Collaborative Research: Tracking nitrogen in mélange matrix from fore-arc to sub-arc depths with implications for deep nitrogen cycling: A combined field and experimental approach

合作研究：追踪从弧前到弧下深度的混合基质中的氮，对深层氮循环的影响：现场和实验相结合的方法

• 批准号: 2138410
• 负责人: Ananya Mallik
• 金额: $ 32.9万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138410&HistoricalAwards=false
• 关键词: Collaborative; Research; Tracking; nitrogen; lange

The nitrogen (N)-cycle as it relates to the bio-, atmo-, and hydro-spheres have been well studied due to N’s abundance in Earth’s atmosphere and importance for life. In the less understood solid Earth N cycle, plate tectonics has regulated N fluxes between surface and deep Earth reservoirs over much of Earth’s history, affecting the bulk Earth N distribution over millennial timescales. Thus, the mass balance of nitrogen (N) delivered to the deep Earth during subduction and then returned to the surface during volcanism and degassing is critically important, yet efficiency estimates are highly variable. Current estimates suggest that 45-74% of subducted N does not return to the surface through arc volcanism. This implies that N is being sequestered in the deep Earth in variable amounts, which could reflect factors such as subducting plate composition or subduction conditions. Candidates for deep, poorly characterized N reservoirs include mid-lower continental crust, subcontinental mantle, fore-arc to sub-arc mantle, or deeper mantle (i.e., deeper upper mantle, transition zone or lower mantle). This highlights a need for N measurements on appropriate samples as well as thorough constraints on N behavior in these reservoirs. New key constraints on nitrogen (N) distribution and processing within the fore-arc to sub-arc regions of subduction zones will be provided. First, some of the first N composition measurements of sediment-rich and serpentinite-rich mélange matrix rocks and minerals to characterize the distribution of N during fore-arc processing will be made. Second, phase equilibria experiments to assess the stability of key N hosting minerals and measure N melt/fluid-mineral partition coefficients on mélange-matrix materials as a function of several factors (pressure, temperature, oxygen fugacity, chlorine content, and partial melt composition) to track N behavior during dehydration and partial melting in the slab at sub-arc depths will be performed. Data from the proposed study along with those from previous studies will be used to quantify the amount of N that is delivered from the fore-arc to the sub-arc processing zone, in which minerals it is hosted, and how it varies by dominant lithology (sediment or serpentinite). How much N is released from the slab during sub-arc processing versus how much is sequestered in the sub-arc mantle in subduction zones of different thermal states will then be quantified. These will constitute novel constraints on N behavior that can be applied to subduction regimes throughout Earth’s history. Hence, it will also be used to address the feedback and evolution of N across the coupled solid Earth-atmosphere systems. This proposal supports two early career female PIs, two graduate students, and two+ undergraduates from University of Arizona (UA) and University of Southern California (USC). To enhance collaboration and broaden participation, the PIs will offer a joint virtual graduate seminar on deep volatile cycling including students at UA and USC. The team at UA will develop a museum display at UA’s Alfie Norville Gem & Mineral Museum on high pressure-high temperature geoscience research (including laboratory equipment and research applications).As the most abundant constituent of the Earth’s atmosphere and as an essential ingredient of life, the behavior of nitrogen (N) in the present-day atmosphere, oceans, crust and biosphere (collectively known as the surficial reservoirs) have been relatively well-studied. However, the N composition of the Earth’s surficial reservoirs may not have remained the same throughout Earth’s history and this may have implications for early Earth climate and evolution of life. Nitrogen is exchanged between the Earth’s surficial reservoirs and the deep interior via plate tectonics, especially subduction zones. In subduction zones, N in the Earth’s crust (along with components from the atmosphere, ocean and biosphere) is pulled into the mantle or the interior of the Earth. Some proportion of the N from the mantle escapes back into the atmosphere and ocean by volcanic degassing. This N exchange between the surface and interior is not well-constrained and this proposed study aims to fulfil a key component of this knowledge gap. The N composition of typical subduction zone rocks will be measured to determine where N is hosted as pressure and temperature increase. Laboratory experiments at conditions in the Earth’s mantle will be performed to understand the behavior of N once the crust enters the mantle and melts. The objective is to eventually use our results to estimate how the N composition of the Earth’s mantle and atmosphere have changed through Earth’s history. This proposal supports two early career female PIs, two graduate students, and two+ undergraduates from University of Arizona (UA) and University of Southern California (USC). To enhance collaboration and broaden participation, the PIs will offer a joint virtual graduate seminar on the proposed theme including students from both institutions. The team at UA will develop a museum display at UA’s Alfie Norville Gem & Mineral Museum on plate tectonics connecting the surface and interior of the Earth, which would be an excellent medium to educate the public on state-of-the-art research.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.

由于N在地球大气中的丰富性和对生命的重要性，与生物，大气和水圈有关的氮（N）循环已经很好地研究了。在不太了解的固体N周期中，板块构造在地球历史的大部分历史上都调节了表面和深地球储层之间的N通量，从而影响了千禧一代时间表的散装地球N分布。这是俯冲期间氮（N）的质量平衡（n）在火山和脱气过程中返回到地面的质量平衡至关重要，但效率估计值高度可变。目前的估计表明，俯冲n中有45-74％的n不会通过弧形火山恢复到表面。这意味着n正在以可变量隔离在深地球中，这可能反映了诸如俯冲板组成或俯冲条件之类的因素。深层，特征较差的n储存库的候选者包括中叶大陆地壳，次大陆地幔，前弧到亚弧形地幔或更深的地幔（即，更深的上层地幔，过渡区或下地幔）。这强调了对适当样本的N测量以及对这些储层中N行为的彻底限制的需求。将提供对氮（N）分布的新密钥限制和俯冲带前弧区域内的加工。首先，将进行富含沉积物和柔软的混合矩阵岩石和矿物质的第一个N组合物测量，以表征N期间N期间N的分布。其次，相等的相等实验，以评估关键n托管矿物质和测量的稳定性N融化/流体矿物分配系数在Mélange-Matrix材料上是多种因素（压力，温度，温度，氧气，氧气，氯的含量和部分熔体组成）的函数，以跟踪在脱发和部分静脉熔化的情况下跟踪N行为的行为。拟议研究的数据以及先前研究的数据将用于量化从前弧到亚弧形处理区传递的N量，其中它被托管在该区域中，以及它如何通过主要的岩性（沉积物或蛇纹石）而变化。然后，将在亚弧处理过程中从平板上释放多少n，而在不同热状态的俯冲带中的隔板地幔中隔离了多少n。这些将构成对N行为的新限制，可以应用于地球历史上的俯冲制度。因此，它也将用于解决N偶联的固体固体 - 大气系统的反馈和演变。该建议支持两名早期的职业女性PI，两名研究生，以及来自亚利桑那大学（UA）（UA）和南加州大学（USC）的两个+本科生。为了增强协作和扩大参与，PIS将为包括UA和USC的学生在内的深度波动骑行提供联合虚拟的研究生中学。 UA的团队将在UA的Alfie Norville Gem＆矿物博物馆开发博物馆展览，该博物馆在高压最高温度的地球科学研究（包括实验室设备和研究应用程序）上。作为地球大气层最丰富的一致性，是生命的必不可少的重要性，并且是当今的大气层和海洋中的氮（N）的行为，是氮的行为（n）的行为（N）。研究得很好。但是，地球表面储层的n组成可能在整个地球历史上可能并不相同，这可能对早期地球的气候和生命的进化具有影响。通过板块构造，尤其是俯冲带，在地球的表面储量和深内部之间交换了氮。在俯冲带中，将地壳中的N（以及来自大气，海洋和生物圈的成分）拉入地幔或地球内部。通过火山脱水，从地幔中的N比例的一部分逃回了大气和海洋。表面和内部之间的N交换没有受到良好的约束，这项拟议的研究旨在满足该知识差距的关键组成部分。将测量典型的俯冲带的N组成，以确定n位托管的位置，随着压力和温度升高。将在地球地幔中的条件下进行实验室实验，以了解一旦地壳进入地幔和熔体的行为。目的是最终利用我们的结果来估计地球和大气的n组成如何在地球历史上改变。该建议支持两名早期的职业女性PI，两名研究生，以及来自亚利桑那大学（UA）（UA）和南加州大学（USC）的两个+本科生。为了增强协作和扩大参与，PI将在拟议的主题上提供联合虚拟研究生半决赛，包括来自这两个机构的学生。 The team at UA will develop a museum display at UA’s Alfie Norville Gem & Mineral Museum on plate tectonics connecting the surface and interior of the Earth, which would be an excellent medium to educate the public on state-of-the-art research.This award reflects NSF's statutory mission and has been deemed precious of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

项目成果

Metabasic Rocks as Important Nitrogen Carriers to Forearc Depths: Implications for Deep Nitrogen Cycling

• DOI: 10.1016/j.gca.2023.10.007
• 发表时间: 2023-10
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: A. Mallik;Anna M Rebaza;Paul Kapp;Long Li;Yifan Du;Ahmed Al Shams;Emily H. G Cooperdock

Multiple Episodes of Rock-Melt Reaction at the Slab-Mantle Interface: Formation of High Silica Primary Magmas in Intermediate to Hot Subduction Zones

板幔界面多期熔岩反应：中热俯冲带高硅质原生岩​​浆的形成

• DOI: 10.1093/petrology/egad011
• 发表时间: 2023
• 期刊: Journal of Petrology
• 影响因子: 3.9
• 作者: Rebaza, Anna M;Mallik, Ananya;Straub, Susanne M
• 通讯作者: Straub, Susanne M