EAGER: Developing a high-resolution late Holocene sediment record of rapid Arctic climate change from the Colville delta and adjacent Beaufort Sea inner shelf

渴望：开发科尔维尔三角洲和邻近波弗特海内陆架的北极气候快速变化的高分辨率全新世晚期沉积物记录

• 批准号: 0935336
• 负责人: Mead Allison
• 金额: $ 29.99万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0935336&HistoricalAwards=false
• 关键词: EAGER; Developing; resolution; late; Holocene

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Project Summary:The PIs propose to develop a new, high-resolution (annual to sub-decadal) paleoclimate record (0-1,000 y) from sediment cores taken on the Arctic inner continental shelf. The proposal is a follow-up to a regular Arctic Natural Sciences panel submission that was criticized during review due to 1) absence of adequate data to substantiate a high-quality paleoclimate record in this setting, and 2) questions about the logistical success in light of the absence of UNOLS vessels to work in the high Arctic. Neither issue can be addressed without a proof of concept study such as proposed here. The PIs will collect sediment cores from the inner shelf on one cruise of the R/V Annika Marie, a local and privately chartered research vessel, presently scheduled for late September 2009 (ice free period) adjacent to the Colville delta on the Beaufort Sea coast of Alaska. Ancillary seismic transect data (sub-bottom CHIRP and side-scan sonar) will be collected prior to coring to locate the best preserved record of depositionally laminated sediments of this time interval. About 5 to 15 sites will be occupied on the shelf and adjacent Simpson Lagoon. All cores will be diver-collected in less than 8 m water depth: short push cores will be used to retrieve the high-porosity recent sediment layers, and longer cores (up to 5 m) will be collected with a submersible portable vibracorer. All cores will be analyzed for stratigraphy (x-radiography), bulk organic and mineral content, and geochronology of the last 100 to 200 y (using 210Pb and 137Cs radiotracers). Two cores will be selected from these for detailed analysis of paleoclimate proxies: the age-depth relationship for the deeper part of these cores will be determined using AMS radiocarbon dating of benthic foraminifera (5/core). Climate indicators that will be applied are organic biomarkers (ligninphenols, plant pigments, and ä13C) and mineral tracers (clay mineralogy, heavy mineral assemblages, granulometry, event layer stratigraphy).The PIs? central hypothesis is that the Colville inner shelf contains a high quality sediment record, that, if exploited, will dramatically improve knowledge of high Arctic paleoclimate over the last centuries to a millennia. They believe this deltaic region has sufficiently high linear sediment accumulation rates (1 cm/y) to preserve a seasonal and interannual record of climate change-induced mineral and particulate organic carbon (POC) flux variations to the seafloor from three distinct sources. These are 1) rivers that drain the Brooks Range and the Arctic Coastal Plain (ACP), 2) coastal erosion of ACP permafrost deposits and 3) marine primary production by phytoplankton, ice algae, and benthos. After an initial micro-scale examination of recent event layer (annual and storm deposits) mineral and POC succession, necessary to interpret paleoclimate-induced fluctuations in composition, they propose to examine the downcore record of temporal variations in layers, comparing the two selected sites to decouple spatial changes in sources. Since the three end-member sources have distinct mineral/POC composition, temporal variations will provide proxy information about climate changes that influence their flux magnitude including 1) landfast ice extent, 2) river sediment supply from glacial (meltwater) and coastal plain (permafrost thawing) input, 3) summer-fall storminess and 4) primary productivity of the coastal zone.

该奖项根据 2009 年《美国复苏和再投资法案》（公法 111-5）提供资金。 项目摘要：PI 建议开发新的高分辨率（年度至十年以下）古气候记录（0-1,000 年）该提案是北极自然科学小组定期提交的文件的后续内容，该文件在审查期间受到批评，原因是：1）缺乏足够的资料。数据来证实这种情况下的高质量古气候记录，以及 2) 由于没有 UNOLS 船只在北极高纬度地区工作，有关后勤成功的问题如果没有概念验证研究（例如拟议的），这两个问题都无法解决。 PI 将在 R/V Annika Marie（一艘当地私人特许研究船）的一次巡航中从内架收集沉积物岩心，目前计划于 2009 年 9 月下旬（无冰期）靠近科尔维尔。在取芯之前，将收集阿拉斯加波弗特海沿岸三角洲的辅助地震横断面数据（海底 CHIRP 和侧扫声纳），以找到该时间间隔内保存最完好的沉积层状沉积物记录。将占据陆架和邻近的辛普森泻湖。所有岩心将在不到 8 m 的水深内由潜水员采集：短推岩心将用于回收高孔隙度的近期岩心。沉积物层和较长的岩心（长达 5 m）将使用潜水式便携式振动取样器进行收集，以进行地层学（X 射线照相）、大量有机物和矿物质含量以及过去 100 至 200 年的地质年代学分析。使用 210Pb 和 137Cs 放射性示踪剂）将从其中选择两个岩心进行古气候代理的详细分析：年龄-深度关系。这些岩心的深层部分将使用底栖有孔虫的 AMS 放射性碳测年法（5/岩心）进行确定，所采用的气候指标包括有机生物标记物（木质素酚、植物色素和 ä13C）和矿物示踪剂（粘土矿物学、重矿物组合、中心假设是科尔维尔内陆架包含高质量的沉积物记录，如果加以利用，将显着改善他们相信这个三角洲地区具有足够高的线性沉积物积累率（1厘米/年），可以保存气候变化引起的矿物和颗粒有机碳（POC）的季节性和年际记录。 ) 三个不同来源对海底的通量变化是：1) 排干布鲁克斯山脉和北极沿海平原 (ACP) 的河流；2) ACP 永久冻土沉积物的海岸侵蚀；以及 3) 海洋初级生产力。在对最近事件层（年度和风暴沉积物）矿物和 POC 演替进行初步微观检查（解释古气候引起的成分波动所必需的）之后，他们建议检查时间的地下记录。层的变化，比较两个选定的地点以解耦源的空间变化，因为三个终端成员源具有不同的矿物/POC 组成，时间变化将提供有关影响其通量大小的气候变化的代理信息，包括 1)。陆地冰范围，2）来自冰川（融水）和沿海平原（永久冻土融化）输入的河流沉积物供应，3）夏秋暴风雨和4）沿海地区的初级生产力。