NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Sci Adv. 2017 Apr 7;3(4):e1602402. doi: 10.1126/sciadv.1602402. eCollection 2017 Apr.
In subduction zones, sediments and hydrothermally altered oceanic crust, which together form part of the subducting slab, contribute to the chemical composition of lavas erupted at the surface to form volcanic arcs. Transport of this material from the slab to the overlying mantle wedge is thought to involve discreet melts and fluids that are released from various portions of the slab. We use a meta-analysis of geochemical data from eight globally representative arcs to show that melts and fluids from individual slab components cannot be responsible for the formation of arc lavas. Instead, the data are compatible with models that first invoke physical mixing of slab components and the mantle wedge, widely referred to as high-pressure mélange, before arc magmas are generated.
在俯冲带中，沉积物和经水热蚀变的大洋地壳（它们共同构成俯冲板块的一部分），影响了在地表喷发形成火山弧的熔岩的化学组成。人们认为，这种物质从板块输送到上覆地幔楔的过程涉及从板块各个部分释放出离散的熔体和流体。我们利用来自全球 8 个具有代表性的弧的地球化学数据的荟萃分析表明，来自单个板块成分的熔体和流体不可能是形成弧熔岩的原因。相反，这些数据与模型一致，这些模型首先假设在生成弧岩浆之前，板块成分和地幔楔之间发生物理混合，这种混合通常被称为高压混杂岩。
