REU: The Stratigraphy of Late Pleistocene Amazon Fan Sediments

亚马逊深海扇是典型的现代大型深海扇。 过去的研究记录了 扇的形态，包括位置和特征， 穿过风扇的最近活动的通道。 核 在这条水道附近采集的沉积物样本 在活动停止之前由渠道化水流沉积的 冰后期海平面上升 我们在这里建议（1）使用 形态学和沉积学数据，以确定 沟道化浊流的特征和（2） 发展出一套地层学， 沉积活动的证据 地层学将是 根据Δ 0-18曲线，补充AMS C-14日期。 NCSU开发的新技术可以在样品上测量0-18 含有很少的有孔虫，在具有高 沉降速率 生物碳酸盐AMSC-14测年 花粉分析将有助于确定 日期. 基准同位素地层学， 下坡流最小的中、下扇区， 将应用于最近活跃的河道/堤坝区域 在那里下坡流更为常见。这样的地层学 将使我们能够确定 沉积事件，如停止流动 废弃的渠道和主要泥石流的位置。 然后，我们可以确定风扇过程的速率， 沉积模式与海平面的关系 高分辨率0-18 地层学也将是有价值的评估晚 亚马逊河的冰川/早期间冰期作用 确定古气候和古海洋变化。

The Amazon Deep-Sea Fan is a typical large modern deep-sea fan. Past studies have documented the structure and surface morphology of the fan, including the location and character of the most recently active channel which crosses the fan. Cores collected in the vicinity of this channel sample the sediments deposited by channelized flows before activity ceased following post-glacial sea level rise. We propose here (1) to use morphological and sedimentological data to determine the likely characteristics of channelized turbidity currents and (2) to develop a stratigraphy which will allow us to determine the age of sedimentary activity on the fan. The stratigraphy will be based on delta 0-18 curves supplemented with AMS C-14 dates. New techniques developed at NCSU can measure 0-18 on samples containing few foraminifera, an advantage in cores with high sedimentation rates. AMS C-14 dates on the biogenic carbonates and pollen analysis will help to constrain the stratigraphic dates. Benchmark isotope stratigraphies, developed in the middle and lower fan areas where downslope flows are minimal, will applied to the most recently active channel/levee areas where downslope flows are more common. Such a stratigraphy will allow us to determine the ages associated with depositional events such as the cessation of flow down abandoned channels and the emplacement of major debris flows. We can then determime rates for fan processes and tie depositional patterns to sea level. The high-resolution 0-18 stratigraphy will also be valuable for assessing the late glacial/early interglacial role of the amazon River in determining paleoclimate and paleoceanograhic changes.