Investigating climate controls on weathering processes in modern and ancient river systems

研究现代和古代河流系统中风化过程的气候控制

• 批准号: RGPIN-2019-05709
• 负责人: Bataille, Clement
• 金额: $ 2.19万
• 依托单位: University of Ottawa
• 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=715758
• 关键词: Investigating; climate; controls; weathering; processes

The overarching goal of this research program is to better understand and predict the controls of chemical weathering at different spatiotemporal scales. Chemical weathering reactions transfer elements from the continental crust to rivers and to the ocean. This process is key to explaining why the earth is habitable by regulating biogeochemical cycles. For example, when the climate warms, the rate of chemical weathering increases, thereby accelerating the rate of marine carbonate precipitation. Carbonate precipitation consumes atmospheric carbon dioxide (CO2) and cools the climate, ultimately lowering chemical weathering rates. This climate-weathering feedback has allowed the Earth to maintain an active water cycle by keeping temperature within a tight and favorable range. Chemical weathering is also an important process at human timescales. For example, chemical weathering influences soil proprieties (e.g., fertility) and the chemistry of rivers, thereby controlling the sustainability of ecosystems and human societies. Global warming is rapidly changing the background conditions for chemical weathering reactions. Novel studies are urgently needed to investigate the interactions of climate and weathering to better reconstruct the past and forecast the future conditions on the Earth's surface. However, studying weathering is challenging because many geo-environmental variables influence this process. In the next 5 years, my group will work towards my overarching goal by studying the response of weathering to warming at different spatiotemporal scales as defined by the three following short-term goals. Our first goal will investigate how changes in permafrost cover influence weathering across the Yukon River catchment. Our second goal will develop novel paleo-weathering proxies to assess how soils of Laramide floodplains responded to early Paleogene warming trends and events. Our third goal will refine the marine strontium isotope budget at present-day to investigate the changes in weathering between glacial and interglacial periods. The results from this work will have regional implications for policy makers, helping them to improve the sustainability of specific environments (e.g., Yukon River catchment). This program will also advance our knowledge on the role of weathering as a long-term driver of climate, ocean composition and biosphere evolution. This knowledge is crucial to develop more robust Earth system models to reconstruct the past and predict the future of Earth's biogeochemical evolution. This research program will use field and laboratory experience, team work and collaborative multi-disciplinary projects to train 7 BSc, 2 MSc and 3 PhD. Through this training, HQP will improve their soft skills while gaining strong technical knowledge in isotope geochemistry and numerical methods. This program will educate versatile environmental geoscientists capable of managing natural resources in Canada and beyond.

这项研究计划的总体目标是更好地了解和预测不同时空尺度上的化学风化控制。 化学风化反应将元素从大陆地壳转移到河流和海洋。这一过程是通过调节生物地球化学循环来解释为什么地球适合人类居住的关键。例如，当气候变暖时，化学风化的速度会增加，从而加快海洋碳酸盐降水的速度。碳酸盐降水消耗大气中的二氧化碳(CO2)，使气候降温，最终降低化学风化速率。这种适应气候变化的反馈通过将温度保持在一个严格和有利的范围内，使地球保持了活跃的水循环。化学风化也是人类时间尺度上的一个重要过程。例如，化学风化影响土壤特性(如肥力)和河流的化学成分，从而控制生态系统和人类社会的可持续性。全球变暖正在迅速改变化学风化反应的背景条件。迫切需要新的研究来调查气候和风化的相互作用，以更好地重建过去和预测地球表面的未来条件。然而，研究风化是具有挑战性的，因为许多地质环境变量影响着这一过程。在接下来的5年里，我的团队将朝着我的总体目标努力，按照以下三个短期目标的定义，在不同的时空尺度上研究气候变化对变暖的反应。我们的第一个目标是调查永冻层覆盖的变化如何影响育空河流域的风化。我们的第二个目标将开发新的古风化指标，以评估拉拉米德洪泛平原的土壤对早古近纪变暖趋势和事件的反应。我们的第三个目标是完善目前的海洋锶同位素预算，以调查冰期和间冰期之间的风化变化。这项工作的结果将对政策制定者产生区域影响，帮助他们改善特定环境(例如育空河流域)的可持续性。该计划还将促进我们对风化作为气候、海洋组成和生物圈演化的长期驱动因素的作用的了解。这些知识对于开发更强大的地球系统模型以重建过去和预测地球生物地球化学演化的未来至关重要。这项研究计划将利用现场和实验室经验、团队合作和多学科协作项目来培养7名理科学士、2名硕士和3名博士。通过这次培训，HQP将提高他们的软技能，同时获得强大的同位素地球化学和数值方法的技术知识。该项目将培养多才多艺的环境地球科学家，能够管理加拿大及其他地区的自然资源。