Collaborative Research: Understanding the influence of tectonic setting on the depth of magmatic processes in the mid-ocean ridge system

合作研究：了解构造环境对大洋中脊系统岩浆过程深度的影响

基本信息

批准号：
2135828
负责人：
Gokce Ustunisik
金额：
$ 40.5万
依托单位：
South Dakota School of Mines and Technology
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：
2022-02-01 至 2025-01-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2135828&HistoricalAwards=false
关键词：
Collaborative Research Understanding influence tectonic

项目摘要

Collaborative Research: Understanding the influence of tectonic setting on the depth of magmatic processes in the mid-ocean ridge system The rocks that pave the seafloor cover ~70% of the Earth’s surface and are produced by volcanoes along the mid-ocean ridge (MOR) system. These volcanoes arguably represent the largest geologic system in the Earth’s crust. By analyzing the lavas erupted at the MOR, geologists understand how these magmas are produced and how they chemically change as they rise to the surface. However, less is understood about depths of formation and how that may change in different parts of the MOR system. New data on depth of formation of the crystals in MOR lavas, based on CO2 in trapped droplets of magma in crystals (melt inclusions), indicate that the crystals are produced over a wide depth range. Those crystals therefore provide a record of magma compositions encountered during transport from depth and of processes controlling ocean crust formation. This study will chemically analyze microscopic melt inclusions and crystals to understand how the depth of magma formation varies globally. This new data will provide information on the depth of crystallization in different MOR environments and the carbon budget of the mantle. A core aspect of this proposal involves outreach to students at the tribal colleges in South Dakota which will consist of three parts including current programs at South Dakota Mines, mentoring students from Oglala Lakota College (OLC), and providing advice on the development of the analytical facilities at OLC.Current understanding of the evolution of the ocean crust relies heavily on submarine volcanic glasses and, more recently, melt inclusion (MI) compositions. Such data is most informative about the complex array of mixing and differentiation processes active in the upper mantle and crust - in essence “what” is happening. What has been difficult to constrain is “where” specific processes are active in terms of depth, making it challenging to resolve the influences of processes occurring in the melting regime versus those that occur during transport to the surface. New data on depth of entrapment for melt inclusions (based on CO2 saturation/concentration) indicate that much of the crystal cargo in ocean floor basalts, particularly those from plagioclase ultraphyric basalts (PUB) are the products of crystallization at a wide range of pressure. They therefore provide an opportunity to investigate how the array of magma compositions evolves during transport and how the distribution of energy and mass of the processes controlling ocean crust formation differs between tectonic settings (different spreading rates, magma supply, extent of melting, etc.). This study will conduct combined analysis by electron microprobe (for major element composition), Laser ICP-MS (trace element compositions), secondary ion mass spectrometry (glass CO2, H2O, S), and Raman spectroscopy (MI bubble density/composition). The samples selected represent a number of PUB lavas from a range of settings, on axis, pull apart basins, ultra-slow to intermediate spreading rates and from ridges characterized by different crustal thicknesses. This new information will improve understanding of a number of fundamental questions in MORB petrology including: 1) the comparative depth of crystallization in different MOR environments for olivine and plagioclase (how crystal sorting influence what is being sampled), 2) the depth dependence of the processes responsible for MOR differentiation, 3) the extent to which CO2/trace element ratios can be used to estimate the mantle C budget. A core aspect of this proposal involves outreach to students at the tribal colleges in South Dakota which will consist of three parts including current programs at South Dakota Mines, mentoring students from Oglala Lakota College (OLC), and providing advice on the development of the analytical facilities at OLC.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.

协作研究：了解构造环境对中山山脊系统中岩浆过程深度的影响。铺平海底的岩石覆盖了地球表面的70％，并由沿着中山山脊（MOR）系统的火山产生。这些火山可以说是地壳中最大的地质系统。通过分析MOR爆发的熔岩，地质学家了解这些岩浆的产生方式以及它们在表面上升时如何化学变化。但是，关于形成的深度以及在MOR系统的不同部位如何改变的理解较少。关于MOR熔岩中晶体形成深度的新数据，基于晶体中岩浆滴落液滴中的二氧化碳（熔体夹杂物），表明晶体是在较宽的深度范围内产生的。因此，这些晶体提供了从深度和控制海皮形成过程的过程中遇到的岩浆成分的记录。这项研究将化学分析微观熔体夹杂物和晶体，以了解岩浆形成的深度在全球范围内。这些新数据将提供有关不同环境中结晶深度和地幔碳预算的信息。该提案的一个核心方面涉及南达科他州部落学院的学生推广，其中包括三个部分，包括在南达科他州矿山的当前计划，来自Oglala Lakota College（OLC）的心理学生，并提供有关OLC的分析设施的发展的建议。（MI）组成。此类数据最有用的关于在上地幔和地壳中活跃的混合和分化过程的复杂阵列 - 本质上正在发生“什么”。很难约束的是“在其中”特定过程在深度方面处于活动状态，这使得解决熔化状态中发生的过程的影响与向表面运输过程中发生的过程的影响。关于熔体夹杂物深度的新数据（基于CO2饱和/浓度）表明，海底玄武岩中的许多晶体货物，尤其是斜长石超乳底层（PUB）的晶体货物是在巨大压力下结晶的产物。因此，他们提供了一个机会，可以调查岩浆成分在运输过程中的发展以及控制海壳形成的能量和质量的分布在构造环境之间的不同（不同的扩展速率，岩浆供应，熔化的程度等）。这项研究将通过电子微探针（对于主要元素组成），激光ICP-MS（痕量元素组成），次级离子质量谱法（玻璃CO2，H2O，S）和拉曼光谱（MI气泡密度/组成）进行联合分析。所选的样品代表了来自各种设置，轴上的许多酒吧熔岩，将低音拉开，超慢慢到中间扩散速率以及以不同的地壳厚度为特征的山脊。这些新信息将提高对MORB岩石学中许多基本问题的理解，包括：1）在不同的MOR环境中，橄榄石和斜长石的比较深度（晶体分类如何影响被取样的内容），2））深度依赖于MOR差异的过程，3）造成了哪些CO2/Trace Element Element Element retairs for Matiate for Mate catimate at Manant catimation the Mant caste ate the Mant估算。 A core aspect of this proposal involves outreach to students at the tribal colleges in South Dakota which will consist of three parts including current programs at South Dakota Mines, mentaling students from Oglala Lakota College (OLC), and providing advice on the development of the analytical facilities at OLC.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 标准。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Correlation of Depth of Formation with Petrogenetic Processes: Evidence from Plagioclase-Hosted Melt Inclusions

地层深度与成岩过程的相关性：斜长石熔融包裹体的证据

DOI：
10.7185/gold2023.17071
发表时间：
2023
期刊：
Proceedings of 2023 Goldschmidt Conference
影响因子：
0
作者：
Daynes, Olivia;Ustunisik, K. Gokce;Nielsen, Roger;Betts, Madison;Gaetani, Glenn
通讯作者：
Gaetani, Glenn

Correlation of Depth of Differentiation to Tectonic Setting: Evidence from Plagioclase Ultraphyric Basalts

分异深度与构造环境的相关性：来自斜长超晶玄武岩的证据