Laboratory measurements of electrical conductivity in a gabbro of the Oman ophiolite at high–pressures and high–temperatures: implications for interpretation of resistivity structures of lower oceanic crust
Laboratory measurements of electrical conductivity in a gabbro of the Oman ophiolite at high–pressures and high–temperatures: implications for interpretation of resistivity structures of lower oceanic crust
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DOI：
10.2465/jmps.171110
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发表时间：
2018
影响因子：
0.7
通讯作者：
S. Saito;N. Bagdassarov
中科院分区：
文献类型：
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作者：
S. Saito;N. Bagdassarov
在高压（0.6和0.8 GPa）、高温（250-908 °C）和干燥条件下，使用活塞-圆柱型高压装置对阿曼蛇绿岩辉长岩样品的电导率进行了实验室测量。根据先前报道的弹性波速度，所研究的辉长岩可以被视为下大洋地壳岩石的代表性样本。将辉长岩样品粉末化并热压，然后在电导率测量之前烧结。测得的样品的电导率随温度的降低而降低，这是符合阿耳忒弥斯关系。与最近在尼加拉瓜近海进行的电磁调查得出的下大洋地壳电导率值相比，在下大洋地壳预期的温度范围内，测得的样品电导率要低得多。这种差异可以用下大洋地壳中存在导电孔隙流体来解释。
We performed laboratory measurements of the electrical conductivity of a gabbro sample of the Oman ophiolite under high–pressures (0.6 and 0.8 GPa), high–temperatures (250–908 °C), and dry conditions using a piston– cylinder type high–pressure apparatus. The studied gabbro can be regarded as a representative sample of the lower oceanic crustal rocks based on its previously reported elastic wave velocities. The gabbro sample was powdered and hot pressed, and then sintered prior to the electrical conductivity measurements. The measured electrical conductivity of the sample decreased with decreasing temperature, which is consistent with the Arrhenius relationship. Compared with the electrical conductivity values of lower oceanic crust derived from a recent electromagnetic survey in offshore Nicaragua, the measured electrical conductivity of the sample was considerably lower in the temperature ranges expected for lower oceanic crust. The discrepancy can be explained by the presence of conductive pore–fluids in the lower oceanic crust.