Abnormal seismological and magmatic processes controlled by the tearing South American flat slabs
Abnormal seismological and magmatic processes controlled by the tearing South American flat slabs
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DOI：
10.1016/j.epsl.2016.06.019
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发表时间：
2016-09
影响因子：
5.3
通讯作者：
Jiashun Hu;Lijun Liu
中科院分区：
文献类型：
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作者：
Jiashun Hu;Lijun Liu
板块俯冲对板内地震、火山活动和地幔地震速度异常的影响尚不清楚。我们试图更好地了解这些过程，通过模拟两个平板在秘鲁和智利使用数据导向的地球动力学模型。我们的结果成功地再现了所观察到的平板，主要是由于两个俯冲海盆脊。与传统的平板俯冲的观点相反，我们发现这些板块是内部撕裂的，这是由于俯冲浮力特征的3D性质。区域层析成像证实的这种断裂板构造，自然地解释了与中深地震相关的异常分布和应力状态。我们进一步表明，板片撕裂过程也可以更好地解释埃达克质和成矿岩浆活动的形成，岩浆弧的演化，以及这些地区之下的神秘的地幔地震结构。我们认为板片撕裂可能是浮力特征俯冲的共同结果，由此产生的地幔过程可能影响大陆的长期地球动力学演化。
The influence of flat slab subduction on the formation of intra-slab earthquakes, volcanic activities and mantle seismic velocity anomalies remains unclear. We attempt to better understand these processes by simulating the two flat slabs in Peru and Chile using data-orientated geodynamic models. Our results successfully reproduce the observed flat slabs as mainly due to two subducting aseismic ridges. In contrast to the traditional view of flat-slab subduction, we find that these slabs are internally torn, as is due to the 3D nature of the subducting buoyancy features. This broken slab configuration, confirmed by regional tomography, naturally explains the abnormal distribution of and stress regimes associated with the intermediate-depth earthquakes. We further show that the slab tearing process could also better explain the formation of adakitic and ore-forming magmatism, the evolution of the magmatic arc, and the enigmatic mantle seismic structures beneath these regions. We propose that slab tearing may represent a common result of buoyancy feature subduction and that the resulting mantle processes could affect the long-term geodynamic evolution of continents.