Sediment transport and deposition on submarine slopes: drivers, feedbacks, and implications

海底斜坡上的沉积物输送和沉积：驱动因素、反馈和影响

• 批准号: RGPIN-2020-04461
• 负责人: Maselli, Vittorio
• 金额: $ 2.55万
• 依托单位: Dalhousie University
• 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=717019
• 关键词: Sediment; transport; deposition; submarine; slopes

Gravity-driven sediment flows and ocean bottom currents shape the ocean sea floor and largely control the transport and deposition of sediment along submarine slopes of continental margins. The proposed research program relies on applying state-of-the-art oceanographic data acquisition methods with high-resolution sedimentological and geophysical datasets to investigate the formation of turbidity currents and submarine landslides in the context of a changing climate, and the development of deep-water depositional sequences influenced by ocean bottom currents. The program is rooted in a large network of national and international collaborations and focuses on three key study areas: the fjords of Baffin Island, the northwestern Atlantic margin, and the western Indian Ocean offshore Tanzania. The study areas are selected based on their uniqueness in addressing the specific problems of this program during the next five years, and for achieving longer-term science goals. In the fjords of eastern Baffin Island, we will investigate the formation of turbidity currents in relation to different trigger mechanisms, such as glacial melting and submarine sediment failures. In addition, we will explore coastal and offshore sedimentary records to provide critical information for assessing the tsunami risk along populated areas of Baffin Island. The goal is to test the overarching hypothesis that the frequency of hazardous tsunamigenic submarine landslides is likely to increase owing to climate change, and to address the vulnerability of northern coastal communities as related to tsunamis. In the northwestern Atlantic margin, we will investigate the distribution, timing, and size of submarine landslides since the deglaciation, and discuss potential trigger mechanisms. An expected outcome is to evaluate the recurrence of tsunamigenic landslides similar to the 1929 Grand Banks event, the only fatal tsunami recorded in Canada, and the likelihood of such hazardous events to occur in the future. In the western Indian Ocean, preliminary investigations have highlighted the existence of deep-water deposits which form when a synchronous turbidity/contour currents interaction occurs, namely mixed turbidite-contourite systems. We will define architectural elements, hierarchy and associated lithological properties of slope depositional systems offshore the margin of Tanzania to develop process-based models for the formation of mixed turbidite-contourite deposits. The detailed characterization of this increasingly recognised and yet poorly understood hydrocarbon-bearing slope deposit will support the petroleum industry, worldwide and in Canada where similar systems have been recently identified. The projects deriving from the proposed research program will train highly qualified personnel (three PhD and one MSc) who will become knowledgeable in international and Arctic research, process sedimentology, seismic stratigraphy, and science communication.

重力驱动的沉积物流动和海底洋流塑造了海底，并在很大程度上控制着沉积物沿大陆边海底斜坡沿着的迁移和沉积。拟议的研究计划依赖于应用最先进的海洋学数据采集方法与高分辨率沉积学和地球物理数据集，以调查在气候变化的背景下浊流和海底滑坡的形成，以及深海沉积序列的发展受海底洋流的影响。该计划植根于一个大型的国家和国际合作网络，重点关注三个关键研究领域：巴芬岛的峡湾，西北大西洋边缘和坦桑尼亚近海的西印度洋。这些研究领域的选择是基于它们在未来五年内解决该计划具体问题的独特性，以及实现长期科学目标。在巴芬岛东部的峡湾，我们将调查浊流的形成与不同的触发机制，如冰川融化和海底沉积物故障。此外，我们将探索沿海和近海沉积记录，为评估巴芬岛沿着人口稠密地区的海啸风险提供重要信息。其目标是检验一个总体假设，即由于气候变化，危险的海啸海底山体滑坡的频率可能会增加，并解决北方沿海社区与海啸相关的脆弱性。在西北大西洋边缘，我们将调查冰消期以来海底滑坡的分布、时间和规模，并讨论潜在的触发机制。一个预期的结果是评估类似于1929年大浅滩事件，在加拿大记录的唯一致命的海啸，海啸致山体滑坡的复发，以及这种危险的事件发生在未来的可能性。在西印度洋，初步调查突出表明存在深水沉积物，这些沉积物是在浊流/等深流同时相互作用时形成的，即浊流-等深流混合系统。我们将定义坦桑尼亚边缘近海斜坡沉积体系的建筑元素、层次结构和相关岩性，以开发混合浊积岩-等深岩矿床形成的基于过程的模型。这种日益得到认可但了解甚少的含烃斜坡存款的详细表征将支持全球和加拿大的石油工业，最近发现了类似的系统。从拟议的研究计划中衍生的项目将培养高素质的人才（三名博士和一名硕士），他们将在国际和北极研究，过程沉积学，地震地层学和科学传播方面拥有丰富的知识。