Water-rich sublithospheric melt channel in the equatorial Atlantic Ocean
Water-rich sublithospheric melt channel in the equatorial Atlantic Ocean
复制标题
赤道大西洋富含水的岩石圈下熔融通道
DOI：
10.1038/s41561-017-0034-z
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发表时间：
2017
影响因子：
18.3
通讯作者：
Satish C. Singh
中科院分区：
文献类型：
--
作者：
F. Mehouachi;Satish C. Singh
岩石圈-软流圈边界是地球上最广泛的边界，它将上面的移动的板块与下面的对流地幔分开，但它的性质仍然是一个有争议的问题。使用超深地震反射技术，在这里，我们展示了一个系统的地震图像的两个深反射，我们解释为上限和下限的岩石圈软流圈边界下的一个40-70万年的海洋岩石圈在大西洋。这两个反射对应于1，260 °C和1，355 °C的等温线，并界定了一个低速通道，表明岩石圈-软流圈边界是热控制的。我们观察到一个明确的年龄依赖性，这亚岩石圈通道：它的深度随着年龄的增加，从72公里，它是40万年到88公里，它是70万年，而它的厚度随着年龄的减少，从18公里到12公里。我们认为，部分熔融，促进水，是负责低速通道的主要机制。融化所需的水浓度随着年龄的增加而增加;然而，其相应的总质量保持相对恒定，这表明海洋岩石圈下通道中的大多数挥发物来自于脊轴附近的水平通量。
The lithosphere–asthenosphere boundary is the most extensive boundary on Earth, separating the mobile plate above from the convecting mantle below, but its nature remains a matter of debate. Using an ultra-deep seismic reflection technique, here we show a systematic seismic image of two deep reflectors that we interpret as the upper and lower limits of the lithosphere–asthenosphere boundary beneath a 40–70-million-year-old oceanic lithosphere in the Atlantic Ocean. These two reflections correspond to 1,260 °C and 1,355 °C isotherms and bound a low-velocity channel, suggesting that the lithosphere–asthenosphere boundary is thermally controlled. We observe a clear age dependency of this sublithospheric channel: its depth increases with age from 72 km where it is 40-Myr-old to 88 km where it is 70-Myr-old, whereas its thickness decreases with age from 18 km to 12 km. We suggest that partial melting, facilitated by water, is the main mechanism responsible for the low-velocity channel. The required water concentration for melting increases with age; nevertheless, its corresponding total mass remains relatively constant, suggesting that most of the volatiles in the oceanic sublithospheric channel originate from a horizontal flux near the ridge axis.A water-rich layer of partial melt marks the base of the lithosphere in the equatorial Atlantic Ocean, according to analyses of seismic data.
影响因子：
3.9
作者：
Rychert, Catherine A.;Shearer, Peter M.
通讯作者：
Shearer, Peter M.