LUMINESCENCE DATING OF CLIMATE-SENSITIVE SEDIMENTS IN YUKON

在加拿大北部，未来几个世纪全球变暖最具经济和社会威胁的影响将是永久冻土的退化。育空以拥有沉积档案而闻名，这些档案可以用来解释过去物理环境对气候变化的敏感性。其中，化石冰楔可能是过去气候条件最壮观的见证者。黄土、冰川以及冰川沉积是育空地区独有的一系列古气候指标的一部分。然而，过去的气候过程被这些地貌的地质年代限制得很差。 本研究的重点是开发一种通用的长石矿物发光测年方法。本文的目标和方法要求这项研究的很大一部分将受益于在育空地区开展的研究。发光现象学将在现代沉积物上进行测试，比如在育空地区南部的圣埃利亚斯山脉冰原山脉发现的沉积物，更具体地说，是在两个正在消退的冰川(卡斯卡武尔什和洛厄尔)的边缘环境附近发现的。还将对化石冰楔中碎屑的年代进行研究，以测试其中一些冰缘特征的年龄。最后，在以前的冰界测定黄土的年代将有助于更好地了解育空地区的冰川和古气候历史。这一研究计划将有助于评价第四纪多年冻土的稳定性。研究和传统知识的结合是在一个永远不同的世界中制定更好的解决方案以确保健康和社会安宁的关键。

In the Canadian North, the most economically and socially threatening impact of Global Warming in centuries to come will be the degradation of permafrost. Yukon is known to host sedimentary archives that could be used to interpret past sensitivity of physical environments to climate change. Among those, fossil ice wedges are probably the most spectacular witnesses of past climate conditions. Loess, glaciers as well as glacial deposits indicators of former ice limits are part of a continuum of paleoclimate proxies that are unique to Yukon. Past climate processes are nonetheless obscured by the poorly constrained geological age of these features. This research proposal is focused on the development of a universal luminescence dating method for feldspar minerals. The objectives and methodology herein require a large part of this research would benefit from being carried out in Yukon. Luminescence phenomenology will be tested on modern sediments, as those found in the St. Elias Mountains Ice Field Ranges of Southern Yukon, more specifically near the marginal environments of two waning glaciers (Kaskawulsh and Lowell). Research will also be conducted on the dating of detrital debris in fossil ice wedges in order to test ideas about the ages of some of these periglacial features. Finally, dating loess at former ice limits will contribute to better understand the glacial and paleoclimate history of Yukon. This research program should contribute to evaluate the stability of permafrost across the Quaternary. The integration of research and Traditional Knowledge is key to elaborate better solutions to secure health and social serenity in a world that will never be the same.