Sedimentary Records of Past Marine Environments

过去海洋环境的沉积记录

• 批准号: 418518-2012
• 负责人: Kienast, Stephanie
• 金额: $ 2.04万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507727
• 关键词: Sedimentary; Records; Past; Marine; Environments

Marine sediments are valuable climate archives and record diverse types of environmental information, which is used to improve our understanding of the ocean-atmosphere system. However, many current studies consider the bulk of the sediment only as the carrier for the information provider, such as fossil remains of plankton. This approach of ignoring the bulk sediment and its size characteristics has led to a) ambiguity in the interpretation of the marine sedimentary record in some areas and b) a loss of valuable information about the depositional environment on the sea floor. In this proposal, we address this issue by investigating the grain size composition of existing sediment cores. Our approach is based on the known behaviour of particles between 10-63 micrometer in size (silts), which are size-sorted according to bottom current speed. In the eastern equatorial Pacific, an area where current interpretations of the sedimentary record are controversial, grain size analyses will be combined with geochemical measurements to accurately quantify the flux of climate relevant material (e.g. carbonate, organic matter) from the sea surface to the sea floor. This will enable us to determine whether or not lateral sediment movement by bottom currents has biased previous interpretations in this region. Reliable data on the past behaviour of the equatorial Pacific are crucially important for a better understanding of the role that the Pacific plays in global climate change on time-scales ranging from interannual (i.e. El-Niño) to glacial-interglacial. Closer to home, on the Scotian Shelf, we are using the same approach with a different goal. Here, storms are thought to resuspend sand grains from the sea bed and redeposit them in characteristic beds elsewhere. By analysing the down core grain size composition of strategically located sites, we will generate a record of storminess over the last 10,000 years. This record will significantly extend the instrumental record and contribute to improving projections of storms in the future. As storms are expected to have an ever increasing impact on people and infrastructure along the Atlantic coast, this research will be of direct benefit to Canada.

海洋沉积物是有价值的攀岩档案，并记录了不同类型的环境信息，用于提高我们对海洋大气系统的理解。但是，许多目前的研究仅将大部分沉积物视为信息提供商的载体，例如浮游生物的化石遗迹。这种忽略散装沉积物及其大小特征的方法导致a）在某些地区解释海洋沉积记录的歧义，b）损失有关海底沉积环境的价值信息。在此提案中，我们通过研究现有沉积物核的晶粒尺寸组成来解决此问题。我们的方法基于10-63微米之间的颗粒的已知行为（淤泥），该行为是根据底部速度尺寸分组的。在东部的赤道太平洋地区，当前对沉积记录的解释是有争议的，晶粒尺寸分析将与地球化学测量相结合，以准确量化从海面到海底的攀爬相关材料（例如碳酸盐，有机物）的相关材料（例如碳酸盐，有机物）的通量。这将使我们能够确定底部电流的横向沉积物运动是否偏向于该地区的先前解释。关于对等效性太平洋过去行为的可靠数据对于更好地理解太平洋在全球气候变化中在全年（即厄尔 - 尼诺）到冰川冰期冰期的时间范围中所扮演的作用至关重要。靠近家，在斯科舍省的架子上，我们正在使用具有不同目标的相同方法。在这里，人们认为风暴可以重悬从海床上重悬，并将其放在其他地方的特征性床中。通过分析策略性位置的核心晶粒尺寸组成，我们将在过去10,000年中产生风暴记录。该记录将大大扩展工具记录，并在未来改善风暴项目。由于预计暴风雨对大西洋海岸沿线的人和基础设施的影响不断增加，因此这项研究将对加拿大带来直接利益。