Data Processing Methodologies to Investigate the Association between Depositional Environments and Trace Fossil Occurrence
Date
2019-07-26
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-8676-4241
Type
Thesis
Degree Level
Masters
Abstract
The transition from late Ediacaran to early Cambrian records important paleobiological and paleoecological changes. These are observed in the Fortunian diversification event and the Agronomic Revolution, which describe significant body plan diversification, increased behavioral complexity in trace fossils, and a shift from matgrounds to mixgrounds ecosystems. To provide a more thorough understanding of this dramatic transition, data mining techniques (i.e. visual and statistical analysis) are used to investigate the relationship between depositional environments and trace fossil occurrence. To facilitate analysis, an ichnological database has been designed and implemented using Microsoft Access. The creation of this database is important in that it provides a platform for data digitization and subsequent data mining, while also accounting for fundamental differences between trace fossils and body fossils. Current paleontology databases do not recognize this distinction, which stems from the fact that trace fossils represent organism behavior, while body fossils record the phylogenetic affinities of an organism. Analysis of the ichnologic data compiled is supported with additional datasets, with a large focus on utilizing detrital zircon to infer geodynamic settings and to provide validation of paleogeographic reconstruction models via visual provenance analysis. A more quantified version of detrital zircon provenance analysis by way of Multidimensional Scaling (MDS) was conducted; however, this study has shown that MDS is best utilized at a regional scale. In combining all supplementary datasets, paleogeographic reconstructions for the Ediacaran, Terreneuvian, and Cambrian Epoch 2 have been constructed. With an appropriate spatial and temporal context, visual analysis of ichnologic data displays a global distribution of trace fossils through this transition, implying the utilization of available ecospace and a lack of paleoclimatic restrictions. Statistical analysis in the form of Correspondence Analysis (CA) displays a clear lack of relationships between ichnogenera and depositional environments during the Ediacaran, suggesting trace fossils were facies-crossing prior to Phanerozoic-style ecosystems. CA produces markedly different results during the early Cambrian, displaying ichnogenera differentiation between depositional environments (i.e. increasing beta ichnodiversity) in the relationship between Oldhamia and deep marine depositional environments. These results lend support to the Agronomic Revolution, as microbial matgrounds were forced into increasingly stressful paleoenvironments (i.e., deep marine settings) during this paleoecological revolution.
Description
Keywords
Ichnology, Databases, Detrital Zircon, Paleogeographic Reconstructions, Data Mining, Ediacaran to Cambrian transition, Paleoecology
Citation
Degree
Master of Science (M.Sc.)
Department
Geological Sciences
Program
Geology