RADIOACTIVE DATING METHODS

1/2 PARENT ISOTOPE DECAYS IN HALF-LIFE

ONLY USEFUL FOR ABOUT 10 HALF-LIVES (otherwise not enough left)

CARBON -> NITROGEN DATING - HALF-LIFE 5750 yrs - GOOD TO ABOUT 57,000 yrs - short compared to most geological time scales.

Hence used some in geology, more in archeology

 

OTHER ISOTOPIC METHODS:

RUBIDIUM --> STRONTIUM HALF-LIFE 48 Billion yr (Byr)

POTASSIUM --> ARGON HALF-LIFE 12 Byr

URANIUM --> LEAD HALF-LIFE 4.5Byr ; 713 Myr

 

NOTE: These reactions give off lots of energy, and are important for heating the earth. The last is the nuclear reactor & atomic bomb reaction.