Flux and Fate of Sediment from Small Mountainous Rivers to the Continental Margin: The Gulf of Alaska Example

点击翻译按钮获取中文摘要

Abstract: ATM-9223114, PI-Henrichs, University of Alaska, "Flux and Fate of Sediment and Water from Small, Mountainous Rivers to the Continental Margin: The Gulf of Alaska Example": Small rivers charging directly from mountains into the ocean carry greater sediment loads than commonly envisioned, a relatively great percentage of which may escape to deeper waters during high stands of sea level. This award supports a study of the flux of Holocene fluvial sediment into the Gulf of Alaska, whose generally small tributary rivers are collectively the largest supplier of sediment from North America. Alaskan rivers are relatively uninfluenced by human activities, although glacial activity has resulted in higher sediment yields than noted for other rivers with similar drainage areas. The investigation will employ high-resolution seismic profiling for the identification of sediment accumulation and discharge patterns on the shelf and slope, and to trace individual sediment layers derived from episodic (flood) events. Sedimentological data will help define the escape routes/processes, and a variety of radiometric datings will show frequency of occurrence and rates of accumulation. Measurements of total organic carbon and total nitrogen, del13C, del15N, and lignin will be used to determine the amount and source of organic matter accumulating in the sediments. Contemporaneous oceanographic processes controlling strata formation will also be evaluated. This information should help in the interpretation of the older strata observed by seismic profiling and coring.