Thermal stability and closure temperature of barite for electron spin resonance dating

Electron spin resonance (ESR) dating has been applied to barite from hydrothermal vents. Barite in hydrothermal vents cools down rapidly after formation so little attention was paid to the thermal stability of the ESR signal of barite for dating. To discern multiple episodes of fluid flow or to date barite in other geological settings, it is essential to know how the ESR intensity decays with heat, the characteristic decay time and the closure temperature. In this study, we demonstrate that the decay of the ESR intensity of the SO3- radical in barite is a second-order reaction. The characteristic decay time for the ESR intensity to drop by half at 100 degrees C, 200 degrees C, 300 degrees C and 500 degrees C is of the order of magnitude of 106 years, 10 years, 10 h and 1 s respectively. The closure temperature of barite is generally between 190 and 340 degrees C. These results provide essential information on environments where the ESR intensity in barite is stable and conditions under which ESR ages can be erased.

Automated summary

The decay of ESR intensity in barite was found to be a second-order reaction and the closure temperature range of barite was determined. These results are essential for assessing the suitable environments for ESR dating in barite and the conditions for age erasure.