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1
Woodfine, Richard Gareth. "Chemostratigraphy of Jurassic-cretaceous Italian carbonate platforms." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:03c84d34-a27d-46fd-89b0-d69a1501d888.
Повний текст джерелаАнотація:
Samples of shallow-water carbonates were collected from Jurassic and Cretaceous Italian carbonate platforms and subjected to petrographic, diagenetic and chemostratigraphic analyses (87Sr/86Sr, δ13Ccarb, δ13Corg, δ18O). In general, the new chemostratigraphic data generated reflect trends established by previous work, some of which has been carried out on biostratigraphically calibrated reference sections. Consequently, chemostratigraphic correlations (87Sr/86Sr, δ13Ccarb) of isotope profiles taken from platform carbonates with well-dated reference sections have allowed the application of high-resolution dating frameworks to the biostratigraphically poorly constrained carbonate platforms. The increased resolution in dating of the Italian carbonate platforms has, furthermore allowed a detailed investigation into the facies response of these carbonate platforms to major geological events. In particular, platform responses to oceanic anoxic events and other periods of major perturbation in the global carbon cycle are analysed (early Toarcian, Aalenian-Bajocian, Oxfordian-Tithonian, Valanginian-Hauterivian, Aptian-Albian, Cenomanian-Turonian, Coniacian-Santonian). Lower Jurassic levels of the Trento Platform record platform devastation in the early Toarcian synchronous with a major negative δ13Ccarb excursion, followed by platform recovery synchronous with a pronounced δ13Ccarb positive excursion and return to background values. The Campania-Lucania Platform shows negligible response to the oceanographic events of the early Toarcian even though the characteristic carbon-isotope profile is readily identifiable. The Trento Platform drowned at approximately the Aalenian-Bajocian Stage boundary, synchronously with a reproducible negative followed by positive δ13Ccarb excursion, whereas the Campania-Lucania Platform underwent a facies transition from oolite to cyclically bedded micrite. The Friuli Platform showed negligible depositional response to the carbon-cycle perturbations of the Kimmeridgian-Tithonian, Valanginian-Hauterivian, Aptian-Albian and Cenomanian- Santonian (as registered in the δ13Ccarb record). The Campania-Lucania Platform registered flooding and increased levels of organic-matter preservation coincident with pronounced positive δ13Ccarb excursions at Cenomanian-Turonian and Coniacian-Santonian levels. Observations on the responses of carbonate platforms to oceanographic conditions during periods of global carbon burial lead to the conclusion that temperature excess is a hitherto neglected control on global carbonate accumulation rates.
2
Jones, Charles Edward. "Strontium isotopes in Jurassic and Early Cretaceous seawater." Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:fe3733bd-8e31-4bba-a78b-6d8275a0075f.
Повний текст джерелаАнотація:
The collection and analysis of a large number of belemnites and oysters with excellent biostratigraphic and diagenetic control has resulted in a highly detailed determination of the seawater Sr-isotope curve through the Jurassic and Early Cretaceous. The new data confirm the broad trends established by previous work, but the much sharper resolution of the new data allows the application of Sr-isotope stratigraphy with an optimal stratigraphic resolution of ± 1 to 4 ammonite subzones (± 0.5 to 2 Ma). The data show a general decline from the Hettangian (Early Jurassic) to a minimum in the Callovian and Oxfordian (Middle/Late Jurassic). This is followed by an increase through the Kimmeridgian (Late Jurassic) to a plateau reached in the Barremian (Early Cretaceous). In addition, there are major negative excursions in the Pliensbachian/Toarcian (Early Jurassic) and Aptian/Albian (Early Cretaceous). Stable isotope data collected from belemnites and oysters have resulted in the most extensive Jurassic δ13C and δ18O database to date. While both the carbon and oxygen data appear to give reasonable marine signals, the scatter in the data suggests that future research must document possible biological fractionation effects and develop better indicators for the diagenetic alteration of 613C and 6i 8O. The final chapter documents an unexpected correlation between sudden shifts in the Sr-isotope curve, the occurrence of positive 513C excursions, and the eruption of flood basalts. In the Jurassic and Cretaceous there is a correlation in time between sudden downward shifts in the Sr-isotope curve (Pliensbachian, Aptian, Cenomanian/Turonian), the occurance of positive 613C excursions, and the eruption of flood basalts. Each of these major downward shifts in the Sr-isotope curve is followed by a sudden upward shift, which although associated with a positive 613C excursion is not associated with an episode of flood basalt volcanism. In the Cenozoic the Sr-isotope curve no longer displays downward shifts, but the correlation continues between the occurrence of flood basalts and positive 513C excursions. Several lines of evidence suggest that the eruption of flood basalts is associated with pulses of hydrothermal activity, and that this hydrothermal activity brings about the conditions necessary for the genesis of carbon-burial events.
3
Tennant, Jonathan. "The Jurassic/Cretaceous boundary : a hidden mass extinction in tetrapods?" Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/44179.
Повний текст джерелаАнотація:
Reconstructing deep time trends in biodiversity remains a central goal for palaeobiologists, but our understanding of the magnitude and tempo of extinctions and radiations is confounded by uneven sampling of the fossil record. In particular, the Jurassic/Cretaceous (J/K) boundary, 145 million years ago, remains poorly understood. By applying a range of techniques for assessing changes in diversity, I demonstrate that both marine and non-marine tetrapod faunas show evidence for a protracted period of regional and global ecological and taxonomic reorganisation across the J/K boundary. Although much of the signal is exclusively European, almost every higher tetrapod group was affected by a substantial decline across the boundary, culminating in the extinction of several important clades and the ecological release and radiation of numerous modern tetrapod groups, including amphibians, birds and sharks. Groups such as pterosaurs and sauropods began their decline before the J/K boundary, whereas others (including mammaliaforms and ornithischians) did not appear to be affected at the J/K boundary, but declined subsequently in the earliest Cretaceous. However, the majority of clades document their greatest magnitude of decline through the Jurassic-Cretaceous boundary, indicating that the overall extinction tempo was staggered and occurred in a 'wave' through the J/K transition. These major shifts in tetrapod diversity are shown to be independent of both global and regional sampling proxies, except for the North American record for which evidence of the common cause hypothesis is strong. Variation in eustatic sea level was the primary driver of these patterns, controlling biodiversity through availability of shallow marine environments and via allopatric speciation on land. I further investigated the systematics of Atoposauridae, poorly known group of highly-specialised crocodyliforms that appear to have crossed through the J/K boundary. A detailed revision of their taxonomy and systematics indicates that they went extinct at the J/K boundary.
4
Currie, Brian Scott 1966. "Jurassic-Cretaceous evolution of the central Cordilleran foreland-basin system." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282582.
Повний текст джерелаАнотація:
During Jurassic and Cretaceous time deposition in the western interior basin was controlled by a combination of subduction-related dynamic subsidence and thrust-generated flexural subsidence. Changes in the angle of oceanic plate subduction along the western margin of North America and thrust deformation in the Cordillera governed the spatial and temporal influences of these mechanisms throughout basin history. Dynamic subsidence was the primary control on basin deposition during Early-Middle Jurassic and Late Cretaceous time. During these periods, shallow-angle oceanic plate subduction beneath the western margin of North America produced convective mantle circulation and long wavelength subsidence in the western interior. A cessation of dynamic subsidence during Early Cretaceous time, brought on by an increase in the angle of subduction, is partially responsible for the ∼20 m.y. unconformity that separates the Jurassic and Cretaceous sequences in the western interior. During Late Jurassic time, thrusting in the Cordillera resulted in flexural partitioning of the back-arc region. Statal geometries in the Upper Jurassic Morrison Formation in Utah and Colorado indicate deposition in the back-bulge and forebulge depozones of the Late Jurassic foreland basin system and suggest the coeval existence of a flexurally subsiding foredeep to the west. During Early Cretaceous time, >200 km of shortening in the thrust belt resulted in uplift and erosion of the Late Jurassic foredeep and the eastward migration of foreland-basin system flexural components. Areas occupied by the Late Jurassic forebulge were incorporated into the Early Cretaceous foredeep while the Late Jurassic back-bulge depozone became the location of the Early Cretaceous forebulge. In eastern Utah and western Colorado, migration of the forebulge enhanced the regional Early Cretaceous unconformity associated with the cessation of dynamic subsidence. During late Early Cretaceous time sediment accumulation across the entire foreland-basin system may have been facilitated by the reinitiation of dynamic subsidence in the western interior. During the Late Cretaceous, thrusting in the Cordillera resulted in continued flexural subsidence of the foredeep in east-central Utah. However, increased dynamic subsidence throughout Late Cretaceous time allowed thick accumulations of strata to be deposited in the forebulge and back-bulge depozones of the foreland-basin system.
5
Ceglar, Nathan. "Late Jurassic to Early Cretaceous sequence stratigraphy, Northern Bonaparte Basin, Timor Sea /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09SB/09sbc389.pdf.
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6
Groecke, Darren Richard. "Isotope stratigraphy and ocean-atmosphere interactions in the Jurassic and Early Cretaceous." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393117.
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7
Smith, Giles A. "Palynology of the Jurassic/Cretaceous boundary interval in the Volga Basin, Russia." Thesis, University of Bristol, 1999. http://hdl.handle.net/1983/a981fc30-fa69-4cf5-aae5-7290d2a489df.
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8
Lott, Graham Keith. "Late Triassic, Jurassic and Early Cretaceous geology of the Southern North Sea Basin." Thesis, University of Leicester, 1985. http://hdl.handle.net/2381/8430.
Повний текст джерелаАнотація:
The primary aim of this thesis is to provide a comprehensive assessment of the geology of the Southern North Sea Basin during the Jurassic and Early Cretaceous. In order to achieve this the integration of a wide variety of data has been undertaken, including the interpretation of shallow seismic profiles, downhole geophysical log correlation and petrographic descriptions of all available core and seabed sample information from the offshore area. A number of onshore cored borehole sequences were examined in some detail to establish some control points with which to compare the largely uncored offshore successions. [Taken from the thesis Introduction]
9
Moreno, Karen. "Jurassic - Cretaceous dinosaur footprints from South America and pedal biomechanics in ornithopod dinosaurs." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424417.
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10
Reis, Jonathan Hunter. "Jurassic and Cretaceous tectonic evolution of the southeast Castle Dome Mountains, southwest Arizona." [Ames, Iowa : Iowa State University], 2009.
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11
Swientek, Oliver. "The Greenland Norwegian Seaway climatic and cyclic evolution of Late Jurassic-Early Cretaceous sediments /." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965036944.
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12
Dolensky, Ingrid. "Rock properties of the Upper Jurassic and Lower Cretaceous, Northern Bonaparte Basin, Timor Sea /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09S.B/09s.bd587.pdf.
Повний текст джерелаАнотація:
Thesis (B. Sc.(Hons.))--University of Adelaide, National Centre for Petroleum Geology and Geophysics, 1996.Volume 2 is boxed and consists of a large folded chart. Includes bibliographical references.
13
James, D. P. "Stratigraphy, sedimentology and diagenesis of Upper Jurassic and Lower Cretaceous (Mannville) strata, Southwestern Alberta." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371509.
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14
Phethean, Jordan Jerad John. "Breakup of the Gondwana supercontinent : East African perspectives from the Early Jurassic to Cretaceous." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12667/.
Повний текст джерелаАнотація:
Accurate mapping of first-order tectonic features such as oceanic fracture zones and continental margins is vital for the production of reliable plate reconstructions. These reconstructions allow for a better understanding of the palaeo-configuration of continental fragments within Gondwana and ultimately provide insight into how and why supercontinents break apart. Detection of spreading lineaments within the heavily sedimented Western Somali Basin (WSB) has been achieved using a novel technique based on directional derivatives of free-air gravity. This new lineament dataset allows for the construction of a high-resolution plate tectonic reconstruction of the WSB, which is in good agreement with ocean magnetic data and the position of the abandoned WSB spreading centre. The model also reveals a change in spreading direction, from NNW-SSE to N-S, during the Late Jurassic. This controversial spreading direction change places the origin of Madagascar within the Tanzania Coastal Basin (TCB), inboard of the Davie Fracture Zone (DFZ), which was previously believed to be the continent-ocean transform margin of the WSB. This tight-fit of Gondwana fragments prior to continental breakup necessitates a reassessment of both the crustal nature of the TCB, which is shown to be partly oceanic in nature, and of the nature of the margins surrounding the WSB. The northern margins of the WSB are likely orthogonally rifted margins. However, the western margins are likely highly segmented and/or obliquely rifted margins. The model also predicts a large transform offset along the Rovuma Basin. Systematic gravity modelling and combined seismic investigations along the Rovuma basin reveals the ‘Rovuma Transform Margin’, which offsets the obliquely rifted margins of northeast Mozambique and Tanzania. The discovery of this transform margin confirms the initial SSE plate motion predicted from gravity lineament analysis and plate reconstructions, and shows that the breakup of the Gondwana supercontinent occurred not just along pre-existing lithospheric weaknesses associated with the Karoo rift system, but also along newly developed highly oblique deformation zones as well. The final breakup of the Gondwana supercontinent, which followed extensive and episodic Karoo aged rifting, was coincident with extensive magmatism in Mozambique and may therefore have been triggered by the interaction of several facilitators of continental breakup (i.e. oblique rifting, pre-existing weaknesses, and magmatism). The oblique breakup of Gondwana along the TCB led to the development of a segmented mid-ocean ridge system within this basin, offset by SSE trending fracture zones. These fracture zones were incompatible with the N-S spreading that followed the Late Jurassic change in plate motion, resulting in the abandonment of mid-ocean ridge segments and compression within this basin. This compression led to the formation of the 250 km long Tanzania Coastal Basin thrust belt, the largest intraplate oceanic thrust belt yet discovered. The cessation of compression within the TCB followed the development of the DFZ, which propagated from south to north. This structure was subsequently dominated by transpression throughout its history, suggesting it was not perfectly compatible with plate driving forces. Formation of the DFZ along aligned weak rifted margins and young oceanic crust may have resulted in the mismatch of plate motions and driving forces, and also suggests a first order ‘top-down’ control on plate motions during the breakup of Gondwana.
15
Garden, I. R. "Provenance of Upper Jurassic and Lower Cretaceous coarse-grained detritus in Southern Britain and Normandy." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380572.
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16
Turner, Holly Emily. "Integrated correlation of the Kimmeridge Clay Formation (Late Jurassic-Early Cretaceous) : a Boreal-Tethyan transect." Thesis, University of Portsmouth, 2018. https://researchportal.port.ac.uk/portal/en/theses/integrated-correlation-of-the-kimmeridge-clay-formation-late-jurassicearly-cretaceous(d56f96c2-d8f4-4c60-a3ea-69913049d917).html.
Повний текст джерелаАнотація:
The Kimmeridge Clay Formation (Upper Jurassic‒Lower Cretaceous) is a widely deposited mudrock that has a high total organic carbon content and is a major petroleum source rock of the North Sea, Norwegian Sea and Barents Sea. The Late Jurassic and Early Cretaceous were characterised by a number of carbon cycle perturbations and a climatic shift in north-western Europe from relatively humid to arid and back to humid conditions. Precise correlation of the KCF in north-western Europe is critical for assessing the temporal and geographic extent of these events, stratigraphic fidelity, and the nature of widespread organic matter deposition in the region. However, correlation is complicated by faunal provincialism and insufficiently constrained chronostratigraphy. Biostratigraphic data alone generally does not allow precise correlation. An integrated approach (bio-, cyclo- and chemostratigraphy) is applied here to correlate several biostratigraphically-constrained organic carbon isotope (훿13Corg) records from the Norwegian Continental Shelf with the (1) Kimmeridgian‒Tithonian (Upper Jurassic) Kimmeridge Clay Formation of the Dorset type area; (2) upper Tithonian‒Berriasian (Upper Jurassic‒Lower Cretaceous) of Svalbard and Siberia; and (3) lower Kimmeridgian of west-central Portugal (Tojeira-1 section), and other Tethyan sites. Identification and correlation of synchronous C-isotope events amongst inter-regional sections reflects the consistency of the C-isotope signal in the seas of north-western Europe at the time of deposition, and include the mid-Eudoxus Zone, mid-Hudlestoni Zone and early Berriasian negative isotope excursions, and the Volgian Isotopic Carbon Excursion (VOICE). The relationship of these records and other Boreal C-isotope accounts for the Late Jurassic and Early Cretaceous are presented as a 훿13Corg stack. In addition, time series analyses of TOC records from wells 7120/2-3 and 16/1-14 reveal cycles that strongly resemble the short-term eccentricity component recorded in the well-studied and relatively complete Dorset section. Implied long-term eccentricity modulation in the Tojeria-1 section is also compared with the cyclostratigraphic framework of SE France. Cyclostratigraphic correlation provides independent support of the constructed age models for the studied sections, and a basis for understanding the timing and extent of Late Jurassic‒Early Cretaceous climate change. As the clay mineral kaolinite is weathered in humid environments, the Early Cretaceous climatic shift from dry-warm conditions is suggested by its abundance, however, palaeoclimatic inferences from clay mineralogical records are complicated by diagenetic overprinting. Clay mineral assemblages from several well constrained sections from the Norwegian Continental Shelf are presented as a N-S transect of the Norwegian-Greenland Seaway.
17
Li, Xiaochi. "The Marine Jurassic and Lower Cretaceous of southern Xizang (Tibet): bivalve assemblages, correlation, paleoenvironments and paleogeography." Thesis, University of Auckland, 1990. http://hdl.handle.net/2292/2167.
Повний текст джерелаАнотація:
This study is based on 15 measured Jurassic to Lower Cretaceous sections and their abundant bivalve faunas distributed mainly in the Nyalam and Gamba districts of southern Xizang. It addresses the establishment of bivalve assemblages, stratigraphic subdivision and correlation, analysis of sedimentary environments, sea-level change and paleogeography in light of the tectonic framework and geological evolution of the Xizang Plateau. The Plateau consists of three terranes: Qangtang, Gangdise and Himalaya They are separated by the sutures: Kunlun-Hoh Xil-Jingsha Jiang, Banggong Co-Nu Jiang, and Yarlu Zangbo Jiang, which represent three closed oceans: Paleo-Tethys, Neo-Tethys and South Xizang Sea. Stratigraphic development of the Jurassic and Lower Cretaceous of southern Xizang is especially closely related to the evolution of the South Xizang Sea Bivalves are one of the most common and important Jurassic and Early Cretaceous fossil groups in the Plateau. From 15 measured sections, 51 bivalve species within 26 genera are described, including 3 new genera and 14 new species. New genera: Vanustus, Yoldioides, Antipectenoides New species: Nuculoma oriens (Nuculidae) Yoldioides jurianoides (Malletiidae) Mesosaccella gangbaensis (Nuculanidae) M. Orienta Grammatodon (Indogrammatodon) sinensis (Parallelodontidae) Oxytoma jiabulensis (Oxytomidae) Meleagrinella minima M. dongshangensis M. sinensis Entolium dongshangensis (Entoliidae) Antipectenoides sinensis Ctenoides shizangensis (Limidae) Anisocardia shizangensis (Arcticidae) Protodiceras lanonglaensis (Megalodontidae) A stratigraphic sequence of ten different bivalve assemblages and four Buchia faunas from the Jurassic to Lower Cretaceous of Nyalam district, and four Jurassic bivalve faunas from the Gamba district are recognised. In addition, the Oxytoma jiabulensis bed and two Meleagrinella beds are also recognised. These assemblages can be seen to be of two types, high and low diversity, indicating different sedimentary environments. These assemblages along with co-existing ammonites also provide a good basis for stratigraphic division and correlation of the sequences. Special attention is given to nomenclatural and other problems associated with the important genus Buchia:. Australobuchia Zakharov is believed to be inseparable generically, and some Xizang species of Buchia an placed in synonymy. On this basis the evolution and migration of the genus is discussed From measured sections in southern Xizang, a comparatively complete Jurassic- Lower Cretaceous sequence has been established, which includes six formations: (in ascending order) Pupugar. Nieniexiongla. Lanongla. Menbu. Xuomo and Gucocun Formations. A new stratigraphic unit, the Gangdong Formation, is established, for Mid-Upper Jurassic strata of the Gamba district. Direct and indirect biostratigraphic correlation within China and between southern Xizang and other places around Gondwanaland is well established. Lithologic features, sedimentary structures and bivalve assemblages allow four environments including nine lithofacies to be recognised in southern Xizang: 1. Inner shelf environment 1] Shoreface sandstone facies 2] Neritic terrigenous clastic facies 3] Open shelf carbonate facies 4] Protected barrier carbonate facies 5] Reef limestone facie 2. Outer shelf environment 6] Siltstone-shale-carbonate facies 3. Slope environment 7] Fine clastic facies 8] Pelagic limestone facies 4. Bathyal environment 9] Dark Buchia-ammonite-lutite facies They can be seen to be organised into sedimentary cycles, which clearly show a huge transgression with three peaks in the Upper Jurassic reaching a maximum at the top of the Jurassic (Upper Tithonian). In the Lower and Middle Jurassic, sea-level changes fluctuated between coastal and shelf-sea environments, whereas in the Upper Jurassic, as a result of sea-floor spreading in the South Xizang Sea and the formation of fault basins, the area descended into bathyal depths. Paleogeographically, the northern part of the Plateau (i.e. the Northern Branch, or Neo-Tethys) underwent a shallowing process along with areal extension during Jurassic times, but shrank in the Early Cretaceous, whereas in the Southern Branch, during Jurassic-Early Cretaceous times, the South Xizang Sea developed a wide variety of sedimentary environments, including inner and outer shelf sea, continental slope and bathyal fault basin.
18
Wilkinson, Ian Paul. "Latest Jurassic and Early Cretaceous ostrocoda in eastern England and southern North Sea Basin : a biostratigraphy." Thesis, Aberystwyth University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576093.
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19
Ayers, James D. "Lithologic Evidence of Jurassic/Cretaceous Boundary Within the Nonmarine Cedar Mountain Formation, San Rafael Swell, Utah." Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1097256637.
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20
Zhao, Tie. "Petrology of the late Jurassic to early Cretaceous coals from the Yang Cao Gou Basin, northeast China /." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09SM/09smz51.pdf.
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21
Sanchez, Hernandez Barbara. "The upper jurassic-early cretaceous dinosaurs and other vertebrates form the Galve and Cameros Basins, NE Spain." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529822.
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22
Spencer-Cervato, Cinzia. "Hydrothermal dolomitization of Jurassic-Cretaceous limestones in the Southern Alps (Italy) : its relationship with tectonics and volcanism /." Zürich : [s.n.], 1990. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9093.
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23
Brandalise, de Andrade Marco. "The Evolution of Mesoeucrocodylia (Crurotarsi, Crocodylomorpha) from Jurassic to Cretaceous : a phylogenetic review with emphasis on Gondwanan taxa." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525451.
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24
Nunn, Elizabeth Victoria. "Late Jurassic to Early Cretaceous stable isotope and geochemical records from the northern high latitudes : implications for palaeoclimate." Thesis, University of Plymouth, 2007. http://hdl.handle.net/10026.1/861.
Повний текст джерелаАнотація:
The Jurassic and Cretaceous periods are widely accepted as being dominated by greenhouse conditions with elevated CO2 levels and warm polar regions. Although much compelling evidence to support this idea of global warmth exists, some recent studies propose that the greenhouse climate may at times have been punctuated by sub-freezing polar conditions and the presence of limited polar ice. The evidence, however, is somewhat equivocal and is both spatially and temporally limited with much of this research until now being concentrated in mid- to low latitudes, despite it being generally accepted that global climate is defined to a significant degree by prevailing conditions at the poles. Existing data are also often plagued by poor sampling resolutions and dubious diagenetic histories. This research presents the first extensive stable isotope and geochemical investigation of well-preserved belemnite rostra from the Callovian-Hauterivian Boreal Realm. Belemnites of the genera Cylindroteuthis, Pachyteuthis, Acroteuthis, Lagonibelus and occasionally Belemnopsis were investigated. Preservation was assessed using Backscattered Scanning Electron Microscopy, Cathodoluminescence, carbonate staining and trace element techniques. Organic carbon isotope analysis of fossilised wood was also undertaken where possible. Material from Staffin Bay, Isle of Skye, and Helmsdale, Sutherland, Scotland; the lzhma River, Timan-Pechora Basin, Russia; the Boyarka River, Yenisei-Khatanga Basin, Siberia; and Festningen and Janusfjellet, Svalbard was analysed. The carbon isotope data record relatively positive values in the Oxfordian, followed by a gradual shift towards more negative values through the Kimmeridgian and into the Volgian/Tithonian. A distinct Late Valanginian positive carbon isotope excursion is identified in both the marine carbonate and terrestrial organic carbon records from the Izhma and Boyarka, rivers. The excursion occurs at a time of relatively low sea level in Russia and Siberia. The exposure and erosion of lowland areas and restricted ocean circulation (and therefore enhanced stratification) associated with a period of sea-level lowstand may account for increased rates of organic carbon burial. The Late Valanginian positive carbon isotope excursion is coeval with a distinct cooling in the Russian lzhma River succession. This could be explained by a fall in atmospheric CO2 concentration and a subsequent drop in temperature as the result of significant burial of sediments rich in organic carbon. Further evidence for cold conditions during the Valanginian interval comes from glendonites and dropstones, which were identified on Svalbard. High latitude warmth is most likely the norm for the Late Jurassic and Early Cretaceous interval, although this warmth is likely to have been punctuated by cold conditions providing the opportunity for the development of at least a seasonal cover of polar ice. The oxygen isotope data record the occurrence of cold episodes during the Lower Oxfordian Cordatum Zone, the mid-Ryazanian Kochi-Analogus zones and the Upper Valanginian Bidichotomus Zone. Palaeotemperatures as low as 2ْC were calculated, providing strong evidence for the existence of cold polar conditions at theses times. Ultimately, climatic instability is probably the key characteristic of this greenhouse interval.
25
Constenius, Kurt Norman 1957. "Extensional tectonics of the Cordilleran foreland fold and thrust belt and the Jurassic-Cretaceous Great Valley forearc basin." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282601.
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Following cessation of contractional deformation, the Sevier orogenic belt collapsed and spread west during a middle Eocene to middle Miocene (∼48-20 Ma) episode of crustal extension coeval with formation of metamorphic core complexes and regional magmatism. The sedimentary and structural record of this event is a network of half-grabens that extends from southern Canada to at least central Utah. Extensional structures superposed on this fold-thrust belt are rooted in the physical stratigraphy, structural relief and sole faults of preexisting thrust-fold structures. Commonly, the same detachment surfaces were used to accommodate both contractional and extensional deformation. Foreland and hinterland extensional elements of the Cordillera that are normally widely separated are uniquely collocated in central Utah where the thrust belt straddles the Archean-Proterozoic Cheyenne belt crustal suture. Here, the Charleston-Nebo allochthon, an immense leading-edge structural element of the Sevier belt collapsed during late Eocene-middle Miocene time when the sole thrust was extensionally reactivated by faults of the Deer Creek detachment fault system and the allochthon was transported at least 5-7 km back to the west. Concurrently, the north margin of the allochthon was warped by flexural-isostatic rise of a Cheyenne belt crustal welt and its footwall was intruded by crustal melts of the Wasatch igneous belt. Collectively, these elements comprise the Cottonwood metamorphic core complex. Extensional processes were also important in the formation of the Jurassic-Cretaceous Great Valley forearc basin. Advocates of a thrust-wedge hypothesis argued that this forearc experienced prolonged Jurassic-Cretaceous contraction and proposed that northwest-southeast-striking fault systems were evidence of a west-dipping blind Great Valley-Franciscan sole thrust and related backthrusts. Based on interpretation of seismic reflection, borehole, map and stratographic data, I propose that these faults and associated bedding geometries are folded synsedimentary normal faults and half-grabens. Thus, late-stage diastrophic mechanisms are not required to interpret a forearc that owes much of its present-day bedding architecture to extensional processes coeval with deposition.
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Nwozor, Kingsley Kanayochukwu. "The nature of the Jurassic-Cretaceous pressure transition zone in the UK sector of the North Sea Central Graben." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230658.
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Cummings, Donald I. "Sedimentology and stratigraphy of an ancient progradational terrigenous clastic shelf margin, Missisauga Formation (Upper Jurassic-Lower Cretaceous), offshore Nova Scotia, Canada." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/29092.
Повний текст джерелаАнотація:
Large-scale stratal architecture, structure, and commonly hydrocarbon distribution in the Mississauga Formation, Sable Subbasin, offshore Nova Scotia, can be satisfactorily explained by shelf margin progradation. Using an integrated subsurface dataset (2-D and 3-D seismic data, biostratigraphy, geophysical well logs, core), the physical characteristics and depositional history of the Missisauga Formation (Tithonian-Barremian) were studied on both local and regional scales. These data suggest that during deposition of the Missisauga, the shelf margin prograded southward from an initial position just basinward of the Venture Field (Tithonian) to a final position just basinward of the Glenelg and Alma fields (Barremian). Growth-faulted, storm-dominated deltaic sandstones deposited at or near the shelf margin during this process are interpreted to contain over half of the discovered in-place gas reserves offshore Nova Scotia. Because shelf-margin delta sand-bodies are typically shore-elongate, tend to occur in groups along a shelf margin and commonly correlate downdip to turbidite sand-bodies, recognition of the shelf-margin delta play-type will not only improve hydrocarbon exploitation strategies offshore Nova Scotia, but will provide an important framework to guide the identification of new exploration opportunities in genetically related parts of the stratigraphic section.
In the Venture Field, Tithonian shelf-margin delta lobes are stacked vertically, suggesting that growth-fault related subsidence at the shelf margin negated depositional topography and created topographic lows through which fluvio-deltaic systems preferentially flowed. Over several relative sea level cycles, the positive feedback between sediment supply and subsidence at the shelf margin potentially focused enough sediment to have constructed slope turbidite systems downdip, which in turn represent new exploration targets.
In the Glenelg Field, Barremian shelf-margin deltas were initially tide-influenced (dominated?) and then changed to a storm-dominated state, possibly because the shoreline initially prograded into a tidally resonant topographic depression, which upon being filled was converted to a wave-dominated setting. Along depositional strike of the main hydrocarbon-bearing sandstones at Glenelg, Barremian sandstone reservoirs in the Alma Field are interpreted to be storm-dominated shelf-margin delta deposits. However, unlike Glenelg, incised valleys were not identified at Alma, suggesting that downdip depocenters were fed by sediment that bypassed Glenelg during the Barremian.
Transgression at the end of the Barremian deposited mudstone of the Naskapi Member throughout the Sable Subbasin, forming a regional seal. Sharp-based, bioturbated shallow marine sandstones deposited locally during this transgression are an important play type in the western Sable Subbasin (e.g., Alma and Panuke fields).
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Brown, Don M. (Don Maximilian) Carleton University Dissertation Geology. "Sedimentology of the upper Jurassic - lower Cretaceous Hibernia member of the Missisauga formation in the Hibernia oil field, Jeanne d'Arc basin." Ottawa, 1985.
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Abid, Iftikhar A. "Mineral diagenesis and porosity evolution in the Hibernia Oil Field, Jurassic-Cretaceous Jeanne d'Arc Rift Graben, eastern Grand Banks of Newfoundland, Canada." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61683.
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Wood, S. E. L. "Late Jurassic to Early Cretaceous dinoflagellate cysts from the eastern Gulf of Mexico : facilitating future exploration and development activities in the basin." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/16271/.
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Brysch, Sven [Verfasser], and Wolfgang [Akademischer Betreuer] Stinnesbeck. "Changes in climate and palaeoenvironment during the Late Jurassic–Early Cretaceous in southern South America and western Antarctica / Sven Brysch ; Betreuer: Wolfgang Stinnesbeck." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177044064/34.
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Langrock, Uwe. "Late Jurassic to Early Cretaceous black shale formation and paleoenvironment in high northern latitudes = Spätjurassische bis frühkretazische Schwarzschiefergenese und Paläoumwelt in hohen nördlichen Breiten /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2004. http://www.gbv.de/dms/goettingen/385716125.pdf.
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Bert, Didier. "L'influence de la variabilité intraspécifique sur la taxinomie, la biostratigraphie et l'évolution des ammonites : une approche paléobiologique : exemples pris dans le Jurassique supérieur et le Crétacé inférieur." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S047/document.
Повний текст джерелаАнотація:
La problématique de ce travail concerne des cas concrets d'application de l'approche paléobiologique chez les ammonites. Une attention spéciale a été donnée à la variabilité intraspécifique et ses conséquences taxinomiques, ainsi qu'à l'étude des patterns et processus évolutifs des groupes étudiés, afin d'en tirer des généralités. Les études paléobiologiques sur des exemples très variés montrent que la variabilité et le degré de sa prise en compte par les auteurs a une influence particulière sur les conceptions taxinomiques, et par conséquent sur la biostratigraphie et sur la compréhension des mécanismes évolutifs. Les lois de Westermann semblent être prépondérantes pour expliquer la variabilité intraspécifique d'un grand nombre de groupes d'ammonites, mais elles ne sont pas la seule source de covariation et leur influence doit être relativisée face à d'autres facteurs habituellement peu pris en compte. Les facteurs de la variabilité intraspécifique reconnus concernent : (1) le dimorphisme, (2) une variabilité dipolaire dans l'application stricte de la première loi de Westermann, (3) des variation par rapport à l'énoncé général de cette loi, (4) une variabilité tripolaire, (5) des relations hétérochroniques morphologiques dépendantes ou indépendantes, (6) un facteur d'atténuation de l'ornementation, et (7) différents facteurs d'enroulement liés ou non à d'autres caractères morphologiques et ornementaux chez les ammonites hétéromorphesThe issue of this work involves concrete case of application of the palaeobiological approach in ammonites. Special attention was given to intraspecific variability and its taxonomic consequences and the study of evolutionary processes and patterns of the groups studied, in order to draw generalizations. Paleobiological studies on a variety of examples show that the degree of variability and its consideration by the authors has a particular influence on taxonomic concepts, and consequently on the biostratigraphy and the understanding of evolutionary mechanisms. Westermann laws seem to be dominant to explain intraspecific variability of a large number of ammonites groups, but they are not the only source of covariation and their influence must be relativized against other factors usually not taken into account. Factors of intraspecific variability recognized are: (1) dimorphism, (2) a dipolar variability in the strict application of the first Westermann’s law, (3) changes compared to the general statement of the law, (4) tripolar variability, (5) heterochronic relationships morphological dependent or independent, (6) an attenuation factor of ornamentation, and (7) various coiling factors related or not to other morphological and ornamental characters in heteromorphic ammonites
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Salazar, Soto Christian Andrés [Verfasser], and Wolfgang [Akademischer Betreuer] Stinnesbeck. "The Jurassic-Cretaceous Boundary (Tithonian - Hauterivian) in the Andean Basin of Central Chile: Ammonites, Bio- and Sequence Stratigraphy and Palaeobiogeography / Christian Andrés Salazar Soto ; Betreuer: Wolfgang Stinnesbeck." Heidelberg : Universitätsbibliothek Heidelberg, 2012. http://d-nb.info/1177040891/34.
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Jenkins, C. C. "The organic geochemical correlation of crude oils from early Jurassic to late Cretaceous Age reservoirs of the Eromanga Basin and late Triassic Age reservoirs of the underlying Cooper Basin /." Title page, contents and abstract only, 1987. http://web4.library.adelaide.edu.au/theses/09SM/09smj521.pdf.
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Mohammed, R. Luma Jassim [Verfasser], Lorenz [Akademischer Betreuer] Schwark, and Wolfgang [Gutachter] Kuhnt. "Petroleum system analysis of the Lower Jurassic-Upper Cretaceous source rocks and Miocene reservoirs in the NE of Iraq / Luma Jassim Mohammed R ; Gutachter: Wolfgang Kuhnt ; Betreuer: Lorenz Schwark." Kiel : Universitätsbibliothek Kiel, 2016. http://d-nb.info/1236286944/34.
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BARBERO, EDOARDO. "Geological and petrological investigation of the western North Makran ophiolites (SE Iran): new constraints for the Late Jurassic – Cretaceous tectono-magmatic and geodynamic evolution of the Neo-Tethys Ocean." Doctoral thesis, Università degli studi di Ferrara, 2021. http://hdl.handle.net/11392/2488101.
Повний текст джерелаАнотація:
The Makran Accretionary Prism (South Iran) is related to the convergence between the Arabia and Eurasia plates accommodated by the northward subduction of the Neo-Tethys Ocean since the Cretaceous. Mesozoic ophiolites, sedimentary successions, and minor continental-derived tectonic units are preserved in the North Makran domain.
This thesis is focused on field-based geological study, as well as petrological and geochemical characterization of the magmatic rocks of the Bajgan and Durkan Complexes, the Band-e-Zeyarat ophiolitic unit, and the Ganj Complex The studied units are included in the North Makran domain and they are up to now interpreted as the remnants of a Mesozoic oceanic basin (the North Makran Ocean) and its southern continental margin. The aim of this thesis is to provide data for understanding the geodynamic significance of these units and new constraints for the Mesozoic geodynamic history of the North Makran Ocean.
The new multidisciplinary data documented a complex tectono-magmatic evolution for the different tectonic units. The Ganj Complex was interpreted in literature as an ophiolitic unit. The new data indicate that it represents a Late Cretaceous volcanic arc succession. The Ganj arc was likely built close or onto the southern margin of Eurasia plate. The Band-e-Zeyarat ophiolitic unit display crustal architecture, geochemical fingerprints of magmatic rocks, and mineral chemistry of rock-forming minerals indicating its formation in a mid-oceanic ridge tectonic setting during Early Cretaceous. Petrogenetic evidence suggests a ridge-mantle plume interaction during the formation of this unit. The Bajgan and Durkan Complexes were up to now considered as the remnants of a microntinental block deformed in the Makran. The multidisciplinary data provided by this thesis point out for a different interpretation of these complexes. The Durkan Complex records the interplay of alkaline magmatism and shallow water and pelagic sedimentation during the Late Cretaceous. The combination of stratigraphic and petrological data and mineral chemistry data suggest that the Durkan Complex represents the remnants of a Late Cretaceous seamounts chain tectonically disrupted in the Makran. The Bajgan Complex include meta-serpentinites, meta-intrusive rocks, meta-volcanic rocks and meta-sedimentary rocks. This type of tectono-stratigraphic architecture is comparable with that of a typical subduction-unrelated oceanic succession. Whole-rock geochemistry of meta-magmatic rocks and petrogenetic study indicate a subduction-unrelated chemical affinity. Dating of magmatic zircon from meta-intrusive rocks testify for Late Jurassic – Early Cretaceous age. These data indicate that the Bajgan Complex corresponds to an assemblage of Mesozoic meta-ophiolitic tectonic slices. Structural data on the Band-e-Zeyarat ophiolitic unit and Durkan Complex provide evidence for a multiphase deformation history occurred during the latest Late Cretaceous – Paleocene-earliest Eocene accretion and subsequent exhumation within the frontal accretionary wedge.
In conclusion this thesis provides significant constraints for the understanding of the Late Jurassic - Cretaceous geodynamic and tectono-magmatic significance of the North Makran Ocean and its role during the convergent tectonic stages starting from the latest Late Cretaceous. The outstanding conclusion is that, in contrast to any previous interpretation, this ocean likely represented a mature and wide oceanic basin rather than a marginal basin or a back-arc basin as previously thought. The implications of these new findings are also discussed in the framework of the regional-scale Cretaceous evolution of the Neo-Tethys realm.Il Prisma di Accrezione del Makran (Iran meridionale) è legato alla convergenza tra la placca Araba e quella Euroasiatica, che è accomodata, a partire dal Cretacico, dalla subduzione verso Nord dell’oceano della Neo-Tetide. Nel dominio tettonico del North Makran sono preservate ofioliti mesozoiche, successioni sedimentarie e minori resti di rocce di derivazione continentale. La presente tesi è focalizzata sui complessi di Bajgan e Durkan, sull’unità di Band-e-Zeyarat e sul complesso di Ganj e comprende un dettagliato studio geologico di queste unità sul terreno così come un dettagliato studio geochimico-petrologico delle rocce magmatiche. Le unità studiate fanno parte del dominio del North Makran e sono state interpretate come i resti del bacino oceanico Mesozoico, noto in letteratura come Oceano del North Makran, e il suo margine continentale meridionale. Lo scopo di questa tesi è di presentare nuovi dati per meglio comprendere il significato geodinamico dei complessi di Bajgan e Durkan, dell’unità di Band-e-Zeyarat e del complesso di Ganj e vincolare l’evoluzione geodinamica dell’Oceano del North Makran. I dati presentati nella presente tesi documentano una complessa evoluzione tettono-magmatica per le diverse unità tettoniche. Il complesso di Ganj rappresenta una successione di arco vulcanico del Cretacico Superiore, probabilmente formatasi vicino alla placca Euroasiatica. L'ofiolite di Band-e-Zeyarat mostra un’architettura crostale, un’affinità geochimica delle rocce magmatiche e la composizione chimica delle fasi mineralogiche compatibile con la genesi in una dorsale medio oceanica durante il Cretacico Inferiore. I nuovi dati petrologici suggeriscono che l’ofiolite di Band-e-Zeyarat si sia formata durante l’interazione tra dorsale e plume di mantello. Il complesso di Durkan registra magmatismo alkalino coevo con sedimentazione pelagica e in ambiente di piattaforma carbonatica durante il Cretacico Superiore. La combinazione dei dati stratigrafici e petrologici indica che il Complesso di Durkan rappresenta i resti di una catena di seamounts deformata nel prisma di accrezione del Makran. Il complesso di Bajgan è costituito da meta-serpentiniti, varie tipologie di rocce metamorfiche da protoliti magmatici e rocce meta-sedimentarie. Questa tipologia di associazione litologica e la composizione chimica delle rocce magmatiche sono confrontabili con le ofioliti di tipo MOR (mid ocean ridge). Le datazioni di zirconi separati da meta-gabbri e meta-plagiograniti hanno fornito età comprese tra il Giurassico Superiore e il Cretacico Inferiore. I nuovi dati sul Complesso di Bajgan suggeriscono che corrisponda a un insieme di scaglie tettoniche di ofioliti Mesozoiche. I dati strutturali sull’ofiolite di Band-e-Zeyarat e il Complesso di Durkan indicano che queste unità hanno subito una storia deformativa polifasica tra il tardo Cretacico Superiore e il Paleocene-Eocene inferiore durante la loro accrezione e successiva esumazione nei settori frontali del prisma del Makran. In conclusione, i risultati della presente tesi forniscono importati vincoli per comprendere l’evoluzione geodinamica dell’Oceano del North Makran durante il tardo Giurassico e il Cretacico, così come il suo ruolo nella tettonica convergente attiva a partire dal tardo Cretacico Superiore. Il risultato principale è che i nuovi dati multidisciplinari suggeriscono che l’Oceano del North Makran rappresentasse un bacino oceanico maturo piuttosto che un bacino marginale o un back-arc come precedentemente suggerito in letteratura. Sono inoltre discusse le implicazioni dei nuovi dati nel contesto dell’evoluzione a scala regionale della Neo-Tetide durante il Cretacico.
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Schneider, Anton Christoph [Verfasser], Jörg [Gutachter] Mutterlose, and Ulrich [Gutachter] Heimhofer. "Stratigraphy, palaeoenvironment, and hydrocarbon potential of a non–marine sedimentary sequence : the Jurassic-cretaceous boundary interval in northern Germany / Anton Christoph Schneider ; Gutachter: Jörg Mutterlose, Ulrich Heimhofer ; Fakultät für Geowissenschaften." Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1202608744/34.
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Baron, Matthew Grant. "The origin and early evolution of the Dinosauria." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271890.
Повний текст джерелаАнотація:
For 130 years dinosaurs have been divided into two distinct clades – Ornithischia and Saurischia. This dissertation looks at the earliest evolution of the clade Dinosauria by focusing upon the interrelationships of the major subsidiary clades within it. It does this following examination, comparison and description of early dinosaur material, and by utilising modern phylogenetic analysis techniques, to rigorously and objectively test the fundamental groupings within the clade Dinosauria using a newly compiled dataset of early dinosaurs and other dinosauromorphs (= close dinosaur relatives). The current consensus on how the principal clades within Dinosauria (Theropoda, Sauropodomorpha and Ornithischia) are related to one another is challenged by the results of these analyses. This study finds, for the first time, a sister-group relationship between Ornithischia and Theropoda, here termed Ornithoscelida. Consequently, a new definition for Dinosauria is presented, as the historic definition would exclude all members of Sauropodomorpha from the clade. As well as this, I propose revisions to the definitions of each of the principal dinosaurian sub-divisions and propose a new timeframe and geographic setting for the origin of Dinosauria. These new hypotheses force re-evaluations of early dinosaur cladogenesis and character evolution, suggest the independent acquisition of hypercarnivory in multiple dinosaur groups and offers an explanation for many of the anatomical features previously regarded as striking convergences between theropods and early ornithischians. As well as presenting new anatomical data on many early dinosaurs and dinosauromorphs, including a comprehensive re-description of the postcranial anatomy of Lesothosaurus diagnosticus (Chapter 2), and a new anatomical dataset of early dinosaurs (the largest ever compiled), this thesis goes on to implement the new dataset to investigate a number of important outstanding questions about early dinosaur evolution and provides new lines of enquiry for future workers to pursue. The results of this thesis reveal the oldest known members of the dinosaurian clades Theropoda and Sauropodomorpha (Chapter 6), as well as a new clade within Ornithischia; a taxon previously thought to represent a derived theropod has been recovered as a potential ‘missing link’ between theropods and ornithischians using the new dataset. This work now provides a unique tool for the assessment of the phylogenetic affinities of early dinosaurs and dinosauromorphs and, once published, will hopefully become the benchmark dataset for palaeontologists working in this area.
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Mojon, Pierre-Olivier. "Les formations mésozoïques à charophytes (Jurassique moyen-Crétacé inférieure) de la marge téthysiennes nord-occidentale : (Sud-Est de la France, Suisse occidentale, Nord-Est de l'Espagne) : sédimentologie, micropaléontologie, biostratigraphie." Grenoble 1, 2001. https://theses.hal.science/tel-00546081.
Повний текст джерелаАнотація:
Le thème principal de ce travail de thèse se rapporte à l'étude micropaléontologique et sédimentologique des dépôts émersifs de la plate-forme jurassienne (S. -E. De la France et Suisse occidentale) entre le Jurassique moyen et le Crétacé inférieur (faciès purbeckiens et wealdiens). Grâce aux données complémentaires de coupes sélectionnées dans le N. -E. De l'Espagne (Maestrazgo) et le S. -E. De la France (Basse-Provence), une biozonation continentale principalement basée sur les Charophytes et un nouveau schéma phylogénétique des Clavatoracées (Charophytes) sont établis pour le Jurassique supérieur - Crétacé de l'Europe occidentale. D'autre part, le polymorphisme des gyrogonites des Porocharacées et des Characées (Charophytes) est mis en évidence avec une révision taxonomique. D'après une comparaison entre les données fossiles du Jurassique-Crétacé avec le matériel récolté dans des environnements similaires de l'Actuel, ce polymorphisme résulte des variations de certains paramètres écologiques (salinité, pH, luminosité, température) influençant la croissance des thalles et des fructifications des Charophytes. L'analyse micropaléontologique et sédimentologique des dépôts émersifs mésozoïques de la plate-forme jurassienne permet en outre de déceler l'activité d'une tectonique synsédimentaire d'origine tardi-hercynienne au Crétacé inférieur (phase néocimmérienne) et de reconnaître un climat subtropical à alternances saisonnières de périodes sèches et humides dans l'intervalle Jurassique moyen - Crétacé inférieur. La présence très particulière dans le Jura de rares restes de Dinosauriens (Allosaurus) et de certaines Characées (Aclistochara bransoni) autorise également à postuler durant le Jurassique supérieur et le Crétacé basal des échanges biologiques entre la marge nord-téthysienne (Eurasie) et l'Amérique du Nord. Plus précisément, d'autres éléments de corrélation (Ostracodes, Charophytes, Dinokystes, Ammonites) originaires respectivement des domaines téthysien ou boréal démontrent la réalité de connexions avec la plate-forme jurassienne au Crétacé basal (Berriasien-Valanginien / Volgien-Ryazanien). Dans ses conclusions, ce travail présente une interprétation séquentielle des dépôts margino-littoraux du Jurassique-Crétacé de la plate-forme jurassienne et évalue l'influence des cycles climatiques glacio-eustatiques ou de la dérive des continents dans la mise en place des faciès d'émersion laguno-lacustres sur les marges continentales et les aires cratoniques. Enfin, la lignée phylogénétique des Hemiglobator-Globator (Clavatoracées, Charophytes) est prise comme exemple significatif pour une réflexion sur la théorie néo-darwiniste de l'Evolution et le créationnisme, apparemment contradictoires mais en fait complémentairesThe main topic of this work concerns the micropaleontological and sedimentological study of the emersive deposits on the Jura platform (S. -E. France and western Switzerland) since the Middle Jurassic to the Lower Cretaceous (Purbeckian and Wealdian facies). By additional data of selected outcrops in N. -E. Spain (Maestrazgo) and S. -E. France (Basse-Provence), a continental biozonation mainly based on the Charophytes and a new phylogenetic diagram of the Clavatoraceae (Charophytes) are set for the Upper Jurassic - Cretaceous of the Western Europe. Moreover, the polymorphous gyrogonites of the Porocharaceae and Characeae (Charophytes) is underlined with a taxonomic review. After a comparison including the Jurassic-Cretaceous fossi! data and the material collected in similar recent environments, this polymorphism is related to the interaction of sorne fluctuating ecologic parameters (salinity, pH, lighting, temperature) on the growth of the Charophytes thallus and fructifications. The micropaleontological and sedimentological analysis of the Jura platform's Mesozoic emersive deposits allows to notice likewise a Lower Cretaceous tectonic activity related to a tardi-hercynian origin and connected with the Neo-Cimmerian phase, as well as to recognize a subtropical climate with alternated seasonal dry and wet periods in the Middle Jurassic - Lower Cretaceous interval. The very particular occurrence in the Jura Mountains of scarce Dinosaurs remains (Allosaurus) and some Characeae (Aclistochara bransoni) agrees to postulate during the Upper Jurassic and the lowermost Cretaceous biological exchanges between the northern Tethyan margin (Eurasia) and North America. More precisely, other correlation tools (Ostracods, Charophytes, Dinokysts, Ammonites) from respectively Tethyan or Boreal realms indicate the evidence of connections with the Jura platform in the lowermost Cretaceous (Berriasian-Valanginian / Volgian-Ryazanian). As conclusions, this study introduces a sequential interpretation of the Jurassic-Cretaceous coastal deposits on the Jura platform and evaluates the share of the glacio-eustatic climatic cycles or of the continental drift inducing the brackish-Iacustrine emersive facies on the continental margins and cratonic areas. At last, the phylogenetic lineage of the Hemiglobator-Globator (Clavatoraceae, Charophytes) is used as a significant exemple to argue about the neo-darwinist theory of Evolution and the creationism, apparently conflicting but in fact complementary
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Warham, Joseph Olav. "Mapping biosphere strontium isotope ratios across major lithological boundaries : a systematic investigation of the major influences on geographic variation in the 87Sr/86Sr composition of bioavailable strontium above the Cretaceous and Jurassic rocks of England." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5500.
Повний текст джерелаАнотація:
Strontium isotope analysis has provided archaeologists with an unprecedented opportunity to study the mobility of humans and animals in the past. However, a lack of systematic environmental baseline data has seriously restricted the full potential of the analytical technique; there is little biosphere data available against which to compare measured skeletal data. This thesis examines the extent to which geographic variation in biosphere 87Sr/86Sr composition can be spatially resolved within the lowland terrain of England, in a geographically and geologically coherent study area. Systematically collected samples of vegetation, stream water and surface soils, including new and archived material have been used. The potential of these sample media to provide reliable estimates of the ⁸⁷Sr/⁸⁶Sr composition of bioavailable strontium are evaluated under both high-density and low-density sampling regimes, and against new analyses of local archaeological material. Areas lying south of the Anglian glacial limit, display a pattern of geographic ⁸⁷Sr/⁸⁶Sr biosphere variation (0.7080-0.7105) controlled by solid geology, as demonstrated by high-density biosphere mapping. Data collected at a wider geographic scale, including above superficial deposits, indicate the dominant influence of re-worked local rocks on the biosphere. These methods have enabled a reclassification of the archaeologically important Cretaceous Chalk domain. Analysis of rainwater and other indicators of atmospheric deposition show that, in this setting, local biosphere variation is not significantly perturbed by atmospheric inputs. Time-related data from archaeological cattle and sheep/goat tooth enamel suggest that the modern biosphere data can be used to understand livestock management regimes and that these are more powerful than using an average value from the enamel. A more complete understanding of possible patterns of mobility in a group of humans has been achieved through analysis of material from Winchester and comparison with the Chalk biosphere domain.
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Warham, Joseph O. "Mapping biosphere strontium isotope ratios across major lithological boundaries. A systematic investigation of the major influences on geographic variation in the 87Sr/86Sr composition of bioavailable strontium above the Cretaceous and Jurassic rocks of England." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5500.
Повний текст джерелаАнотація:
Strontium isotope analysis has provided archaeologists with an unprecedented opportunity to study the mobility of humans and animals in the past. However, a lack of systematic environmental baseline data has seriously restricted the full potential of the analytical technique; there is little biosphere data available against which to compare measured skeletal data.
This thesis examines the extent to which geographic variation in biosphere 87Sr/86Sr composition can be spatially resolved within the lowland terrain of England, in a geographically and geologically coherent study area. Systematically collected samples of vegetation, stream water and surface soils, including new and archived material have been used. The potential of these sample media to provide reliable estimates of the 87Sr/86Sr composition of bioavailable strontium are evaluated under both high-density and low-density sampling regimes, and against new analyses of local archaeological material.
Areas lying south of the Anglian glacial limit, display a pattern of geographic 87Sr/86Sr biosphere variation (0.7080¿0.7105) controlled by solid geology, as demonstrated by high-density biosphere mapping. Data collected at a wider geographic scale, including above superficial deposits, indicate the dominant influence of re-worked local rocks on the biosphere. These methods have enabled a reclassification of the archaeologically important Cretaceous Chalk domain. Analysis of rainwater and other indicators of atmospheric deposition show that, in this setting, local biosphere variation is not significantly perturbed by atmospheric inputs.
Time-related data from archaeological cattle and sheep/goat tooth enamel suggest that the modern biosphere data can be used to understand livestock management regimes and that these are more powerful than using an average value from the enamel. A more complete understanding of possible patterns of mobility in a group of humans has been achieved through analysis of material from Winchester and comparison with the Chalk biosphere domain.British Geological Survey¿s British University Funding Initiative (BUFI) and the School of Life Sciences at the University of Bradford joint funding.
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Greenhalgh, Brent W. "A Stratigraphic and Geochronologic Analysis of the Morrison Formation/Cedar Mountain Formation Boundary, Utah." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1392.pdf.
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Nohra, Youssef A. "Résines végétales actuelles et fossiles : origine, caractérisation chimique et évolution." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S165.
Повний текст джерелаАнотація:
Les travaux de cette thèse portent sur la caractérisation chimique des ambres provenant de plusieurs gisements d’âges et d’origines géographiques variés, dont certains sont inédits. Des protocoles identiques à tous les échantillons et combinant les analyses spectroscopiques (IR et RMN 13C) et chromatographiques (THM-CPG-SM) ont été appliqués, permettant d’identifier l’origine botanique des ambres et fournissant des indices pour la reconstitution des paléoenvironnements terrestres. La caractérisation chimique des gisements d’ambre du Jurassique supérieur (Kimméridgien) jusqu’au Crétacé supérieur (Santonien) du Liban, de Jordanie, du Congo, d’Equateur et de France, permet de proposer des biomarqueurs pour les résines de Cheirolepidiaceae, une famille exclusivement mésozoïque de Conifères. Une évolution des sources botaniques des résines produites durant le Mésozoïque et le Cénozoïque est alors discutée. Une production dominée par les familles de Conifères Araucariaceae et Cheirolepidiaceae est remarquée au Jurassique supérieur et Crétacé inférieur. La production au Crétacé supérieur est plutôt dominée par des Cupressaceae. Au Cénozoïque, les origines botaniques des ambres sont plus variées, et des familles d’Angiospermes sont à l’origine de nombreux gisements, dont l’ambre du Pérou produit par une Fabaceae. La production par des Conifères reste toutefois importante au Tertiaire, à l’exemple des ambres de Nouvelle-Zélande qui ont pour origine les Araucariaceae. Les données obtenues ont permis une ré-évaluation de la classification des ambres par Py-GC-MS. Ainsi, une nouvelle molécule dont la structure est inconnue encore, a été identifiée dans les chromatogrammes d’ambres de classe Ib et Ic, ajoutant un caractère discriminant entre ces deux sous-classes. Enfin, la relation âge / maturation des résines fossiles est discutée, qui dépend avant tout des conditions d’enfouissement des résines. Une large base de données moléculaires est ainsi établie pour un grand nombre de gisements d’âges et d’origines botaniques variés, qui permettra une comparaison globale dans les travaux futursThis work focuses on the chemical characterisation of amber from different outcrops from different localities, and varied ages. Some of these outcrops had never been studied. All the amber samples were analysed with the same analytical techniques. The combination of the data obtained from spectroscopic (IR and 13C NMR) and chromatographic (THM-GC-MS) analysis allows the identification of the botanical origin of the amber and provide some information, for the reconstruction of the palaeoenvironment. Biomarkers for the cheirolepidiaceous resins were proposed based on the chemical characterisation of different amber outcrops dating from the Upper Jurassic (Kimmeridgian) to the Upper Cretaceous (Santonian) from Lebanon, Jordan, Congo, Ecuador and France. The Cheirolepidiaceae familt was exclusively present in the Mesozoic era. Hence, the evolution of the botanical origins of the produced resins during the Mesozoic and Cenozoic eras was discussed. It seems that Araucariaceae and Cheirolepidiaceae were the dominant resin producing trees during the Upper Jurassic and the Lower Cretaceous. While, cupressaceous resiniferous plants were dominant during the Upper Cretaceous. Howerver, resins dating from the Cenozoic era, were produced by a wider variety of plants, as resiniferous families of Angiosperm intensively participated in the resin production, i.e. the Peruvian amber produced by Fabaceae. Conifer resins traces were also detected in the Tertiary, such as the amber from the Araucariaceae found in New Zealand. The obtained data allowed a re-evaluation of the classification of ambers by Py-GC-MS, leading to the discovery of a novel molecule. This molecule of an unknown structure brings a new discrimination factor between the classes Ib and Ic. Finally, the age / maturity relationship is showed to be dependent on the burial and the conservation conditions of the resins. A broad molecular database is established based a large group of amber outcrops from different ages, and having diverse botanical origins. This database could be used as a comparative platform for further work in the future
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Holtzapffel, Thierry. "Minéraux argileux lattes : les smectites du domaine atlantique." Angers, 1986. http://www.theses.fr/1986ANGE0006.
Повний текст джерелаАнотація:
Les smectites des sédiments atlantiques du jurassique supérieur à l'actuel ; on distingue des particules floconneuses mixtes et lattées. Les premières, d'origine détritique probable, n'ont subi aucune modification post-sédimentaire ; les dernières résultent du réajustement diagenétique précoce des premières. L'intensité de ce réajustement, qui a lieu à bilans chimique et minéralogique pratiquement constants, a été quantifiée puis comparée à de nombreux paramètres sédimentaires. Trois facteurs importants : microperméabilité initiale du sédiment, temps de contact entre particules et fluides interstitiels et la composition de ces fluides.
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Gallet, Yves. "La magnetostratigraphie : aspects fondamentaux et appliques." Paris 7, 1988. http://www.theses.fr/1988PA077056.
Повний текст джерелаАнотація:
Une eetude magnetostratigraphique de la limite jurassique/cretace au maroc permet de discuter les possibilites de correlation stratigraphique en l'absence d'une biostratigraphie bien etablie. Avec des donnees du forage de cony, on met en evidence des series triasiques et permiennes. Les resultats paleomagnetiques permettent de preciser la derive des poles magnetiques de l'eurasie. On modelise aussi le champ magnetique a l'interieur d'un forage
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Haddoumi, Hamid. "Les couches rouges (bathonien à barrémien) du synclinal des ait attab (haut atlas, Maroc) : Étude sédimentologique et stratigraphique." Nancy 1, 1988. http://www.theses.fr/1988NAN10144.
Повний текст джерелаАнотація:
Étude des couches rouges du synclinal des Ait Attab, Haut Atlas central du Maroc. Après avoir précisé le cadre stratigraphique de l'étude, on décrit une série de coupes géologiques : l'étude des lithofacies, des séquences sédimentaires, des structures et du contenu faunique permet de proposer des interprétations concernant les milieux de dépôts. On précise l'inventaire faunique des formations étudiées ainsi que leur implication
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Mendoza, Talavera Oscar. "Les formations orogéniques mésozoiques du Guerrero (Mexique méridional) : contribution à la connaissance de l'évolution géodynamique des cordillères mexicaines." Grenoble 1, 1993. http://www.theses.fr/1993GRE10037.
Повний текст джерелаАнотація:
Dans le secteur de taxco-zihuatanejo (Mexique méridional) affleurent six séquences volcano-sédimentaires et/ou volcano-plutoniques d'arc datées du jurassique supérieur au crétacé inferieur qui se sont accrétées au craton nord-américain à la fin du crétacé inférieur. La séquence de taxco-taxco viejo comprend des andésites, des dacites et des rhyolites calco-alcalines inter stratifiées dans une sédimentation exclusivement détritique. Elle est affectée par un métamorphisme syncinématique de basse température (221-276c). Cette formation représente vraisemblablement le témoin d'un arc insulaire édifié sur un substratum continental. La séquence de teloloapan comprend des pillow lavas basiques surmontes en concordance par des dépôts volanoclastiques à lentilles de calcaires récifaux de l'aptien et des calcaires récifaux de aptien-albien. Elle est affectée par deux métamorphismes de bas degré: (i) hydrothermal océanique et (ii) syn-cinématique. Le volcanisme comprend surtout des basaltes et des andésites calco-alcalins avec de rares roches acides (andésites et rhyolites tholeiitiques). Comparées aux séries calco-alcalines d'arc intra-océanique les basaltes et andésites sont enrichis en hfse et lree. Les basaltes et andésites présentent des différences géochimiques et un nd compris entre 4,6-1,6. Cette séquence s'est développée dans un environnement d'arc insulaire intra-océanique. La séquence plutono-volcanique d'arcelia comprend un ensemble plutonique qui repose en klippe sur des basaltes en coussins recoupes par des filons basiques. La sédimentation est soit micritique au sein de la pile volcanique soit pelitique à radiolaires au sommet et datée de l'albien-cénomanien. Laves et filons sont affectés par un métamorphisme statique et hydrothermal prehnite-pumpellyite. Les roches basiques d'arcelia y compris les rhyolites montrent des affinités de tholeiite typique d'arc insulaire intra-océanique (nd compris entre +8 et +6). La séquence de huetamo représente le comblement d'un bassin fortement subsident qui se développe entre des îles volcaniques appartenant à un environnement d'arc insulaire. La séquence volcano-sédimentaire de zihuatanejo alocenomanienne est composée de pyroclastites et de laves calco-alcalines déjà différenciées, associées à des calcaires récifaux et/ou des couches rouges continentales. Le complexe de subduction de las ollas comprend des blocs de roches basiques et ultrabasiques enchâssés dans une matrice de serpentine ou de flysch. Ces blocs sont affectés par un métamorphisme hp-bt. Les roches basiques montrent des affinités de tholeiites d'arc, appauvries en terres rares légères. Leurs caractères géochimiques communs suggèrent qu'elles représentent des fragments dissociés d'une croûte supérieure d'un arc insulaire intra-océanique, formée aux tous premiers stades de l'activité de l'arc. Les affinites magmatiques des séries d'arc mésozoïques du Guerrero terrane sont très diversifiées à la fois d'une séquence à l'autre et à l'intérieur d'une même séquence. Cependant, deux ensembles peuvent être reconnus: (i) des tholeiites d'arc appauvries à légèrement enrichies en lree, composées exclusivement de basaltes et de leurs filons nourriciers et présentés a arcelia et las ollas. Quelle que soit la séquence, des cumulats ultrabasiques et basiques sont tectoniquement associés aux laves. Leur source mantellique appauvrie (nd compris entre +8 et +5. 5) est du type lherzolite a spinelles ; (ii) des séries calco-alcalines enrichies ou appauvries en hfs. Les roches basiques prédominent dans la série calco-alcaline enrichie en hfs (famille i), représentée par les basaltes et les andésites de l'aptien-albien de teloloapan et qui dérivent d'une source enrichie de type lherzolite à grenat. La série appauvrie en hfs (nd compris entre +9 et +7,5) est représentée par les andésites de zihuatanejo et les galets de l'aptien-albien de huetamo (famille ii) et qui dérive d'une source mantellique appauvrie, identique à celle des tholeiites mais avec des taux de fusion partielle moins élevés. Enfin la famille iii regroupe les laves de taxco et présente des caractères intermédiaires entre les familles i et ii. Ainsi, les séquences magmatiques orogéniques du Guerrero terrane reflètent la complexité de cet arc ou de ces arcs qui, néanmoins, ont fonctionné pratiquement en même temps
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Kariminia, Seyed Mohsen. "Upper jurassic and lower cretaceous radiolaria biostratigraphy of California coast ranges /." 2006. http://proquest.umi.com/pqdweb?did=1324366821&sid=1&Fmt=2&clientId=10361&RQT=309&VName=PQD.
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Rosenthal, Lorne Richard Philip. "The stratigraphy, sedimentology and petrography of the Jurassic-Early Cretaceous clastic wedge in western Alberta." 1989. http://hdl.handle.net/1993/16928.
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