Mantle volatiles: processes, reservoirs and fluxes

地幔挥发物：过程、储层和通量

• 批准号: NE/M000303/1
• 负责人: Madeleine Humphreys
• 金额: $ 51.39万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FM000303%2F1
• 关键词: Mantle; volatiles; processes; reservoirs; fluxes

We have brought together a consortium of UK investigators and international partners with the key objective of providing a new process based understanding of volatile element (e.g. H2O, C, S, noble gases and halogens) fluxes into the deep mantle at subduction zones and out of the mantle at mid ocean ridges and ocean island settings. The mantle is by many orders of magnitude the largest silicate reservoir for carbon, nitrogen and sulphur on Earth and the input and output of volatiles (e.g., H2O, C, N, S, P, and halogens) at plate boundaries provides long-term controls on the climate and the biosphere. Nevertheless, our understanding of the deep-Earth volatile cycle is crude. In part because we have a very poor understanding of the relative contribution of recycled to primordial volatiles in the mantle system and how this might vary in different mantle reservoirs. In part this is because volatile elements are extensively lost during the eruptive process from many sample types making it hard to identify the controlling processes necessary to develop coherent models. To address our objective the consortium combines several advances in new sample resources and analytical tools:i) The recognition that rapidly quenched melt inclusions (MIs) within erupted material often preserve mantle-source volatile compositions; ii) The ability to determine sulphur and boron isotopes in addition to major volatiles in the MIs;iii) The discovery that boron isotopes can track the extent of volatile loss to the surface from subducting slabs and preserve this signal in the deeper mantle; iv) The innovations in noble gas isotope determination that allow us to resolve recycled volatiles from those trapped during accretion and provide links to halogens, H2O and C;v) The development of non-traditional stable isotopes such as Fe, Cu and Se to identify system oxidation state (a key variable in understanding sulphur) and chalcophile trace element determinations;vi) The advances in computing power and techniques that allow better representation of mantle-like systems.By coordinating the combined consortium expertise and analytical resources on the same sample suites in two thermally contrasting subduction regimes (Kamchatka (cool) and Southern Chile (hot)) we plan to investigate how both the processes and thermal setting control the efficiency and geochemical character (isotopic composition and relative abundance to other volatiles) of volatile subduction into the deep mantle. This allows us to take into consideration changes in subduction temperature as the Earth cools in the development of flux models that run for the age of the Earth. At mid ocean ridges and ocean island settings with different geochemical provenance (e.g. HIMU, EMI, EMII, FOZO) we will determine the proportion and character of volatile elements that have been recycled compared to those that were incorporated into the mantle during its formation (primitive volatiles). This is an essential component in building our understanding of the volatile flux into the mantle required to support the signals in the mantle today. New experimental partitioning developed within the consortium and our ability to track oxidation state will allow us to make a step change in understanding the sulphur cycle - barely understood to date but critical in understanding climate and commercial mineral deposit formation. Numerical simulations of mantle transport for suites of geochemical elements, iterating the geophysical parameters to approach matches for the geochemical observables, will allow us to identify the key geophysical processes in subduction zones and during whole mantle convection that control the geochemical distribution of subducted vs. primordial volatiles in the mantle. Together, these will lead to a significant advance in reconstructing the deep Earth volatile fluxes over Earth history - a grand science challenge.

我们将一个英国调查人员和国际合作伙伴的联盟汇集在一起​​，其主要目标是提供对挥发性元件（例如H2O，C，S，贵重气体和卤素）通量的新理解，并在俯冲区域中的深层范围内，并从中海山脊和海洋岛环境中的地幔中。地幔在许多数量级上是地球上碳，氮和硫的最大硅酸盐储层，以及在板边界处的挥发物（例如H2O，C，C，N，S，P和Halogens）的挥发物的输入和输出（例如H2O，C，C，N，S，P和Halogens）在气候和生物环上提供了长期的控制。然而，我们对深地球波动循环的理解是粗略的。部分原因是我们对地幔系统中回收对原始挥发物的相对贡献的相对贡献非常差，以及在不同地幔储层中的相对贡献。部分原因是，在许多样本类型的喷发过程中，挥发性元素在喷发过程中被广泛损失，因此很难确定开发相干模型所需的控制过程。为了满足我们的目标，财团结合了新样本资源和分析工具的几个进步：i）认识到喷发材料中快速淬火熔体夹杂物（MIS）的认识通常保留地幔 - 源挥发性的组成； ii）除了MIS中的主要挥发物外，还可以确定硫和硼同位素的能力； iv）贵气体同位素确定的创新，使我们能够从收获过程中被困的挥发物中解决回收的挥发物，并提供与卤素，H2O和c; v的链接的链接；通过在两个热对比的俯冲状态（Kamchatka（Cool）和Southern Chile（Hot））中协调同一样品套件上的联合财团专业知识和分析资源的组合，我们计划如何调查过程和热的效率（ISOCopopopopopial Comprient of Isopopial complotitive），从而可以更好地代表地幔式系统。深层地幔。这使我们能够考虑俯冲温度的变化，因为地球在为地球时代延伸的通量模型的发展中冷却。在海脊和海洋岛环境中，具有不同的地球化学出处（例如Himu，Emi，Emii，Fozo），我们将确定与在形成过程中被掺入地幔的挥发性元件的比例和特征（原始挥发物）。这是将我们对挥发性通量的理解纳入支持当今地幔信号所需的地幔的重要组成部分。在财团内开发的新实验分区以及我们追踪氧化状态的能力将使我们能够在理解硫周期的情况下做出逐步改变 - 迄今为止几乎尚未理解，但对于理解气候和商业矿物沉积物的形成至关重要。地幔传输的数字模拟用于地球化学元素的套件，迭代地球物理参数以接近地球化学可观察物的匹配，将使我们能够识别俯冲区中的关键地球物理过程以及在整个地幔对流中控制俯冲vics vilorordial primorordial primordial folatele the mantle the Mantle的地震对流。共同，这些将导致重建地球历史上深层挥发性的磁通的重大进步 - 这是一个宏伟的科学挑战。

项目成果

Assessing sulfur redox state and distribution in abyssal serpentinites using XANES spectroscopy

• DOI: 10.1016/j.epsl.2017.02.029
• 发表时间: 2017-05-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Debret, Baptiste;Andreani, Muriel;Williams, Helen
• 通讯作者: Williams, Helen

Tracing Volatiles, Halogens, and Chalcophile Metals During Melt Evolution at the Tolbachik Monogenetic Field, Kamchatka

• DOI: 10.1093/petrology/egac087
• 发表时间: 2022-08
• 期刊: Journal of Petrology
• 影响因子: 3.9
• 作者: Alexander A. Iveson;M. Humphreys;F. Jenner;B. Kunz;I. Savov;J. D. De Hoog;T. Churikova;B. Gordeychik-B

Experimentally derived F, Cl, and Br fluid/melt partitioning of intermediate to silicic melts in shallow magmatic systems

• DOI: 10.2138/am-2022-8109
• 发表时间: 2022-10-26
• 期刊: AMERICAN MINERALOGIST
• 影响因子: 3.1
• 作者: Cassidy, Mike;Iveson, Alexander A.;Pyle, David M.
• 通讯作者: Pyle, David M.

Deciphering variable mantle sources and hydrous inputs to arc magmas in Kamchatka

• DOI: 10.1016/j.epsl.2021.116848
• 发表时间: 2021-05
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Alexander A. Iveson;M. Humphreys;I. Savov;J. D. De Hoog;S. Turner;T. Churikova;C. Macpherson

Iron and zinc stable isotope evidence for open-system high-pressure dehydration of antigorite serpentinite in subduction zones

• DOI: 10.1016/j.gca.2020.12.001
• 发表时间: 2020-12
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: B. Debret;C. Garrido;M. Pons;P. Bouilhol;E. Inglis;V. L. Sánchez‐Vizcaíno;H. Williams