DATING FELDSPAR USING POST-ISOTHERMAL LUMINESCENCE AND APPLICATION TO CLIMATE-SENSITIVE PALEOENVIRONMENTS

利用等温后发光测定长石的年代及其在气候敏感古环境中的应用

• 批准号: RGPIN-2018-06422
• 负责人: Lamothe, Michel
• 金额: $ 3.72万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=755115
• 关键词: DATING; FELDSPAR; USING; POST; ISOTHERMAL

Our planet is facing a critical part of its history as modern societies need to implement adaptation strategies to rapidly changing surface environments in response to global warming. Using the past to better apprehend the future, one should take advantage of the geological record as it contains archives that can be used to interpret the resilience or sensitivity of physical environments to climate change. These archives are represented mainly by sediments and in order to be accurately interpreted, they need to be inserted in a proper time-frame, hence dated. The main objective of this research program is therein to develop new dating methodologies in the field of feldspar luminescence for assessing the chronology of climate-sensitive geological and archaeological sedimentary archives. The scientific approach is to focus on the luminescence properties and the phenomenology of single feldspar grains in sediments. Due to the nature of its solid-state physics, luminescence dating of feldspar shall be applicable to a large part of the last million years of Earth history. This method can therefore probe one order of magnitude deeper into geological time than radiocarbon and more than 5 times the current age range of quartz optically-stimulated luminescence, routinely used in luminescence dating. Our recent work as resulted in the development of an innovative protocol in which low-temperature IRSL following post-isothermal treatments is shown to yield ages in accordance with the stratigraphical assignment for several samples from different parts of the world. This novel approach is now possible following the development of new instrumentation in luminescence readers, most of these are now available in the Montréal laboratory as a result of a major CFI funding to the UQAM geochronology group. This innovation shall provide precise as well as accurate age determinations as no correction for fading is needed. The detailed methodology is two-fold. 1) In order to develop a new method, laboratory protocols have to be devised and implemented, that will investigate the phenomenology of feldspar luminescence. This research shall contribute to HQP training for laboratory-focused and physics-inclined students. 2) These innovative methodologies will then be tested and validated in climate-sensitive geological contexts: a) “warm” interglacial coastal sediments, indicators of high sea level (e.g. USA, Brazil, Morocco), b) “cold” periglacial features (e.g. Yukon, Alaska). HQP training is strongly entangled in the specific research projects for field-oriented Earth sciences students.The novelty of this research and its upmost significance is in offering new ideas and concepts to the luminescence dating field as well as providing access to a new chronological tool for the natural sciences community involved in the science of Global Changes.

我们的地球正面临着其历史的一个关键部分，因为现代社会需要实施适应战略，以应对全球变暖迅速变化的地表环境。利用过去更好地理解未来，人们应该利用地质记录，因为它包含的档案可以用来解释物理环境对气候变化的适应力或敏感性。这些档案主要以沉积物为代表，为了准确地解释，需要将它们放入适当的时间范围内，从而确定日期。该研究计划的主要目标是在长石发光领域开发新的测年方法，以评估气候敏感的地质和考古沉积档案的年代学。科学的方法是关注沉积物中单个长石颗粒的发光特性和现象学。由于其固态物理性质，长石的发光测年法应适用于地球历史上最后一百万年的大部分时间。因此，这种方法可以探测一个数量级更深的地质时间比放射性碳和超过5倍的石英光激发发光，常规用于发光测年的当前年龄范围。我们最近的工作，导致在一个创新的协议的发展，其中低温IRSL后等温处理显示出产量的年龄根据地层分配的几个样品来自世界不同地区。 这种新的方法现在是可能的发光阅读器的新仪器的发展，其中大部分是现在在蒙特利尔实验室作为一个主要的CFI资金的UQAM地质年代组的结果。这种创新将提供精确和准确的年龄测定，因为不需要对褪色进行校正。详细的方法是双重的。1)为了开发一种新的方法，必须设计和实施实验室协议，这将调查长石发光现象。本研究将有助于对实验型和物理型学生的HQP培训。 2)然后将在对气候敏感的地质背景下对这些创新方法进行测试和验证：a）“温暖的”间冰期沿海沉积物，高海平面的指标（例如美国、巴西、摩洛哥），B）“寒冷的”冰缘地貌（例如阿拉斯加的育空地区）。HQP培训与面向领域的地球科学专业学生的具体研究项目密切相关。这项研究的新奇及其最重要的意义在于为发光测年领域提供新的想法和概念，并为参与全球变化科学的自然科学界提供新的年表工具。