Thermal Effect of Magma Intrusion on Electrical Properties of Magnetic Rocks from Hamamat Sediments, NE Desert, Egypt

Thermal effects of magmatic intrusion on electrical properties, of magnetic rocks from Hamamat sediments, NE desert, Egypt, were investigated experimentally. An intrusion of granitic magma was intruded in the Hamamat sediments, which is a mixture (mainly magnetite with sandstone) and due to the thermal effect the area around it was altered, with different degrees and magnetite was transformed into hematite with different degrees according to its location. Complex impedance measurements were performed in the frequency range from 10 Hz to 100 KHz. Experimental data indicates that the electrical properties vary strongly with distance. The conductivity of hematite is higher than that of magnetite. As we move from magnetite to hematite it is supposed that the conductivity will decrease, but it was found that the conductivity increases. The increase of conductivity as we move from magnetite to hematite were argued to the heating that make partial or complete melting of the samples, then the porosity of the samples were decreased and accordingly the conductivity and dielectric constant increase. Also, it was supposed that the grains of the conductor in the samples are coated completely or isolated with insulator material.