Permafrost archives of northern environmental change and permafrost landsystems of the Mackenzie valley

北部环境变化的永久冻土档案和麦肯齐山谷的永久冻土土地系统

• 批准号: RGPIN-2019-06820
• 负责人: Froese, Duane
• 金额: $ 4.44万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716230
• 关键词: Permafrost; archives; northern; environmental; change

The longterm impact of climate change on the permafrost landscape of northern Canada will be a defining issue in the 21st century. We have made little progress in decreasing our collective greenhouse gas emissions to the atmosphere, and the impacts of a warming climate are quickly exceeding nearly all of our terrestrial Quaternary analogues. For northern landscapes and communities, we must develop better tools to prepare for future thaw. Today, the most severely affected areas of the western Arctic are associated with buried glacier ice that has been relict for the last 10,000 years, but is now warming and becoming thaw susceptible at regional scales. This distribution of ground ice reflects the dynamics of glaciation and the burial of ice near the former ice margin in the Quaternary. Similarly, ground ice properties throughout northern Canada are a reflection of the recent geologic history and its interaction with past vegetation and climate. The interactions of these historical contingencies define regional permafrost landscape units, or Landsystems, that will define patterns of future response. Understanding other regional trajectories of thaw will depend on similar legacies of regional Quaternary geology that have strongly influenced the distribution and character of ground ice. Models exist at continental scales for future climate change impacts on permafrost, but the veracity of these models is limited by our understanding of the nature and distribution of ground ice, which in large part, will determine the susceptibility of areas to thaw. The objectives of this research are threefold: (1) to detail the landscape history of the Mackenzie valley, the impact of rapid deglaciation and resulting landforms during the late Pleistocene; (2) to establish these properties, regionally, through field mapping to provide a model for future thaw landscapes of the central and southern Mackenzie valley; and (3) develop and test new approaches to permafrost characterization using new tools such as CT scanning and gamma density that allow the non-destructive characterization of permafrost cores. This work requires multiple summers of fieldwork in the Mackenzie valley.

气候变化对加拿大北部永久冻土景观的长期影响将成为 21 世纪的一个决定性问题。我们在减少向大气中集体温室气体排放方面几乎没有取得什么进展，而且气候变暖的影响正在迅速超过几乎所有陆地第四纪类似物。对于北部景观和社区，我们必须开发更好的工具，为未来的解冻做好准备。如今，北极西部受影响最严重的地区与过去一万年来残留的埋藏冰川有关，但现在正在变暖，并且在区域范围内变得容易融化。地面冰的这种分布反映了第四纪前冰缘附近冰川作用和冰埋藏的动态。同样，加拿大北部的地冰特性反映了最近的地质历史及其与过去植被和气候的相互作用。这些历史突发事件的相互作用定义了区域永久冻土景观单元或土地系统，这将定义未来响应的模式。了解其他区域的融化轨迹将取决于区域第四纪地质学的类似遗产，这些遗产强烈影响了地面冰的分布和特征。存在大陆尺度的未来气候变化对永久冻土影响的模型，但这些模型的准确性受到我们对地面冰的性质和分布的理解的限制，而地面冰在很大程度上将决定该地区解冻的敏感性。这项研究的目标有三个：（1）详细介绍麦肯齐山谷的地貌历史、更新世晚期冰川快速消融的影响以及由此产生的地貌； (2) 通过实地测绘，在区域范围内建立这些特性，为麦肯齐山谷中部和南部的未来解冻景观提供模型； (3) 使用 CT 扫描和伽马密度等新工具开发和测试永久冻土表征的新方法，从而对永久冻土核心进行非破坏性表征。这项工作需要在麦肯齐山谷进行多个夏天的实地考察。