Hawaiian Ridge Age, Source, Composition and Melt Flux Variations: Implications for Plume Dynamics and Plate Kinematics

智力上的功绩。线性海洋岛链是我们星球上最独特的特征之一。夏威夷-帝王连锁就是典型的例子。它是地球上最长的链之一，无论是在时间上还是在空间上，它的活动时间都在80+Myr以上，长度约6000公里。这条链在构造上很简单，在过去的70多年里远离任何板块边缘或大陆。尽管它对我们理解地幔羽流和新生代板块运动很重要，但我们对该链夏威夷部分的年龄和地球化学变化的了解存在很大差距。此外，它还记录了过去30年来无法解释的、急剧增加的岩浆流量。为了弥补我们认识上的这些差距，建议：[1]利用夏威夷大学收集的现有岩石样本，提供新的40Ar/39Ar年龄和全岩主要、痕量和同位素(铅、锶、钕和氢)地球化学，用于20座火山的熔岩，这些火山跨越夏威夷山脉(夏威夷群岛西北部)约2150公里。这些地球化学数据将被用来确定夏威夷地幔热柱源组分的长期演化，并评估在夏威夷海脊形成期间，地幔潜在温度、熔融压力和/或源岩性是否有系统的变化。只要区域差异发生，它们将被利用来限制沿山脊的熔体生产的变化。[2]使用路易斯维尔海脊的新年龄和IODP结果以及更新的水深测量数据，计算和比较夏威夷海脊和路易斯维尔海脊的岩浆通量。[3]利用新的年龄对新生代太平洋板块运动进行修正，并计算差动作为海脊应力随时间变化的指标，以评价板块运动对岩浆产生的影响。这个跨学科的项目可能会改变我们对大洋岛和海山链是如何形成和演化的理解，以及生命是如何沿着夏威夷山脊传播的。例如，这个项目的结果将使生物学家能够更好地预测夏威夷本土物种的生物地理及其进化。此外，这项研究有可能改变我们目前对地幔热柱和板块构造如何相互影响的看法。更广泛的影响。将开发一个将研究与教育相结合的教育模块。它将专注于开发合作的、基于探究的教材，有效地模拟研究经验，并在教育工作者和科学家之间建立伙伴关系。夏威夷山脊上的互动实验室模块也将与用户友好的指南一起发布，教师可以在著名的卡尔顿大学教育网站(http://serc.carleton.edu/NAGTWorkshops/petrology/index.html)上访问该指南，并在教育列表服务器网站上发布广告。这本指南将为大学层面的教师(包括入门课程和更高级的本科课程)提供基础，让他们使用有关世界的新研究-S的经典例子--夏威夷海脊--来吸引学生进行研究性学习。博士后、研究生和本科生将在这个项目中得到指导。项目成果将发表在国际文献和国际数据库(如PetDB；GEOROC；GEOCHRON)中存档的数据中。所有样品都将被赋予唯一的识别号和分割物，供地球科学界进行其他研究。

Intellectual Merit. Linear ocean island chains are one of the most distinctive features on our planet. The Hawaiian-Emperor Chain is the classic example. It is one of the longest chains on Earth, both in time and space, active for 80+ Myr and extending ~6000 km in length. The Chain is tectonically simple, being distant from any plate margin or continent for the last 70+ Myr. Despite its importance to our understanding of mantle plumes and Cenozoic plate motion, there are large gaps in our knowledge of the age and geochemical variations along the Hawaiian portion of the Chain. Also, it records an unexplained, dramatic increase in magma flux over the last 30 Myr. To address these gaps in our understanding, it is proposed to: [1] Provide new 40Ar/39Ar ages, and whole-rock major, trace and isotopic (Pb, Sr, Nd and Hf) geochemistry for lavas from 20 volcanoes that span ~2150 km of the Hawaiian Ridge (NW of the Hawaiian Islands) using existing rock samples from the University of Hawaii collection. The geochemical data will be used to determine the long-term evolution of the Hawaiian mantle plume source components and to evaluate whether there have been systematic variations in mantle potential temperature, melting pressure, and/or source lithology during the creation of the Hawaiian Ridge. To the extent regional variations occur, they will be exploited to constrain variation in melt production along the Ridge. [2] Compute and compare the magma flux for the Hawaiian and Louisville Ridges using new age and IODP results for Louisville Ridge, and updated bathymetric data. [3] Utilize the new ages to revise Cenozoic Pacific plate motions and to compute differential motions as proxies for stress changes along the Ridge over time so as to evaluate the influences of plate motion on magma production. This cross-disciplinary project is potentially transformative regarding our understanding of how oceanic island and seamount chains are formed and evolve, and also how life has propagated along the Hawaiian Ridge. For example, results from this project will allow biologists to make better predictions about biogeography of native Hawaiian species and their evolution. Also, this study has the potential to shift our current perception of how mantle plumes and plate tectonics influence one another. Broader Impacts. An education module will be developed that integrates research with education. It will focus on developing cooperative, inquiry-based teaching materials that effectively simulate research experiences and build partnerships between educators and scientists. An interactive laboratory module on the Hawaiian Ridge will also be published with a user-friendly guide that will be accessible to teachers on the well-known Carleton University education website (http://serc.carleton.edu/NAGTWorkshops/petrology/index.html) and advertised on education listserver sites. This guide will provide a foundation for instructors at the university level (both introductory and for more advanced undergraduate courses) to use pertinent new research on the world?s classic example of a linear island chain, the Hawaiian Ridge, to engage students in research-based learning. A post-doc, and graduate and undergraduate students will be mentored in this project. Project results will be published in the international literature and data archived in international databases (e.g., PetDB; GEOROC; GEOCHRON). All samples will be given unique identification numbers and splits made available to the geosciences community for other studies.