UK-IODP Moratorium Award for Lewis Grant - Shipboard Scientist Expedition 390: The role of ridge flank dolomitization in the ocean Mg budget

英国 IODP 暂停奖授予 Lewis Grant - 船上科学家第 390 次探险：山脊侧翼白云石化在海洋镁预算中的作用

• 批准号: NE/X002446/1
• 负责人: Damon Teagle
• 金额: $ 3.52万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX002446%2F1
• 关键词: UK; IODP; Moratorium; Award; Lewis

Ocean crust is created at submarine volcanic mid-ocean ridges and spreads away over time to form the ocean basins that cover two thirds of Earth's surface. Seawater circulates through cracks in the cooling crust, removing heat and chemically interacting with the rocks. This 'hydrothermal circulation' influences both the composition of the oceans and Earth through time. As the crust ages, sediment accumulates above it, and seawater flows along the contact between these sediments and the underlying crust, making this an important site for seawater-rock chemical exchange. Magnesium (Mg) is the second most abundant cation in seawater and is supplied to the oceans by rivers, before being removed during hydrothermal alteration of ocean crust and precipitation of Mg-rich carbonates (i.e., dolomite) in the sediments. These same processes also directly influence the global carbon budget, making Mg a useful proxy when reconstructing past climate change, which is key to understanding the future evolution of our planet.In the geological 'rock record', dolomite was a major store for oceanic Mg, although the extent of dolomite formation has decreased significantly over the last 150 million years. However, dolomite has been found within the sediments immediately overlying the volcanic crust, where hydrothermal fluid-rock exchange is occurring. It is important to decipher the timing, temperature, and the source of Mg of this dolomite formation to determine how and why it forms, and whether it is an important Mg reservoir. Mg isotopes provide a geochemical fingerprint of the source of the Mg in different reservoirs in the Earth. However, the Mg isotopic composition of dolomites formed close to the sediment-basement interface has not yet been determined.Scientific ocean drilling allows us to sample marine sediments and the oceanic crust buried deep below them. International Ocean Discovery Program (IODP) Expeditions 390 and 393 will drill a transect of six sites across the South Atlantic, recovering ocean crust formed at the Mid-Atlantic ridge between 7 and 61 million years ago and providing a unique opportunity to investigate dolomite formation along the contact between sediments and the ocean crust. I will use the recovered cores to reassess the Mg budget of the oceans over the last 60 million years and determine whether dolomite formation still exerts a significant control on modern seawater chemistry.

海壳是在海底火山中部山脊上产生的，随着时间的流逝而散开，形成了覆盖地球表面三分之二的海盆。海水通过冷却外壳的裂缝循环，去除热量并与岩石进行化学相互作用。这种“热液循环”会随着时间的流逝影响海洋和地球的组成。随着年龄的增长，沉积物在其上方积聚，海水沿着这些沉积物与下面的外壳之间的接触流动，这使得这是海水摇滚化学交换的重要地点。镁（mg）是海水中第二大阳离子，并由河流供应海洋，然后在海壳的水热改变和沉积物中富含MG的碳酸盐（即白云岩）的沉淀过程中去除。这些相同的过程也直接影响了全球碳预算，在重建过去的气候变化时，MG成为有用的代理，这是了解我们星球的未来演变的关键。在地质“岩石记录”中，白云岩是海洋毫克的主要商店，尽管在过去的150亿年中，白云岩形成的程度大大减少。然而，已经发现白云岩在立即覆盖的火山壳的沉积物中，那里发生了热液液岩体交换。描述了该白云石形成的时序，温度和MG的来源，以确定其形成以及为什么形成以及它是否是重要的MG储层。 MG同位素提供了地球不同储层中MG来源的地球化学指纹。但是，尚未确定靠近沉积物底座界面的白云岩的MG同位素组成。ScientificOcean钻孔使我们能够采样海洋沉积物和埋藏在其深处的海洋壳。国际海洋发现计划（IODP）探险队390和393将钻出南大西洋六个地点的样品，在7到6100万年前在中大西洋山脊形成的海皮，并提供独特的机会，提供一个独特的机会，以研究沿着物质和海洋甲壳之间的接触群落形成白云岩。在过去的6000万年中，我将使用回收的核心重新评估海洋的MG预算，并确定白云岩的形成是否仍然对现代海水化学作用。

项目成果

South Atlantic Transect

南大西洋横断面

• 发表时间: 2024
• 期刊: Proceedings of the International Ocean Discovery Program Expedition reports
• 作者: Coggon, R.M.;Teagle, D.A.H.;Sylvan, J.B.;Reece, J.;Estes, E.R.;Williams, T.J.;Christeson, G.L.
• 通讯作者: Christeson, G.L.

Expedition 393 Preliminary Report: South Atlantic Transect 2

• DOI: 10.14379/iodp.pr.393.2023
• 发表时间: 2023-01
• 期刊: International Ocean Discovery Program Preliminary Report
• 作者: D. Teagle;J. Reece;R. Coggon;J. Sylvan;G. Christeson;T. Williams;E. Estes

Expedition 390 Preliminary Report: South Atlantic Transect 1

• DOI: 10.14379/iodp.pr.390.2022
• 发表时间: 2022-10
• 期刊: International Ocean Discovery Program Preliminary Report
• 作者: R. Coggon;J. Sylvan;D. Teagle;J. Reece;G. Christeson;E. Estes;T. Williams