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

智力优势。位于夏威夷岛上的基拉韦厄是世界上最活跃、监测最好的火山之一。它的高岩浆供应率和良好划定的岩浆管道系统使基拉韦厄一个理想的场所，解决有关玄武岩浆成因的基本问题。它的熔岩提供了必要的岩石学和地球化学线索，描绘的性质组成的异质性在夏威夷羽和评估岩浆生成过程，不能很容易地确定其他方法。PI先前记录了基拉韦厄近期熔岩中系统的短期和中期（数十年至数百年）地球化学变化。几个世纪以来，基拉韦厄火山顶熔岩记录了与火山过程相关的周期性地球化学趋势，如喷发率（更多的枯竭来源似乎经历了较低程度的熔融，产生较少的岩浆）。为了继续这项工作，提出了一个三管齐下的方法相结合的野外工作与岩相学，矿物化学，全岩的主要元素和微量元素丰度，O，Pb，Sr，Nd同位素比值，以评估地幔的原因（源和过程）组成变化的基拉韦厄熔岩。第1部分涉及继续监测Puu Oo喷发的地球化学演化，这表明与地壳和地幔过程有关的显著成分变化。不断变化的熔岩成分为岩浆过程提供了新的见解。第二部分研究了公元900年至1400年乌韦卡胡纳海崖熔岩部分的西北壁上的基拉韦厄的破火山口。这项研究将允许在几个世纪的时间尺度上，在基拉韦厄明显的周期性地球化学变化的评价，并阐明小规模的非均匀性分布和地幔熔融的动力学在夏威夷羽。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火山历史顶峰熔岩中高镁橄榄石（86%）中的橄榄石熔融包裹体。对这些包裹体的初步研究表明，单个熔岩中的成分具有巨大的多样性，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。主要和微量元素丰度，O和Pb同位素比值将在这些包裹体中确定，以更好地约束地幔的不均匀性和熔融过程中的夏威夷羽。这项研究的更广泛的影响包括：（1）利用我们的基拉韦厄研究成果为本科生和研究生岩石学课程开发教学模块，以突出活火山的岩浆过程，并强调合作学习和高阶思维技能的发展，（2）指导研究生和本科生，（3）为学校团体和当地社区举办公开讲座，（4）更好地了解可能对生活质量产生负面影响的火山，（5）通过合作和利用多用户设施，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.