Reliable Determination of Paleointensity in Igneous Rocks Bearing Thermochemical Remanent Magnetization

Abstract

Oxidation decomposition of titanomagnetite grains to the magnetite–ilmenite lattice during the formation of igneous rock can lead to thermochemical remanent magnetization (TCRM). Computer simulation of TCRM in the system of single-domain interacting particles and numerical simulation of the Thellier experiments to determine the paleointensity have been carried out. Contrary to the concerns, the Thellier technique factually applied to the TCRM-bearing samples yields a result that is very close to the true value of the external magnetic field applied to the sample during formation of the TCRM. Together with the recently published laboratory experimental data, these calculations are indicative of a good perspective for obtaining reliable paleomagnetic data on TCRM-bearing samples and can expand the class of rocks suitable for determination of the paleointensity.