Noble Gases Deliver Cool Dates from Hot Rocks

Abstract

Heat transfer in the solid Earth drives processes that modify temperatures, leaving behind a clear signature that we can measure using noble gas thermochronology. This allows us to record the thermal histories of rocks and obtain the timing, rate, and magnitude of phenomena such as erosion, deformation, and fluid flow. This is done by measuring the net balance between the accumulation of noble gas atoms from radioactive decay and their loss by temperature-activated diffusion in mineral grains. Together with knowledge about noble gas diffusion in common minerals, we can then use inverse models of this accumulation–diffusion balance to recover thermal histories. This approach is now a mainstream method by which to study geodynamics and Earth evolution.