The Elemental and Isotopic Partitioning Behavior of Nitrogen During Magmatic Differentiation

岩浆分异过程中氮的元素和同位素分配行为

• 批准号: 2890693
• 金额: --
• 依托单位: University of St Andrews
• 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-2890693
• 关键词: Elemental; Isotopic; Partitioning; Behavior; Nitrogen

Nitrogen is the dominant element in Earth's atmosphere at 78% by mass. It is a core element to our DNA, it is an essential nutrient for life and is a crucial ingredient to form the building blocks for life. Yet, we know little about how earth's atmosphere came to be so nitrogen rich, and how nitrogen moves between earth's reservoirs. These questions are still a topic of debate, and the answers have great implications to our understanding of Earth's elemental fluxes, evolution of our atmosphere, evolution of life on earth, and how other planets differ to our own. Due to the wide range in valency of nitrogen, nitrogen can form a variety of species (e.g. N2, nitride, nitrate, ammonium, ammonia, etc) under different geochemical conditions. Many of these nitrogen species behave very differently in silicate Earth, with different compatibilities, charges, volatility etc. Due to their wide range of traits, they can substitute for many similar ions in the crystal lattice of common minerals in the crust and mantle. Therefore, we must better constrain how nitrogen behaves in silicate earth, and what factors affect its behaviour, to understand how nitrogen occupies, and moves through, our planet.This project aims to identify the behaviour of nitrogen under different geochemical conditions: specifically, its elemental and isotopic partitioning behaviour during magmatic differentiation. A range of alkaline and subalkaline rocks from volcanic and plutonic settings will be analysed to speak to the behaviour of nitrogen atoms and isotopes under different tectonic and geochemical conditions. The samples will show a variation in P-T-X-fO2 conditions during formation and the research results should therefore be able to speak to the effect of each of these parameters on the behaviour of nitrogen. Specific findings are expected to include: the source of nitrogen in investigated igneous systems; the key controlling factors on nitrogen behaviour; the elemental and isotopic partitioning behaviour of nitrogen as igneous systems evolve, how nitrogen partitions between key silicate minerals within an evolving system, and how volcanic degassing of nitrogen is influenced by igneous differentiation.

氮是地球大气中的主要元素，占质量的 78%。它是我们 DNA 的核心元素，是生命的必需营养素，也是构成生命基石的关键成分。然而，我们对地球大气层如何变得如此富含氮以及氮如何在地球储存库之间移动知之甚少。这些问题仍然是一个争论的话题，而答案对于我们理解地球的元素通量、大气层的演化、地球上生命的演化以及其他行星与我们的行星有何不同具有重大意义。由于氮的化合价范围很广，氮在不同的地球化学条件下可以形成多种形态（如N2、氮化物、硝酸盐、铵、氨等）。许多这些氮物种在硅酸盐地球中的行为非常不同，具有不同的相容性、电荷、挥发性等。由于其广泛的特性，它们可以替代地壳和地幔中常见矿物晶格中的许多相似离子。因此，我们必须更好地限制氮在硅酸盐地球中的行为，以及哪些因素影响其行为，以了解氮如何占据并穿过我们的星球。该项目旨在确定氮在不同地球化学条件下的行为：特别是在岩浆分异过程中氮的元素和同位素分配行为。将分析来自火山和深成环境的一系列碱性和亚碱性岩石，以说明氮原子和同位素在不同构造和地球化学条件下的行为。样品将显示形成过程中 P-T-X-fO2 条件的变化，因此研究结果应该能够说明每个参数对氮行为的影响。预计具体发现包括： 所调查的火成系统中氮的来源；氮行为的关键控制因素；随着火成岩系统的演化，氮的元素和同位素分配行为，演化系统中关键硅酸盐矿物之间的氮如何分配，以及火成岩分异如何影响火山脱气。