Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"Triassic-Jurassic"”.
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Extinction and recovery dynamics of Triassic-Jurassic macro-invertebrate communities
… the marine fauna from the Late Permian to Early Jurassic. The ecospace can be represented as a combination of the three axes of tiering, motility and feeding, each divided into six subcategories. From the Cambrian to Recent, ecospace utilisation has tripled, however the trend through the …
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Triassic-Jurassic biochronology of the eastern Iskut River map area, northwestern British Columbia
Norian to Early Callovian faunas in the eastern half of the Iskut River map area can be divided into three suites: a benthonic fauna consisting of bivalves, corals, and gastropods; a planktonic fauna of radiolarians; and a nektonic fauna of coleoids and ammonoids. The ammonoids (27 genera, 47 …
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Biodiversity crisis and recovery during the Triassic-Jurassic greenhouse interval: testing ocean acidification hypotheses
The Late Rhaetian (Late Triassic) extinction event is characterised by shelled species showing a reduction in size, and thickness, which together with changed mineralogy is thought to be as a result of increased atmospheric pCO2 levels. Similar morphological changes have been demonstrated for …
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Evaluation of tridactyl theropod tracks in southern Africa: quantitative morphometric analysis across the Triassic–Jurassic boundary
… steadily increased from the Carnian to the Triassic booming soon after the end Triassic Mass-Extinction event (ETE), marking a key period in archosaur history. In southern Africa, the Triassic–Jurassic Boundary (TJB) is contained in the richly fossiliferous, fluvio-lacustrine-aeolian Upper …
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Position of the Triassic-Jurassic boundary in South Africa and Lesotho : a multidisciplinary approach aimed at improving the chronostratigraphy and biostratigraphy of the Elliot Formation, Stormberg Group
… regional and global understanding of the Late Triassic - Early Jurassic evolution of terrestrial vertebrate faunas, however, the temporal resolution of its biostratigraphy is inadequate for detailed regional and global correlations. The main aim of this dissertation is to build a more …
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Piecing Together the Triassic/Jurassic Stratigraphy Along the South Flank of the Uinta Mountains, Northeast Utah: A Stratigraphic Analysis of the Bell Springs Member of the Nugget Sandstone
<p>Nomenclature for the Upper Triassic and Lower Jurassic strata along the south flank of the Uinta Mountains has been somewhat confusing because of the position of the study area between southern Wyoming, where one set of names is used, and central/southern Utah where a different set of formation …
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Critical assessment of a proposed biostratigraphic scheme for Late Triassic fissure sediments from South West England
… and mode of changes in faunal composition at the Triassic/Jurassic boundary remain unanswered. Inquiries are hampered by a general paucity of sections containing correlatable Late Triassic/Early Jurassic strata. Vertebrate fossil material from Cromhall Quarry, recovered as part of an extended …
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The geology of China
… Silurian-devonian. Carboniferous-permian. Triassic-jurassic. Post jurassic. Chapter V Igneous rocks in China. Chapter VI General geological structure of China. Chapter VII The geological history of China. SECTION III Economic geology Chapter VIII The economic aspect of Chinese geology. A. …
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Study of seismic reflection data over Virginia Mesozoic basins
… Vibroseis reflection profiles over the exposed Triassic-Jurassic Culpeper, Richmond, and Scottsville Basins, and another profile over a probable early Mesozoic basin (Toano) beneath the Atlantic Coastal Plain sediments, in Virginia indicate that resolution of the geometry of the basins is …
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Forelimb and Pectoral Anatomy of Arcticodactylus cromptonellus, an Early Pterosaur from the Late Triassic, and the Origins of Pterosaurs
… or two-dimensional preservation of the earliest (Triassic—Jurassic) pterosaur remains. An exceptional early pterosaur specimen that is preserved in three dimensions, the holotype and only known specimen of Arcticodactylus cromptonellus (Fleming Fjord Formation, Greenland) may help address these …
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The Spearfish Formation in the Williston Basin of western North Dakota
… Black Hills. The Saude Member is predominantly Triassic in age although its upper part in extreme northern North Dakota and Canada may contain the Triassic-Jurassic boundary. The Saude in North Dakota is probably non-marine in origin and was deposited in a different depositional environment than …
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Stratigraphy and Petroleum Production potential of the Spearfish Formation in North Central North Dakota
… the overlying Saude Member is predominantly Triassic. In North Dakota, the Saude is considered to be an onlapping transgressive unit, probably supplied by a source area to the west and becoming younger to the east and north where it rests with angular discordance on progressively older …
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From grains to tracks: high-resolution sedimentology of track-bearing Stormberg strata, southern Africa
… trace fossils, primarily comprising Upper Triassic– Lower Jurassic dinosaur tracks, are preserved. Extensive studies have been carried out to document these individual tracksites and to examine the variations between sites and through time, with recent studies suggesting that track …
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Magnetic records from latest Triassic to earliest Jurassic red beds, Utah and Arizona, and from mid-Pleistocene lake beds, New Mexico
Paleomagnetic data obtained from the Upper Triassic to Lower Jurassic strata of the Moenave Formation, southern Utah and northern Arizona, were used to construct a composite magnetostratigraphy and further refine the position of the base of the Jurassic in the southwest U.S.A. The composite …
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Timing and drivers of exhumation in the hinterland of the North American Cordillera from detrital zircon U-Pb and (U-Th)/He double-dating
… reveal the major sources for zircons: Permian-Triassic, Jurassic, and Cretaceous arc rocks, the Paleo- and Mesoproterozoic Mojave and Mogollon Highlands, and the Idaho Batholith/Challis Volcanic Center. Samples north of the Transverse Ranges display a stronger arc signature, while samples south …
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Terrestrial Impacts of the Central Atlantic Magmatic Province on western Pangea
… CO2 and CH4, over geologic time. The late Triassic is a period of abrupt climate change that has been associated with a disruption to the global carbon cycle due the emplacement of the Central Atlantic Magmatic Province (CAMP). Evidence has shown that this global carbon cycle perturbation …
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Mesozoic Rift Evolution and Crustal Structure of the Gulf of Mexico Basin from Integration of Multiple Geological and Geophysical Datasets
… in the world. However, our understanding of the Triassic-Jurassic rift history and crustal structure of the GOM is limited. This dissertation integrates satellite free-air gravity data, full-tensor gravity gradient data, 104,000 line-kilometers of 2D reflection data, and publicly available …
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Fluvial sequence stratigraphy and paleoclimate of the Upper Triassic (Norian-Rhaetian) Chinle Strata, northern New Mexico.
Two age-equivalent Upper Triassic (Norian and Rhaetian) fluvial successions in New Mexico were evaluated from a sequence-stratigraphic and paleopedologic perspective. Meter-scale fining-upward fluvial aggradation cycles (FACs) comprise fluvial aggradational cycle sets (FACSETs) 4-15 m thick. …
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Rise of present-day tetrapods in the paleotropics of Late Triassic equatorial Pangaea: new insights from microvertebrate data
The Triassic Period (~252–201.5 Ma) saw a transformative radiation and reorganization of continental tetrapod diversity following the end-Permian Extinction, including an assemblage of diverse forms that do not survive the end-Triassic (herein termed the 'endemic Triassic fauna', =ETF), as well as …
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Ancient origins of a diverse stygofaunal group: The Australian Bathynellidae (Crustacea)
… in the rate of diversification during the Triassic-Jurassic period, which could represent multiple freshwater invasions, facilitated perhaps by sea level fluctuations. A consequent dispersion thanks to a much wetter climate may explain the presence of Bathynellidae in areas of the country …
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