The ionic reordering in Fe-Ti ferrimagnetics as a dominant source of the reversed RM in basaltic rocks

Abstract

The  basalts of  the Pleistocene to Quaternary age  from  southern  part of Slovakia  were  investigated.  These  are  the basalts containing  predominantly  the titano- maghemites (Ti-Mgh-es) which  carry  the  reversed  remanent  magnetization (RM).  The partial thermoremanent magnetization (PTRM) in original  and artificially prepared sam- ples was induced  in the geomagnetic field of normal  polarity and intensity H ≈ 48μT.  The PTRM reversed  by the  self-reversed  mechanism was induced  in all the  above-mentioned types  of basalts, in the interval  300 to 475 °C.  In  this  temperature  interval  an  increase of magnetic susceptibility with  a peak about 450 °C was detected. The  acquired reversed RM and  PTRM of basalts have been explained on the basis of the reordering of magnetic ions in the A and  B sub-lattices of the oxidized  Fe-Ti  ferrimagnetics in basalts.