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

夏威夷山脊年龄、来源、成分和熔体通量变化：对羽流动力学和板块运动学的影响

• 批准号: 1219955
• 负责人: Michael Garcia
• 金额: $ 34.99万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1219955&HistoricalAwards=false
• 关键词: Hawaiian; Ridge; Age; Source; Composition

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.

智力优点。 线性海洋岛链是我们地球上最独特的特征之一。夏威夷皇家连锁店是经典的例子。它是地球上最长的链条之一，无论是在时空和空间上，都有80+ MYR的活动，长度约为6000公里。链条在构造上很简单，在最后70多个Myr的任何板缘或大陆都与任何板缘或大陆相距甚远。尽管它对我们对地幔羽流和新生代板运动的理解重要，但我们对沿夏威夷链的年龄和地球化学变化的了解仍然存在很大的差距。此外，它记录了过去30 MYR的岩浆通量的无法解释的急剧增加。为了解决我们的理解，它提议：[1]提供新的40AR/39AR年龄，以及全摇滚专业，痕量和同位素（PB，SR，SR，ND，ND和HF）的地球化学，用于从夏威夷山脉（夏威夷群岛NW）（使用现有山地岛）的20个火山的熔岩，这些熔岩跨越约2150 km。地球化学数据将用于确定夏威夷地幔羽流源成分的长期演变，并评估在夏威夷山脊创建期间地幔电势温度，熔解压力和/或源岩性学的系统变化。在发生区域变化的范围内，它们将被利用以约束沿山脊融化产生的变化。 [2]使用新时代和IODP结果对夏威夷和路易斯维尔山脊进行计算并比较了路易斯维尔山脊的结果，并更新了测深数据。 [3]利用新时代来修改新生代太平洋板块运动，并计算差异运动，因为随着时间的推移，沿脊的压力变化的代理，以评估板运动对岩浆产生的影响。这个跨学科的项目在我们对海洋岛和海洋链如何形成和进化以及生活如何在夏威夷山脊沿岸传播的理解方面具有潜在的变革性。例如，该项目的结果将使生物学家可以更好地预测夏威夷本地物种及其进化的生物地理学。同样，这项研究有可能改变我们当前对地幔羽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整合在一起的教育模块。它将着重于开发基于合作的，基于询问的教材，这些教学材料有效地模拟了研究经验并建立教育者与科学家之间的伙伴关系。夏威夷山脊上的交互式实验室模块还将发布用户友好的指南，该指南将在著名的Carleton大学教育网站（http://serc.carleton.edu/nagtworkshops/portryology/index.html）上访问，并在Education ListServer Server Sites上进行广告。本指南将为大学级别的讲师（介绍性和更高级的本科课程）提供基础，以使用有关世界的新研究的线性岛屿连锁店的经典示例，即夏威夷山脊，以吸引学生参与基于研究的学习。 该项目将指导大约一名以及研究生和本科生。项目结果将发表在国际文献中，并在国际数据库中存档的数据（例如PETDB； Georoc； Geochron）。所有样本将获得向地球科学社区提供的其他研究的唯一识别数字和拆分。