Collaborative Research: Assessment of Sulfur Recycling in Arc Magmatism through Secondary Ion Mass Spectrometry Study of Sulfur Isotopes in Experimental and Natural Mafic Glasses

合作研究：通过二次离子质谱研究实验和天然镁铁质玻璃中的硫同位素来评估电弧岩浆作用中的硫回收

• 批准号: 0838436
• 负责人: Nobumichi Shimizu
• 金额: $ 8.7万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838436&HistoricalAwards=false
• 关键词: Collaborative; Research; Assessment; Sulfur; Recycling

Intellectual merit. This proposal requests funding for acollaborative experimental and analytical study of global recycling of sulfur based on the isotopic fractionation between S-bearing gases, silicate melt, and condensed S phases (sulfate and sulfide). Scientists from three institutions are involved (American Museum of Natural History (C. Mandeville, lead PI), Woods Hole Oceanographic Institution (N. Shimizu, PI), and University of Rhode Island (K. Kelley, PI). The proposed research comprises two separate aspects. First, laboratory experiments will be carried out to determine mechanisms and magnitudes of S isotopic fractionations between coexisting phases as a function of pressure, temperature, chemical composition of silicate melt, fugacity of oxygen, and speciation of S in silicate melt and gas phase. S isotopic analysis will be made using secondary ion mass spectrometry (SIMS) techniques with the IMS 1280 ion microprobe at Woods Hole Oceanographic Institution. This new SIMS technique for sulfur isotopic measurements can now be applied to silicate glasses at the melt inclusion (10's of microns) scale thus allowing analysis of sulfur isotopes in trapped magma inclusions, evaluation of volcanic degassing, and assessment of the ultimate source of sulfur in arc magmas. In a second phase, S isotopic compositions will be determined for natural primitive magmas trapped as glass inclusions hosted by olivine, orthopyroxene and clinopyroxene; complementary volatile, lithophile and high field strength trace element abundances will be determined on the same glasses via laser ablation ICP-MS analysis at Rhode Island. This will be carried out for samples from Galunggung (Indonesia), Etna (Italy), and Augustine (Alaska), volcanoes so as to investigate S isotopic compositions of source mantle, effects of water and oxygen fugacity on S isotopic fractionation between silicate melt and S-bearing phases, and effects of degassing processes on S isotopic composition of silicate melts. Together, these research paths are expected to establish routine measurement of S isotope geochemistry as a powerful tracer for chemical fluxes across subduction zones and for assessment of sulfur recycling among Earth's major reservoirs (mantle, lithosphere (including crust), and coupled hydrosphere-atmosphere). Broader Impacts. Understanding of volatile degassing is central to monitoring and forecasting volcanic eruptions. Also. improved understanding of sulfur isotope geochemistry is vital to volcanic hazard mitigation. The PIs will incorporate the scientific results into educational and outreach programs at their respective institutions. PI Kelley is an early-career female scientist, supported by the University of Rhode Island's NSF-funded ADVANCE program, which is aimed at nurturing the careers of female scientists. She will advise a Summer Undergraduate Research Fellowship in Oceanography (SURFO) student (Univ. of Rhode Island, Graduate School of Oceanography's NSF-funded REU program) under the umbrella of this project. PI Mandeville will advise two American Museum of Natural History REU students in years 2 and 3 of this project. The PI will participate as a lecturer in the Training Renewal for Urban Science Teaching (TRUST) program at AMNH which provides professional development opportunities for greater New York City high school Earth science teachers. A TRUST session will be administered by AMNH in each year of the project.

智力上的优点。该提案要求提供资金，用于基于含硫气体、硅酸盐熔体和凝聚态硫相（硫酸盐和硫化物）之间的同位素分馏对全球硫再循环进行合作实验和分析研究。来自三个机构的科学家参与其中（美国自然历史博物馆（C。曼德维尔，首席PI），伍兹霍尔海洋研究所（N。清水，PI）和罗得岛大学（K。Kelley，PI）。拟议的研究包括两个独立的方面。首先，将进行实验室实验，以确定作为压力，温度，硅酸盐熔体的化学成分，氧逸度，和形态的S在硅酸盐熔体和气相之间的共存相的S同位素分馏的机制和幅度。S同位素分析将在伍兹霍尔海洋研究所使用IMS 1280离子微探针使用二次离子质谱（西姆斯）技术进行。这种用于硫同位素测量的新西姆斯技术现在可以应用于熔融包裹体（10微米）尺度的硅酸盐玻璃，从而允许分析捕获的岩浆包裹体中的硫同位素，评价火山脱气，并评估弧岩浆中硫的最终来源。在第二阶段，S同位素组成将被确定为橄榄石，斜方辉石和单斜辉石托管的玻璃包裹体捕获的天然原始岩浆;互补的挥发性，亲石性和高场强微量元素丰度将通过激光烧蚀ICP-MS分析在罗得岛相同的玻璃确定。这将进行从Galunggung（印度尼西亚），埃特纳（意大利）和奥古斯丁（阿拉斯加），火山样品，以研究源地幔的S同位素组成，水和氧逸度对硅酸盐熔体和含S相之间的S同位素分馏的影响，和脱气过程对硅酸盐熔体的S同位素组成的影响。总之，这些研究路径预计将建立常规测量的S同位素地球化学作为一个强大的示踪剂的化学通量在俯冲带和地球的主要水库（地幔，岩石圈（包括地壳），耦合水圈-大气）之间的硫循环的评估。更广泛的影响。了解挥发性脱气是监测和预测火山爆发的核心。Also.提高对硫同位素地球化学的认识对于减轻火山灾害至关重要。PI将把科学成果纳入各自机构的教育和推广计划。PI Kelley是一位早期职业女性科学家，由罗得岛大学的NSF资助的ADVANCE项目支持，该项目旨在培养女性科学家的职业生涯。她将建议夏季本科研究奖学金海洋学（SURFO）的学生（罗得岛大学，海洋学研究生院的NSF资助的REU计划）在这个项目的保护伞下。PI Mandeville将在该项目的第2年和第3年为两名美国自然历史博物馆REU学生提供建议。PI将作为讲师参加AMNH的城市科学教学培训更新（TRUST）计划，该计划为更大的纽约市高中地球科学教师提供专业发展机会。AMNH将在项目的每一年管理一次TRUST会议。