Geochemical tracers to establish the significance and timing of gas hydrate induced slide failure in the Hikurangi margin, as a component of the SLAMZ project

作为 SLAMZ 项目的一部分，地球化学示踪剂用于确定 Hikurangi 边缘天然气水合物引起的滑动破坏的重要性和时间

• 批准号: 1557519
• 负责人: Marta Torres
• 金额: $ 29.84万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1557519&HistoricalAwards=false
• 关键词: Geochemical; tracers; establish; significance; timing

This project investigates the relationship between landslides and gas hydrate formation on the northeastern Hikurangi margin of New Zealand. Submarine landslides pose a significant socio-economic hazard, not only because they may destabilize offshore installations (e.g. underwater cables), but more significantly because the tsunamis generated by such slope failures have caused significant human fatalities and destruction of coastal infrastructure. The Hikurangi margin off New Zealand is ideally suited to study the various processes known to act as drivers/preconditioners for slope failure. The project will assess the importance of many factors on slope stability including gas hydrates and sediment composition and diagenesis (e.g., what makes a particular sedimentary layer weak); tectonic stress and geometry (e.g., slope steepening); and margin hydrogeology (e.g., transient pore pressure changes associated with climate and faulting). The geochemical component of this project complements a large, international, multi-year German-led project termed Slide Activity on the Hikurangi Margin, New Zealand (SLAMZ). Results from this study will serve to test various current ideas on the role of gas hydrate on slope stability, and will also address issues such as the water and carbon budgets along the margin and the presence and extent of fluid flow within the sediments. The results will thus have a broader relevance in the context of our understanding of the hydrogeology, element cycling, and earthquake generation in subduction zones worldwide. The project includes the training of an undergraduate student as well as mentoring of a postdoctoral investigator.Submarine slope failure is a major sedimentary process along ocean margins worldwide, with consequences that include margin architecture, hydrogeology and tsunamogenesis. Numerous studies have proposed that gas hydrates play a major role in controlling slope failure initiation and mass-movement processes, including a new hypothesis that postulates that gas hydrate itself may lead to seafloor weakening through plastic, very slow (creeping) deformation similar to rock glaciers in the terrestrial environment. In contrast to the extensive geophysical and near-seafloor data sets available for the Hikurangi margin, there is a lack of deep core geochemical data to address the interdependence of fluid, temperature, and gas hydrate dynamics in slope stability. This project aims at generating the first data set on geochemical parameters that complements ongoing geophysical, petrophysical and modeling efforts to unravel the role of gas hydrate in slope stability of the Hikurangi Margin in a partnership with scientists from Germany and New Zealand. The SLAMZ program (led by the University of Bremen) will use a seafloor to sample sediment at eight locations with contrasting tectonic settings and geometries, depth of gas hydrate stability, slump characteristics and fluid flow. The geochemical component of this large international project will generate and analyze pore fluid data that are key to: 1) Establish distribution and concentration of gas hydrate; 2) Evaluate postulated changes in gas hydrate stability associated with seamount subduction; 3) Constrain transients associated with gas hydrate and sediment slumping processes; and 4) Detect and characterize the nature and sources of fluid flow. Our results will contribute to our understanding of the geochemical, and geomechanical transformations in gas-hydrate bearing subduction zones, with implications to the societally-relevant processes that contribute to slope instability.

该项目调查了新西兰东北部山库兰岛山脉边缘的滑坡与气体水合物形成之间的关系。海底滑坡构成了重大的社会经济危害，这不仅是因为它们可能破坏海上装置稳定（例如水下电缆），而且更重要的是，因为这种斜坡失败产生的海啸导致了重大的人类致命性和沿海基础设施的破坏。新西兰外的Hikurangi余量非常适合研究被称为斜坡故障的驱动因素/预处理的各种过程。 该项目将评估许多因素对坡度稳定性的重要性，包括气体水合物和沉积物组成和成岩作用（例如，是什么使特定的沉积层弱）；构造应力和几何形状（例如，坡度陡峭）；和边缘水文地质学（例如，瞬态孔隙压力变化与气候和断层相关）。该项目的地球化学组成部分补充了一个大型，国际多年的德国领导的项目，该项目被称为新西兰山川（Hikurangi）利润率（Slamz）的幻灯片活动。 这项研究的结果将用于测试有关气体水合物在斜坡稳定性中的作用的各种思想，还将解决诸如沿着边缘的水和碳预算以及沉积物内流体流量的存在和程度。 因此，在我们对全球俯冲区域中水文地质，元素循环和地震产生的理解的背景下，结果将具有更广泛的相关性。该项目包括培训本科生的培训以及对博士后研究员的指导。SubmarineSlope失败是沿全球海洋利润率的主要沉积过程，其后果在内，包括保证金建筑，水文地质学和海拔低下。许多研究表明，气体水合在控制坡度故障开始和质量移动过程中起着重要作用，包括一个新的假设，该假设假设气体水合本身可能导致海底通过塑料削弱，非常缓慢（蠕变）的变形，类似于地面环境中的岩石冰川。与可用于Hikurangi边缘的广泛的地球物理和近乎层状数据集相反，缺乏深层核心地球化学数据来解决坡度稳定性中流体，温度和气体水合动力学的相互依存关系。该项目旨在生成有关地球化学参数的第一个数据集，该数据与正在进行的地球物理，岩石物理和建模努力相辅相成，以揭示气体水合物在与德国和新西兰科学家合作的Hikurangi Margin斜率稳定性中的作用。 SLAMZ计划（由不来梅大学领导）将使用海底在八个位置进行沉积物进行对比的构造环境和几何形状，气体水合物稳定性深度，倒塌特性和流体流动的深度。这个大型国际项目的地球化学组成部分将生成和分析孔流体数据的关键：1）建立气体水合物的分布和浓度； 2）评估与海拔俯冲相关的气体水合物稳定性变化； 3）约束与气体水合物和沉积物倾斜过程相关的瞬态； 4）检测和表征流体流的性质和来源。我们的结果将有助于我们理解气体合并俯冲带的地球化学和地质力学转变，这对有助于坡度不稳定性的社会相关过程产生了影响。