Geochemical evidence for invasion of Kilauea's plumbing system by Mauna Loa magma
Geochemical evidence for invasion of Kilauea's plumbing system by Mauna Loa magma
复制标题
莫纳罗亚岩浆入侵基拉韦厄管道系统的地球化学证据
作者：
J. M. Rhodes;K. Wenz;C. Neal;J. Sparks;J. Lockwood
从夏威夷火山活动研究的开始，就存在着对邻近的莫纳罗亚火山和基拉韦厄火山1 -5之间可能存在的关系的争议。地震活动，被认为反映了岩浆的向上迁移，揭示了岩浆管道系统显然在深处汇聚，在地幔内形成了一个广泛的漏斗6。虽然在罕见的情况下，它们同时喷发，但简短的历史喷发记录似乎表明，当基拉韦厄最活跃时，莫纳罗亚山处于休眠状态，反之亦然，这表明它们可能在争夺相同的岩浆供应5，7。然而，岩石学、地球化学和同位素数据却需要一个截然相反的结论。熔岩的主元素、微量元素和同位素组成的明显差异被认为是两座火山具有独立的岩浆管道系统的有力证据，这些系统由来自物理和地球化学上不同的地幔源的母岩浆提供8 -13。在这里，我们提出初步的地球化学数据表明，在过去的2,000年里，基拉韦厄火山喷发的熔岩成分光谱类似于历史上的基拉韦厄火山熔岩在一端和莫纳罗亚火山熔岩在另一端。我们讨论了这种多样性的原因，并推测，从莫纳罗亚火山的岩浆可能侵入基拉韦厄的“高层次”岩浆管道系统。
From the beginning of the study of Hawaiian volcanism there has been controversy over possible relationships between the neighbouring active volcanoes Mauna Loa and Kilauea1–5. Seismic activity, thought to reflect upward migration of magma, reveals that the magmatic plumbing systems apparently converge at depth to form a broad funnel within the mantle6. Although on rare occasions they have erupted concurrently, the brief historical eruptive record appears to show that when Kilauea is most active, Mauna Loa is in repose and vice versa, suggesting that they may be competing for the same magma supply5,7. Petrological, geochemical and isotope data, however, require a diametrically opposite conclusion. Distinct differences in major-element, trace-element and isotope compositions of lavas are regarded as compelling evidence that the two volcanoes have separate magmatic plumbing systems, supplied by parental magmas from physically and geochemically distinct mantle sources8–13. Here we present preliminary geochemical data which show that in the past 2,000 years Kilauea has erupted a spectrum of lava compositions resembling historical Kilauea lavas at one end and Mauna Loa lavas at the other. We discuss the cause of this diversity, and speculate that magma from Mauna Loa may have invaded Kilauea's 'high-level' magmatic plumbing system.