Oceanic lithosphere carries volatiles, notably water, into the mantle through subduction at convergent plate boundaries. This subducted water exercises control on the production of magma, earthquakes, formation of continental crust and mineral resources. Identifying different potential fluid sources (sediments, crust and mantle lithosphere) and tracing fluids from their release to the surface has proved challenging 1 . Atlantic subduction zones are a valuable endmember when studying this deep water cycle because hydration in Atlantic lithosphere, produced by slow spreading, is expected to be highly non-uniform 2 . Here, as part of a multi-disciplinary project in the Lesser Antilles volcanic arc 3 , we studied boron trace element and isotopic fingerprints of melt inclusions. These reveal that serpentine—that is, hydrated mantle rather than crust or sediments—is a dominant supplier of subducted water to the central arc. This serpentine is most likely to reside in a set of major fracture zones subducted beneath the central arc over approximately the past ten million years. The current dehydration of these fracture zones coincides with the current locations of the highest rates of earthquakes and prominent low shear velocities, whereas the preceding history of dehydration is consistent with the locations of higher volcanic productivity and thicker arc crust. These combined geochemical and geophysical data indicate that the structure and hydration of the subducted plate are directly connected to the evolution of the arc and its associated seismic and volcanic hazards. Serpentine subducted below the Lesser Antilles volcanic arc supplies water to the arc, controlling the location of seismicity, volcanic productivity and thickness of crust.

中文翻译：

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可变水输入控制小安的列斯群岛火山弧的演化

大洋岩石圈通过会聚板块边界的俯冲将挥发物，尤其是水，带入地幔。这种俯冲水控制着岩浆的产生、地震、大陆地壳的形成和矿产资源。识别不同的潜在流体源（沉积物、地壳和地幔岩石圈）并追踪流体从它们释放到地表已被证明具有挑战性 1 。在研究这种深水循环时，大西洋俯冲带是一个有价值的末端成员，因为大西洋岩石圈中的水合作用由缓慢扩散产生，预计将高度不均匀 2。在这里，作为小安的列斯群岛火山弧 3 多学科项目的一部分，我们研究了硼微量元素和熔体包裹体的同位素指纹。这些揭示了蛇纹石——也就是说，水合地幔而不是地壳或沉积物——是向中心弧提供俯冲水的主要供应者。在大约过去的一千万年里，这条蛇纹石最有可能位于中央弧下方俯冲的一组主要断裂带中。这些断裂带的当前脱水与当前地震发生率最高和显着的低剪切速度的位置一致，而先前的脱水历史与更高的火山生产力和更厚的弧形地壳的位置一致。这些结合的地球化学和地球物理数据表明，俯冲板块的结构和水合作用与弧的演化及其相关的地震和火山灾害直接相关。俯冲在小安的列斯火山弧下方的蛇纹石为弧提供水，