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岩浆弧和地槽 本文所说的“岩浆弧”一名,系指海沟近侧呈曲线状展布的火山带,大致平行于大洋岩石圈自海沟处消减的俯冲带。它的火山作用特征,一般为爆发式中性岩浆喷发,形成一套熔岩和火山碎屑岩交互出现的地层。成份基本属于安山质或英安质,局部可有丰富的玄武质熔岩或流纹质熔结凝灰岩,甚至可在其中占为优势。这类岩浆的生成,可能与岩石圈板块沿一斜面降入弧下地幔有关。这一斜面就是弧下位于中震源深度的地震倾
Magma Arcs and Slotts The term “magmatic arcs” referred to herein refers to a volcanic belt distributed curvilinearly in the vicinity of the trench, generally parallel to the subduction zone where the oceanic lithosphere is depleted from the trench. Its volcanic features are generally explosive neutral magma eruptions, forming a set of lava and pyroclastic interaction of the formation. Basically belong to the composition of an anti-mountain quality or British quality, the local can be rich in basaltic lava or rhyolitic melted tuff, which can even be accounted for in the advantages. The formation of this type of magma may be related to the lithospheric plate being lowered into the arc mantle along an inclined plane. This slope is the seismic dip below the epicenter depth