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

摘要：ATM-9223114，美国阿拉斯加大学Pi-Henrichs，《从山区小河流到大陆边缘的沉积物和水的流量和命运：以阿拉斯加湾为例》：从山脉直接流入海洋的小河流携带的泥沙负荷比通常想象的要大，在海平面高的时候，相对较大比例的泥沙可能会逃逸到更深的水域。该奖项支持一项关于全新世河流沉积物流入阿拉斯加湾的研究，阿拉斯加湾的支流一般较小，是北美沉积物的最大供应者。阿拉斯加河相对不受人类活动的影响，尽管冰川活动导致的泥沙产量高于其他具有类似流域面积的河流。调查将采用高分辨率地震剖面，以确定陆架和斜坡上的泥沙堆积和排放模式，并追踪事件(洪水)事件产生的个别沉淀层。沉积学数据将有助于确定逃逸路线/过程，各种放射性测量数据将显示出现的频率和累积速度。总有机碳和总氮、del13C、del15N和木质素的测量将用于确定沉积物中积累的有机质的数量和来源。同时还将对控制地层形成的同期海洋过程进行评估。这些信息应该有助于解释地震剖面图和取心观察到的较老地层。

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.