Helium-4 is produced within the Earth by the decay of 238U, 235U and 232Th. Shortly after the discovery of the radioactivity of U and Th, the idea of using the accumulation of He in minerals as a dating tool was proposed by Ernest Rutherford (Hurley, 1954). The U-He dating method for rocks is based on the assumption that U- and Th- bearing minerals quantitatively retain the He produced within them. However, comparison of U-He dates with other methods (e.g., K-Ar) has shown that U-He ages frequently underestimate the true age of the sample as a result of incomplete He retention.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- 4He in Groundwater
D. Kip Solomon
- Springer US