Deep-marine basins linked to active continental margins by sloped ocean-floor profiles commonlyhost the final accumulation of sediment that was eroded and transported from the continents. Thedeep-marine sediment archives preserved in these settings commonly offer the most completerecord of sediment transfer from continents to ocean basins over geologic time scales. This isespecially true in basins associated with regions of active tectonism, where loss or alteration ofsediment source terrains leave submarine basin deposits as the only record of the tectonic and cli-matic forcings that govern the transfer of sediment to the deep basin. The overarching goal of thisdissertation is to evaluate controls on submarine slope and basin-floor sedimentation that considersboth large-scale system drivers and the internal complexities and autogenic processes associatedwith sediment routing systems. In pursuit of this goal, the research presented in this dissertationspans a range of spatial and temporal scales. At the largest scale, the influence of sediment recy-cling is addressed to evaluate how changes in intrabasinal sediment sources reflect phases of basinevolution and what influence recycling of previously deposited basin sediments has on the fidelityof the deep-marine sedimentary record at geologic time scales. At the smaller scale, analysis ofsedimentation units and characterization of sedimentary bodies form the foundation for linkingthe stratigraphic preservation of depositional processes to discrete submarine geomorphic condi-tions. Such a linkage can provide insight into changes in slope gradient and the transition fromsediment transport and bypass to sediment deposition along the slope profile. Thirdly, a detailedinvestigation of deformed slope deposits addresses how depositional processes and stratigraphicstacking of submarine fan deposits influences slope stability. Synthesis across these broad spatialand temporal scales required integration of various tools and data types including: (1) detailedoutcrop measurements, (2) cliff-face correlation and characterization of depositional architecture,(3) geologic mapping, (4) basin-scale correlation, (5) detrital geochronology, and (6) carbonategeochemistry. / Ph. D. / Continental-scale sediment routing systems extend from continental highlands where sediment is exposed and eroded, across the land surface and continental shelf where sediment is transported and temporarily stored, and onto the slope and floor of deep-marine basins where sediment is ultimately deposited. Deep-marine basin deposits are the terminal and arguably most complete sedimentary archives for continental-scale sediment routing systems. Such systems link the earth’s continents to the modern oceans and have been abundant throughout earth’s history. The overarching goal of this dissertation is to better understand how sediment is transported and deposited in deep-marine slope and basin-floor settings, and how those processes and their associated products change and evolve at geologic timescales. In pursuit of this goal, the research presented in this dissertation spans a range of spatial and temporal scales. At the largest scale, the source of sediment transported and deposited in deep-marine basins is addressed, with special consideration given to the concept that sediment that has already been deposited in submarine slope and basin floor settings can be eroded and redeposited further into the basin. Developing a better understanding for the spatial and temporal extent of sediment recycling in ancient deep-marine sedimentary systems has important implications for how we interpret and understand the sedimentary record. At the smaller scale, analysis of rock outcrops addresses how sediment is transported and deposited in deep-marine settings, and how that sediment can move and deform after it is buried. Developing a better understanding for how sediment is deposited in the deep ocean and how it can move after deposition addresses key knowledge gaps about the spatial and temporal dynamics of submarine depositional systems. This is especially the case at longer time scales >10<sup>6</sup> Myr, which are challenging to address with modern sea floor studies and are of lower resolution using seismic reflection surveys. Synthesis across these broad spatial and temporal scales required integration of various tools and data types. Findings from these studies improve our understanding of fundamental sedimentary processes and the geologic evolution of deep-marine basins, and have applications for the exploration and production of oil and gas, aquifer management, and carbon dioxide sequestration.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83541 |
| Date | 20 December 2016 |
| Creators | Auchter, Neal C. |
| Contributors | Geosciences, Romans, Brian W., Hubbard, Stephen M., Eriksson, Kenneth A., Gill, Benjamin C. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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