Modeling Geomorphological and Cosmogenic-Nuclide Constraints on the Volume of the Quebec-Labradorean Sector of the Last Laurentide Ice Sheet

主要研究员将继续进行一项长期的合作研究，研究劳伦泰德冰盖（LIS）东部沿海高地周边沿着出现的高度可分离的差异风化基岩表面的意义。 该项目的重点是：（1）利用陆地宇宙成因核素和地貌数据，确定基岩表面的暴露和埋藏历史;（2）将这些数据与冰盖和冰流的地质证据结合起来，纳入地雷影响调查魁北克-拉布拉多地段几何形状的新模型。 重点将放在整个世纪都集中在“冰原岛之争”中的地区的最风化的地形上。这个项目有三个主要组成部分：1）通过测量暴露于宇宙辐射的岩石中的10 Be和26 A1来获得年代限制; 2）根据地质和地貌现场证据解释年代学证据，以解决三个世纪以来有争议的问题;（3）发展了一种新的地面真实几何模型，该模型采用了对地表地质边界条件以及沿东缘沿着固定的垂直和横向边界条件敏感的正演和反演冰盖模型，其研究结果将对地幔流变学的当前和未来研究产生直接影响，将为检验现有和广泛使用的LIS冰盖模型的有效性提供一种机制，并将改善我们对海洋同位素记录的解释。 东部LIS的地面真实模型，将有助于我们了解北大西洋次米兰科维奇气候和冰山漂流事件的LIS。

The Principal Investigator will continue an ongoing, long-term, collaborative study of the significance of altitudinally separable differentially weathered bedrock surfaces that occur along the eastern coastal highland periphery of the Laurentide Ice Sheet (LIS). This project will focus on 1) determining the exposure and burial histories of bedrock surfaces, using terrestrial cosmogenic nuclides and geomorphic data; and 2) incorporating these data with geological evidence for ice cover and ice flow into new models for the geometry of the Quebec-Labradoran sector of the LIS. Emphasis will be placed on the most weathered terrains in regions that have focussed throughout the twentieth century in the 'nunatak controversy'.This project has three principal components: 1) obtaining chronological constraints by making measurements of 10Be and 26A1 in rock exposed to cosmic radiation; 2) interpreting chronological evidence in terms of the geological and geomorphological field evidence to address three century-old controversial questions; 3) developing a new ground-truthed geometry using a combination of forward and inverse ice sheet models that are sensitive to surface geological boundary conditions and vertical and lateral limits as pinned along the eastern margin.Results of this research will have direct implications on present and future studies of mantle rheology, will provide a mechanism to test the validity of existing and widely-used LIS ice sheet models, and will improve our interpretation of marine isotopic records. A ground-truthed model of the eastern LIS and will help our understanding of the LIS on sub-Milankovitch climate and iceberg rafting events in the north Atlantic.