Sedimentation and morphology on the outer shelf/upper slope transition, Waipaoa River margin, New Zealand / by Benjamin W. Sumners.
| Author/creator | Sumners, Benjamin W. author. |
| Other author | Walsh, J. P. (John Patrick), 1973- degree supervisor. |
| Other author | East Carolina University. Department of Geological Sciences. |
| Format | Theses and dissertations |
| Production | 2007. |
| Description | 129 leaves : illustrations (some color), maps (some color) ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | Previous studies of continental margins have shown that the combination of high sediment supply and narrow shelf widths can lead to high rates of sediment accumulation on slopes and create strata which relate to the mode sediment dispersal. The combination of narrow shelf with active tectonics, high sediment yield, and an energetic wave climate make the Waipaoa River Margin (WRM) a prime location to investigate sediment dispersal beyond the shelf. This study addresses the nature of sediment dispersal on the outer shelf and upper slope using a high-resolution dataset of radionuclide, sedimentary, and bathymetric/morphologic interpretations accompanied with seismic reflection data,. Results suggest that sediments are escaping to the outer shelf and upper slope by contrasting modes. On the outer shelf in the vicinity of Lachlan canyon, "steady-state" accumulation profiles ( Pb) characterize sedimentation, indicating a constant supply of sediments (-0.35 cm/yr), likely supplied by nepheloid layer sedimentation. Sedimentological data and stable carbon signatures suggest that the outer shelf receives fluvial sediments from a similar source, most likely the mid-shelf basin. Sediment accumulation rates in Lachlan canyon are an order of magnitude higher (-2.0 cm/yr) and the Pb profiles suggest that event-driven deposition (e.g., sediment-gravity flows) dominates the sediment record (-69%), with events of considerable thickness (-9.9 cm) occurring every -8.9 yrs. High rates of sedimentation across the outer shelf/upper slope transition are associated with less expressive morphologies, characterized by an overall lower degree of curvature and muted relief. |
| General note | Presented to the faculty of the Department of Geological Sciences. |
| General note | Advisor: J. P. Walsh |
| Dissertation note | M.S. East Carolina University 2007 |
| Bibliography note | Includes bibliographical references (leaves 95-107). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
Availability
| Library | Location | Call Number | Status | Item Actions |
|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
| Electronic Resources | Access Content Online | ✔ Available |