EaGER:The influence of CO2 solubility on trace element partitioning in clinopyroxene-alkali basalt systems: towards the development of a magmatic carbon meter

EaGER：二氧化碳溶解度对单斜辉石-碱性玄武岩系统中微量元素分配的影响：致力于开发岩浆碳计

• 批准号: 1057611
• 负责人: Julia Bryce
• 金额: $ 4.5万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1057611&HistoricalAwards=false
• 关键词: EaGER; influence; CO2; solubility; trace

This EaGER will support a feasibility study to evaluate the influence of carbon dioxide (CO2) on the concentration of trace elements in clinopyroxene, in equilibrium with basaltic magma. The ultimate goal of the experimental plan is to assess if the trace element compositions recorded in clinopyroxene (cpx) may serve as a proxy for magmatic CO2. If successful, results from the study could be applied both to those wishing to decipher the source history of a magma as well as the Earth's degassing history. The proposed research plan will complement to existing experiments in CO2-diopside-albite ternary systems that show a large variation in cpx-melt partitioning for alkali, alkaline earth and high field strength elements between carbonatitic and silicate liquids. Since CO2 enrichment is often concomitant with water enrichment in mafic lavas, the experimental design also includes experiments with varying water content so that it is possible to assess the role of dissolved water and carbonate on elemental partitioning. The target starting composition for this pilot study will be chosen from an in-hand suite of clinopyroxene-phyric, calcium and sodium-rich alkaline basalts from Mt. Etna, Sicily (MgO ~ 6 wt. %).Reconstructing the history of volatile emissions on Earth is an essential part of understanding climate controls, yet volatile mobility hampers preservation in the rock record. A recent study using large statistical analysis of recent volcanism has linked the latest episode of deglaciation with enhanced subaerial volcanism and, presumably, subsequently increased volcanic carbon dioxide emissions. This potential role of solid Earth carbon storage in promoting deglaciation impacts the long-established argument that climate is controlled by ocean-atmosphere exchange alone. Presently, other than by amassing records of volcanism chronologically constrained to coincide with episodes of deglaciations, it is difficult to test and refine this hypothesis from the rock record alone, largely because CO2 is not quantitatively contained during magma transport at shallow depths, with up to 90% degassed prior to eruption. The proposed research activities seek to identify whether magmatic carbon dioxide contents impact high field strength element chemistry of basaltic magmas, thereby potentially providing a proxy that enables documentation of carbon dioxide contents in magmas. Links with a world-class experimental facility will enhance technique development in newly established laboratories at UNH. The award provides postdoctoral support for a promising female scientist on an interdisciplinary project within a collaborative multi-institutional work group.

EaGER将支持一项可行性研究，以评估二氧化碳（CO2）对与玄武岩浆平衡的单斜辉石中微量元素浓度的影响。实验计划的最终目标是评估是否微量元素组合物记录在单斜辉石（cpx）可以作为岩浆CO2的代理。如果成功的话，这项研究的结果可以应用于那些希望破译岩浆源历史以及地球脱气历史的人。拟议的研究计划将补充现有的实验中的CO2透辉石钠长石三元系统，显示了一个大的变化，在碳酸盐和硅酸盐液体之间的碱金属，碱土金属和高场强元素的cpx熔体分配。由于CO2富集往往是伴随着水富集在镁铁质熔岩，实验设计还包括不同的水含量的实验，以便有可能评估溶解水和碳酸盐元素分配的作用。该试验性研究的目标起始组合物将从来自Mt.埃特纳，西西里（MgO ~ 6 wt.重建地球上挥发性排放的历史是理解气候控制的重要组成部分，但挥发性流动性阻碍了岩石记录的保存。最近的一项研究使用了对近期火山活动的大量统计分析，将最近一次冰川消退与陆上火山活动的增强联系起来，并推测随后火山二氧化碳排放量增加。固体地球碳储存在促进冰川消退方面的潜在作用影响了长期以来的论点，即气候仅受海洋-大气交换控制。目前，除了通过收集火山活动的记录来限制与冰川消退事件相一致之外，很难单独从岩石记录中测试和完善这一假设，主要是因为在浅层的岩浆运输过程中，二氧化碳没有定量地被包含，在喷发之前，高达90%的二氧化碳被脱气。拟议的研究活动旨在确定岩浆中的二氧化碳含量是否会影响玄武岩浆的高场强元素化学，从而可能提供一个替代品，使岩浆中的二氧化碳含量的文件。与世界级实验设施的联系将加强联合国总部新设立的实验室的技术发展。该奖项为一位有前途的女科学家在一个多机构协作工作组内开展跨学科项目提供博士后支持。