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

• 批准号: 1118738
• 负责人: Aaron Pietruszka
• 金额: $ 16.98万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1118738&HistoricalAwards=false
• 关键词: Collaborative; Research; Magmatic; Evolution; Kilauea

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

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过程的首要地点。它是世界上监测最完善、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描绘了从地幔源头到地表的基本岩浆管道系统。现代和古代基拉韦厄熔岩为破译夏威夷地幔柱内成分异质性的性质以及评估岩浆生成、运输和储存过程提供了重要线索。先前对历史和史前基拉韦厄山顶熔岩的研究记录了数十年至数百年时间尺度的循环地球化学变化。从历史上看，这些成分变化与喷发率（更枯竭的来源似乎经历了较低程度的熔化并产生较少的岩浆）和罕见的爆炸性喷发（例如，1924年）等因素相关。对持续 28 年的大规模（3 平方公里）Pu?u O?o 喷发的详细调查揭示了熔岩化学（年）的短期趋势，该趋势可能受到喷发过程中小规模成分异质性融化的控制。夏威夷羽流，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的喷发：东部裂谷区的 Pu`u O?o（1983 年至今）和火山顶峰的新喷发 Halema?uma?u（2008 年至今）。提议进行一项由三部分组成的研究，涉及岩相学、矿物化学、全岩主量和微量元素丰度以及 Pb、Sr、Nd 和 O 同位素比率，以调查基拉韦厄熔岩过去、现在和未来的成分变化。现在和未来的变化：将涉及使用当前 Pu`u O?o 和 Halema?uma?u 喷发的熔岩进行两个时间序列实验。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。在评估地壳过程的影响（例如晶体分馏和/或岩浆混合）后，这些数据将允许评估地幔过程。其次，Halema?uma?u 峰顶喷发的幼年玻璃状火山灰的化学成分将与同时期的 Pu`u 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比较，以更好地描绘火山结构基拉韦厄火山的岩浆管道系统。两个遥远的喷口位置（山顶和裂谷带）的持续喷发提供了利用熔岩化学来跟踪岩浆通过火山管道系统的运动作为时间和空间的函数的机会。这项工作将对其他玄武岩火山产生影响。第三，将使用约 1.7 公里和 2.0 公里长、连续取芯的科学观测孔 (SOH) 钻孔中的熔岩来评估基拉韦厄火山最后 200 多年的演化。 (SOH) 岩心代表了夏威夷火山早期盾构阶段的研究很少，莫纳克亚火山的夏威夷科学钻探项目 (HSDP) 并未对其进行采样。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。结果将用于模拟基拉韦厄火山的火山生长速度和时间地球化学演化。将比较同时代的基拉韦厄火山（SOH，早期地盾阶段）和莫纳克亚火山（HSDP，晚期地盾阶段）熔岩的化学成分，以评估同时从夏威夷羽流东部、基亚山一侧提取的熔岩的地幔来源和熔化条件。更广泛的影响。拟议的研究将包括（1）利用我们基拉韦厄研究的结果开发本科生和研究生课程的教学模块，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）指导后博士研究员、研究生和本科生，(3) 向学校团体和当地社区提供有关基拉韦厄火山喷发的公开讲座，(4) 更好地了解火山，因为火山会对生活质量产生不利影响，以及 (5 ）增加国际和国内通过协作和利用设施进行科学合作。