Origin and Deformation of the Ontong Java Plateau

翁通爪哇高原的起源和变形

• 批准号: 1459152
• 负责人: Brian Savage
• 金额: $ 32.24万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459152&HistoricalAwards=false
• 关键词: Origin; Deformation; Ontong; Java; Plateau

The Ontong Java Plateau (OJP) covers 2 million km2 of seafloor, made up of 100 million km3 lavas that erupted rapidly ~120 Ma. This event represented a major heat and mass transfer from the Earth's deep interior to the surface. The cause of this magmatic event and the associated deformation of the plate on which this large load was emplaced are unclear. Recent work by these scientists has identified seismic structure in the mantle beneath the OJP that can only be explained by rock composition that would correspond to recycled oceanic crust. If true, this would suggest that subducted oceanic plates do not complete assimilate in the deep Earth. At least portions can survive the high temperatures and pressures and be caught up in global mantle circulation. Validating the presence of a mechanically strong mantle root beneath the OJP with quantitative estimates of its physical and chemical characteristics is expected to further understanding of the evolution of the oceanic lithosphere and the formation and survival of continental cratonic keels.A team of scientists from Japan, UK, and US are deploying ocean-bottom seismometers, electromagnetometers, and land based seismic stations on and around the Ontong Java between 2014-2016. This project supports US scientists and students to participate in onshore seismic data collection and analysis of the full amphibious dataset. All the seismic data for the combined projects will be shared among all the team and analyzed in collaboration. The US scientists will conduct advanced seismic analysis using 3-D full-wave tomography, and characterizations of anisotropy and attenuation. The new results would achieve 1° resolution, much improved over the current ~5° resolution that has led to contrasting interpretations of the distribution of low velocity within the OJP root. Teaching modules will be created and made available at Carleton College's On the Cutting Edge Geoscience site. Aspects of the data, analysis techniquest, and interpretation will be incorporated in undergraduate and graduate courses.

安通爪哇高原(OJP)覆盖了200万平方公里的海底，由1亿平方公里的熔岩组成，这些熔岩在~120 Ma左右迅速喷发。这一事件代表了从地球内部到地表的一次重大的热量和质量转移。这一岩浆事件的原因以及与之相关的大负荷板块的变形尚不清楚。这些科学家最近的工作已经确定了OJP之下地幔中的地震结构，这种结构只能通过与回收的洋壳相对应的岩石成分来解释。如果这是真的，这将表明俯冲的海洋板块并没有完全同化于地球深处。至少有一部分可以在高温和高压下存活下来，并被卷入全球地幔循环。通过对其物理化学性质的定量估计，验证OJP之下存在机械强度较强的地幔根部，有望进一步了解大洋岩石圈的演化以及大陆克拉通龙骨的形成和生存。来自日本、英国和美国的一个科学家团队将在2014-2016年间在安通爪哇及其周围部署海底地震仪、电磁仪和陆基地震台。该项目支持美国科学家和学生参与陆上地震数据收集和对完整的两栖数据集的分析。合并项目的所有地震数据将在所有团队之间共享，并在协作中进行分析。美国科学家将使用3D全波层析成像技术进行高级地震分析，并对各向异性和衰减进行表征。新的结果将达到1°的分辨率，比目前的~5°分辨率有了很大的提高，这导致了对OJP根部内低速分布的对比解释。教学模块将在卡尔顿学院的尖端地球科学网站上创建和提供。数据、分析技术和口译方面的内容将被纳入本科生和研究生课程。