The thermo，electric coefficients oftwenty—six magnetite samples，formed either by magmatism or metamorphism．were tested by the thermo—electric instrument BHET-06．Results showed that the coefficientiSofaconstantvalueofabout
C．ItiSemphasizedthatbecause everymagnetitegrainwas tested randomly．the coem cient iS independent ofthe crystallographic direction．This faCt means the therma1 voltage generated from a single magnetite crystal can be accumulated，and as a result a new thermo-electric field can arise when a gradient thermal field exists and iS active within the earth’S crust．Because magnetite iS widespread in the earth’S crust fgenerally appearing more in the middle—lower crust)，there iS more—than—random probability that the additional thermo．electric field can be generated when certain thermal condi—
tions are fulfilled.....
