ESR thermochronometry; A Status update

ESR熱年代法; 最新情報

King, G. E.*; 末岡 茂   ; 小形 学 ; 他11名*

King, G. E.*; Sueoka, Shigeru; Ogata, Manabu; 11 of others*

The electron spin resonance (ESR) of charges (electrons, holes) that have accumulated in natural lattice defects in quartz minerals offer an ultra-low temperature multi-thermochronometry system with closure temperatures between 10 and 80C. This system offers the potential to resolve rock temperature changes precisely within the last 1-2 km of Earth's crust throughout the late Cenozoic. Over the past 10 years we have worked intensively on the development of this technique and here we provide an overview of the status of ESR thermochronometry. Using quartz samples from a diverse range of settings (Mont Blanc and Aiguilles Rouges massifs - European Alps, Nepalese Himalaya, Japanese Alps, Grand Canyon - USA, Anadarko basin - USA, KTB borehole - Germany, MIZ1 borehole - Japan) we have established experimental protocols for measuring ESR signals in the laboratory. We have developed numerical models that accurately describe signal accumulation and thermal decay; these equations are now implemented within the 3D thermo-kinematic model, Pecube. We have successfully validated the technique against borehole data and have applied it to constrain exhumation rates within the Japanese and European Alps. We show that ESR-thermochronometry is now a robust technique that can constrain exhumation rates of as low as 0.1 mm/yr over kyr to Myr timescales with great potential for Earth science research.