published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy

This thesis deals with the stratigraphy and brachiopod systematic palaeontology of the latest Devonian (Famennian) to Early Permian (Kungurian) sedimentary sequences of the Tarim Basin, NW China. Brachiopod faunas of latest Devonian and Carboniferous age have been published or currently in press in the course of the Ph.D candidature and are herein appendixed, while the Early Permian brachiopod faunas are systematically described in this thesis. The described Early Permian brachiopod faunas include 127 species, of which 29 are new and 12 indeterminate, and six new genera (subgenera) are proposed; Tarimella, Bmntonella, Marginifera (Arenaria), Marginifera (Nesiotia), Baliqliqia and Ustritskia. A new integrated brachiopod biostratigraphical zonation scheme is proposed, for the first time, for the latest Devonian-Early Permian sequences of the entire Tarim Basin on the basis of this study as well as previously published information (including the Candidate's own published papers). The scheme consists of twenty three brachiopod acm biozones, most of which replace previously proposed assemblage or assemblage zones. The age and distribution of these brachiopod zones within the Tarim Basin and their relationships with other important fossil groups are discussed. In terms of regional correlations and biostratigraphical affinities, the Late Devonian to Early Carboniferous brachiopod faunas of the Tarim Basin are closest to those from South China, while the Late Carboniferous faunas demonstrate strong similarities to coeval faunas from the Urals, central Asia, North China and South China. During the Asselian-Sakmarian, strong faunal links between the Tarim Basin and those of the Urals persisted, while at the same time links with central Asia, North China and South China weakened. On the other hand, during the Artinskian-Kungurian times, affinities of the Tarim faunas with the Urals/Russian Platform rapidly reduced, when those with peri-Gondwana (South Thailand, northern Tibet) and South China increased. Thirty lithofacies (or microfacies) types of four facies associations are recognised for the Late Devonian to early Permian sediments. Based on detailed lithostratigraphy, biostratigraphy and facies analysis, 23 third-order sequences belonging to four supcrsequences are identified for the Late Devonian to Early Permian successions, from which sea-level fluctuation curves are reconstructed. The sequence stratigraphical analysis reveals that four major regional regressions, each marking a distinct supersequence boundary, can be recognised; they correspond to the end-Serpukhovian, end-Moscovian, late Artinskian and end-Kungurian times, respectively. The development of these sequences is considered to have been formed and regulated by the interplay of both eustasy and tectonism. Using the system tract of a sequence as the mapping time unit, a succession of 47 palaeogeographical maps have been reconstructed through the Late Devonian to Early Permian. These maps reveal that the Tarim Basin was first immersed by southwest-directed (Recent geographical orientation) transgression in the late Famennian after the Caledonian Orogeny. Since then, the basin had maintained its geometry as a large, southwest-mouthed embayment until the late Moscovian when most areas were the uplifted above sea-level. The basin was flooded again in late Asselian-Artinskian times when a new transgression came from a large epicontinental sea lying to its northwest. Thereafter, marine deposition was restricted to local areas (southwestern and northwestern margins until the late Kungurian, while deposition of continental deposits prevailed and continued through the Middle and late Permian into the Triassic.

L'enregistrement biosédimentaire Ordovicien du bassin de Tarim offre la possibilité de s'attaquer à quatre grands enjeux scientifiques liés au «grand événement de biodiversité ordovicienne » (Great Ordovician Biodiversification Event ou GOBE en anglais): i) la phylogenèse des organismes incertae sedis, ii) la paléodiversité des producteurs primaires benthiques (algues calcaires, calcimicrobes), iii) la nature des précipités authigénique des fonds marins (automicrite), et iv) la diagénèse en termes d'évolution de la porosité et de l'enregistrement géochimique des perturbations environnementales provoquant des changements biosédimentaires majeures (éponges, crinoïdes contre algues benthiques). L'analyse typologique, morphométrique et microstructurale du microfossile problématique Halysis Høeg, 1932, conclut pour une algue verte siphonnée avec une affinité à Bryopsidales, Udoteaceae, morphotype Flabellia petiolata (Turra) Nizamuddin 1987. Les monticules d’Halysis (Katian) font partie d'une rampe carbonatée peu profonde et subtidale dominée par des tapis de sable de granules d'algues. L’accrétion de monticules était contrôlée par des phénomènes autocycliques, produisant des épisodes sédimentaires et d’enfouissement suivis de lacunes et de périodes de croissance d’algue. Dans le bassin de Tarim, la diversité des producteurs primaires benthiques augmente considérablement au cours de la zone de Belodina confluens d’Ordovicien supérieur (Katian). Par rapport aux courbes de diversité dérivées d'autres régions (Laurentia, Baltoscandia), dans le bassin de Tarim, il y a une propagation de la diversification d'environ 4 Ma. La courbe de diversité des producteurs primaires benthiques sont semblables à celles enregistrées par certains groupes de fossiles herbivores et suspensivores (Échinodermes eleuthérozoaires, gastéropodes). Cinq types de précipitations authigénique des fonds marins (automicrite) sont présents dans les monticules carbonatés de calathid-demosponge (Darriwilian), tout d'abord interprété comme « carbonate microbien ». Une bonne corrélation de la fluorescence et de la cathodoluminescence des automicrites indique que l'organominéralisation induite et soutenue a produit de l'automicrite, probablement par la perminéralisation de substrats organiques non vivants adsorbant des complexes métal-humâtes dissous. À l'aide de six paramètres et de dix-sept caractères, quatre automicrites se révèlent non microbiennes au lieu de représenter probablement des reliques de métazoaires calcifiés (éponges, structures d'attachement des invertébrés tendus). Un automicrite est d'origine microbienne, mais l'âge de l'après-monticule réussit une disconformité. En utilisant un ensemble de séquences paragénétiques, un échantillonnage géochimique des composants spécifiques a été effectué pour déterminer la variation de la composition isotopique stable au carbone et à l'oxygène. Il existe deux niveaux stratigraphiques distincts séparés par Δδ13C ≈ +2.5 ‰ (PDB). Les deux niveaux suivent la même tendance partielle de diminution de δ18O typique pour l’augmentation de la température pendant l'enfouissement. Les valeurs de δ18O les moins modifiées sont également séparées selon les mêmes deux niveaux stratigraphiques (Δδ18O ≈ +2.0 ‰). Cette excursion positive couplée de δ13C-δ18O est considérée comme le résultat d'une augmentation du taux d'enfouissement du carbone organique (formation de roches mères d'hydrocarbures) et d'un refroidissement climatique subséquent provoquant un changement biosédimentaire majeure (éponges, crinoïdes contre algues benthiques) le long de l'intervalle limite Sandbian-Katian / The Ordovician biosedimentary record of the Tarim Basin offers the opportunity to tackle four major scientific issues related to the Great Ordovician Biodiversification Event: i) the phylogenesis of organisms incertae sedis, ii) the paleodiversity of benthic primary producers (calcareous algae, calcimicrobes), iii) the nature of authigenic sea-floor precipitates (automicrite), and iv) diagenesis in terms of porosity evolution and the geochemical record of environmental perturbations causing major biosedimentary turnovers (sponges, crinoids versusbenthic algae). The typological, morphometric and microstructural analysis of the mound-forming microproblematicum Halysis Høeg, 1932 concludes for a siphonous green alga with an affinity to Bryopsidales, Udoteaceae, morphotype Flabellia petiolate (Turra) Nizamuddin 1987. Early Katian Halysismounds form part of a shallow-subtidal carbonate ramp dominated by algal-pellet sand sheets. Their accretion was controlled by autocyclic drivers such as increments of sediment flux and burial followed by episodes of omission and algal growth. In the Tarim Basin, the diversity of benthic primary producers increases substantially during the Upper Ordovician (Katian) Belodina confluens Zone. Compared to diversity curves derived from other regions (Laurentia, Baltoscandia), in the Tarim Basin there is a protraction of diversification by about 4 Ma. The global diversity curve of benthic primary producers is similar to those derived from some herbivorous and suspension-feeding fossil groups (eleutherozoan echinoderms, gastropods). Five kinds of authigenic sea-floor precipitates (automicrite) are present in Darriwilian calathid-demosponge carbonate mounds, altogether formerly interpreted as ‘microbial carbonate’. A good correlation of fluorescence and cathodoluminescence of automicrites indicates that induced and supported organomineralization produced automicrite, probably via the permineralization of non-living organic substrates adsorbing dissolved metal-humate complexes. Using six parameters and seventeen characters, four automicrites turn out to be non-microbial instead likely represent relics of calcified metazoan tissue (sponges, attachment structures of stalked invertebrates). One automicrite is microbial in origin but is post-mound in age succeeding a disconformity. Using a set of paragenetic sequences, component-specific geochemical sampling was performed to determine the variation of carbon and oxygen stable isotopic composition. There are two distinct stratigraphic levels separated by Δδ13C ≈ +2.5‰ (PDB).Both levels display a subparallel trend of decreasing δ18O typical for increasing temperature during burial. Least altered δ18O values are equally separated along the two stratigraphic levels (Δδ18O ≈ +2.0‰). This coupled positive δ13C-δ18O excursion is considered the result of an increasing burial rate of organic carbon (formation of hydrocarbon source rocks) and subsequent climatic cooling causing a biosedimentary turnover (sponges, crinoids versusbenthic algae) along the Sandbian-Katian boundary interval.

Deux questions scientifiques critiques sont adressées dans cette thèse présentées comme suit. ( 1 ) L’évolution mésozoïque du bassin d’avant-pays dans les piémonts nord et sud du Tian Shan. ( 2 ) L’évolution au Cénozoïque précoce du soulèvement du Tian Shan. Dans le chapitre 1, l'évolution du nord Tian Shan est étudiée par datation U/Pb (LA- ICP-MS) de zircons détritiques sur 14 échantillons de grès d'une série continue d’âge fin Paléozoïque à Quaternaire dans la marge sud du bassin de Junggar (région de Manasi). Dans le chapitre 2, l'évolution encore mal contrainte entre le Mésozoïque et le début du Cénozoïque de la marge sud-ouest du Tian Shan est étudiée en utilisant les datations U/Pb ( LA- ICP-MS ) sur zircons détritiques et les traces de fission sur apatites détritiques. Dans le chapitre 3, nous présentons une étude magnétostratigraphique détaillée de la zone Ulugqat au sud-ouest du Tian Shan, dans le but d'améliorer la compréhension de son soulèvement et de l'histoire de la déformation de la région au cours du Cénozoïque. Ce travail à permis de montrer que l'érosion du paléo-Tian Shan commencée au Trias moyen s’est traduite par le pénéplanation générale au Mésozoïque du Tian Shan qui était dominé par un système de drainage large pendant une longue période de quiescence tectonique. Le piémont nord du Tian Shan était caractérisé par un bassin en subsidence thermique post- extensive avec peu d'activité tectonique, et le piémont sud a également connu un aplanissement général de la topographie. Au cours du début du Jurassique, du Crétacé inférieur et du Crétacé supérieur, trois inversions tectoniques mineures sont identifiées avec des ajustements du bassin d’avant-pays du Tian Shan. Ces inversions peuvent correspondre respectivement à l’accrétion des terrains Cimmérien, de Lhassa, et du Kohistan-Dras à la limite sud de la plaque eurasienne. Les données U-Pb sur zircons détritiques et les données traces de fission sur apatite indiquent une première réorganisation du bassin à la fin du Crétacé – début du tertiaire, contemporaine d’une réactivation de l’érosion le long du piémont sud du Tian Shan. Nous avons interprété cette réactivation fin Crétacé – début Paléogène du Tian Shan sud à la réponse initiale des effets lointains de la collision Inde-Eurasie. Pendant le reste du Cénozoïque, la principale réactivation du Tian Shan est initiée fin Oligocène – début Miocène. Cela est attesté dans le piémont nord du Tian Shan par nos données U-Pb sur zircons détritiques et dans le piémont sud du Tian Shan par les données traces de fission sur apatite suggérant des chevauchements entre 18 et 16 Ma, par les résultats magnétostratigraphiques révélant une importante lacune de sédimentation oligocène ainsi que l’augmentation des taux d’accumulation à ~ 18.5 Ma. / Two critical scientific issues are adressed in the présent thesis as follows. (1) Mesozoic basin-range relationship in the northern and southern piedmonts of the Tian Shan. (2) Spatio-temporal differences in the Early Cenozoic uplift of the Tian Shan. In chapter 1, the évolution of the northern Tian Shan is investigated through U/Pb (LA-ICP-MS) dating of detrital zircons from 14 sandstone samples from a continuous series ranging in age from latest Palaeozoic to Quaternary in the southern margin of the Junggar Basin (Manasi area). In chapter 2, the still poorly constrained Mezosoic to early Cenozoic evolution of the southwestern Tian Shan piedmont is investigated using U/Pb (LA-ICP-MS) dating of detrital zircons and fission track analysis on detrital apatites. In chapter 3, we present a detailed magnetostratigraphic study from the Ulugqat area in piedmont of the Southwest Tian Shan, in order to improve understanding of the uplift and deformation history of the Southwest Tian Shan during the Cenozoic. This work enabled to show that erosion of the Paleo-Tian Shan initiated in the Middle Triassic results in the general peneplanation of the Mesozoic Tian Shan dominated by a wide drainage system and long-lasting tectonic quiescence. The northern piedmont of the Tian Shan was characterized by a post-extensional thermally subsiding basin without much tectonic activity, and the southern piedmont also experienced a general flattening of topography. During the Early Jurassic, Early Cretaceous and Late Cretaceous, three identified minor tectonic inversions and adjustments of basin-range pattern in the Tian Shan, may potentially correspond respectively to the accretions of Cimmerian, Lhasa, and Kohistan-Dras in the southern margin of the Eurasian plate. Detrital zircon U-Pb and apatite fission-track data indicate an initial late Cretaceous – Early Tertiary basin reorganization and coeval renewed erosion along the southern Tian Shan piedmont. We interpreted this late Cretacesou to Paleogene activity in STS as the initial response of the distant effects of India-Eurasia collision as previously argued. During the Late Cenozoic, the major reactivation of the Tian Shan initiated around the Late Oligocene-Early Miocene times. This is evidenced mainly from the detrital zircon U-Pb geochronology in the northern piedmont of the Tian Shan, the apatite fission-track data suggesting a possible activation of the Talas Fergana Fault between 18 and 16 Ma, the major Oligocene depositional hiatus and conspicuous increase in accumulation rates at ~ 18.5 Ma revealed by the magnetostratigraphic results in the southern piedmont of the Tian Shan.

This study focuses on the burial practices in the Bronze Age Xiaohe-Gumugou cemeteries, north-west China, in order to understand how people constructed their social identities and delivered the social cognitions through generations. The Xiaohe-Gumugou cemeteries, as the main sites of the Xiaohe cultural horizon, have central roles for the understanding of the formation of the Bronze Age cultural groups and the cultural interactions between the west and the east in the Tarim Basin. However, current research is lacking in-depth examinations of the material culture of the cemeteries, and the contexts of the surrounding archaeological cultures in a timespan from Bronze Age to Iron Age. Through detailed comparisons of the construction of coffins and monuments, the dress of the dead, and the burial goods assemblages, this study provides an overview of the social structural development, from the Gumugou group’s heterogenous condition to the Xiaohe group’s homogeneous and mature state. Also, through relating to the results of biological and osteological analyses, and applying geographical analyses to the material, this study suggests that the early settlers in the Tarim Basin, the Xiaohe-Gumugou people have created their own social identities. Although the Xiaohe-Gumugou people might have migrated from southern Siberia or Central Asia, the archaeological material shows indications of their own typical features. When newcomers joined the society, the local burial customs were accepted and applied in a new cultural setting. / Denna studie fokuserar på gravskick på gravfälten Xiaohe och Gumugou i nordvästra Kina, för att förstå hur människor konstruerade social identitet och överförde kulturella föreställningar mellan generationer. Xiaohe-Gumugou-gravfälten, som de viktigaste platserna i Xiaohe-kulturhorisonten, är centrala för förståelsen av bildandet av bronsålderns kulturgrupper och de kulturella växelverkningarna mellan väst och öst i Tarimbäckenet. Tidigare forskning saknar fördjupade undersökningar av gravfältens materiella kultur samt den historiska kontexten med de omgivande arkeologiska kulturerna under tidsperioden från bronsålder till järnålder. Genom detaljerade jämförelser av konstruktionen av kistor och monument samt de dödas klädsel och gravgåvor, ger denna studie en översikt över utvecklingen av sociala strukturer, från Gumugou-gruppens heterogena situation till Xiaohe-gruppens homogena och mogna tillstånd. Genom att relatera till resultaten från biologiska och osteologiska analyser och tillämpa geografiska analyser på materialet, tyder den här studien på att de tidiga bosättarna i Tarimbäckenet, Xiaohe-Gumugou-folket, har utvecklat egna sociala identiteter. Trots att Xiaohe-Gumugou-folket kan ha migrerat från södra Sibirien eller Centralasien visar det arkeologiska materialet indikationer på egna typiska egenskaper. När nykomlingar anslöt till samhället accepterades de lokala begravningssederna och tillämpades i ett nytt kulturellt sammanhang.

Several studies indicates China is experiencing a water crisis, were several regions are suffering of severe water scarcity and rivers are heavily polluted. On the other hand, water is used inefficiently and wastefully: water use efficiency in the agriculture sector is only 40% and within industry, only 40% of the industrial wastewater is recycled. However, based on statistical data, China’s total water resources is ranked sixth in the world, based on its water resources and yet, Yellow River and Hai River dries up in its estuary every year. In some regions, the water situation is exacerbated by the fact that rivers’ water is heavily polluted with a large amount of untreated wastewater, discharged into the rivers and deteriorating the water quality. Several regions’ groundwater is overexploited due to human activities demand, which is not met by local. Some provinces have over withdrawn groundwater, which has caused ground subsidence and increased soil salinity. So what is the situation in China? Is there a water crisis, and if so, what are the causes?This report is a review of several global water scarcity assessment methods and summarizes the findings of the results of China’s water resources to get a better understanding about the water situation. All of the methods indicated that water scarcity is mainly concentrated to north China due to rapid growth, overexploitation from rivers and reduced precipitation. Whereas, South China is indicated as abundant in water resources, however, parts of the region are experiencing water scarcity due to massive dam constructions for water storage and power production. Too many dam constructions in a river disrupts flow of the river water and pollutants are then accumulated within floodgates.Many Chinese officials and scholars believe that with economic growth comes improved environmental quality when the economy has reached to a certain of per-capita level. However, with the present water situation it is not sustainable or possible for China to keep consuming and polluting its water resources. Improvement of environmental quality does not come automatically with increased income, and policies, laws and regulations are needed in order to stop further deterioration of the environment.China’s water situation is not any news and the key factor is human activities, but the question is how to solve it. China’s water crisis is much more complex than over exploitation of groundwater and surface water. There are three water issues in China: “too much water – floods, too little water – droughts, and too dirty water – water pollution” (Jun & Chen, 2001). Thus, solving China’s water crisis is a huge challenge to solve without negatively affecting the economic growth.