Testing the Significance of Melt Inclusions for Ocean Ridge Petrogenesis

测试熔体包裹体对洋脊成岩作用的意义

• 批准号: 0850442
• 负责人: Charles Langmuir
• 金额: $ 33.28万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0850442&HistoricalAwards=false
• 关键词: Testing; Significance; Melt; Inclusions; Ocean

This research tests the fidelity of melt inclusion compositions and provides new insights on the generation of magmas at ocean ridges, the most abundant volcanic province on Earth. The work involves examining the compositions of small melt inclusions in olivine crystals in seafloor volcanic rocks. The work will determine if the inclusions indicate initial conditions of magma formation or if they are modified by late-stage processes occurring at shallow crustal levels. The sample suite comes from the FAMOUS segment of the mid-Atlantic Ridge and the Gakkel Ridge in the Arctic. This study represents the first comprehensive, quantitative, and consistent dataset of olivine melt inclusions for multiple samples. Samples are phyric and primitive in composition. They have well-developed local variations that have been ascribed to melting column effects. Geochemical work includes the analysis of major, volatile and trace elements in melt inclusions from 15-20 samples. Questions to be addressed include: (1) are unusual compositions a common feature of melt inclusions from various samples; (2) is the occurrence of these unusual compositions related to segment position, lava type, or mineralogy; and (3) are major and trace element variations consistent with predictions from petrogenetic models or are they better explained by diffusion in the host crystal. Broader impacts of the work include engaging undergraduates in research and incorporation of results into university courses. It will support a postdoctoral fellow whose gender is under-represented in the sciences and increase bonds between a French and US laboratory. The work will also be featured in a new exhibit at the Harvard Museum of Natural History (HMNH). Geochemical data will be archived in PetDB. a public and Internet accessible database funded by NSF.

这项研究测试了熔融包裹体成分的保真度，并为地球上最丰富的火山区洋脊的岩浆生成提供了新的见解。 这项工作包括检查海底火山岩中橄榄石晶体中小熔融包裹体的成分。 这项工作将确定包裹体是否表明岩浆形成的初始条件，或者它们是否被发生在地壳浅层的后期过程所改变。 样本组来自大西洋中脊和北极加克尔脊的著名部分。 这项研究代表了第一个全面的，定量的，一致的数据集的橄榄石熔体包裹体多个样品。 样品为斑状，成分原始。 他们有发达的地方变化，已被归因于熔融柱效应。 地球化学工作包括对15-20个样品中熔融包裹体的主量元素、挥发性元素和微量元素的分析。 要解决的问题包括：（1）是不寻常的组合物的一个共同特征的熔融包裹体从不同的样品;（2）是这些不寻常的组合物的发生有关段的位置，熔岩类型，或矿物学;和（3）是主要和微量元素的变化与预测一致的岩石成因模型，或者他们更好地解释了扩散的主机晶体。 这项工作的更广泛影响包括让本科生参与研究，并将研究结果纳入大学课程。 它将支持一名博士后研究员，其性别在科学领域代表性不足，并增加法国和美国实验室之间的联系。 这项工作也将在哈佛自然历史博物馆（HMNH）的一个新展览中展出。 地球化学数据将在PetDB中存档。一个由NSF资助的公共和互联网访问数据库。