Date Thesis Awarded
Honors Thesis -- Open Access
Bachelors of Science (BS)
Regarding sedimentation associated with rivers, nearly all terrigenous material reaches the continental shelf and becomes deposited close to the coast, including organic carbon. While major rivers on passive margins have been studied in the past as to their effects offshore, relatively little is known about small, active margin rivers such as the Waipaoa in New Zealand. This research study examines the marine sedimentary record of the Waipaoa River through grain size distribution, δ 13C and C/N analysis, 210Pb activity, and sub-bottom profiles at various sites on the continental shelf. More importantly, the geological effects of European colonization and deforestation were also investigated. Results showed that grain size has generally decreased through time and with decreasing proximity to the mouth of the river. Organic carbon analysis showed more terrestrial carbon closer to shore as well as in the past 100-150 years, suggesting carbon burial varies temporally and spatially. Accumulation rates derived from 210Pb activity were lower than expected and sub-bottom profiles suggested contrasting depositional environments for Waipaoa sediments. Such findings provide more general knowledge as to the nature of these highly eroding rivers which can have dramatic biogeochemical and other environmental effects.
Moodhe, Keith, "Waipaoa River: Physical & Chemical Analysis of an Active Margin River" (2006). Undergraduate Honors Theses. William & Mary. Paper 453.
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