Gilbert Kahara HBSc thesis abstract

Thesis Title: 
The Behaviour of Isothermal Remanent Magnetization of Magnetite and Hematite in Non-coaxial Strain

Gilbert J. Kahara - 1992

Recent studies have shown that remanent magnetization can be affected by tectonic deformation.  It can be reoriented by the effects of plastic strain.  Its magnitude may change also.  This project was undertaken to test the behaviour of remanence rotation and to determine whether it behaves as a passive line or a material line.  Two magnetic minerals, magnetite and hematite were suspended in silicone-putty.  The two rock analogues were individually given an isothermal remanent magnetization (IRM) and deformed by simple shear.  The results show that the IRM in each mineral rotates as a rigid line, although the IRM in hematite tends to behave as a passive line.  These results are perhaps explained by a microscopic examination of both magnetite and hematite, which showed that hematite was plate-like and magnetite was equidimensional.  IRM rotation was accompanied by a decrease in intensity due to grain-scale scattering of remanence directions.