Collaborative Research: Geophysical Constraints on Mechanisms of Ocean Plateau Formation from Shatsky Rise, Northwest Pacific

该奖项是根据2009年美国复苏和再投资法(公法111-2)资助的。确定巨大的大火成岩省的起源是了解地幔动力学及其与陆地岩浆作用关系的关键因素。在海洋中的十几个大型海洋高原中，沙茨基隆起是一个重要的目标，因为它独特的构造环境。这是唯一一个在磁反转异常频繁的时候形成的巨大高原，表明它与同时代的扩张脊有关。IODP 324探险队目前还计划在2009年底对沙茨基隆起五个地点的沉积物和上层火成岩层进行采样，这可能会提供重要的地面真相。PIS提出了一个具有两个焦点的合作地球物理项目：(1)通过OBS反射和折射实验来约束地壳结构；(2)通过MCS剖面图以及对水深和地磁数据的再分析来描绘构造历史。一种新的地壳地震结构模型将在厚度与速度相关的基础上约束地幔熔融的性质。MCS揭示的详细的上地壳结构将有助于重建沙茨基隆起的构造史，该隆起似乎是一座巨大的火山，形成于三重交界处，然后因海底扩张而分裂。PIS将综合这些地球物理研究的结果，以建立一个全面的构造框架，包括对喷发速度、其时间变化、其与海脊运动学的关系以及父母地幔的同时代演化的更好估计。与日本和俄罗斯科学家以及研究生和本科生的国际合作以及航海经验是这项研究的一些更广泛的影响。还计划向在校学生进行宣传。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-2).Deciphering the origins of the giant large igneous provinces is a critical element for understanding mantle dynamics and its relation to terrestrial magmatism. Among a dozen or so large oceanic plateaus in the oceans Shatsky Rise is an important target because of its unique tectonic setting. It is the only giant plateau formed at a time of frequent magnetic reversal anomalies that show its relationship to coeval spreading ridges. IODP Expedition 324 is currently also scheduled to sample the sediments and upper igneous layers at five sites on Shatsky Rise in late 2009, which could provide important ground-truthing. The PIs propose a collaborative geophysical project with two foci: (1) constraining the crustal structure by an OBS reflection and refraction experiment, and (2) delineating the tectonic history by MCS profiling and reanalysis of bathymetry and magnetic data. A new model of crustal seismic structure will constrain the nature of mantle melting on the basis of correlation between thickness and velocity. The detailed upper crustal structure revealed by MCS will help to reconstruct the tectonic history of Shatsky Rise, which appears to be a huge volcano formed at a triple junction and then split apart by seafloor spreading. The PIs will synthesize the results of these geophysical studies to build a comprehensive tectonic framework, including better estimations of eruption rate, its temporal variation, its relation to ridge kinematics, and the coeval evolution of the parental mantle.International collaboration with the Japanese and Russian scientists and graduate and undergraduate students training and sea-going experience are some of the broader impacts of the study. Outreach to school students is also planned.