Helium dating

rdf:langString Helium dating

rdf:langString Helium dating may refer to the traditional uranium–thorium dating (abbreviated U–Th/He dating) or to a variety of He diffusion methods that utilize the mobility of He atoms to determine the thermal history of a rock. Helium diffusion experiments are often used to help interpret information retrieved from U–Th/He thermochronometric experiments. Kinematic parameters derived from He diffusion is done through estimating He diffusion over a range of temperatures. The use of density functional theory helps in estimating energy barriers for He to overcome as it diffuses across various crystallographic directions. Discrepancies, however, between observed and predicted He diffusion rates is still a problem and likely stem from unresolved problems in crystal defects and radiation damage in natural grains as opposed to theoretical grains. Depending on the mineral analyzed there are different assumptions to be made on He mobility. For example, He diffusion in minerals such as zircon, rutile, and monazite have been shown to be strongly anisotropic. A relatively new dating method, tritium–helium dating has been developed for determining rates of oxygen utilization in the ocean.