Consolidation and Calibration of the New England Varve Chronology (NEVC): An Annual Continental Record of Ice Dynamics and Terrestrial Change, 18-11.5 kyr BP

新英格兰 Varve 年表 (NEVC) 的合并和校准：冰动力和陆地变化的年度大陆记录，18-11.5 kyr BP

• 批准号: 0639830
• 负责人: John Ridge
• 金额: $ 33.88万
• 依托单位: Tufts University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0639830&HistoricalAwards=false
• 关键词: Consolidation; Calibration; New; England; Varve

Rapid climate change during deglaciation is linked to interactions between the ice sheet, the ocean, and the atmosphere. Understanding these interactions requires high resolution comparisons of climate and continental ice. Although general patterns of Laurentide Ice Sheet variation have been found, they are not continuously resolved at a sub-century scale. This lack of continuous, high-resolution terrestrial glacial chronologies with accurate radiometric controls continues to be a limiting factor in understanding deglacial climate. Such records, especially from the southeastern sector of the ice sheet can provide critical comparisons to N. Atlantic climate records (marine and ice core) and a rigorous test of hypotheses linking glacial activity to climate change.Consolidation of the New England Varve Chronology, and the development of records of glacier dynamics and terrestrial change, is a rare opportunity to formulate a complete, annual-scale terrestrial chronology from 18,000 -11,500 years before present. Glacial varve deposition, which is linked to glacial meltwater discharge, can be used to monitor ice sheet retreat and has a direct tie to glacier mass balance and climate. Complete records of readvances, ice recession rates, and annual meltwater discharge of the southeastern ice sheet could be compared to climatic events in the N. Atlantic region to determine whether the ice sheet was in lock-step with climate and ice rafting events, whether it was a driver or responder, or whether it behaved independently or with time lags. The varve chronology's use as a precise regional chronology of glacial events, including floods that may have been triggers for rapid climate change, would be critical to evaluating climate models and the thresholds necessary for individual floods to influence ocean circulation and climate.The project will be to join sequences of the New England Varve Chronology, forming a single sequence spanning over 6000 years (18.0-11.5 kyr BP). This will be the longest continuous, high resolution record of terrestrial ice front changes, ice recession rates, and glacial lake history in North America. Cores will be collected in critical areas to join existing sequences of the varve chronology and new Carbon-14 ages will be used to improve its calendar-year calibration.Broader impacts:1) The exceptional accuracy and precision of the New England Varve Chronology will demonstrate the potential usefulness of glacial varve chronology in other regions of North America where glacial varve sequences have not been studied for either their glacial chronologies or climate records. This project will serve as a stepping stone to an expansion of the chronology to cover the entire last deglaciation (~24-11.5 kyr BP) and is likely to stimulate varve studies in many other regions of the United States and Canada. 2) Varve chronology will serve as a calibration or consistency test of other dating techniques. The NEVC represents the most precise and accurate opportunity for comparison of cosmogenic-nuclide ages for deglaciation with an independently-calibrated deglacial chronology. Refinement of the varve chronology will dramatically improve the accuracy and confidence in this geological calibration.3) Dissemination of results, in addition to normal publication in scientific journals, will include internet availability of a library of varve records and images for other researchers; instructional presentations on how to collect, formulate, and match varve records; and an image glossary of varve characteristics and features as a reference for students and instructors.4) This project will expand the research program at Tufts University. Undergraduates (two per summer for three years), will be active research participants in field and laboratory phases of the project. Each student will be supervised through a start-to-finish analysis of a complete varve section leading to a year-long thesis or research project. Over three years the project will effectively double the number of people in the United States trained in the analysis of glacial varve cores.

脱气过程中的快速气候变化与冰盖，海洋和大气之间的相互作用有关。了解这些相互作用需要对气候和大陆冰的高分辨率比较。尽管已经发现了月球冰盖变化的一般模式，但并未在低于本世纪的规模下连续解决。缺乏具有准确辐射控制的连续高分辨率陆地冰期年代，仍然是理解冰流气候的限制因素。这样的记录，特别是冰盖东南部地区可以提供与大西洋气候记录（海洋和冰核）的关键比较，以及对将冰川活动与气候变化联系起来的假设进行严格的测试。新英格兰杂货学的结合。对新英格兰的年代学的持续发展，以及从18000年的发展中形成了冰川动力学和地面变化的发展。在现场之前 - 11,500年。与冰川融合水排放相关的冰川杂志沉积可用于监测冰盖静修，并直接与冰川质量平衡和气候有直接的关系。可以将阅读量，冰衰退率和东南冰盖的年度融水排放的完整记录与N. Atlantic地区的气候事件进行比较，以确定冰盖是否与气候和冰冻事件锁定，是驾驶员还是驱动器，还是独立或与时间滞后。 Varve年代学用作冰川事件的精确区域年表，包括可能是快速气候变化的洪水，对于评估气候模型以及影响海洋循环和气候所必需的阈值至关重要。该项目将加入新英格兰范围的序列，形成了6000年的新英格兰范围。这将是北美陆地冰面变化，冰衰退率和冰川湖历史的最长连续，高分辨率的记录。 Cores will be collected in critical areas to join existing sequences of the varve chronology and new Carbon-14 ages will be used to improve its calendar-year calibration.Broader impacts:1) The exceptional accuracy and precision of the New England Varve Chronology will demonstrate the potential usefulness of glacial varve chronology in other regions of North America where glacial varve sequences have not been studied for either their glacial chronologies or climate记录。该项目将成为跨年代扩展的垫脚石，以涵盖整个最后一次脱位（〜24-11.5 kyr bp），并且很可能会刺激美国和加拿大许多其他地区的Varve研究。 2）varve年表将作为其他约会技术的校准或一致性测试。 NEVC代表了与独立校准的脱气冰期年表进行脱脂化的宇宙基因核年龄进行比较的最精确和准确的机会。 varve年表的完善将显着提高对这种地质校准的准确性和信心。3）结果，除了在科学期刊上的正常出版物外，结果传播还将包括其他研究人员的互联网杂文记录和图像库；有关如何收集，制定和匹配Varve记录的教学演示；图像表和特征作为学生和讲师的参考。4）该项目将扩大塔夫茨大学的研究计划。本科生（三年夏季两个）将是该项目的现场和实验室阶段的积极研究参与者。每个学生将通过对完整的杂文部分的开始分析来监督每个学生，从而导致长达一年的论文或研究项目。在三年的时间里，该项目将有效地使美国接受冰川动物核心的培训的人数增加一倍。