Crustal structure and evolution of the Mariana intra-oceanic island arc
Crustal structure and evolution of the Mariana intra-oceanic island arc
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DOI：
10.1130/g23212a.1
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发表时间：
2007-03
期刊：
影响因子：
5.8
通讯作者：
N. Takahashi;S. Kodaira;S. Klemperer;Y. Tatsumi;Y. Kaneda;K. Suyehiro
中科院分区：
文献类型：
--
作者：
N. Takahashi;S. Kodaira;S. Klemperer;Y. Tatsumi;Y. Kaneda;K. Suyehiro
利用有源地震剖面获得的马里亚纳弧-弧后系统的高分辨率速度模型显示了中、长、基性成分的弧中下地壳内的速度变化。洋-岛弧地壳的特征是速度为~ 6 km/s的中地壳，速度为~ 7 km/s的横向非均匀下地壳，以及异常低的地幔速度。岩石学模拟表明，提取中地壳后，下地壳的体积应明显大于观测到的体积，表明下地壳的一部分，特别是堆积，在地震上是地幔的一部分。
A new high-resolution velocity model of the Mariana arc-backarc system obtained from active-source seismic profiling demonstrates velocity variations within the arc middle and lower crusts of intermediate to felsic and mafic compositions. The characteristics of the oceanic-island-arc crust are a middle crust with velocity of ∼6 km/s, laterally heterogeneous lower crust with velocities of ∼7 km/s, and unusually low mantle velocities. Petrologic modeling suggests that the volume of the lower crust, composed of restites and olivine cumulates after the extraction of the middle crust, should be significantly larger than is observed, suggesting that a part of the lower crust, especially the cumulates, is seismically a part of the mantle.