Abstract
Continental or oceanic basaltic rocks which contain optically homogeneous titanomagnetites are defined as magnetic class I rocks and exhibit thermochemical remanent magnetization (TCRM) behavior when heated. Heating of magnetic class I rocks results in an increase in:
(a) Curie point (Tc)
(b) susceptibility (X)
(c) coercive force (Hc)
(d) remanent magnetization (Jr)
(e) demagnetization stability
(f) saturation magnetization (Js).
Though the titanomagnetites are optically homogeneous, they are chemically heterogeneous, and may contain textures which cannot be optically resolved. The extent of optically unresolved textures and degree of chemical heterogeneity will depend on the previous history of the sample. The development of iron-oxide textures and correlative magnetization behavior can be understood through experimental studies of magnetic class I rocks. The magnetic characteristics of rocks which exhibit the TCRM behavior are presented and discussed. Three processes can be operative in the development of TCRM in basaltic rocks:
(a) thermal process
(b) thermochemical process
(c) oxidation process.
