plateau, ist es mein Ziel, die bestehenden Unstimmigkeiten bezüglich des Zeitpunktes und des Ausmaßes des Umweltwandels zu erklären. Dafür wurden von mir zeitliche Variationen fossiler Pollen- und Diatomeenspektren und geochemische Untersuchungen an Seesedimenten unterschiedlicher Zeitskalen (Spätquartär und die letzten 200 Jahre) aus zwei Kernregionen auf dem NO und SO Tibet-Plateau analysiert. Zur Unterstützung der Interpretation wurden die hier erhobenen Daten mit bereits vorhandenen paläoökologischen Aufzeichnungen der Lokalitäten kombiniert, um Datensätze der entsprechenden aquatischen und terrestrischen Proxy-Daten (Stellvertreterdaten) zweier Seenpaare aus den beiden Regionen gegenüberstellen zu können. Hierbei konzentrierte ich mich auf den direkten Vergleich von Proxies, die die Seenentwicklung reflektieren (z.B. Diatomeen, Ostracoden, geochemische Eigenschaften), mit Proxies, die Veränderungen der terrestrischen Umgebung des Sees beschreiben (terrestrische Pollen). Durch diesen Vergleich lässt sich beurteilen, ob Veränderungen im See selbst mit Umweltveränderungen in dem jeweiligen Einzugsgebiet zeitlich übereinstimmen. Dafür habe ich die bereits etablierte numerische Methode Procrustes-Rotation als neuen Ansatz in der Paläoökologie eingeführt. Damit ist ein quantitativer Vergleich von Rohdaten zweier beliebiger sedimentärer Datensätze möglich, um den Grad der Übereinstimmung zu prüfen. Um die in dieser Arbeit rekonstruierten Umwelt- und Klimaereignisse des nordöstlichen Tibet-Plateaus in einen größeren Zusammenhang hinsichtlich holozäner Klimaentwicklung des gesamten Plateaus setzen zu können, und um schlüssige zeitliche und räumliche Klimatrends auf dem Plateau erkennen zu können, habe ich auf alle vorhandenen Paläoklimadatensätze einen Fünf-Skalen Feuchtigkeitsindex und eine Clusteranalyse angewandt. Es konnten jedoch keine einheitlichen zeitlichen und räumlichen Trends der holozänen Klimaentwicklung nachgewiesen werden, was meiner Analyse entsprechend, auf die komplexen Reaktionen verschiedener Proxies auf Umweltveränderungen in einer ohnehin sehr heterogen Berglandschaft, zurückgeführt werden kann. Die Ergebnisse des numerischen Proxy-Vergleichs beider Seenpaare zeigen, dass die Verwendung von verschiedenen Proxies und die Arbeit mit paläo-ökologischen Datensätzen unterschiedlicher See-Typen zu abweichenden Klimaableitungen führen können. Unabhängig vom untersuchten Zeitraum (Holozän oder die letzten 200 Jahren) oder der Region (SO oder NO Tibet-Plateau), ist die Übereinstimmung zweier Datensätze hinsichtlich der Richtung, des Zeitpunktes und des Ausmaßes der abgeleiteten Paläo-Umweltverhältnisse in der Regel zwischen den entsprechenden terrestrischen Datensätzen besser als zwischen den entsprechenden lakustrinen Datensätzen. Die derzeitige Uneinigkeit über stimmige zeitliche und räumliche Klimatrends auf dem Tibet-Plateau kann daher teilweise der Komplexität der verschieden Proxies und ihrer individuellen Empfindlichkeiten gegenüber Umweltveränderungen sowie der unterschiedlichen Reaktionsweise verschiedenartiger See-Systeme auf dem Plateau zugeschrieben werden. Meine Ergebnisse zeigen, dass ein „Multi-Proxy-Multi-Site-Ansatz“ für zuverlässige Paläoklimaableitungen für das Tibet-Plateau von zentraler Bedeutung ist.
Jessup, Micah John. "Kinematic Evolution, Metamorphism and Exhumation of the Greater Himalayan Sequence, Mount Everest Massif, Tibet/Nepal." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/37678.
Повний текст джерелаPh. D.
Zhu, Mangzheng. "Offshore Red River fault and slope sediments in northern South China Sea : implications for paleoceanography and uplift of the tibet plateau /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Повний текст джерелаGodard, Vincent. "Couplage érosion-tectonique en contexte de convergence intracontinentale : étude comparée de la chaîne himalayenne et des Longmen Shan (est-Tibet)." Paris 11, 2006. http://www.theses.fr/2006PA112292.
Повний текст джерелаMargins of large continental plateaus often present significant topographic escarpments, localizing active tectonics and denudation processes. For that reason they constitute a favorable setting for the study of the links between internal and external processes. The main objective of this thesis is to conduct a comparative study of the southern and eastern borders of the Tibetan Plateau: the Himalayas and the Longmen Shan. Both areas present comparable topographic gradients, with contrasting tectonic regimes. The Himalayas are a place of active shortening, associated with the India-eurasia convergence, whereas no significant present tectonic activity can be detected across the Longmen Shan. The quantification of denudation at different timescales in the Longmen Shan allows to balance the classical model proposed for the evolution of this area. In this model the topographic front is actively sustained by lower crustal material flow from the Plateau, toward the foreland. Our data suggests that the evolution of this part of the Plateau is rather controlled by the propagation of a regressive erosion wave toward the Plateau interior on a passive escarpment inherited from earlier deformation stages. The focalisation of erosion at the edge of the Plateau induces a global flow in the crust, toward the foreland. The Himalayas present a significantly contrasting dynamics where the link between tectonic and erosion is inverted with respect to the Longmen Shan case. In opposition to a widely proposed evolution mechanism, our modelling of the dynamics of this area indicates that the localization of erosion is dictated by the structural context, rather than by the repartition of precipitation. The two investigated mountain ranges present contrasting dynamics, where the respective influences of erosion and tectonics are different
Nunn, Ceri. "Tomographic images of the crust and upper mantle beneath the Tibetan Plateau : using body waves, surface waves and a joint inversion." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708398.
Повний текст джерелаAiraghi, Laura. "Etude pétro-chronologique de la chaîne des Longmen Shan (Tibet oriental) : héritage géologique et implications pour la géodynamique actuelle." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAU029/document.
Повний текст джерелаOne of the major challenges in Earth Sciences is understanding how the continental lithosphere deforms in convergent settings, according to which timescales. For its elevation and extension the Tibetan plateau is an ideal natural laboratory for the study of deep crustal processes in active convergent settings. The rise and thickening of the Tibetan plateau has generally been related to the only collision between the Eurasian and Indian plates during the Cenozoic. However, this interpretation has been recently put into question by apparently contrasting geophysical and geological features observed at different locations on the plateau.The aim of this PhD is to quantify the importance of the geological inheritance in the long-term and short-term deformation of an active thrust belt, focusing on the Longmen Shan orogen, the most enigmatic border of the Tibetan plateau. In the Longmen Shan (eastern Tibet) the Tibetan crust is over thickened (>60 km), the tectonic activity is localized along lithospheric faults -as demonstrated by the occurrence of the Mw 7.9 Wenchuan (2008) and Mw 6.6 Lushan (2013) earthquakes- and a high topography survives despite low convergence rates measured by GPS (<3 mm/yr). These observations are hardly reconcilable in a unique model of crustal deformation, suggesting a contribution of the geological inheritance from the geological history preceding the India-Asia collision.A petro-chronological approach that combines microstructural observations, compositional mapping of major and accessory mineral phases, thermodynamic modelling, in-situ 40Ar/39Ar dating, Ar diffusion modelling and in-situ U/Pb-Th allanite dating was applied to metamorphic rocks on each side of the major faults that strike parallel to the belt. This high-resolution study shows that in garnet-bearing rocks of the internal units of the belt matrix minerals record different stages of the metamorphic path in their composition. This is due to an incomplete chemical re-equilibration explained by a variable fluid availability during metamorphism. Different stages of metamorphism and fluid-assisted reactions sequences are also recorded in the 40Ar/39Ar signal of micas and in the composition and textures of the accessory phases.The understanding of petrological processes at the small scale was combined with field observations to quantify the Mesozoic thickness of the Tibetan crust at > 30 km and to unravel a metamorphic jump of greater than 150°C across the major faults, inherited from the Mesozoic tectonics. While internal units of the belt were strongly deformed, decoupled from the basement and metamorphosed at T ~ 580-600°C (P ~11 kbar), external units were less deformed and experienced lower temperatures conditions (T < 400°C, P < 5 kbar). The partial exhumation of the crystalline basement from c. 20 km depth along the major fault (in both internal and external units) occurred at c. 120-140 Ma during a previously poorly documented tectonic event.The multi-method approach applied on a wide geographical area and on a large time interval enabled to quantify the rates and conditions of the different stages of the maturation of the belt; internal units reached the thermal relaxation at ~600°C 40 Ma after the beginning of the propagation of the orogenic load. The basement was re-activated 40 Ma later, at similar thermal conditions than its sedimentary cover. The Mesozoic geological inheritance is therefore a key element in the present structure of the belt and strongly controlled the rheological and structural state of the upper crust at the moment of the Cenozoic re-activation.The petro-chronological study of different segments of the belt showed an along-strike metamorphic segmentation of the Longmen Shan inherited from the Mesozoic. This segmentation corresponds to the present fault segmentation, underlying the potential role of inherited structure in controlling the geographic distribution of the recent earthquakes
Valli, Franck. "Décrochement lithosphériques dans l'ouest du plateau du Tibet : géométrie, âge, décalages cumulés et vitesse de glissement long-terme sur la Faille du Karakorum." Paris, Institut de physique du globe, 2005. http://www.theses.fr/2005GLOB0005.
Повний текст джерелаDuret, Florian. "Étude des anomalies de propagation sismique dans la croûte européenne." Paris, Institut de physique du globe, 2012. http://www.theses.fr/2012GLOB0003.
Повний текст джерелаFirst of all, presence of strong radial anisotropy in the middle of the Tibetan crust has been confirmed using records of 2008 Sichuan earthquake's aftershocks that exclusively sampled the Tibetan plateau. Measurements of surface waves' average group velocity dispersion curves and their inversion using Monte-Carlo method showed that introduction of strong mid-crustal radial anisotropy dramatically improves the modeling with respect to isotropic parametrization. We then developed a microseismic noise analysis procedure aimed at extracting the Green's function of the medium from continuous ambient noise records and measuring surface waves group velocity dispersion curves. This procedure has been applied in Europe on a data set composed of a year of broad-band continuous seismic records from about fifty three-components stations. Analysis of the measured dispersion curves via regionalization, and comparison with published work confirmed their validity. We last proposed a 3D S-wave velocity model of the European crust. This model has been obtained by inverting simultaneously reconstructed Rayleigh and Love wave group velocity dispersion curves on each point of the regionalization grid using Monte-Carlo method. We introduced crustal radial anisotropy in the Alps in order to further improve the modeling of both Rayleigh and Love wave dispersion curves
Huintjes, Eva [Verfasser]. "Energy and mass balance modelling for glaciers on the Tibetan Plateau : extension, validation and application of a coupled snow and energy balance model / Eva Huintjes." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1065848064/34.
Повний текст джерелаBillerot, Audrey. "De la marge Ouest du craton du Yangtze à la bordure Est du plateau Tibétain : évolution géodynamique à partir de l'étude structurale, pétrologique, géochimique et géochronologique de roches magmatiques et métamorphiques." Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10025/document.
Повний текст джерелаThe present geometry of the Eastern Tibetan plateau, made of the Songpan Ganze terrane and the Longmen Shan range, is probably due to a rheological contrast between the Yangtze craton to the East, and the Songpan Ganze, which bump into the craton margin in response to the India-Asia collision. We reconstituted the geodynamic evolution of the area from Neoproterozoic times to present to evaluate how the different orogenic cycles influence the thermal, mineralogical and chemical structures observed today. Studies of the crystalline massifs of the western margin of the Yangtze craton and of the San Dao Qiao ophiolite show that during the Neoproterozoïc times, the craton margin was a subduction zone with opening of marginal basin due to mantle plumes. Petrologic and structural studies of the Danba metamorphic complex allow determining that during the Indosinian orogeny (200-180 Ma), exhumation mechanism of the deep structural level of the complex is an extrusion along a ductile thrust. Plutons position relative to sutures zones in the Tibetan plateau lead to a model of double slab roll-back under the Songpan Ganze at the end of the Indosinian orogeny which explain the diversity of the granites. The double slab roll-back and the difference in deformation between the Songpan Ganze and the Yangtze craton lead to a slab tear along the craton margin. The complete delamination of the lithospheric mantle under the Songpan Ganze terrane can explain the present juxtaposition of a thick crust and thin mantle lithosphere against a cratonized one
Bosch, Anna [Verfasser], and Thomas [Akademischer Betreuer] Scholten. "Quantification of soil CO2 emissions under the influence of climate change on the Qinghai-Tibet Plateau based on freely accessible data / Anna Bosch ; Betreuer: Thomas Scholten." Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/1165578069/34.
Повний текст джерелаBosch, Anna Verfasser], and Thomas [Akademischer Betreuer] [Scholten. "Quantification of soil CO2 emissions under the influence of climate change on the Qinghai-Tibet Plateau based on freely accessible data / Anna Bosch ; Betreuer: Thomas Scholten." Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/1165578069/34.
Повний текст джерелаWang, Yongbo. "Late glacial to Holocene climate and vegetation changes on the Tibetan Plateau inferred from fossil pollen records in lacustrine sediments." Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2013/6315/.
Повний текст джерелаDas Paläoklima in Zentralasien, besonders in der Hochebene von Tibet (HT), ist von großer Bedeutung um globale Klimaprozesse zu verstehen und mögliche Voraussagung für die zukunft zu treffen. Als wichtigstes Klimaphänomen nehmen der asiatische Sommermonsun (ASM) und seine Entwicklungsgeschichte eine Schlüsselposition ein. Dennoch sind derzeit weder das Entwicklungsschema noch der antreibende Vorgang ausreichend verstanden. Dies gilt insbesondere für das Holozän, für welches große Kimaschwankungen und regionale Diskrepanzen weithin belegt sind. Deshalb habe ich zuerst holozäne Klimadaten zusammengefasst. Bereits veröffentlichte Publikationen aus den Monsungebieten Zentralasiens dienten als Grundlage, um die wichtigsten Klimasignale und die zugehörigen Intensitäten des Sommermonsuns heraus zu arbeiten. Anhand von Pollensequenzen aus tibetischen Seen erzeugte ich neue Klima- und Vegetationssequenzen, welche auf verbesserten quantitativen Methoden und rezenten Datensätzen beruhen. Außerdem wurden die Verhältnisse Pollen-Vegetation und Vegetation-Klima bewertet, um Schlussfolgerungen fossiler Pollensequenzen zu verbessern. Die Zusammenfassung der zuvor veröffentlichten, niederschlagsbezogenen Paläoklimadaten im Monsungebiet Zentralasiens ergab generell unterschiedliche Muster für die zwei Teilsysteme des ASMs, den Indischen Sommermonsun (ISM) und den Ostasiatischen Sommermonsun (OASM). Der ISM weist maximale feuchte Bedingungen während des frühen Holozöns auf, während viele Datensätze aus dem Gebiet des OASMs einen relativ trockenen Zustand anzeigen, besonders im nördlichen Zentralchina, wo maximale Niederschläge während des mittleren Holozäns registriert wurden. Genaue Betrachtungen der Antriebsfaktoren des Sommermonsuns ergaben, dass der ISM hauptsächlich durch Veränderungen der Sonneneinstrahlung auf der Nordhemisphäre angetrieben wird, während der OASM potentiell durch den ISM beherrscht wird - dies führt zu asynchronen Entwicklungen. Diese Hypothese wird durch rezente Monsunindizes gestützt. Sie weisen eine signifikant negative Korrelation zwischen den beiden Sommermonsun-Teilsystemen auf. Für die quantitative Klimarekonstruktion von Pollensequenzen wurde ein Sedimentkern aus dem See Donggi Cona im Nordosten der HT analysiert, der bis zum letzten glazialen Maximum (LGM) zurückdatiert wurde. Aufgrund der Tatsache, dass Donggi Cona ein relativ großer See ist, wird hiermit ein neuer Pollen-Klima-Kalibrierungsdatensatz auf Grundlage großer Seen in ariden und semiariden Regionen Zentralasiens vorgelegt. Das Konzept des Pollenherkunftsgebietes wurde in diese rezente, pollenbasierte Klimakalibrierung eingebracht und auf die Pollensequenz von Donggi Cona angewendet. Die Auswertung ergab, dass extrem trockene Bedingungen während des LGM (ca. 100 mm/yr) vorherrschten. Ein ansteigender Trend von Niederschlägen während des späten Glazials wurde durch einen abrupten Rückgang zu einer etwa 1000-jährigen Trockenphase beendet, welche mit Heinrich-Ereignis 1 in der Nordatlantik-Region übereinstimmt. Danach entsprechen die Klimaperioden dem warmen Bølling/Allerød und dem Kälteereignis der Jüngeren Dryas. Anschließend herrschten feuchte Bedingungen im frühen Holozän (bis zu 400 mm/yr). Ein etwas trockenerer Trend nach dem Holozänen Klimaoptimum wurde dann von einer zweiten Feuchtphase abgelöst, welche bis 4,5 cal. ka vor heute andauerte. Relativ gleichmäßige Bedingungen dominierten das späte Holozän bis heute. Die Klimadynamik seit dem LGM wurde vor allem durch Entgletscherung und Intensitätsschwankungen des ASM bestimmt. Bei der Betrachtung des Vegetation-Klima-Verhältnisses habe ich die zeitlichen Variationen der bestimmenden Faktoren hinsichtlich der Vegetationsdynamik auf der nördlichen HT untersucht. Dabei wurden hochauflösende holozäne Pollendaten des Kusai-Sees verwendet. Eine Redundanzanalyse (RDA) wurde angewendet um die Korrelation zwischen Pollenvergesellschaftungen und individuellen sedimentären Klimaanzeigern als auch die damit verbundene Signifikanz zu bewerten. Es stellte sich heraus, dass das Klima einen wichtigen Einfluss auf den Veränderungen in der Vegetation besaß, wenn die Bedingungen relativ warm und feucht waren. Trotzdem scheint es, dass, dass die Vegetation bei zu geringer Bedeckung stärker durch Extremereignisse wie Staubstürme oder fluviale Erosion beeinflusst wurde. Pollenspektren der vergangen 600 Jahre erwiesen sich als signifikant unterschiedlich verglichen mit den älterer Proben, was auf verstärkten anthropogenen Einfluss hindeutet. Dieser resultierte in einem beispiellosen Wandel in der Zusammensetzung der Vegetation. In Hinsicht auf das Pollen-Vegetation-Verhältnis und der quantitativen Rekonstruktion der Vegetationshäufigkeit habe ich theoretische Modelle, welche für europäische Regionen entwickelt und weithin angewendet wurden, respektive die Modelle "Extended R-Value" (ERV) sowie "Regional Estimates of Vegetation Abundance from Large Sites" (REVEALS), auf die hochalpinen Ökosysteme der HT überführt. Dafür wurden rezente Pollen-Vegetations-Verhältnisse von vier weit verbreiteten Pollen-Arten der HT überprüft. Poaceae wurden als Referenztaxa verwendet. Bei der Anwendung dieser Verhältnisse auf vier Pollensequenzen, welche die Paläoumweltbedingungen seit dem letzten Glazial widerspiegeln, wurden die Häufigkeiten von Pflanzen auf der zentralen und nordöstlichen HT quantifiziert. Anteile von Artimisia und Chenopodiaceae waren dabei im Vergleich zu ihren ursprünglichen Pollenprozenten deutlich verringert. Cyperaceae hingegen wies eine relative Zunahme in dieser Vegetationsrekonstruktion auf. Die rekonstruierten Vegetationsvergesellschaftungen an den Standorten der vier Pollensequenzen ergaben stets geringere Umwälzungen in der Artenzusammensetzung, als durch die Pollenspektren zu vermuten gewesen wäre. Dies kann ein Hinweis darauf sein, dass die Intensität der bislang angenommenen Vegetationsveränderungen überschätzt worden ist. Zusammengefasst sind die Hauptresultate dieser Dissertation, dass (a) die zwei ASM Teilsysteme asynchrone Muster während des Holozäns und heute aufweisen, dass (b) fossile Pollensequenzen großer Seen regionale Klimasignale widerspiegeln sofern die Herkunftsgebiete der Pollen berücksichtigt werden, dass (c) Klima nicht immer der Haupteinflussfaktor für Vegetationswandel ist und dass (d) das Ausmaß von Vegetationsveränderungen in zuvor veröffentlichten Studien auf der Hochebene von Tibet überschätzt worden sein kann, weil Diskrepanzen der Pollenproduktivität zwischen den Arten nicht einbezogen wurden.
Matuszak, Sabine Verfasser], Alexandra [Akademischer Betreuer] Müllner-Riehl, Adrien [Akademischer Betreuer] Favre, and Georg [Akademischer Betreuer] [Zizka. "Evolution of Mountain Plants in the region of the Qinghai-Tibet Plateau and beyond / Sabine Matuszak. Betreuer: Alexandra Müllner-Riehl ; Adrien Favre. Gutachter: Alexandra Müllner-Riehl ; Georg Zizka." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2016. http://d-nb.info/1092187448/34.
Повний текст джерелаBotsyun, Svetlana. "Modélisation de l'impact de l'évolution tectonique himalayennes et tibétaines sur le climat et les isotopes stable de l'oxygène au Cénozoïque." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV006/document.
Повний текст джерелаThe 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
Devès, Maud. "Continental magmatism by shear heating in "Process Zones" : at geometric complexities on fault systems." Paris, Institut de physique du globe, 2010. http://www.theses.fr/2010GLOB0004.
Повний текст джерелаYanchuan, Li. "Observation géodésique et modélisation de la déformation des failles dans le Plateau Tibétain." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4002.
Повний текст джерелаOngoing plate convergence between India and Eurasia during the past ∼40 million years has created the Tibetan Plateau, a region with average elevation of ~4500 m, area of over 600×1000 km2, and active faulting and crustal deformation extends more than 2000 km into central Asia. Approximately one-half of India’s 36–40 mm/a northward motion is partitioned in the Tibetan Plateau, resulting in crustal thickening, shortening, folds, and complex fault systems. The active crustal deformation cause diverse styles of strain accumulation and release on crustal faults, expressed as distinct faulting behavior or earthquake cycles. Investigating into crustal fault deformation and earthquake cycles in the Tibetan Plateau using space-based geodesy, i.e., Global Positioning System (GPS) and Synthetic Aperture Radar Interferometry (InSAR), has started 30 years ago. Currently, high spatial-temporal resolution geodesy provides us with abundant data and sufficient resolution to study the ground deformation associated with earthquake cycle processes.In this dissertation, I focus on the interseismic deformation along three boundary large strike-slip fault systems of the Tibetan Plateau, the Altyn Tagh fault, the Haiyuan fault system and the Xianshuihe-Anninghe-Zemuhe-Xiaojiang fault system (XAZX). I use GPS (1999-2018) and InSAR (2003-2016) geodetic observations, along with 2D dislocation and 3D block models, to invert for slip rates and interseismic fault coupling, assess seismic hazard and investigate earthquake cycles along these faults; moreover, study the kinematics of deformation across the Tibetan Plateau. My results show slip rates ranging from ~2 to ~12 mm/a, highly heterogeneous interseismic fault coupling (fully locked coexist with fully creeping), distinct seismic potential and different earthquake cycles along these faults. In particular, I identify two and one new aseismic creeping segments along the Haiyuan fault system and the Xianshuihe fault respectively. My geodetic observation and modeling results demonstrate the spatio-temporal diversity and complexity of interseismic fault deformation in the Tibetan Plateau, highlight the significance of considering vertical deformation in InSAR, and allow a new and in-depth understanding of earthquake cycles along the above three fault systems
Roupioz, Laure. "Modélisation et suivi de l'éclairement et de l'albédo de surface à partir de données satellitaires : le cas du Tibet." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD022/document.
Повний текст джерелаMonitoring the solar radiation budget on a daily basis is a prerequisite to study land surface processes, especially in climatology and hydrology. As part of the CEOP-Aegis project studying the hydrology of the Tibetan Plateau, this thesis focuses on developing a method to adequately estimate at-surface daily solar radiation budget over this particular area. A radiation budget time series produced based on existing satellite data products highlights the necessity to consider terrain and clouds sub-pixel variability when working over heterogeneous areas such as the Tibetan Plateau. The analysis of the impact of spatial and temporal variability of clouds on solar radiation demonstrates that the surface irradiance estimation would benefit from using cloud distribution instead of cloud fraction and the significance of high temporal resolution. A new sub-pixel topographic correction method is proposed and shows that using high resolution digital elevation model improves the irradiance as well as the albedo retrieval. Two approaches are proposed to improve solar radiation budget estimates taking into account adequately the sub-pixel heterogeneity
Guilmette, Carl. "High-P Granulite facies metamorphism from the tibetan plateau and the Himalaya: Metamorphic history and geochemistry of lower crustal and early subduction metamorphic rocks." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27631/27631.pdf.
Повний текст джерелаWang, Qian. "Aspects socio-économiques et éco-épidémiologiques de l'échinococcose alvéolaire dans les communautés pastorales tibétaines en République populaire de Chine." Besançon, 2004. http://www.theses.fr/2004BESAA002.
Повний текст джерелаMultivariate analysis of data from 7,138 subjects revealed that increasing age, in all communities, "non-preventing flies from food" in herdsmen communities, "residence in Ganzi county", "number of dogs kept" and "ownership of fox skin" in farmers' communities, "female gender", "drinking water from streams" and "playing with dogs" in urban communities were risk factors for Alveolar Echinococcosis in the respectiye populations. Questionnaires on husbandry practices, transects to detect small mammal indices and measure the extent of fenced pastures, and assessment of dog infection confirmed our hypothesis that oyergrazing in common pastures was significantly associated with the extent of fenced pastures in the winter settlements and appeared to increase the density of small mammals that may serve as reservoir for the parasite, which might in tum promote maintenance and transmission of E. Multilocularis, through dog infection, in the Tibetan pastoralist communities of Sichuan, PR China
Robert, Alexandra. "Déformation polyphasée et importance de l'héritage structural dans les longmen shan (sichuan, chine) : apports d'une approche couplée entre géophysique et géologie." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00647321.
Повний текст джерелаGuilbert, Jocelyn. "Caractérisation des structures lithosphériques sous le Nord Tibet et sous le Massif Central à partir des données sismologiques du programme Lithoscope." Phd thesis, Université Joseph Fourier (Grenoble), 1995. http://tel.archives-ouvertes.fr/tel-00721900.
Повний текст джерелаMartin, Léo. "Les paléoglaciers et paléolacs de l'Altiplano, archives climatiques de la dernière déglaciation." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0058/document.
Повний текст джерелаThe transition between the last glacial maximum and the actual interstadial (from 20 to 12 ka before present) is characterized by short and abrupt climate reorganizations at different scales. Over the Bolivian Altiplano, giant palaeo-lakes wax and wane within 2000 years. The glaciers dynamics is controlled by the climate, making the deposits from the former glaciers one of the few climatic archives available on this arid plateau. The exposure age method enables to reconstruct the history of former glaciers. This thesis brings new tools for the calculation of these ages. It also presents new ages coupled with palaeo-climate reconstructions. These results indicates that the palaeo-lake formations are concomitant with mean coolings of 2.5 to 4.2°C compared to present and with an enhanced moist transport from the East, crossing the Bolivian Oriental Cordillera
Mailler, Sylvain. "Influence dynamique de l'Himalaya sur le climat en Extrême-Orient." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00598530.
Повний текст джерелаCotte, Nathalie. "Détermination des variations latérales de la lithosphère par l'analyse des ondes de surface enregistrées par des réseaux régionaux." Phd thesis, Grenoble 1, 2000. http://tel.archives-ouvertes.fr/tel-00703264.
Повний текст джерелаBiltekin, Demet. "Vegetation and climate of north anatolian and north aegean region since 7 Ma according to pollen analysis." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00720892.
Повний текст джерелаWANG, JIM-ZEN, and 王俊仁. "The uplift history of south Tibet plateau constrained by thermochronological data." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/42439238742205621482.
Повний текст джерела國立臺灣大學
地質學系
85
Systematic fission-track dating analysis on the minerals extracted from Gangdese batholiths, South Tibet have been carried out in this study. The preliminary FTD result shows that the granitic basement had not uplifted to the surface level until early-Miocene. According to FTD dates of apaites, which exhibit lower closure temperature (ca. 90~110oC) and could be able to indicate the last stage thermal record of the basement, diachronous uplift of Tibetan plateau occurred, at least in Lhasa block, during earl to middle- Miocene age.
"Heterogeneous changes in hydrologic system of the Tibetan Plateau in response to climate variability: application of multi-source satellite data." 2014. http://library.cuhk.edu.hk/record=b6115413.
Повний текст джерела青藏高原自上世紀八十年代出現快速升溫,從多方面的研究以達成共識。然而,由於資料的不確定性及高原地區降雨本身的空間異質性,降雨的時空變化尚存在不一致的結論。本研究對八種常用的降雨產品的時空相關性進行相互比較,也採用有限的網站觀測對格網降雨資料集進行評價。結果顯示,GPCP, CMAP-1, CMAP-2和PREC/L四個降雨資料集與網站觀測降雨具有更好的相關性,APHRODITE 和TRMM資料次之,兩個再分析降雨資料最不相關。基於GPCP, CMAP-1, PREC/L和APHRODITE降雨資料,分析青藏高原及周邊地區降雨在1979 - 2011期間的變化趨勢。四個資料集一致反映在高原中部及東北部地方,降雨在上世紀90年代開始出現明顯的增長趨勢,在藏東南地區降雨減少,但趨勢不明顯。而在喜馬拉雅地區,四個降雨資料反映的趨勢不一致。本研究進一步分析降雨對青藏高原地區陸地水儲量的在2003 - 2011期間的影響關係發現,高原中部及東北部的降雨增加及天山地區的降雨減少與GRACE衛星觀測的陸地水儲量變化有十分密切的關係。而在喜馬拉雅山脈及藏東南地區,降雨的變化對陸地水儲量的相關性相對較低,一方面可能是降雨資料在該地區由於更複雜的地形具有更大的不確定性,另外一方面,可能存在其他氣候因素(如變暖引起的冰川融水損失等)影響陸地水量的平衡。
因此,選擇藏東南地區為研究典型區,調查青藏高原冰凍圈水文系統的陸地水儲量平衡狀態及其與冰川變化關係。利用2003 - 2009時段內GRACE衛星觀測,藏東南地區的物質平衡以5.99 ± 2.78 Gt/yr的速率減少。然而,基於GLDAS/Noah和CPC的模型輸出資料進行分析發現,該地區的土壤含水量、雪水當量及植被冠層含水量等水文因數均無顯著的降低(或增加)趨勢。而根據ICESat測高衛星對藏東南地區冰川的表面高程進行測量得出,冰川在2003 - 2009期間以平均- 0.31 ± 0.14 m/yr的速率消融,相當於- 4.83 ± 2.46 Gt/yr的負物質平衡量。可以推斷,冰川消融引起的水量流失大約能解釋該地區80%的GRACE衛星觀測的物質負平衡量。進一步分析GRACE衛星連續觀測的區域陸地水儲量平衡與氣候因數的統計關係表明,時間序列中的突變、季節性波動及多年週期振盪信號與降水的變化具有高度的相關性,而區域物質平衡的年際收支及長期趨勢更明顯受溫度的控制。該結論進一步證實藏東南地區近年來的陸地水儲量負平衡很大程度上由增加冰川融水流失引起的。
在青藏高原內陸湖泊水文研究方面,由於缺乏長期的湖泊水量平衡、水位及湖底地形等實測資料,大尺度定量估算湖泊水量變化的難題一直尚未解決。上世紀70年代以來的光學遙感影像及2003 - 2009期間的ICESat衛星測高資料成為大尺度觀測青藏高原湖泊面積及水位變化的有力工具。遙感觀測結果表明,整個高原湖泊(選取312個大於10 km²的湖泊)面積從1970年代早期的35,638.11 km²增加到2011年的41,938.66 km²。ICESat測高資料覆蓋的湖泊平均水位變化速率為0.23 m/yr。其中,青藏高原中部地區的湖泊,如色林錯,擴張速度最快,而藏南地區的湖泊在2000年代出現迅速萎縮趨勢。基於2003 - 2009期間的湖泊面積及對應的水位資料,建立湖泊水位隨面積變化的統計關係,從而重建湖泊在缺少ICESat測高資料的時段(2003年之前及2009年之後)的湖泊水位資料,有效估算青藏高原湖泊從1970年代約40年來水量增加92.43 Gt (主要增長髮生在2000年代)。對湖泊群密集的羌塘高原湖泊水量平衡進一步分析,該地區湖泊水量在2000年代以6.79 Gt/yr的速率增加,該類比結果與GRACE觀測的該地區物質正平衡趨勢6.81 Gt/yr十分接近。
為了解釋青藏高原地區內陸湖泊在2000年代迅速擴張的主要氣候影響機制,針對117個具有測高資料,分析其湖泊水位的趨勢、突變及季節性變化與氣候變數的關係。結果表明,高原湖泊水位的季節性變化表現明顯的時空異質性:昆侖山南部的密集的小湖泊群在暖(濕)季水位降低,而冷(幹)季水位增加,可能更多依賴于季節性雪蓋融水補給,而暖季該地區強烈蒸發作用造成水量負平衡;其他大部分湖泊暖季由於降水徑流補給水位升高,而冷季水位降低或較小地波動。根據水位季節性變化和突變,湖泊可以劃分為8個聚類,不同聚類表現出不同的水位變化態勢,一些明顯的水位增減與該地區降水和蒸發高低密切相關,而冰川融水補給(表現為溫度波動)並未表現出顯著的相關性。將高原範圍內的湖泊劃分為冰川補給型與非冰川補給型湖泊,兩類湖泊群的水位變化在統計上沒有明顯分異。而水位變化速率與湖泊的補給係數(一定程度上反映湖泊降水徑流對水量平衡的影響)具有顯著相關。從不同的氣候子區具體分析,在高原中部地區,冰川融水補給確實更加加劇了降水引起的湖泊水位增長。此外,集成多顆衛星的測高資料,對18個高原典型大湖泊的水位年際增量與氣候因數進行相關分析發現,水位波動呈現出與降水和蒸發更顯著的相關性。總之,該研究綜合多種新型技術手段,在大尺度上調查青藏高原高寒水文系統(主要針對季風型溫性冰川與內陸湖泊)水量變化及其空間異質性特徵,並解釋其氣候影響因素。
The Tibetan Plateau (TP) and surrounding mountains are known as the Third Pole, with an average elevation of 4,000 meters above sea level. It holds the largest reserves of glacier ice outside of Antarctica, Greenland, and Canada. It is thus referred as Asian water towers, which form the source of more than ten major rivers in Asia. In the broad basins of the inner plateau, there are more than one thousand lakes, mostly featured by closed watersheds. In the context of climate change and variability, regional terrestrial water storage (TWS) budgets of the TP are critical terms in the global water balance, yet they are poorly observed at high altitude. Thus new strategies are required to investigate changes of mountain glaciers and lakes in the high-altitude hydrologic system. Multiple remote sensing techniques are deployed here to address questions in high-latitude hydrology.
The temperature of the TP has risen rapidly since the 1980s, but spatio-temporal variability of precipitation remains unclear partly due to more spatial incoherence in precipitation variation. Eight gridded precipitation datasets are inter-compared with each other and evaluated by gauge-based data over the TP and surroundings between 1979 and 2011. The results show that the GPCP, CMAP-1/2 and PREC/L precipitation data agreebetter with gauge-based precipitation. The two reanalysis data have the weakest correlations with gauge-based data, and the APHRODITE and TRMM data are in between. Analyses of precipitation trends based on the GPCP, CMAP-1, PREC/L and APHRODITE datasets consistently reveal that an obvious increase is observed in the inner TP since the mid-1990s and insignificant decreasing trends areobserved in the southeastern TP. In the Himalayas, the precipitation trends are rather inconsistent among the four datasets. Comparisons of the GRACE TWS changes and precipitation variability between 2003 and 2011 show that increasing precipitation in the central and northeastern TP and decreasing precipitation in the Tienshan Mountains are tightly associated with the TWS variations in the two regions. However, there are relatively lower correlations between TWS changes and precipitation in the Himalayas and southeastern TP. It implies that there areprobably other factors (such as glacier meltwater loss induced by warming climate) which are also correlated with the GRACE-observed mass changes.
The southeastern TP (SETP) is selected as a demonstrative area to investigate the TWS changes in the cryo-hydrologic system and relations with glacier variations. The GRACE observations during 2003 - 2009 reveal a serious mass loss with rate of - 5.99 ± 2.78 Gt/yr in the SETP. Based on hydrological data by model calculations from the GLDAS/Noah and CPC, other hydrologic elements, including soil moisture, snow water equivalent and canopy water storage, showed no obvious change trends. The glacier measured by the ICESat altimetry showed a thinning rate of - 0.31 ± 0.14 m/yr during 2003 - 2009. An approximate estimation of the glacier mass budget was - 4.83± 2.46 Gt/yr, which accounted for ~ 80% of the GRACE-observed mass loss in this area. The further examinationon climate forces of TWS changes in the SETP suggest that abrupt, seasonal and multi-year undulating signals of GRACE TWS anomaly time series were tightly associated with precipitation variability, while the annual mass budgets and trends were more related to temperature variability.
In contrast to glacial meltwater loss in outflow areas of the SETP, the hydrological processes in the inner TP are characterized by closed lake systems. In-situ measurements of lake water balance and lake bathymetry are missing to monitor the TWS changes in lake-hydrologic system of the TP. Remote sensing allows observation of area and water level variations in Tibetan lakes (312 lakes larger than 10 km²). The total lake area increased from 35,638. 11km² in the early-1970s to 41,938.66 km² in 2011. The mean rate of change in water level for all examined lakes was 0.23 m/yr between 2003 and 2009. The most dramatic lake expansion was observed in the central TP. Lakes in South Tibet showed shrinking tendency in the past decade. Then, based on the time series of lake area and water level, the statistical relationships between lake area and water level are established to estimate lake water volume (storage) variations and compare with GRACE-observed mass gains in this area. The results show that the total water storage increased by 92.43 Gt (km³) from the early 1970s to 2011.The positive water mass budget of 6.81 Gt/yr in the Changtang Plateau derived from GRACE data agrees well with the change rate of lake water storage (6.79 Gt/yr) derived from the statistical models in the 2000s.
Based on satellite altimetry data, the trends, abrupt and seasonal changes of water level for 117 lakes with elevation measurements are examined to explore the potential climate forces of lake variations in the 2000s. Results suggest that seasonal water-level variations were featured by strong spatio-temporal heterogeneity which was largely associated with the seasonally and spatially varied climate. The rates of change of non-glacier-fed lakes in the 2000s were basically as high as those of glacier-fed lakes across the plateau while the lake level changes were closely associated with the lake supply coefficients (the basin / lake area ratio, which partly indicates the role of precipitation and runoff on lake water balance). The lake variations agreed well with the spatial pattern of precipitation changes.In addition, the correlation analyses between water level variations and climatic variables for 18 typical large lakes indicate that lake dynamics were more related to precipitation and evaporation than temperature. In sum, this study provides new insight and large-scale investigation on high-altitude hydrologic systems of the TP.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Song, Chunqiao.
Thesis (Ph.D.) Chinese University of Hong Kong, 2014.
Includes bibliographical references (leaves 181-203).
Abstracts also in Chinese.
Schleuss, Per-Marten. "The Kobresia pastures on the Tibetan Plateau." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0023-3EFD-8.
Повний текст джерела