Collaborative Research: Magmatic Evolution of Kilauea Volcano, Hawaii: Past, Present and Future

合作研究：夏威夷基拉韦厄火山的岩浆演化：过去、现在和未来的智力价值。基拉韦厄火山是研究玄武岩岩浆作用的首选场所。它是世界上监测最好、最活跃的火山之一。野外、岩石学、地球化学和地球物理研究已经勾勒出其从地幔来源到地表的基本岩浆管道系统。现代和古代的基拉韦厄熔岩为破译夏威夷地幔热柱内成分不均一的性质和评估岩浆的产生、运输和储存过程提供了基本线索。以前对历史和史前基拉韦厄峰顶熔岩的研究记录了几十年到几个世纪的时间尺度上的周期性地球化学变化。从历史上看，这些成分变化与喷发速度(更枯竭的物源似乎经历了较低程度的熔融和产生较少的岩浆)和罕见的爆炸性喷发(例如1924年)等因素有关。对持续28年、规模巨大(3千米3)的Pu？u？u？o？o喷发的详细研究揭示了熔岩化学的短期趋势(年数)，这种趋势可能受夏威夷羽流中小规模成分不均匀的融化控制，包括最近耗尽的和类似莫纳罗亚的来源。目前，基拉韦厄火山有两次活跃喷发：在其东部裂谷带的Puu O？o(1983年至今)和在Halema？Uma？U的S火山顶峰(2008年至今)的一次新喷发。为了研究基拉韦厄熔岩的过去、现在和未来的成分变化，提出了一项包括岩石学、矿物化学、全岩常量元素和微量元素丰度以及铅、锶、钕和氧同位素比值的三部分研究。现在和未来的变化：将涉及两个时间序列实验，使用来自当前Puu O？o？和Halema？Uma？U喷发的熔岩。首先，时间序列岩石学和地球化学监测将记录喷发行为和/或熔岩化学的变化。在评估了地壳过程(例如，晶体分馏和/或岩浆混合)的影响之后，这些数据将能够评估地幔过程。其次，将Halema？Uma？U峰顶喷发的幼年玻璃状火山岩的化学成分与同时代的Puu‘o？o裂谷带熔岩以及美国地质调查局夏威夷火山观测站收集的地球物理和其他数据进行对比，以更好地圈定基拉韦厄？S岩浆管道系统的结构。在两个遥远的喷口位置(山顶和裂谷地带)的持续喷发提供了利用熔岩化学追踪岩浆通过火山-S管道系统作为时间和空间函数的机会。这项工作将对其他玄武岩火山产生影响。第三，基拉韦厄-S演化的最后200ka将利用长约1.7千米和2.0千米的连续取心的科学观察孔(SOH)钻孔中的熔岩进行评估。(SOH)核心代表了夏威夷火山早期屏蔽阶段的研究很少，夏威夷科学钻探项目(HSDP)没有对莫纳克亚火山进行采样。为了更好地约束SOH岩心样品的年龄，建议获得14个样品的高精度40Ar-39Ar年龄。这一结果将用于模拟基拉韦厄-S火山的生长速率和时间地球化学演化。将比较同古基拉韦厄(SOH，早期盾构阶段)和莫纳克亚(HSDP，盾构晚期)熔岩的化学，以评估从夏威夷羽流东部Kea侧同时提取的熔岩的地幔来源和熔融条件。拟议的研究将涉及：(1)利用基拉韦厄火山喷发的研究成果，为本科生和研究生课程开发教学模块，突出活火山的岩浆作用，并强调合作学习和高级思维技能的培养；(2)指导博士后研究人员、研究生和本科生；(3)向学校团体和当地社区举办关于基拉韦厄火山喷发的公开讲座；(4)更好地了解火山喷发可能对生活质量产生不利影响的情况；以及(5)通过合作和利用设施，加强国际和国家的科学合作。

Collaborative Research: Magmatic Evolution of Kilauea Volcano, Hawaii: Past, Present and FutureIntellectual Merit. Kilauea volcano is the premier location to study basaltic magmatic processes. It is one of the best monitored and most active volcanoes in the world. Field, petrologic, geochemical, and geophysical studies have delineated its basic magmatic plumbing system from the mantle source to the surface. Modern and ancient Kilauea lavas provide essential clues for deciphering the nature of compositional heterogeneity within the Hawaiian mantle plume and for assessing processes of magma generation, transport and storage. Previous studies of historical and prehistoric Kilauea summit lavas documented cyclic geochemical variations on a time scale of decades to centuries. Historically, these compositional variations correlate with factors such as eruption rate (more depleted sources appear to have undergone lower degrees of melting and produced less magma) and rare, explosive eruptions (e.g., 1924). Detailed investigation of the ongoing, 28-year-old, voluminous (3 km3) Pu?u O?o eruption has revealed shorter-term trends in lava chemistry (years) that may be controlled by the melting of small-scale compositional heterogeneities within the Hawaiian plume, including recently depleted and Mauna Loa-like sources. Currently, Kilauea has two active eruptions: Pu`u O?o (1983-present) on its east rift zone and a new eruption at the volcano?s summit, Halema?uma?u (2008-present).A three-part study is proposed involving petrography, mineral chemistry, whole-rock major and trace element abundances, and Pb, Sr, Nd and O isotope ratios to investigate past, present and future compositional variations in Kilauea lavas. Present and future variations: will involve two time series experiments using lavas from the current Pu`u O?o and Halema?uma?u eruptions. First, time-series petrologic and geochemical monitoring will document changes in eruptive behavior and/or lava chemistry. After assessing the effects of crustal processes (e.g., crystal fractionation and/or magma mixing), these data will allow evaluation of mantle processes. Second, the chemistry of juvenile glassy tephra from the Halema?uma?u summit eruption will be compared with contemporaneous Pu`u O?o rift zone lavas, and geophysical and other data collected by the USGS Hawaiian Volcano Observatory, to better delineate the architecture of Kilauea?s magmatic plumbing system. Sustained eruptions at two distant vent locations (summit and rift zone) provide opportunity to track the movement of magma through the volcano?s plumbing system as a function of time and space using lava chemistry. This work will have implications for other basaltic volcanoes. Third, the last 200+ ka of Kilauea?s evolution will be assessed using lavas from the ~1.7- and 2.0-km long, continuously cored Scientific Observation Hole (SOH) drill holes. The (SOH) core represents the poorly studied early shield stage of a Hawaiian volcano, which was not sampled by the Hawaii Scientific Drilling Project (HSDP) at Mauna Kea volcano. To better constrain ages for SOH core samples it is proposed to obtain high precision 40Ar-39Ar ages for 14 samples. The results will be used to model Kilauea?s volcanic growth rate and temporal geochemical evolution. The chemistry of coeval Kilauea (SOH, early shield stage) and Mauna Kea (HSDP, late shield stage) lavas will be compared to evaluate mantle source and melting conditions for lavas extracted contemporaneously from the eastern, Kea side of the Hawaiian plume.Broader Impacts. The proposed research will involve (1) developing teaching modules for undergraduate and graduate courses using the results from our Kilauea research to highlight magmatic processes at an active volcano and emphasize cooperative learning and development of higher order thinking skills, (2) mentoring a post-doctoral researcher, and graduate and undergraduate students, (3) giving public lectures to school groups and the local community on the eruptions of Kilauea, (4) gaining a better understanding of volcanoes, which can adversely influence the quality of life, and (5) increasing international and national scientific cooperation through collaboration and utilization of facilities.