Volcanism in response to plate flexure
Volcanism in response to plate flexure
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DOI：
10.1126/science.1128235
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发表时间：
2006-09-08
期刊：
影响因子：
56.9
通讯作者：
Suyehiro, Kiyoshi
中科院分区：
文献类型：
--
作者：
Hirano, Naoto;Takahashi, Eiichi;Suyehiro, Kiyoshi
已知地球上的火山活动发生在三种构造环境中：发散的板块边界（如洋中脊），收敛的板块边界（如岛弧）和热点。我们报告的1.35亿年前的太平洋板块上的火山活动不属于上述任何一类。从微量元素地球化学和稀有气体同位素组成可以看出，小型碱性火山是由小比例的熔体形成的，起源于软流圈。我们认为这些小火山是在俯冲过程中由于板块弯曲而沿着岩石圈裂缝喷发的。较小程度的软流圈融化和火山的构造排列和年龄进展与板块运动方向相反，为软流圈存在小比例的融化提供了证据。
Volcanism on Earth is known to occur in three tectonic settings: divergent plate boundaries ( such as mid-ocean ridges), convergent plate boundaries ( such as island arcs), and hot spots. We report volcanism on the 135 million-year-old Pacific Plate not belonging to any of these categories. Small alkalic volcanoes form from small percent melts and originate in the asthenosphere, as implied by their trace element geochemistry and noble gas isotopic compositions. We propose that these small volcanoes erupt along lithospheric fractures in response to plate flexure during subduction. Minor extents of asthenospheric melting and the volcanoes' tectonic alignment and age progression in the direction opposite to that of plate motion provide evidence for the presence of a small percent melt in the asthenosphere.