Magma storage, transport and degassing during the 2008-10 summit eruption at Kilauea Volcano, Hawai'i
Magma storage, transport and degassing during the 2008-10 summit eruption at Kilauea Volcano, Hawai'i
复制标题
DOI：
10.1016/j.gca.2013.05.038
复制
发表时间：
2013-12-15
影响因子：
5
通讯作者：
Elias, T.
中科院分区：
文献类型：
--
作者：
Edmonds, M.;Sides, I. R.;Elias, T.
夏威夷基拉韦厄火山2008年至今的最高峰喷发提供了一个独特的机会来测试脱气和岩浆管道模型，并提高我们对不稳定预算的理解。这项工作的目的是检验这样一种假设，即从山顶熔岩湖排放的气体将富含二氧化碳（CO2），并且与世纪初在基拉韦厄火山持续的熔岩湖活动期间测量的气体相似（盖拉赫和Graeber，1985）。2009年4月，我们使用电化学和非色散红外传感器测量了来自Halema'uma' u的气体羽流中的二氧化硫（SO2）和CO2浓度。我们还分析了橄榄石托管熔融包裹体火山喷发在2008年和2010年的主要，微量和挥发性元素。气体和熔体的数据都是一致的平衡的一个相对进化的岩浆批在1.2-2.0公里的深度Halema'uma' u之前，目前的脱气活动。熔体夹杂物和基质玻璃之间的挥发性浓度的差异与所观察到的气体组成是一致的。硫和卤素气体从熔体中脱气需要低压，因此我们调用对流将岩浆带到靠近表面的地方脱气，然后再沉入管道中。气体通量（分别为900和80 t/d SO2和CO2）用于估计2009年4月流向地表的岩浆通量（1.2-3.4 m（3）/s）。从熔体夹杂物中观察到最小的氢损失意味着快速的上升速率（小于几个小时），这将管道半径限制在1-2 m。推断的管道半径比地表的熔岩湖要窄得多，这意味着一个张开的几何形状。熔体包裹体数据表明，在2008-2010年期间，熔体挥发分浓度随着时间的推移逐渐减少，与封闭或半封闭岩浆系统中的对流、脱气和混合一致。目前的山顶熔岩湖活动的脱气制度是不类似于观察到的世纪初，相反，气体中的二氧化碳被广泛耗尽。(C)2013作者由爱思唯尔有限公司出版。保留所有权利。
The 2008-current summit eruption at Kilauea Volcano, Hawai'i offers a unique opportunity to test models of degassing and magma plumbing and to improve our understanding of the volatile budget. The aim of this work was to test the hypothesis that gases emitted from a summit lava lake will be rich in carbon dioxide (CO2) and similar to those measured during the persistent lava lake activity in the early 20th century at Kilauea Volcano (Gerlach and Graeber, 1985). We measured the sulfur dioxide (SO2) and CO2 concentrations in the gas plume from Halema'uma'u using electrochemical and non-dispersive infrared sensors during April 2009. We also analysed olivine-hosted melt inclusions from tephra erupted in 2008 and 2010 for major, trace and volatile elements. The gas and melt data are both consistent with the equilibration of a relatively evolved magma batch at depths of 1.2-2.0 km beneath Halema'uma'u prior to the current degassing activity. The differences in the volatile concentrations between the melt inclusions and matrix glasses are consistent with the observed gas composition. The degassing of sulfur and halogen gases from the melt requires low pressures and hence we invoke convection to bring the magma close to the surface to degas, before sinking back into the conduit. The fluxes of gases (900 and 80 t/d SO2 and CO2 respectively) are used to estimate magma fluxes (1.2-3.4 m(3)/s) to the surface for April 2009. The observation of minimal loss of hydrogen from the melt inclusions implies a rapid rise rate (less than a few hours), which constrains the conduit radius to 1-2 m. The inferred conduit radius is much narrower than the lava lake at the surface, implying a flared geometry. The melt inclusion data suggest that there is a progressive decrease in melt volatile concentrations with time during 2008-2010, consistent with convection, degassing and mixing in a closed, or semi-closed magma system. The degassing regime of the current summit lava lake activity is not similar to that observed in the early 20th century; instead the gases are extensively depleted in CO2. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.