Rock erosion during cold climates of the next 1 million years: risk assessment for siting a UK Geological Disposal Facility.

未来一百万年寒冷气候期间的岩石侵蚀：英国地质处置设施选址的风险评估。

• 批准号: 2889450
• 金额: --
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2889450
• 关键词: Rock; erosion; during; cold; climates

This project will provide unique data and understanding for sites identified by community partners as a potential UK Geological Disposal Facility (GDF) for nuclear waste. A UK GDF will be located in bedrock at depths up to a 1000 m, but the access infrastructure that will be backfilled will extend to the surface; therefore, the impacts of erosion down to 1000 m depths must be considered for each UK GDF site. Rock surface erosion (i.e. denudation) relates to all of the geological processes that work to reduce the Earth's surface, both in terms of elevation and relief. The UK is tectonically stable (i.e. non- orogenic environment) where chemical weathering and subsequent erosion accounts for much of the rock erosion; thus, this study will focus upon quantifying erosion rates as indicators of denudation. It will adopt the following objectives: (1) quantifying long-term erosion rates for targeted rock-types of potential UK GDFs; (2) resolving erosion rates for past cold climates of the UK; (3) creating a "look-up table" of erosion potential for site-specific rock-types and climate conditions over the next 1 million years. The project will use a new, state-of-the art luminescence erosion-meter (Smedley et al. 2021) to derive rock surface erosion rates on unprecedented length and time scales. The technique works on the principle that the luminescence signal with depth into a rock surface resets to greater depths during longer exposure to sunlight over time, which can be measured. Erosion works to reduce the depth of that signal resetting, bringing it closer to the rock surface with higher erosion. Thus, for rock surfaces of known-age (e.g., existing cosmogenic nuclide dating), we can derive time-averaged erosion rates. The project will also apply state-of-the-art quantitative electron microscopy to measure the geochemistry and crystallography of rock samples and determine the chemical, physical and mechanical properties that control the rock response to erosion, and complement luminescence data (e.g., Prior, Mariani et al., 2009, Mariani et al., 2006). Rock samples for testing and analyses will be collected from locations identified by community partners to potentially host the UK GDF (e.g., Cumbria, Lincolnshire), and will be assessed for their different contexts: host bedrock (Objective 1), cold climate conditions (Objective 2). Objective 1: The host rock environment can control the erosion rates of rock surfaces (e.g., Hall et al. 2012). However, the importance of this control is often hidden because data is compiled from a wide variety of climate zones, i.e., the environmental variables mask any impact of the rock-type (e.g., Shaw et al. 2012). Rock-type will have a significant impact upon rock surface erosion in the UK over the next 1 million years. Given that the UK (and the sites currently identified by community partners for a GDF) has highly variable local rock-types with lower to higher strengths, it is vital to quantify the potential erosion rates of the geology that hosts a UK GDF site. This project will use the new luminescence erosion-meter to quantify long-term erosion rates for a variety of lower and higher strength host rock environments targeted for any UK GDF, in combination with detailed geochemical and structural analyses. Objective 2: There is currently no record of rock erosion rates in the UK over the glacial- interglacial cycles of the last 1 million years; thus, it is impossible to know how much erosion can be expected over the next 1 million years. A global study of rock outcrop erosion rates from across different climate variables (but not the UK) recorded a maximum erosion rate of 140 m/Ma (Portenga and Bierman, 2011) where climate parameters could explain some of the variability. Although the UK may be a non-orogenic environment considered to have low erosion rates, the combined impact of environmental variables (especially cold temperatures and high precipitation) and host rock properties

该项目将为社区合作伙伴确定为核废料的潜在英国地质处置设施（GDF）的站点提供独特的数据和理解。英国GDF将位于基岩中的深度最高1000 m，但将被回填的访问基础设施延伸到表面；因此，必须考虑每个英国GDF站点的侵蚀的影响降低至1000 m。岩石表面侵蚀（即剥夺）涉及所有用于减少地球表面的地质过程，无论是在高程和救济方面。英国在构造方面是稳定的（即非造山学环境），其中化学风化和随后的侵蚀占大部分岩石侵蚀；因此，这项研究将集中于量化侵蚀速率作为剥离的指标。它将采用以下目标：（1）量化潜在英国GDF的目标岩石类型的长期侵蚀率； （2）解决英国过去寒冷气候的侵蚀率； （3）在未来100万年内，创建了针对特定地点岩石类型和气候条件的侵蚀潜力的“查找表”。该项目将使用新的，最先进的发光侵蚀仪（Smedley等，2021）来得出前所未有的长度和时间尺度上的岩石表面侵蚀率。该技术的作用是基于一个原理，即在较长的阳光随着时间的时间暴露期间，具有深度的发光信号将其深度重置为更大的深度，这可以测量。侵蚀可减少该信号重置的深度，使其更接近岩石表面，并具有较高的侵蚀。因此，对于已知年龄的岩石表面（例如现有的宇宙基因核素约定），我们可以得出时间平均的侵蚀速率。该项目还将应用最先进的定量电子显微镜来测量岩石样品的地球化学和晶体学，并确定控制岩石对侵蚀响应的化学，物理和机械性能，并补充发光数据（例如Prior，Mariani等，Mariani等，2009，Mariani等，Mariani等，2006）。将从社区合作伙伴确定的位置收集测试和分析的岩石样品，以可能接待英国GDF（例如坎布里亚郡，林肯郡），并将针对其不同的情况进行评估：寄宿基岩（目标1），寒冷的气候条件（目标2）。目标1：宿主岩石环境可以控制岩石表面的侵蚀速率（例如，Hall等人，2012年）。但是，这种控制的重要性通常是隐藏的，因为数据是从多种气候区域汇编而成的，即环境变量掩盖了岩石类型的任何影响（例如，Shaw等人，2012年）。在未来100万年内，岩石型将对英国的岩石表面侵蚀产生重大影响。鉴于英国（以及社区合作伙伴目前为GDF确定的地点）具有高度可变的本地岩石类型，其优势较低，因此至关重要的是，量化拥有英国GDF站点的地质侵蚀率至关重要。该项目将使用新的发光侵蚀表来量化针对任何英国GDF的各种较低和更高强度的宿主岩石环境，并结合详细的地球化学和结构分析。目标2：目前，英国尚未在过去一百万年的冰川间周期中尚无岩石侵蚀率的记录；因此，不可能知道在未来100万年内会预期多少侵蚀。一项全球对不同气候变量（但不是英国）的岩石露头侵蚀率的研究记录了140 m/ma的最大侵蚀率（Portenga and Bierman，2011），气候参数可以解释一些可变性。尽管英国可能是一个非遗传环境，但被认为具有较低的侵蚀率，但环境变量（尤其是寒冷温度和高降水量）和宿主岩石特性的综合影响