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: 0958417
• 负责人: Peter Clark
• 金额: $ 21.98万
• 依托单位: Oregon State University
• 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 2015-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0958417&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-0958417ABSTRACTA 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：改进了对劳伦蒂德和斯堪的纳维亚冰盖全新世退缩历史的限制，来自宇宙成因测年，并对海平面上升的影响。安德斯·E·卡尔森(威斯康星大学麦迪逊分校)EAR-0958872彼得·U·克拉克(俄勒冈州立大学)冰盖和气候研究的一个主要目标是了解冰盖对气候变化的反应。在自然比现在温暖的气候下，确定过去冰盖退缩的速度和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。在这里，这个研究小组建议改进冰川消融年代学，并研究全新世早期到中期(11.7ka)劳伦蒂德(LIS)和斯堪的纳维亚(SIS)冰盖的退缩速度，这段时间提供了一个很好的自然实验，这些陆地冰盖在比现在更温暖但可能与本世纪末相似的气候下消融。该项目建议使用原位宇宙成因地表暴露年龄直接测定LIS东南部和东部边缘以及SIS南部、东部和北部边缘在全新世早期到中期的撤退时间，显著改善LIS最大的穹隆和大部分SIS的年代学。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小放射性碳测年和变星记录结合在一起。这些数据将可以计算LIS和SIS在全新世早期到中期的退缩速度和海平面上升的贡献，其余的海平面上升主要归因于南极冰盖。结果将提供冰盖在辐射强迫下融化的自然速度的估计，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海平面上升以应对全球变暖的最大不确定性是剩余冰盖的贡献，在比目前更温暖的气候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估计，在自然比现在温暖的气候下，陆地冰盖的退缩速度和随之而来的海平面上升的贡献。从这项研究中获得的信息将对政策决策具有重要意义，并将引起广泛的地球科学家和广大公众的兴趣。这项研究计划将支持2名博士生，他们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。它还将为一名未终身任职的早期职业助理教授提供支持，以进一步发展他的学术生涯。