Evidence suggests slab melting in arc magmas
Evidence suggests slab melting in arc magmas
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DOI：
10.1029/01eo00038
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发表时间：
2001-02
期刊：
影响因子：
--
通讯作者：
Marc J. Defant;P. Kepezhinskas
中科院分区：
文献类型：
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作者：
Marc J. Defant;P. Kepezhinskas
大多数最近的地质学教科书指出，与俯冲有关的火山活动是由于下行岩石圈的融化。然而，在过去的30年里，该领域很少有人认真相信俯冲板片是弧玄武岩的来源。公认的假说是俯冲玄武岩从斜长角闪岩向榴辉岩过渡过程中产生的含水流体使板片上方的地幔楔熔融。母岩玄武岩主要通过结晶分馏、岩浆混合和莫霍洛维奇不连续面上升过程中的安山岩和英安岩的分化而分化;玄武岩密度太大，无法通过下陆壳上升。这解释了弧中差异化岩石的相对丰度。
Most recent geology textbooks state that subduction-related volcanism is due to the melting of the down-going lithosphere. However, for the last 30 years, few in the field have seriously believed that the subducting slab is the source of arc basalts. The accepted hypothesis involves melting of the mantle wedge above the slab via hydrous fluids produced during the transition of the subducting basalt from amphibolite to eclogite. The parental basalts differentiate primarily through crystal fractionation, magma mixing, and differentiation at the Mohorovicic discontinuity into andesites and dacites as they ascend; the basalts are too dense to rise through the lower continental crust. This explains the relative abundance of differentiated rocks in arcs.