Accomplishment Based Renewal: Magmatic Processes at Mid-Ocean Ridges

摘要（0524922）辛顿 学术成就：该项目研究控制洋中脊火山岩化学成分和矿物学的过程。 它具体解决了上涌地幔熔融的变化如何影响原生岩浆的成分，以及这些岩浆在地壳和地幔不同深度的冷却和结晶作用下如何在化学和矿物学上发生变化。 这项研究结合了理论模型、对地壳厚度的地球物理限制以及对来自加拉帕戈斯扩张中心和冰岛西部火山区中洋脊的天然样品的化学和岩相分析。 这些对照样品组将有助于评价扩张速率、地幔源成分、地幔温度、地壳厚度的变化和喷发方式的变化如何造成大洋中脊熔岩在沿着扩张脊特定地点的物理和化学变化。 这项工作包括确定选定样品中个别矿物（橄榄石、长石、辉石和氧化物）的相对比例，并分析这些矿物以及整个岩石样品的化学成分。 具体样品集包括：（1）来自加拉帕戈斯地区的不寻常的海底熔岩，铝含量非常高;（2）来自加拉帕戈斯地区的至少另外两组样本，代表距离造成加拉帕戈斯群岛的地幔异常不同距离的样本;以及（3）两个喷发单元，其年龄和位置接近冰岛暴露的陆上中洋脊。 冰岛的工作将调查在单一喷发事件中不同时间喷发的样本，这将使我们能够以加拉帕戈斯地区不可能的方式处理喷发过程。 它还允许调查地幔源的变化，熔融条件和岩浆演化过程在短的空间（~20公里）和时间（~400年）scales.Broader影响：这项工作支持教师和研究生在夏威夷大学。 学生培训将包括广泛的分析和岩石学技术和理论，以及对冰岛地质学的介绍。 本科生将参与化学和岩相分析岩石样品的制备。 这项研究的结果将被纳入课堂教学和社区演示，并发表在广泛访问的同行评审期刊文章。

ABSTRACT (0524922) Sinton Intellectual Merit: This project investigates processes that control the chemical composition and mineralogy of mid-ocean ridge volcanic rocks. It specifically addresses how variations in melting of upwelling mantle affect the composition of primary magmas and how these magmas are changed in chemistry and mineralogy by cooling and crystallization at different depths in the crust and mantle. This research combines theoretical models, geophysical constraints on the thickness of the crust, and chemical and petrographic analyses of natural samples from the Galapagos Spreading Center and Icelandic Western Volcanic Zone mid-ocean ridges. These contrasting sample sets will allow evaluation how variations in spreading rate, mantle source composition, mantle temperature, crustal thickness and variations in eruptive style create physical and chemical variations in mid-ocean ridge lavas at specific locations along spreading ridges. The work involves determining the relative proportions of individual minerals (olivine, feldspar, pyroxene and oxide) in selected samples and analyzing for the chemical compositions of these minerals as well as of whole-rock samples. Specific sample sets include: (1) unusual submarine lavas from the Galapagos area with very high aluminum contents; (2) at least two other sample sets from the Galapagos area that represent samples with varying distance from the mantle anomaly that is responsible for the Galapagos archipelago; and (3) Two eruptive units close in age and location from the subaerial mid-ocean ridge exposed in Iceland. The Icelandic work will investigate samples erupted at different times during single eruption episodes, which will allow us to address eruptive processes in ways not possible in the Galapagos area. It also permits investigation of variations in mantle sources, melting conditions and magma evolution processes over short spatial (~20 km) and temporal (~400 years) scales.Broader Impacts: This work supports a faculty member and graduate student at the University of Hawaii. Student training will include a wide range of analytical and petrological techniques and theory, as well as an introduction to Icelandic geology. Undergraduate students will be involved in the preparation of rock samples for chemical and petrographic analysis. Results of this research will be incorporated into classroom teaching and community presentations and published in widely accessible peer-reviewed journal articles.