Holocene sediment dynamics and environmental changes across the Canadian Arctic Archipelago

加拿大北极群岛全新世沉积物动态和环境变化

• 批准号: RGPIN-2019-05720
• 负责人: MonteroSerrano, JeanCarlos
• 金额: $ 1.82万
• 依托单位: Université du Québec à Rimouski
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680755
• 关键词: Holocene; sediment; dynamics; environmental; changes

Over recent decades, marine and terrestrial Arctic environments have responded strongly to modern climate warming. This response includes the reduction of summer ice thickness and extent, the increase in permafrost thaw and river runoff, the alteration of ice-drift paths, and sea-level rise, as well as a strong intensification of ice mass loss of the ice caps on the Canadian Arctic Archipelago (CAA). Another consequence of such warming is the alteration of sediment dynamics, which is characterized by distinct spatial differences. To place these environmental changes in a long-term historical perspective and to provide a basis for future Arctic climate simulations, one needs to better understand the natural evolution of marine CAA through the Late Quaternary. Thus, sedimentary sequences extending beyond instrumental records could provide a critical link for examining how different climate settings may influence both the sedimentary regimes and the Arctic marine ecosystems in the future. Sediments with different mineral assemblages and geochemical signatures are delivered into the CAA mainly as suspended particulate matter and bedloads from several river systems, iceberg rafting and sediment laden meltwater plumes from tidewater glaciers, as well as from coastal erosion, which is subsequently dispersed by ocean currents and sea-ice rafting. Consequently, the detrital signatures preserved in the CAA sedimentary records may be used to reconstruct past variations in sediment dynamics related to Late Quaternary climate changes. Under this context, the overall objective of this research program is to use a powerful multiproxy approach combining grain-size, mineralogy, elemental geochemistry, and radiogenic isotope compositions from a set of sediment samples recovered in the CAA, in order to unravel sediment sources and transport processes and to determine the pathways of possible chemical contaminants, glacier fluctuations and environmental changes during the Holocene (last 11,700 years). This innovative research program will offer a unique opportunity to improve the spatial and temporal resolution of sedimentological, mineralogical and geochemical data available in the CAA and will also help to unravel the fundamental processes controlling the Holocene sediment dynamics and environmental changes in this important polar region. A better understanding of the natural baseline of sedimentary regimes and their variability in the past can help Canada's government (e.g., Transport Canada and Environment and Climate Change Canada) to develop adaptation and mitigation strategies for possible contaminant dispersal, geohazards and the future navigability of Canadian Arctic sea routes. Finally, this research program will offer a dynamic training environment for highly qualified personnel with access to expertise in different fields of marine geology and geochemistry, as well as to hands-on training in Arctic ship-based coring and sampling operations.

近几十年来，海洋和陆地北极环境对现代气候变暖作出了强烈反应。这种反应包括夏季冰的厚度和范围的减少，永久冻土融化和河流径流的增加，冰漂移路径的改变，海平面上升，以及加拿大北极群岛（CAA）冰盖的冰质量损失的强烈加剧。这种变暖的另一个后果是沉积物动态的改变，其特点是明显的空间差异。为了将这些环境变化置于长期的历史视角中，并为未来的北极气候模拟提供基础，需要更好地了解晚第四纪海洋CAA的自然演变。因此，超出仪器记录的沉积序列可以为研究不同的气候环境如何影响未来的沉积体系和北极海洋生态系统提供关键的联系。具有不同矿物组合和地球化学特征的沉积物主要作为悬浮颗粒物和来自几个河流系统的底沙、冰山漂流和来自冰川的载有沉积物的融水羽流以及来自海岸侵蚀的沉积物被输送到CAA中，这些沉积物随后被洋流和海冰漂流分散。因此，CAA沉积记录中保存的碎屑特征可用于重建与晚第四纪气候变化有关的沉积动力学变化。在此背景下，本研究计划的总体目标是使用一个强大的多代理方法，结合粒度，矿物学，元素地球化学和放射性同位素组成，从一组沉积物样品中回收的CAA，以解开沉积物来源和运输过程，并确定可能的化学污染物，冰川波动和环境变化的路径在全新世（11,700年）。这项创新的研究计划将提供一个独特的机会，以提高CAA中沉积学，矿物学和地球化学数据的空间和时间分辨率，也将有助于揭示控制全新世沉积动力学和环境变化的基本过程在这个重要的极地地区。更好地了解沉积体系的自然基线及其在过去的变化可以帮助加拿大政府（例如，加拿大运输部和加拿大环境和气候变化部），为加拿大北极航道可能出现的污染物扩散、地质灾害和未来的通航能力制定适应和减缓战略。最后，这一研究方案将为高素质人员提供一个动态的培训环境，使他们能够获得海洋地质学和地球化学不同领域的专门知识，并获得北极船基取芯和取样作业的实践培训。