Hawaiian xenolith populations, magma supply rates, and development of magma chambers
Hawaiian xenolith populations, magma supply rates, and development of magma chambers
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夏威夷捕虏体种群、岩浆供应率和岩浆房的发育
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
D. Clague
中科院分区：
文献类型：
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作者：
D. Clague
夏威夷火山经历了四个喷发阶段，以不同的熔岩类型、岩浆供应率和捕虏体数量为特征。最早和最晚两个碱性阶段的岩浆供应速率较低，拉斑玄武岩第二阶段的岩浆供应速率较高。岩浆储集层在早期随着岩浆供应速率的增加而在浅层和中等深度发育，在碱性第三阶段随着供应速率的下降而固化。这些岩浆储集层起到水力过滤器的作用，并清除上升岩浆携带的致密包体。在早期和晚期，不存在岩浆储存带，二辉橄榄岩的地幔包体在原始碱性熔岩中被带到地表。在拉斑玄武岩第二阶段，岩浆储集层在洋壳底部和破火山口下方3-7公里处发育并持续存在；只有浅源的捕虏体被差异熔岩带到地表。在碱性第三阶段，浅火山口下储集层中的岩浆凝固，地壳包体，包括大洋-地壳岩石，以熔岩的形式被带到地表，在中等深度的储集层中进行分馏。拉斑玄武岩和碱性熔岩中的全球捕虏体种群可能反映了次火山岩浆储集层的存在或不存在。
Hawaiian volcanoes pass through a sequence of four eruptive stages characterized by distinct lava types, magma supply rates, and xenolith populations. Magma supply rates are low in the earliest and two latest alkalic stages and high in the tholeiitic second stage. Magma storage reservoirs develop at shallow and intermediate depths as the magma supply rate increases during the earliest stage; magma in these reservoirs solidifies as the supply rate declines during the alkalic third stage. These magma storage reservoirs function as hydraulic filters and remove dense xenoliths that the ascending magma has entrained. During the earliest and latest stages, no magma storage zone exists, and mantle xenoliths of lherzolite are carried to the surface in primitive alkalic lava. During the tholeiitic second stage, magma storage reservoirs develop and persist both at the base of the ocean crust and 3–7 km below the caldera; only xenoliths of shallow origin are carried to the surface by differentiated lava. During the alkalic third stage, magma in the shallow subcaldera reservoir solidifies, and crustal xenoliths, including oceanic-crustal rocks, are carried to the surface in lava that fractionates in an intermediate-depth reservoir. Worldwide xenolith populations in tholeiitic and alkalic lava may reflect the presence or absence of subvolcanic magma storage reservoirs.