CAREER: Stable Isotope (18O/16O and D/H) Studies of Continental Arc Magmatism

职业：大陆弧岩浆作用的稳定同位素（18O/16O 和 D/H）研究

• 批准号: 9983769
• 负责人: Todd Feeley
• 金额: $ 36.07万
• 依托单位: Montana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9983769&HistoricalAwards=false
• 关键词: CAREER; Stable; Isotope; 18O; 16O

Feeley9983769Stable isotope ratios can provide important constraints on the origins of the magmatic and volatile sources of igneous rocks and the differentiation processes by which they evolve. However, traditional whole-rock isotopic measurements of glassy volcanic rocks may not reflect magmatic values because of modification during eruptive and post-eruptive degassing and alteration. In contrast, analyses of phenocrysts provides an accurate and precise means of determining isotopic variations resulting from magmatic processes. This Career research will examine variations in stable isotope compositions (18O/16O and D/H) of phenocrysts from subduction-related volcanic rocks, emphasizing (but not restricted to) intermediate lavas that provide information on the petrologic mass balance and shallow crustal degassing processes at calc-alkaline stratovolcanoes. The proposed Research Plan involves two parts: (1) detailed study of oxygen isotope variations for magmatic products erupted at the Lassen volcanic center during individual eruptive cycles and over the prolonged magmatic history of the center and (2) study of hydrogen isotope compositions of hydrous phenocrysts in rocks from Lassen and Mount St. Helens. The Education Plan involves three levels of instruction: 1) new course development; 2) traditional graduate student training, and 3) specialized undergraduate research training. The new courses created will be a lower-division, service-learning course focusing on volcanic hazards in southwest Montana, and an upper-division course in isotope geochemistry. The purpose of the undergraduate training program is to provide talented students, especially those planning on a research-oriented career, with one-on-one training in field, laboratory, and dissemination skills.

Feeley9983769恒定同位素比可以对火成岩岩石的岩浆和挥发性来源的起源以及它们进化的分化过程提供重要的约束。 但是，由于在喷发和爆发后的脱气和变化期间的修饰，传统的玻璃火山岩岩石的全岩同位素测量可能不会反映岩浆值。 相比之下，对表晶的分析提供了确定由岩浆过程产生的同位素变化的准确而精确的方法。 这项职业研究将研究稳定的同位素组成（18o/16o和d/h）的近距离火山岩石的稳定同位素组成（18o/16o和d/h）的变化，强调（但不限于）中间熔岩，这些熔岩可提供有关岩石学质量平衡和浅层层状型层状层次层层分层层层层层层层层层层层层层的熔岩。 拟议的研究计划涉及两个部分：（1）详细研究在个别喷发周期和（2）研究中心的岩浆史以及（2）研究岩石中的氢同位素组成的岩石历史上，在拉森火山中心爆发的岩浆产品的氧同位素变化。 教育计划涉及三个级别的教学：1）新课程发展； 2）传统的研究生培训和3）专业的本科研究培训。 创建的新课程将是一门较低的服务学习课程，重点是蒙大拿州西南部的火山危险，以及同位素地球化学的上限课程。 本科培训计划的目的是为有才华的学生提供，尤其是那些计划在研究的职业上的计划，并在现场，实验室和传播技能方面进行一对一的培训。