Fourier Transform Infrared Spectroscopy data (NERC grant NE/M000087/1)

Raw FTIR data from olivine samples used for NERC grant NE/M000087/1. Grant abstract: In 2011, NERC began a scoping exercise to develop a research programme based around deep Earth controls on the habitable planet. The result of this exercise was for NERC to commit substantial funding to support a programme entitled "Volatiles, Geodynamics and Solid Earth Controls on the Habitable Planet". This proposal is a direct response to that call. It is widely and generally accepted that volatiles - in particular water - strongly affect the properties that control the flow of rocks and minerals (their rheological properties). Indeed, experiments on low-pressure minerals such as quartz and olivine show that even small amounts of water can weaken a mineral - allowing it to flow faster - by as much as several orders of magnitude. This effect is known as hydrolytic weakening, and has been used to explain a wide range of fundamental Earth questions - including the origin of plate tectonics and why Earth and Venus are different. The effect of water and volatiles on the properties of mantle rocks and minerals is a central component of this NERC research programme. Indeed it forms the basis for one of the three main questions posed by the UK academic community, and supported by a number of international experts during the scoping process. The question is "What are the feedbacks between volatile fluxes and mantle convection through time?" Intuitively, one expects feedbacks between volatiles and mantle convection. For instance, one might envisage a scenario whereby the more water is subducted into the lower mantle, the more the mantle should weaken, allowing faster convection, which in turn results in even more water passing into the lower mantle, and so on. Of course this is a simplification since faster convection cools the mantle, slowing convection, and also increases the amount of volatiles removed from the mantle at mid-ocean ridges. Nevertheless, one can imagine many important feedbacks, some of which have been examined via simple models. In particular these models indicate a feedback between volatiles and convection that controls the distribution of water between the oceans and the mantle, and the amount topography created by the vertical movement of the mantle (known as dynamic topography). The scientists involved in the scoping exercise recognized this as a major scientific question, and one having potentially far reaching consequences for the Earth's surface and habitability. However, as is discussed in detail in the proposal, our understanding of how mantle rocks deform as a function of water content is remarkably limited, and in fact the effect of water on the majority of mantle minerals has never been measured. The effect of water on the flow properties of most mantle minerals is simply inferred from experiments on low-pressure minerals (olivine, pyroxenes and quartz). As argued in the proposal, one cannot simply extrapolate between different minerals and rocks because different minerals may react quite differently to water. Moreover, current research is now calling into question even the experimental results on olivine, making the issue even more pressing. We propose, therefore, a comprehensive campaign to quantify the effect of water on the rheological properties of all the major mantle minerals and rocks using a combination of new experiments and multi-physics simulation. In conjunction with 3D mantle convection models, this information will allow us to understand how the feedback between volatiles and mantle convection impacts on problems of Earth habitability, such as how ocean volumes and large-scale dynamic topography vary over time. This research thus addresses the aims and ambitions of the research programme head on, and indeed, is required for the success of the entire programme.本数据集为用于英国自然环境研究委员会（Natural Environment Research Council, NERC）资助项目NE/M000087/1的橄榄石样品原始傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy, FTIR）数据。项目资助摘要：2011年，NERC启动一项范围界定研究，旨在开发一项围绕“宜居行星的深部地球控制因素”的研究计划。该研究的最终成果是NERC投入大额资金，支持一项题为“挥发分、地球动力学与固体地球对宜居行星的控制作用”的研究计划。本提案正是对该征集号召的直接响应。学界已普遍达成共识：挥发分——尤其是水——会显著影响控制岩石与矿物流变的物理性质。针对石英、橄榄石等低压矿物的实验表明，即使微量水分也可使矿物弱化程度提升数个数量级，使其流动速率大幅加快，该效应被称为水解弱化（hydrolytic weakening），该理论已被用于解释诸多地球科学基础问题，包括板块构造的起源，以及地球与金星演化路径差异的原因。水分与挥发分对地幔岩石与矿物物理性质的影响，是该NERC研究计划的核心组成部分。事实上，这也是英国学术界在范围界定研究期间提出的三大核心问题之一，并获得了多位国际专家的支持。该问题为：“挥发性物质通量与地幔对流之间随时间演化的反馈机制是什么？”直觉上，人们可推测挥发分与地幔对流之间存在反馈机制。例如，可设想这样一种场景：俯冲进入下地幔的水分越多，地幔弱化程度越高，对流速率随之加快，进而导致更多水分被带入下地幔，以此循环往复。当然，这是一种简化模型，因为更快的对流会使地幔冷却，减缓对流速率，同时也会增加洋中脊处地幔释放的挥发分量。尽管如此，仍存在诸多重要的反馈机制，其中部分已通过简单模型开展研究。具体而言，这些模型揭示了挥发分与对流之间的反馈机制，该机制控制着海洋与地幔之间的水分分布，以及由地幔垂向运动形成的地形（即动态地形（dynamic topography））。参与范围界定研究的科学家认为，这是一项重大科学问题，其研究成果可能对地球表面环境与宜居性产生深远影响。然而，正如提案中详细讨论的那样，学界对于“地幔岩石的形变如何随含水量变化”这一问题的认知仍极为有限，事实上，绝大多数地幔矿物受水影响的效应从未被直接测量过。当前对多数地幔矿物流动性质的认知，仅基于橄榄石、辉石与石英等低压矿物的实验结果进行推断。正如提案中所述，我们无法简单地在不同矿物与岩石之间进行外推，因为不同矿物对水的响应可能存在显著差异。此外，当前的研究甚至对橄榄石的相关实验结果提出了质疑，使得这一问题愈发紧迫。因此，我们提出一项综合性研究计划，结合全新实验与多物理场模拟，量化水分对所有主要地幔矿物与岩石流变性质的影响。结合三维地幔对流模型，该研究将帮助我们理解挥发分与地幔对流之间的反馈如何影响地球宜居性相关问题，例如海洋体积与大型动态地形随时间的演化规律。因此，本研究直接契合该研究计划的目标与愿景，事实上，也是整个计划取得成功的必要前提。