Kinetics of argon diffusion in calcite
2013
Cassata, William S. | Renne, Paul R.
Here we present results of detailed diffusion experiments on ³⁷Ar in laser-heated calcite crystals. The data define linear Arrhenius arrays that yield an average apparent activation energy of 417.4±4.3kJ/mol and average frequency factor of 43.2±0.6 ln(s⁻¹), which correspond to a closure temperature of 385±2°C (for a 10°C/Ma cooling rate). These results indicate that calcite quantitatively retains trapped atmospheric and in situ produced cosmogenic argon at Earth surface and upper crustal temperatures over geologic time. Furthermore, these are the first reported data on argon diffusion in a rhombohedral or carbonate mineral, an important constraint on models of noble gas diffusion kinetics in crystalline materials.
显示更多 [+] 显示较少 [-]