The Electrical Resistivity of the Main Minerals in Ultramafic Rock, Eclogite and Gabbro under High Pressures

Clinopyroxene, Labrador, omphacite, garnet and enstatite as the main minerals in ultramafic rock, eclogite and gabbro are selected as the samples to study the variations of resistivity of the mantl materials with pressures between 3 GPa and 20 GPa using a DAC device. The results indicated that the resistivities of these minerals increase obviously with pressures between 3 and 8 GPa, the effect of the pressure is reduced, and the resistivities of pyroxenes decrease with the pressure in variety of degrees. In the range of 14 to 20 GPa, the resistivity of enstatite increases obviously again with pressure, but the other minerals do not increase so clearly. In the mantle, in the depth of about 400 km, sudden increase of the conductivity was presented (McDonald, 1975), and the negative correlation between the resistivity of pyroxene and the pressure occurs just under this pressure (about 12 GPa). Is that a coincidence? It is a problem we shall study later.