Assessing the redox state of Mariana forearc

评估马里亚纳弧前的氧化还原状态

• 批准号: NE/P020860/1
• 负责人: Helen Williams
• 金额: $ 4.7万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP020860%2F1
• 关键词: Assessing; redox; state; Mariana; forearc

Subduction zones ("arcs") are the geological setting where one tectonic plate ("slab") is dragged underneath another into the Earth's deep interior ("mantle"). They are sites of major chemical exchange between the Earth's surface and interior. Water and other volatiles (e.g. sulfur, chlorine, fluorine, carbon) are released from the subducting slab in the form of fluids and transported to the overlying plate ("fore-arc mantle"). These fluids are considered to play a critical role in the transport and concentration of economically-important elements like copper and gold in subduction zones and the chemistry of arc magmas and associated volcanic gases. Deciphering the chemistry of these fluids is also fundamental to understanding the Earth's carbon and sulfur cycles and the evolution of the Earth's atmosphere and oceans. These cycles rely on knowing both the efficiency of carbon and sulfur burial by subduction, and the loss of these elements from the subducting slab to the fore-arc mantle. However there are major gaps in our knowledge of slab fluid chemistry and especially in relation to the redox cycling of sulfur, iron and carbon. The goal of this project is to constrain the nature of slab fluids and quantify the budgets and oxidation states of sulfur, carbon and iron in these fluids using a combination of novel chemical fingerprinting tools that we have demonstrated to be highly effective for this purpose. In this project we will take advantage of the IODP expedition 366 to visit and sample the Mariana arc. The Marianas are one of the best-studied arcs, and one of the few places where we can directly access and sample the fore-arc mantle. This expedition presents a unique opportunity to study the zone where fluids are released from the subducting slab and react with the mantle of the overlying plate. From working on samples collected during this expedition we will be able to directly study the reactions between the fluids released from the subducting slab and the overlying fore-arc mantle and we will be able to use our results to determine the compositions and redox budgets of these fluids and to address their role in global carbon and sulfur cycles.

俯冲带（“弧”）是一个构造板块（“板”）被拖到另一个板块之下进入地球内部深处（“地幔”）的地质环境。它们是地球表面和内部之间主要化学交换的场所。水和其他挥发性物质（如硫、氯、氟、碳）以流体的形式从俯冲板块中释放出来，并被输送到上覆板块（“弧前地幔”）。这些流体被认为在俯冲带中的铜和金等经济重要元素的运输和浓缩以及弧岩浆和相关火山气体的化学性质方面发挥着关键作用。破译这些流体的化学性质对于理解地球的碳和硫循环以及地球大气和海洋的演变也至关重要。这些循环依赖于了解俯冲作用对碳和硫的埋藏效率，以及这些元素从俯冲板片到弧前地幔的损失。然而，在我们对板状流体化学的认识方面，特别是在硫、铁和碳的氧化还原循环方面，存在着重大的空白。该项目的目标是限制板流体的性质，并使用我们已证明对此目的非常有效的新型化学指纹工具的组合来量化这些流体中硫，碳和铁的预算和氧化态。在这个项目中，我们将利用IODP探险366访问和采样马里亚纳弧。马里亚纳群岛是研究得最好的弧之一，也是少数几个我们可以直接接触和取样弧前地幔的地方之一。这次探险提供了一个独特的机会，研究流体从俯冲板块释放并与上覆板块地幔反应的区域。通过对这次考察期间收集的样品进行研究，我们将能够直接研究俯冲板片和上覆弧前地幔释放的流体之间的反应，我们将能够利用我们的结果来确定这些流体的组成和氧化还原预算，并解决它们在全球碳和硫循环中的作用。

项目成果

Secondary magnetite in ancient zircon precludes analysis of a Hadean geodynamo

• DOI: 10.1073/pnas.1811074116
• 发表时间: 2018-12
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Fengzai Tang;Richard J. M. Taylor;J. Einsle;C. Borlina;R. Fu;Benjamin P. Weiss;Helen M. Williams;W. Williams;L. Nagy;Paul A. Midgley;E. Lima;Elizabeth A. Bell;T. M. Harrison;Ellen W. Alexander;R. Harrison

High-pressure synthesis and storage of solid organic compounds in active subduction zones.

• DOI: 10.1126/sciadv.abo2397
• 发表时间: 2022-09-16
• 期刊: SCIENCE ADVANCES
• 影响因子: 13.6
• 作者: Debret, Baptiste;Menez, Benedicte;Walter, Bastien;Bouquerel, Helene;Bouilhol, Pierre;Mattielli, Nadine;Pisapia, Celine;Rigaudier, Thomas;Williams, Helen Myfanwy
• 通讯作者: Williams, Helen Myfanwy

Redox transfer at subduction zones: insights from Fe isotopes in the Mariana forearc

• DOI: 10.7185/geochemlet.2003
• 发表时间: 2020-01-31
• 期刊: GEOCHEMICAL PERSPECTIVES LETTERS
• 影响因子: 4.9
• 作者: Debret, B.;Reekie, C. D. J.;Williams, H. M.
• 通讯作者: Williams, H. M.

Shallow forearc mantle dynamics and geochemistry: New insights from IODP Expedition 366

• DOI: 10.1016/j.lithos.2018.10.038
• 发表时间: 2019-02-01
• 期刊: LITHOS
• 影响因子: 3.5
• 作者: Debret, B.;Albers, E.;Williams, H.
• 通讯作者: Williams, H.

The Fe and Zn isotope composition of deep mantle source regions: Insights from Baffin Island picrites

• DOI: 10.1016/j.gca.2018.07.021
• 发表时间: 2018-10
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: A. McCoy-West;J. Fitton;M. Pons;E. Inglis;H. Williams