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 18 of 18 for “"exceptional preservation"”.
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Exceptional Preservation and Bias in the Fossil Record
… described herein focus on two instances of exceptional preservation and on potential source of bias in the fossil record. The occurrence of exceptionally preserved fossil assemblages and the existence of systematic bias in the fossil record from a variety of sources represent opposing forces …
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Taphonomy and Palaeoecology of multi-element skeleton invertebrates: a genetic model for exceptional preservation
… of disarticulated remains randomly oriented. The preservation state and preferred orientation of arthropods in the tf1 leads to infer gentle transport by mud plumes, related to hyperpycnal flows, rapid burial and low scavenging and bioturbation. The second case focused on four clypeasteroid mass …
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The impact of global environmental changes on exceptional preservation, extinction, and recovery in the early Jurassic (late Pliensbachian-Toarcian)
… biotic crises, but they may have also enhanced exceptional fossil preservation (Lagerstätte preservation). This Ph.D. dissertation addresses how changing environmental conditions in the Early Jurassic affected the exceptional preservation, extinction, and recovery of organisms, specifically …
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An Effective Polychromatic X-ray Beam for Quantitative Analysis of Fossil Compositions
… locations, offering an explanation for the exceptional preservation of a three dimensional skin fossil in the latter locality.
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Are 'exceptionally' preserved skeletal fossils necessarily exceptional chemically and cytologically?
… scale, vertebrate fossils are considered exceptional when non-biomineralized (soft) tissues are preserved. Histologically, high quality is defined by trueness to original shape of a bone, preservation of fine details (e.g. canaliculi), and presence or absence of matrix material in void …
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The integration of petrologic and isotopic data from the Boulder Conglomerate to determine the age of the Navan orebody, Ireland
… mud supports plant fragments which exhibit exceptional preservation by pyrite, sphalerite and galena. The 34S of the laminated and reworked sulphides ranges from -37‰ to -41‰. (DXN008,313)
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Wrapped in Meaning: Chumash Cache Caves
… conditions in these caves have resulted in exceptional preservation of perishable materials; and the assemblage contains items such as wooden bullroarers, feather bands, deer bone whistles, basketry and curated plant materials. A significant proportion of this material appears to have been …
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Dating of alluvial fans from NW Argentina using cosmogenic nuclides and optically stimulated luminescence technique
… due to the low weathering impact and thus well preservation of sedimentary features. Twelve samples for optically/infrared stimulated luminescence (OSL/IRSL) dating and one depth profile for cosmogenic radionuclide dating (10Be) were collected in the Santa Maria Valley in NW Argentina, where the …
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Contributions to late Ediacaran geobiology in South China and southern Namibia
… my chapters. In chapter two I examined the preservation of trace fossils in the late Ediacaran. In chapter three I analyzed the taphonomy of an exceptionally preserved Ediacaran fossil to solve its affinity, tubular trace or tubular soft-bodied fossil. In chapter four, understanding the …
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Applying U-Th Disequilibrium to Dating Siliceous Sinter
… at El Tatio and its arid climate offers exceptional preservation of deposits. Our resulting U-Th ages, along with the water and deposit chemistry, suggest trends of U and Th accumulation along the sinter apron. While distal facies containing the highest U concentrations (> 50 μg/g) show …
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Contributions and New Methods in Paleontology: Geochemical, Ultrastructural, and Microstructural Characterization of Archean, Proterozoic, and Phanerozoic Fossils
… of South China, which is a prime example of exceptional preservation. Finally, the fourth primary research chapter reported here uses field emission scanning electron microscopy and environmental scanning electron microscopy in a field of paleobiology in which advanced instrumentation has …
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Biogeographic and biological comparisons between the Emu Bay Shale (Kangaroo Island, South Australia) and other Cambrian Burgess Shale-type biotas
… or fossil deposits exhibiting exceptional preservation of non-biomineralised material, are particularly prevalent in the Cambrian, and offer us great insight into the evolution and ecology of early animals and communities. The Emu Bay Shale (EBS) from the north coast of Kangaroo …
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Middle Miocene carbon cycle dynamics: A multi-proxy approach
… the Serravallian Blue Clay Formation has led to exceptional preservation of foraminifera and organic biomarkers. <br></br><br></br> Stable isotope analysis of bulk carbonate and planktonic foraminifera <i>Globigerinoides trilobus</i> at Ras il-Pellegrin show the globally recognised positive …
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An assessment of archive stereo-aerial photographs for 3-dimensional reconstruction of damaged and destroyed archaeological earthworks
… in Dorset, UK, were also selected due to the exceptional preservation state of some earthworks, versus the plough-damaged remains of others. These sites thus offered an opportunity to rigorously test the reconstruction capabilities of the SAPs. The results from both study sites confirmed that …
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Reconstructing local redox conditions, mineral precipitation processes and nutrient availability in seawater during deposition of the Transvaal Supergroup, South Africa
… for studying ancient marine chemistry due to its exceptional preservation across a range of facies. This study aims to uncover early ocean conditions by investigating carbonate and IF sequences from across a shelf environment using laser ablation inductively coupled plasma-mass spectrometry. …
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Exploring the Soft Tissue of the Archosaurian Feeding System through Evolutionary and Developmental Temporal Space
… completely undetectable in the fossil record. In exceptional preservation sites, materials such as keratinous integuments and gut materials have been found, but more commonly, we utilize osteological correlates such as muscle attachment scars that are derived from studying modern homologs to make …
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Globalizing the Sculptural Landscapes of the Sarapis and Isis Cults in Hellenistic and Roman Greece
… the Egyptian sanctuary at Marathon, a site where exceptional preservation allows us to study how viewers would have experienced images in architectural space. Using the Isiac visuality established in Chapter 3, I reconstruct the viewer's experience, arguing that the patron, Herodes Atticus, …
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Resolving Details of the Nonbiomineralized Anatomy of Trilobites Using Computed Tomographic Imaging Techniques
Remains of two trilobite species, Elrathia kingii from the Wheeler Formation (Cambrian Series 3), Utah, and Cornuproetus cornutus from the Hamar Laghdad Formation (Middle Devonian), Alnif, Morocco, were studied using computed tomographic (CT) and microtomographic (micro-CT) imaging techniques for …