Browsing by Author "Taylor, Wendy L."
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- ItemA micro X-ray computed tomography dataset of fossil echinoderms in an ancient obrution bed : a robust method for taphonomic and palaeoecologic analyses.(Oxford University Press, 2019-03) Reid, Mhairi; Bordy, Emese M.; Taylor, Wendy L.; Le Roux, Stephan G.; Du Plessis, AntonBackground: Taphonomic and palaeoecologic studies of obrution beds often employ conventional methods of investigation such as physical removal and extraction of fossils from their host rock (matrix) by mechanical preparation. This often-destructive method is not suitable for studying mold fossils, which are voids left in host rocks due to dissolution of the original organism in post-depositional processes. Findings: Microcomputed tomography (µCT) scan data of 24 fossiliferous rock samples revealed thousands of Paleozoic echinoderms. Digitally "stitching" together individually µCT scanned rock samples within three-dimensional (3D) space allows for quantifiable taphonomic data on a fossil echinoderm-rich obrution deposit from the Devonian (Emsian) of South Africa. Here, we provide a brief step-by-step guide on creating, segmenting, and ultimately combining sections of richly fossiliferous beds to create virtual models suited for the quantitative and qualitative taphonomic analyses of fossil invertebrate assemblages. Conclusions: Visualizing the internal features of fossiliferous beds in 3D is an invaluable taphonomic tool for analyzing delicate fossils, accounting for all specimens irrespective of their preservation stages and with minimal damage. This technique is particularly useful for analyzing fossiliferous deposits with mold fossils that prove to be difficult to study with traditional methods, because the method relies on the large density contrast between the mold and host rock.
- ItemSystematic experiments to quantitatively assess image quality for CT scans of a Karoo tetrapod fossil(Evolutionary Studies Institute, 2019) Tshibalanganda, Muofhe; Du Plessis, Anton; Le Roux, Stephan G.; Taylor, Wendy L.; Smith, Roger M. H.; Browning, ClaireOver the past decade non-destructive, three-dimensional visualization and analysis of fossils using X-ray tomography has greatly advanced palaeontological studies worldwide. Micro-computed tomography (microCT) is now accepted as best practice in palaeontological studies to augment the anatomical description of newly discovered fossils. Despite advances in laboratory microCT hardware, software and skills of users, there is a lack of clear methodologies for scanning and analysing fossils. Here we report on a systematic and detailed study of the quantitative effects of the variation of different microCT scanning parameters on the image quality of an unprepared fossilized Karoo tetrapod skull and parts of the postcrania. Results indicate that voltage variations do not increase the contrast for the bone as one would expect, and the best image quality solution is found using high frame averaging and high X-ray flux (current). Although this study was limited to one specimen, the results may find a practical use for future studies involving similar fossils.