Slope channel systems represent significant but highly variable deep-water stratigraphic features and reservoir targets. Variations in architecture and component facies can take place along strike, depositional dip and stratigraphically. A better understanding of these variations permits improved sedimentological and architectural models. By integrating two outcrops (San Clemente, California and Baja California, Mexico) and one subsurface example (offshore Nile Delta), this study provides an opportunity to investigate cross-channel asymmetry, stratigraphic evolution and variability, vertical facies trends, and controls of slope channel systems. This study demonstrates that cross-channel asymmetry in facies and architecture is a lithology- and scale-independent feature, and preferentially occurs at channel bends and in the upper part of slope channel systems. Facies and architectural asymmetry are generally expressed as amalgamated, coarser-grained deposits displaced to the steeper channel edge (outer bend), and finer-grained deposits dominate towards the gentler channel edge (inner bend). A comparison of the systems exposed in Mexico and buried in the subsurface reveals a similar evolutionary trend, from initial sediment erosion/bypass, through early-stage laterally amalgamated channels, late-stage sinuous channels with levees/terraces, and final abandonment. However, pronounced variations exist in the late stage (e.g., presence or absence of lobes), and abandonment stage (e.g., presence or absence of MTDs plugging and channel avulsion). Additionally, for the first time, this study quantitatively demonstrates that early-stage and late-stage architectural elements are characterized by distinct patterns in preferred vertical facies transitions, based on Markov chain analysis of vertical successions. This study also suggests that both extrabasinal factors (e.g., relative sea-level) induced flow energy cycles and intrabasinal factors (e.g., folding and faulting, MTDs, channel bends) can exert a significant control on the architecture and/or evolution of slope channel systems.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:715465 |
| Date | January 2017 |
| Creators | Li, Pan |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=231778 |
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