How anomalous is the Marion Rise asthenosphere?

马里恩隆起软流圈有多反常？

• 批准号: 2126496
• 负责人: Vincent Salters
• 金额: $ 28.73万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2126496&HistoricalAwards=false
• 关键词: How; anomalous; Marion; Rise; asthenosphere

Mid-ocean ridge volcanism is the largest element flux from the Earth’s interior to the surface and is an important contributor of carbon to the atmosphere. The magnitude of this flux is assumed to be controlled by temperature, with high temperatures causing increased melt production and magmatism, and shallow ridges. However, compositional differences in the mantle can potentially also influence melt production, but this has not been convincingly shown yet. The Marion Rise is anomalous in that melt production is low although the Rise depth is shallow. This can potentially be explained by a mantle composition that is more depleted in melt components than “normal” ridges. This research will investigate through the chemistry of the basalts and the mantle rocks from the seafloor if the Marion Rise mantle has experienced an ancient melt depletion and thus the effect of composition on ridge depth and melt production. This project is in collaboration with researchers at laboratories in Germany, Italy, and Finland and supports research training and mentoring opportunities for early career scientists.Researchers will investigate, through use of samples collected with two recent cruises to the Marion Rise as well as samples from previous cruises, to determine the nature of the Indian Ocean mantle at the eastern part of the South West Indian Ridge (SWIR). The eastern part of the SWIR includes the Marion Rise, which has anomalously thin crust for its axial depth that must be related to anomalous geochemical characteristics of the mantle beneath. This proposal is to determine the nature and extent of this anomalous mantle and thereby the cause of the Marion Rise. The Indian Ocean mid-ocean ridge basalts (MORB) differ in isotopic composition from Atlantic and Pacific MORB. The differences in Pb-isotopes (207Pb/204Pb) indicates that this difference is created early in Earth’s history. Model age determinations of the abyssal peridotites will further determine if the asthenosphere of the different ocean basins has different ages. Two recent cruises to the Marion Rise, brought back samples that address the above questions, as well as the recent availability of the samples from French expeditions further east on the SWIR allows for new insights and testing of existing hypotheses. The effort is concentrated on geochemical analyses of abyssal peridotites and associated basalts and interpreting these data in the context of geophysical constraints.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

中海脊火山症是从地球内部到表面的最大元素通量，并且是碳对大气的重要贡献。假定这种通量的大小是由温度控制的，高温会导致熔体产生和岩浆和浅脊。但是，地幔的组成差异也可能影响熔体的产生，但这尚未令人信服。 Marion上升是异常的，因为熔体产量较低，尽管升高深度很浅。这可以通过地幔成分来解释，该地幔成分比“正常”山脊更深入。这项研究将通过玄武岩的化学和海底的地幔岩石进行调查，如果Marion Rise Mantle经历了古老的熔体部署，从而对组成对山脊深度和融化产生产生的影响。该项目与德国，意大利和芬兰实验室的研究人员合作，并支持早期职业科学家的研究培训和心理机会。研究人员将通过使用最近的两个巡游来调查Marion上升的样本以及先前巡游的样本，以确定印度海洋南部印度山脉东部地区的性质（Swir）的性质。对于其轴向深度的异常薄层，必须与下面的地幔异常的地球化学特征有关。该提议是为了确定这种异常地幔的性质和程度，从而确定马里恩上升的原因。印度洋中部山脊玄武岩（MORB）的同位素组合与大西洋和太平洋病态不同。 PB - 同位体（207pb/204pb）的差异表明，这种差异是在地球历史早期创建的。深渊橄榄岩的模型年龄确定将进一步确定不同海洋鲈鱼的小圈是否具有不同的年龄。最近的两次巡游马里恩（Marion）崛起，带回了解决上述问题的样本，以及最近在SWIR东部向东的法国探险队的样本可用性，可以提供新的见解和测试现有假设。这项工作集中在地球化橄榄岩和相关的玄武岩的地球化学分析上，并在地球物理约束的背景下解释这些数据。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的审查标准通过评估来诚实地认为通过评估来诚实地支持。

项目成果

Transition from orogenic-like to anorogenic magmatism in the Southern Alps during the Early Mesozoic: Evidence from elemental and Nd-Sr-Hf-Pb isotope geochemistry of alkali-rich dykes from the Finero Phlogopite Peridotite, Ivrea–Verbano Zone

• DOI: 10.1016/j.gr.2023.12.011
• 发表时间: 2023-12
• 期刊: Gondwana Research
• 影响因子: 6.1
• 作者: Abimbola C. Ogunyele;M. Bonazzi;T. Giovanardi;M. Mazzucchelli;V. Salters;A. Decarlis;Alessio Sanfilippo;Alberto Zanetti

Preserved Nd-Hf-Os isotope variability in replacive channels from the Lanzo ophiolite: Traces of incomplete melt aggregation in the shallow mantle

• DOI: 10.1016/j.chemgeo.2023.121779
• 发表时间: 2023-10
• 期刊: Chemical Geology
• 影响因子: 3.9
• 作者: A. Sanfilippo;C.Z. Liu;V. Salters;A. Mosconi;A. Zanetti;R. Tribuzio

Shallow recycling of lower continental crust: The Mahoney Seamount at the Southwest Indian Ridge

下大陆地壳的浅层再循环：西南印度洋脊的马奥尼海山

• DOI: 10.1016/j.epsl.2022.117968
• 发表时间: 2023
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Woelki, Dominic;Salters, Vincent;Beier, Christoph;Dick, Henry;Koepke, Juergen;Romer, Rene
• 通讯作者: Romer, Rene