Collaborative Research: Developing a high-resolution late Holocene sediment record of rapid Arctic climate change from the Beaufort Sea coastal zone

合作研究：开发波弗特海沿岸地区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: 1203934
• 负责人: Thomas Bianchi
• 金额: $ 17.64万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-15 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203934&HistoricalAwards=false
• 关键词: Collaborative; Research; Developing; resolution; late

The PIs propose to develop a new, high-resolution (annual to subdecadal) paleoclimate record (0 to ~2,000 y) from sediment cores taken in Arctic lagoonal settings adjacent to rivers emptying into the Beaufort Sea. This effort is a follow-up to an EAGER award that allowed collection of initial core material and a seismic dataset in Simpson Lagoon near the Colville River delta in August 2010. Initial results suggest that these sediment cores contain a valuable history of system response to climate change on the adjacent continent (e.g., river drainage basins) and terrestrial-marine linkages. All cores will be analyzed for stratigraphy (X-radiography), bulk organic and mineral content, granulometry, and geochronology (239,240Pu/137Cs). Detailed analysis for paleoclimate proxies will be carried out: the age-depth relationship for the deeper part of these cores will be determined using radiocarbon. Climate indicators that will be applied are organic biomarkers (lignin-phenols, cutins, plant pigments, and ä13C) and mineral tracers (major and trace element chemistry, stable isotopes, clay mineralogy, heavy mineral assemblages, granulometry, event-layer stratigraphy). The central hypothesis is that lagoonal settings within the Beaufort Sea contain high quality sediment records because they receive sediment input from larger rivers that drain the Brooks Range, that, if exploited, will dramatically improve our knowledge of high Arctic paleoclimate over the last two millenia. The PIs hypothesize three distinct sources: 1) rivers that drain the Brooks Range and the Arctic Coastal Plain (ACP), 2) storms that erode shoreline permafrosted ACP deposits and overwash barrier islands, 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 will examine the downcore record of temporal variations in layers, contrasting sites to decouple spatial changes in sources. Since the three source end-members have distinct mineral/POC composition, they believe that temporal variations will provide proxy information about climate changes that influence their flux magnitude including 1) landfast ice extent, 2) river sediment supply from the glaciated uplands, 3) permafrost thawing, 4) summer-fall storminess, and 5) coastal primary productivity.Noting the rapid changes that have occurred in the Arctic during the latter half of the 20th century, the federal interagency Study of Environmental Arctic Change (SEARCH) program has cited the need to determine to what extent recent and ongoing climate changes in the Arctic can be attributed to anthropogenic forcing. A successful project will contribute to answering that question.

PIS提议从北极泻湖环境中采取的沉积物岩心开发出新的高分辨率（每年至子少量）的古气候记录（0至2,000 y），与河流相邻的河流相邻排空进入Beaufort Sea。这项工作是急切奖励的后续措施，该奖项允许收集最初的核心材料和2010年8月在科尔维尔河三角洲附近的辛普森泻湖中收集的地震数据集。最初的结果表明，这些沉积物核心包含对邻近大陆气候变化的宝贵历史（例如，河流排水板和河流底层和地球层的链接）。将分析所有核心的层学（X射线照相术），散装有机和矿物质含量，颗粒法和地质学（239,240PU/137C）。将对古气候代理进行详细分析：这些核心深层的年龄深度关系将使用放射性碳确定。将应用的气候指标是有机生物标志物（木质素 - 苯酚，切蛋白，植物色素和ä13c）和矿物示踪剂（主要和微量元素化学，稳定的同位素，粘土矿物质组合，颗粒，颗粒仪法，事件层层次学）。中心假设是，Beaufort Sea内的泻湖环境包含高质量的沉积物记录，因为它们从较大的河流中输入了排水溪流范围的沉积物输入，如果探索的话，这将显着提高我们对最后两千年中高北极气候的知识。 PIS假设三个不同的来源：1）排干溪流范围的河流和北极沿海平原（ACP），2）风暴，这些风暴侵蚀了永久冻土ACP沉积物和覆盖屏障岛的海岸，以及3）海洋初级生产，由植物浮游植物，冰藻类，冰algae和Benthos。在对最近的事件层（年度和风暴沉积物）矿物质和POC成功进行了最初的微尺度检查以解释古气候引起的组成中的波动所需的必要条件后，他们将研究层中临时变化的下降记录，与位点相反，以使源代码中的空间变化与空间变化。由于三个来源末端会员具有独特的矿物/POC组成，因此他们认为临时变化将提供有关影响其气候变化的代理信息，这些变化会影响其通量的幅度，包括1）陆上冰的范围，2）河流沉积物的供应，3）长期冻结，4）4）夏季夏季的风暴，以及5）沿海的生产力。联邦环境变化（搜索）计划的联邦互动研究提到了确定北极近期和持续的气候变化的必要性，这可以归因于人为强迫。一个成功的项目将有助于回答这个问题。