Collaborative Research: Improved Constraints on Holocene Retreat History of the Laurentide and Scandinavian Ice Sheets from Cosmogenic Dating and Implications for Sea-level Rise

合作研究：通过宇宙成因测年改进对劳伦太德和斯堪的纳维亚冰原全新世后退历史的限制以及对海平面上升的影响

• 批准号: 0958872
• 负责人: Anders Carlson
• 金额: $ 21.68万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0958872&HistoricalAwards=false
• 关键词: Collaborative; Research; Improved; Constraints; Holocene

Collaborative Research: Improved constraints on Holocene retreat history of the Laurentide and Scandinavian Ice Sheets from cosmogenic dating and implications for sea-level riseAnders E. Carlson (U. of Wisconsin-Madison) EAR-0958872 Peter U. Clark (Oregon State U.) EAR-0958714ABSTRACTA major objective of ice sheet and climate research is to understand the responses of ice sheets to climate change. Ascertaining the past rates of ice-sheet retreat and contributions to sea-level rise under climate that was naturally warmer than present provides context for the future Greenland Ice-Sheet response to global warming. Here, this research team proposes to improve the deglacial chronologies and investigate retreat rates of the Laurentide (LIS) and Scandinavian (SIS) Ice Sheets during the early to mid-Holocene (11.7 ka), a period of time that provides an excellent natural experiment where these terrestrial ice sheets deglaciated under a climate warmer than present but potentially similar to the end of this century. This project proposes to directly date the retreat of the southeastern and eastern LIS margins and the southern, eastern, and northern SIS margins during the early to mid-Holocene using in situ cosmogenic surface exposure ages, significantly improving the chronology for the largest of the LIS domes and the majority of the SIS. The resulting chronologies will be combined with already existing cosmogenic chronologies from western Quebec, northeastern Labrador and southern Finland, and existing minimum limiting radiocarbon dates and varve records. These data will allow calculations of LIS and SIS retreat rates and sea-level rise contributions during the early to mid-Holocene, with the remainder of sea-level rise largely attributable to the Antarctic Ice Sheet. The results will provide estimates of the natural rates at which ice sheets can melt under radiative forcing that may be analogous to the climate of the end of this century. Broader ImpactsGiven that the greatest uncertainty in predicting future sea-level rise in response to global warming are the contributions from the remaining ice sheets, it is critical to constrain melt rates under warmer than present climates. Results of this research will provide climate scientists with estimates of the retreat rates and attendant sea-level rise contributions from terrestrial ice sheets under a climate naturally warmer than present. The information gained from this research will be of significant importance for policy decisions and of interest to a broad range of earth scientists and the public in general. This research proposal will support 2 Ph.D. students who will be exposed to a multi-disciplinary scientific approach that includes paleoclimatology, glacial geology, cosmogenic isotope geochemistry and paleoceanography. It will also provide support for an untenured, early career Assistant Professor furthering his academic career.

合作研究：通过宇宙成因测年改进对劳伦泰德和斯堪的纳维亚冰盖全新世退缩历史的限制以及对海平面上升的影响Anders E. Carlson（威斯康星大学麦迪逊分校）EAR-0958872 Peter U. Clark（俄勒冈州立大学） EAR-0958714摘要冰盖和气候研究的主要目标是了解冰盖对气候变化的响应。确定过去的冰盖退缩速度以及在比现在自然温暖的气候下对海平面上升的贡献，为未来格陵兰冰盖对全球变暖的反应提供了背景。 在此，该研究小组提出改进冰消年表，并研究全新世早至中期（11.7ka）期间劳伦泰德（LIS）和斯堪的纳维亚（SIS）冰盖的退缩率，这段时期提供了绝佳的自然实验这些陆地冰盖在比现在温暖但可能与本世纪末类似的气候下消融。该项目建议利用原位宇宙成因表面暴露年龄，直接确定全新世早期至中期期间 LIS 东南部和东部边缘以及 SIS 南部、东部和北部边缘的退缩日期，从而显着改善最大 LIS 的年代学圆顶和 SIS 的大部分。由此产生的年表将与魁北克西部、拉布拉多东北部和芬兰南部现有的宇宙成因年表以及现有的最低限度放射性碳日期和瓦夫记录相结合。 这些数据将允许计算全新世早期到中期期间的 LIS 和 SIS 退缩率以及海平面上升的贡献，而其余的海平面上升主要归因于南极冰盖。 研究结果将提供冰盖在辐射强迫下融化的自然速率的估计，这可能类似于本世纪末的气候。 更广泛的影响鉴于预测未来因全球变暖而导致的海平面上升的最大不确定性是剩余冰盖的贡献，因此在比当前气候更温暖的情况下限制融化速度至关重要。 这项研究的结果将为气候科学家提供在气候自然比现在温暖的情况下陆地冰盖的退缩率和随之而来的海平面上升贡献的估计。 从这项研究中获得的信息对于政策决策非常重要，并且会引起广泛的地球科学家和广大公众的兴趣。 该研究计划将支持 2 名博士生。学生将接触到多学科的科学方法，包括古气候学、冰川地质学、宇宙成因同位素地球化学和古海洋学。它还将为一位未终身任职的早期职业助理教授提供支持，以进一步推动他的学术生涯。