Collaborative Research: Hawaiian Plume Heterogeneity Revealed by Kilauea's Ongoing Eruption, Prehistoric Lavas and Olivine-hosted Melt Inclusions

知识价值。夏威夷岛上的基拉韦厄火山是世界上最活跃、监测最严密的火山之一。基拉韦厄火山岩浆供应速率高，岩浆管道系统清晰，是研究玄武岩岩浆成因基本问题的理想场所。它的熔岩提供了重要的岩石学和地球化学线索，用于描绘夏威夷羽流中成分非均质性的本质，并用于评估其他方法无法轻易确定的岩浆生成过程。pi先前记录了基拉韦厄火山近期熔岩中系统的短期和中期（几十年到几百年）地球化学变化。几个世纪以来，基拉韦厄山顶的熔岩记录了与火山喷发速率等火山过程相关的循环地球化学趋势（枯竭的火山源似乎经历了较低程度的融化，产生的岩浆较少）。为了继续这项工作，提出了一种三管齐下的方法，将野外工作与岩石学、矿物化学、全岩主元素和微量元素丰度以及O、Pb、Sr和Nd同位素比值相结合，以评估基拉韦厄熔岩组成变化的地幔原因（来源和过程）。第一部分对Puu Oo火山喷发的地球化学演化进行了持续监测，显示出与地壳和地幔过程相关的显著成分变化。不断变化的熔岩成分为岩浆过程提供了新的认识。第二部分考察了公元900年至1400年基拉韦厄火山口西北壁上的Uwekahuna Bluff熔岩部分。这项研究将允许在几个世纪的时间尺度上评估基拉韦厄火山明显的循环地球化学变化，并阐明夏威夷羽流内部的小尺度非均质性分布和地幔融化动力学。第三部分利用电子探针、LA-ICPMS、O同位素激光质谱和SHRIMP离子探针研究了基拉韦厄历史峰顶熔岩中高橄榄石橄榄石（86%）中含橄榄石的熔体包裹体。对这些包裹体的初步研究表明，在单个熔岩中存在着巨大的成分多样性，这可能与岩浆在山顶储层中相对较短的停留时间（30-100年）有关。这些包裹体中主要元素和微量元素丰度以及O和Pb同位素比值将被确定，以更好地约束夏威夷地幔柱内部的地幔非均质性和熔融过程。更广泛的影响。本研究的广泛影响包括：(1)利用基拉韦厄火山的研究成果，为本科生和研究生的岩石学课程开发教学模块，突出活火山的岩浆过程，强调合作学习和高级思维技能的发展；(2)指导研究生和本科生；(3)向学校团体和当地社区进行公开讲座；(4)更好地了解可能对生活质量产生负面影响的火山；(5)通过协作和多用户设施的利用，加强国际和国家科学合作。

Intellectual Merit. Kilauea, on the island of Hawaii, is one of the most active and best-monitored volcanoes in the world. Its high magma supply rate and well delineated magmatic plumbing system make Kilauea an ideal venue for addressing fundamental questions about basaltic magma genesis. Its lavas provide essential petrologic and geochemical clues for delineating the nature of compositional heterogeneity within the Hawaiian plume and for assessing magma generation processes that cannot be readily ascertained by other methods. The PIs previously documented systematic short- and moderate-term (decades to centuries) geochemical variations within Kilauea's recent lavas. Over several centuries, Kilauea summit lavas record cyclic geochemical trends that correlate with volcanic processes such as eruption rates (more depleted sources appear to have undergone lower degrees of melting and produced less magma). To continue this work, a three-pronged approach is proposed combining field work with petrography, mineral chemistry, whole-rock major element and trace element abundances, and O, Pb, Sr, and Nd isotope ratios to assess the mantle causes (source and process) for compositional variation in Kilauea lavas. Part 1 involves continued monitoring of the geochemical evolution of the Puu Oo eruption, which has shown remarkable compositional variation related to crustal and mantle processes. Changing lava compositions provide new insights into magmatic processes. Part 2 examines the AD 900 to 1400 Uwekahuna Bluff lava section on the northwestern wall of the Kilauea's caldera. This study will allow evaluation of apparently cyclic geochemical variations at Kilauea on a few century time scale, and elucidate distribution of small-scale heterogeneities and the dynamics of mantle melting within the Hawaiian plume. Part 3 utilizes electron microprobe, LA-ICPMS, O isotope laser mass spectrometry and SHRIMP ionprobe to study olivine-hosted melt inclusions in high forsterite olivines (86%) from selected Kilauea historical summit lavas. Preliminary work on these inclusions shows tremendous compositional diversity within individual lavas that may be related to the relatively short residence of magma in the summit reservoir (30-100 years). Major- and trace-element abundances, and O and Pb isotope ratios will be determined in these inclusions to better constrain the mantle heterogeneities and melting processes within the Hawaiian plume.Broader Impacts. Broader impacts of this research include (1) developing teaching modules for undergraduate and graduate petrology classes using the results from our Kilauea research to highlighting magmatic processes at an active volcano and emphasing cooperative learning and development of higher order thinking skills, (2) mentoring graduate and undergraduate students, (3) giving public lectures to school groups and the local community, (4) gaining a better understanding of volcanoes that can negatively influence the quality of life, and (5) increasing international and national scientific cooperation through collaboration and utilization of multiuser facilities.