Collaborative Research: P2C2: A High Resolution Paleoclimate Archive of Termination I in Oneida Lake and Glacial Lake Iroquois Sediments

合作研究：P2C2：奥奈达湖和易洛魁冰川湖沉积物中 I 期高分辨率古气候档案

• 批准号: 1803944
• 负责人: Anders Noren
• 金额: $ 2.38万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1803944&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Resolution; Paleoclimate

At the end of the last ice age, the vast ice sheet still covering much of northeastern North America served as a dam for ponded meltwaters along its southern edge. When the ice sheet collapsed, those fresh lake waters were released to the Atlantic Ocean, and are thought to have disrupted ocean circulation, causing abrupt cold spells in the northern hemisphere, and perhaps globally. Near southern Ontario and northern New York State, enormous Glacial Lake Iroquois contained massive amounts of cold fresh water, and modern remnants of that lake include Lake Ontario and Oneida Lake. Oneida Lake is located near the easternmost part of ancient Glacial Lake Iroquois, and this area and the Mohawk Valley were a key valve for the release of meltwaters to the Hudson River and to the Atlantic. The Oneida Lake project will study the ancient sediments laid down during these meltwater releases, to determine their precise timing, and will then compare those timings to past climate records derived from Greenland ice cores and from sediments from the Southern and the Atlantic Oceans. The researchers will use geophysical (sonar) methods to image the sediments below the bottom of Oneida Lake, and then collect sediment cores for detailed analyses. Special Carbon-14 dating techniques will be used to date sediments in the cores and to correlate the layered sediments to similar records previously collected in New England. Project outreach efforts include a public lecture series for lake-side communities, engagements with Oneida Nation high school science classes, and the installation of science information kiosks at a State Park on the lake?s eastern edge.This project is examining the Late Quaternary sediment record from the Oneida Basin in Upstate New York, through analyses of new geophysical data and new sediment cores. The unusually rich stratigraphic archive will constrain the paleoclimate evolution along the SE margin of the Laurentide Ice Sheet in the terminal Pleistocene. The researchers will also develop an energy balance hydrologic model of ancient Glacial Lake Iroquois to better constrain fill and discharge events from this basin. Non-linear episodes that perturb the global climate system (e.g., the Younger Dryas cooling) include major meltwater pulses and drainage pathway switches associated with Glacial Lake Iroquois and its precursors. The researchers will evaluate Termination I (the end of the last glaciation, ~20,000 years ago) at seasonal resolution over several millennia, using the rich varved sediment record in Oneida Lake and surrounding outcrops. Outcrop observations of newly discovered lake sediment exposures (varves) in the basin will be integrated with correlative sedimentary sequences recovered by cores from Oneida Lake. The glacial varve record will be chronologically constrained via paleomagnetic methods (cross-dating) with the North American Varve Chronology and further fixed by selective use of Ramped PyrOx radiocarbon dating of organic matter and separately of pollen 14C dating. Preliminary high-resolution seismic data reveal a remarkable, high-fidelity stratigraphy with evidence for outburst flood events, ice sheet instabilities, and a continuous time series from deglaciation through the Holocene. The full lake will be surveyed at high spatial resolution using CHIRP (sweep signal seismic) and multichannel seismic reflection methods. The calibrated time series of events will be compared to three well-established global archives: the Greenland ice core record, the Antarctic Peninsula Palmer Deep and Cariaco Basin marine sections. Beyond the direct scientific outcomes and graduate student training, the researchers will mount an outreach effort including: 1) a riparian community lecture series; 2) construction of two information kiosks describing the geologic evolution of Glacial Lake Iroquois and subsequent evolution of Oneida Lake at two lakeside parks; and 3) engage under-represented groups including secondary school students from the Oneida Nation during both field and laboratory activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在最后一个冰河时代结束时，庞大的冰盖仍然覆盖着北美东北部大部分地区的大部分地区，成为了沿其南部边缘的池塘熔化者的大坝。 当冰盖倒塌时，那些新鲜的湖水被释放到大西洋，被认为破坏了海洋循环，在北半球以及在全球范围内引起了突然的寒冷。 在安大略省南部和纽约州北部附近，巨大的冰川湖易洛魁湖含有大量的冷淡水，该湖的现代残留物包括安大略湖和奥尼达湖。 Oneida湖位于古代冰川湖易洛魁湖的最东端，该地区和莫霍克山谷是将熔体释放到哈德逊河和大西洋的关键阀门。 Oneida Lake项目将研究在这些融水发行期间制定的古老沉积物，以确定其确切的时机，然后将这些时间与从Greenland Ice核心以及来自南部和大西洋的沉积物中获得的气候记录进行比较。 研究人员将使用地球物理（声纳）方法对Oneida Lake底部下方的沉积物进行成像，然后收集沉积物核心进行详细分析。 特殊的碳-14约会技术将用于与核心中的沉积物一起使用，并将分层沉积物与先前在新英格兰收集的类似记录相关联。 项目外展活动包括针对湖边社区的公开讲座系列，与Oneida Nation高中科学课程的交往以及在湖中东部边缘的州立公园安装科学信息亭。该项目通过分析新的地球物理学数据和新的沉积物。异常丰富的地层档案库将限制末端更新世的劳伦德冰盖的SE边缘的古气候进化。研究人员还将开发一种能量平衡的水文模型的古代冰川湖易洛魁湖，以更好地限制该盆地的填充和排放事件。扰乱全球气候系统（例如，年轻的Dryas冷却）的非线性发作包括主要的融水脉冲和与冰川湖Iroquois及其前体相关的排水途径开关。研究人员将使用Oneida Lake及其周围露头的丰富的杂物沉积物记录来评估几千年来季节性分辨率的终止I（最后一个冰川的结束，大约20,000年前）。对盆地中新发现的湖泊沉积物暴露（Varves）的露头观察将与核心从Oneida Lake恢复的相关沉积序列集成。冰川杂志记录将通过古磁方法（交叉约会）与北美杂志的年表限制，并通过选择性地使用有机物的pyrox放射性碳速度和花粉14C约会的选择性使用。初步的高分辨率地震数据揭示了一个显着的，高保真的地层学，并有证据表明爆发洪水事件，冰盖不稳定性以及从脱离到全新世的连续时间序列。完整的湖泊将使用CHIRP（扫描信号地震）和多通道地震反射方法以高空间分辨率进行调查。校准的时间序列将与三个公认的全球档案馆进行比较：格陵兰冰核心记录，南极半岛帕尔默和卡里亚科盆地海洋段。除了直接的科学成果和研究生培训之外，研究人员还将进行外展工作，包括：1）河岸社区讲座系列； 2）构建两个信息亭，描述了冰川湖易洛魁湖的地质进化以及随后在两个湖边公园的Oneida Lake的演变；和3）在现场活动和实验室活动期间，包括来自Oneida国家的中学生在内的代表性不足的团体。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估审查标准来通过评估来支持的。