Deep electrical resistivity structure of northwestern Costa Rica
Deep electrical resistivity structure of northwestern Costa Rica
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DOI：
10.1029/2008gl036397
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发表时间：
2009-01-30
影响因子：
5.2
通讯作者：
Jegen, M.
中科院分区：
文献类型：
--
作者：
Brasse, H.;Kapinos, G.;Jegen, M.
第一次长期大地电磁调查于2008年初在哥斯达黎加西北部进行，沿着一条从太平洋海岸延伸的剖面，穿过火山弧，目前止于尼加拉瓜边境。本研究的目的是了解Cocos板块俯冲至加勒比海板块之下的大陆边缘的电阻率结构，从而了解流体分布。初步二维模型绘制了尼科亚半岛仅有的中等电阻性基性/超基性复合体（电阻率为几百ω m）、导电弧前盆地和弧后盆地（电阻率为几个ω m）。在弧后盆地下方，资料显示在基底有一个不良导体，在南部有一个明显的终止，这可以初步解释为圣埃琳娜缝合带。火山弧在深度上没有明显的异常，但在弧后下方有一个中等的导体，可能与上地幔有联系。在弧前地壳深处的导体可以反映从下行板块释放出来的流体。引文：Brasse， H.， G. Kapinos， L. Mutschard， G. E. Alvarado， T. Worzewski和M. Jegen(2009)，哥斯达黎加西北部深部电阻率结构，地球物理。卷。， 36, L02310, doi: 10.1029/2008GL036397。
First long-period magnetotelluric investigations were conducted in early 2008 in northwestern Costa Rica, along a profile that extends from the coast of the Pacific Ocean, traverses the volcanic arc and ends currently at the Nicaraguan border. The aim of this study is to gain insight into the electrical resistivity structure and thus fluid distribution at the continental margin where the Cocos plate subducts beneath the Caribbean plate. Preliminary two-dimensional models map the only moderately resistive mafic/ultramafic complexes of the Nicoya Peninsula (resistivity of a few hundred Omega m), the conductive forearc and the backarc basins (several Omega m). Beneath the backarc basin the data image a poor conductor in the basement with a clear termination in the south, which may tentatively be interpreted as the Santa Elena Suture. The volcanic arc shows no pronounced anomaly at depth, but a moderate conductor underlies the backarc with a possible connection to the upper mantle. A conductor at deep-crustal levels in the forearc may reflect fluid release from the downgoing slab. Citation: Brasse, H., G. Kapinos, L. Mutschard, G. E. Alvarado, T. Worzewski, and M. Jegen (2009), Deep electrical resistivity structure of northwestern Costa Rica, Geophys. Res. Lett., 36, L02310, doi: 10.1029/2008GL036397.