Secondary Hawaiian Hotspot Volcanism: What, When, Where, and Why?

夏威夷次生热点火山活动：什么、何时、何地以及为什么？

• 批准号: 0510482
• 负责人: Michael Garcia
• 金额: --
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-10-01 至 2011-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510482&HistoricalAwards=false
• 关键词: Secondary; Hawaiian; Hotspot; Volcanism; What

Many oceanic volcano chains are formed by hotspots in the Earth's mantle. Most of the volcanism associated with hotspots is thought to occur directly over the mantle hotspot constructing features Hawaiian, Canary, Society island chains. However, this main phase is commonly followed by a period of quiescence and then a secondary volcanic phase. Diamond Head volcano on O`ahu, Hawaii, is a textbook example of secondary volcanism. The cause of such late-stage volcanism remains an enigma. This three-year project, funded jointly by the Divisions of Earth and Ocean Sciences, will examine the what (compositions), where (distribution and volumes), when (ages), and why (mechanisms) of secondary volcanism on and around the northern Hawaiian Islands. It is a coordinated land- and sea-based project with four main phases: (1) onshore mapping, sampling, and compilation of water well information to determine the volumes, ages and compositions of rejuvenated volcanism on Kaua`i and O`ahu. (2) A 28-day marine expedition to map the Kaua`i and Ni`ihau submarine volcanic fields with multibeam bathymetry and acoustic imagery, and to sample many of its volcanoes using the JASON2 ROV to characterize the petrology, geochemistry (major & trace elements, and isotopes) and ages of these lavas. (3) Integration of these results with previous surveys and petrologic/geochemical studies to establish a quantitative database for Hawaiian volcanic evolution. (4) Geodynamic modeling of this database to evaluate mechanisms for secondary volcanism. A first-order objective will be to establish how the submarine form of volcanism relates in space, time, volume, and composition to the nearby main shield volcanoes and their associated onshore secondary volcanism. Results will feed numerical modeling efforts to test proposed origins of secondary volcanism such as small-scale mantle convection driven by thermal and/or compositional buoyancy. The broader impacts of the proposed project include a K-12 interactive education program involving lesson-planning and interactive web activities with sciences classes throughout the state of Hawaii before, during and after our marine work. Also, we will mentor several graduate and undergraduate students on research projects. We will recruit underrepresented students in our research, give public lectures to school groups and the local community on Hawaiian volcanism, and gain a better understanding of the volcanic environment which impacts all life in Hawaii.

许多海洋火山链是由地幔中的热点形成的。 大多数与热点有关的火山活动被认为直接发生在地幔热点上，构成了夏威夷、加那利群岛和社会群岛的特征。然而，这一主要阶段之后通常是一段平静期，然后是第二次火山阶段。 位于夏威夷奥克拉荷马州的钻石头火山是次级火山作用的典型例子。 这种晚期火山活动的原因仍然是一个谜。 这个为期三年的项目，由地球和海洋科学司共同资助，将研究什么（成分），在哪里（分布和体积），何时（年龄），为什么（机制）的次生火山活动的北方夏威夷群岛上和周围。 这是一个协调的陆地和海上项目，分为四个主要阶段：（1）陆上绘图、取样和水井资料汇编，以确定考艾岛和奥巴桑乔岛复活火山活动的数量、年龄和组成。(2)进行为期28天的海洋考察，利用多波束测深和声学成像绘制考艾岛和尼豪岛海底火山区的地图，并利用JASON 2号卫星对许多火山进行取样，以确定这些熔岩的岩石学、地球化学（主要微量元素和同位素）和年龄特征。(3)将这些结果与以前的调查和岩石学/地球化学研究相结合，建立夏威夷火山演化的定量数据库。(4)这个数据库的地球动力学建模，以评估次生火山作用的机制。 一个首要目标是确定海底火山活动在空间、时间、体积和成分上与附近的主要盾状火山及其相关的陆上次生火山活动之间的关系。结果将饲料数值模拟的努力，以测试拟议的起源次生火山活动，如小规模的地幔对流驱动的热和/或成分浮力。 拟议项目的更广泛影响包括一个K-12互动教育计划，涉及课程规划和互动网络活动，在我们的海洋工作之前，期间和之后，整个夏威夷州的科学课程。此外，我们将指导几个研究生和本科生的研究项目。我们将在我们的研究中招募代表性不足的学生，为学校团体和当地社区举办关于夏威夷火山活动的公开讲座，并更好地了解影响夏威夷所有生命的火山环境。