Crustal resistivity structure at 9°50′N on the East Pacific Rise: Results of an electromagnetic survey
Crustal resistivity structure at 9°50′N on the East Pacific Rise: Results of an electromagnetic survey
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东太平洋海隆 9°50′N 处地壳电阻率结构：电磁测量结果
DOI：
10.1029/2001gl014106
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发表时间：
2002
影响因子：
5.2
通讯作者：
D. Doherty
中科院分区：
文献类型：
--
作者：
R. Evans;S. Webb;W. Crawford;C. Golden;K. Key;L. Lewis;H. Miyano;E. Roosen;D. Doherty
本文报道了在东太平洋海隆（EPR）9°50′N进行的大范围电磁测量的第一批结果，该测量采用磁电阻率（MMR）技术测量了扩展中心附近海底的电阻率结构。在已知热液活动区域、无喷口轴向位置和离轴约4公里处部署了10个海底磁力计。在离轴站点收集的数据显示海底曲率比轴向站点高。该响应与孔隙度控制的电阻率结构所预期的响应相反，如地震数据所要求的，具有离轴的较厚的高孔隙度突出层2A。对轴向电阻率降低的一种解释是，最上面几百米的地壳在脊顶下面比离轴几公里的地方热得多，降低了孔隙流体的电阻率。
We report the first results of an extensive electromagnetic survey of the East Pacific Rise (EPR) at 9°50′N, which used the magnetometric resistivity (MMR) technique to measure the electrical resistivity structure of the seafloor in the vicinity of the spreading center. Ten seafloor magnetometers were deployed in areas of known hydrothermal activity, in axial sites devoid of venting, and further off‐axis to a distance of approximately 4 km. Data collected at off‐axis sites show higher seafloor resistivities than at axial sites. This response is opposite to that expected from porosity controlled resistivity structure, with a thicker high‐porosity extrusive layer 2A off‐axis, as required by seismic data. An explanation for the reduced axial resistivities is that the uppermost few hundred meters of crust are much hotter beneath the ridge crest than a few kilometers off‐axis, lowering the pore‐fluid resistivity.