Fine-scale segmentation of the crustal magma reservoir beneath the East Pacific Rise
Fine-scale segmentation of the crustal magma reservoir beneath the East Pacific Rise
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DOI：
10.1038/ngeo1933
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发表时间：
2013-10-01
影响因子：
18.3
通讯作者：
Perfit, Michael R.
中科院分区：
文献类型：
--
作者：
Carbotte, Suzanne M.;Marjanovic, Milena;Perfit, Michael R.
全球洋中脊在其海底形态和岩浆系统方面是分段的，但对这种构造和岩浆分段的起源及其之间的关系知之甚少（1-5）。在快速扩张的海脊，构造分段被观察到在一个精细的规模（2，4，6 -8），但目前还不清楚这种分割是否也发生在岩浆系统。精细规模的构造分段可能有一个深源，由上涌地幔熔体的分布引起，或浅源，与长的，更连续的地壳水库（2，9）的偏移侵入岩脉有关。在这里，我们使用地震反射数据，从快速扩展的东太平洋隆起，在8 ffi 20度N和10 ffi 10度N之间，其中包括一个独特的地区，两个记录的火山爆发发生（10-15），以高分辨率成像地壳岩浆体。我们发现，岩浆库形成5至15公里长的部分，符合在海底的精细规模的构造分段和三个透镜段美联储最近的喷发。喷发熔岩的成分、体积和形态的转变与定义岩浆段的透镜的破裂相吻合。我们的结论是，在东太平洋隆起的火山喷发与岩浆的垂直上升，大多是物理隔离的镜头，导致不同的熔岩在表面的喷发，符合精细规模的构造分割。
The global mid-ocean ridge is segmented in its seafloor morphology and magmatic systems, but the origin of and relationships between this tectonic and magmatic segmentation are poorly understood(1-5). At fast-spreading ridges, tectonic segmentation is observed on a fine scale(2,4,6-8), but it is unclear whether this partitioning also occurs in the magmatic system. Fine-scale tectonic segmentation could have a deep origin, arising from the distribution of upwelling mantle melt, or a shallow origin, linked to offset intruding dikes from long, more continuous crustal reservoirs(2,9). Here we use seismic reflection data from the fast-spreading East Pacific Rise, between 8 ffi 20 degrees N and 10 ffi 10 degrees N, which includes a unique area where two documented volcanic eruptions have occurred(10-15), to image the crustal magma bodies in high resolution. We find that the magma reservoirs form 5-to 15-km-long segment s that coincide with the fine-scale tectonic segmentation at the seafloor and that three lens segments fed the recent eruptions. Transitions in composition, volume and morphology of erupted lavas coincide with disruptions in the lens that define magmatic segments. We conclude that eruptions at the East Pacific Rise are associated with the vertical ascent of magma from lenses that are mostly physically isolated, leading to the eruption of distinct lavas at the surface that coincide with fine-scale tectonic segmentation.