Hawaiian Volcanoes - From Source to Surface
Hawaiian Volcanoes - From Source to Surface
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夏威夷火山 - 从源头到地表
DOI：
10.1002/9781118872079.ch15
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Edmonds M
中科院分区：
文献类型：
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作者：
Edmonds M
原始岩浆的性质和海洋岛屿火山的深层管道系统是神秘的，人们对此知之甚少。熔体包裹体提供了原始熔体的岩浆历史的窗口，允许洞察熔体的异质性，混合，分馏和脱气。我们提出的主要，微量和挥发性元素组成的熔体包裹体火山灰和熔岩样品爆发在25史前和历史性的爆发在过去的600年Kasslauea火山。一旦对包埋后结晶进行校正，最原始的熔体具有14.7重量%的MgO，使其接近原始熔体。熔体形成的组成阵列广泛控制橄榄石分馏，但叠加显着的不均匀性。这种不均匀性超过了以前对历史上的克拉伊纳岩浆的全岩成分和玻璃的研究中观察到的，并且是由分馏过程中成分不同的熔体混合造成的。原始熔体包裹体的H2O含量高达1.07wt%，H2O/Ce高达1.290，表明某些原始熔体可能是从地幔熔融区继承的固有的富H2O。熔体成分的时间趋势与全岩中观察到的相似，表明基拉韦厄火山的地幔熔融程度和地幔源成分在50-100年的时间尺度上发生了显着变化。
The nature of primitive magmas and the deep plumbing system at ocean island volcanoes is enigmatic and poorly understood. Melt inclusions provide windows into the magmatic history of primitive melts, allowing insights into melt heterogeneity, mixing, fractionation, and degassing. We present the major, trace, and volatile element composition of melt inclusions from tephra and lava samples erupted during 25 prehistoric and historic eruptions of Kīlauea Volcano over the past 600 years. Once corrected for post‐entrapment crystallization, the most primitive melts have 14.7 wt% MgO, making them close to primary. The melts form a compositional array broadly controlled by olivine fractionation, but with significant heterogeneity superimposed. This heterogeneity exceeds that observed in previous studies of whole‐rock compositions and glasses of historical Kīlauea magmas and is caused by mixing of compositionally distinct melts during fractionation. Primitive melt inclusions show a range in H2O contents up to ˜0.7 wt% and H2O/Ce up to ˜290, suggesting that some primary melts may be inherently enriched in H2O, inherited from the mantle melting region. Temporal trends in melt compositions are similar to those observed in whole rocks, suggesting that there are significant changes in the degree of mantle melting and mantle source composition at Kīlauea Volcano over 50–100 year timescales.