Thermal stabilities of paramagnetic defect and impurity centers in quartz: Basis for ESR dating of thermal history.

TLDR

ESR ages of different defect centers in quartz can be used to reconstruct the thermal history of quartz‑bearing rocks. The study examined the thermal stabilities of E′, Al, and Ti centers in quartz from Mannari granite using ESR with isothermal and isochronal annealing experiments. Second‑order decay kinetics best explain the data, yielding closure temperatures of 91 °C for E′, 78 °C for Al, and 31 °C for Ti (with an estimated cooling rate of ~10 °C/Ma), and similar values were derived for rocks surrounding an intrusive dike.

Abstract

Thermal stabilities of E′, Al, and Ti centers in quartz from the Mannari granite were investigated by electron spin resonance (ESR) with isothermal and isochronal annealing experiments. Second order decay kinetics best explain the results. The closure temperatures at which the ESR clocks start were estimated to be 91°C, 78°C, and 31°C for E′, Al, and Ti centers, respectively, with a cooling rate of about 10°C/Ma. Closure temperatures were also estimated for rocks around an intrusive dike. The thermal history of a quartz bearing rock can be investigated using ESR ages for different centers.