ANTH 1001 Chapter : Relative Dating
Document Summary
Calibrated relative dating techniques: uses regular processes that can be correlated to an absolute chronology to estimate the age site. Direction is used to correlate with geometric polarity time scale to infer an age for the site. Radiometric: chronometric techniques that use radioactive decay of isotopes. Radiocarbon dating: compares the ratio of radioactive carbon (14^c) to stable carbon (12^c). It accumulate 14^c during life; equal to levels in the atmosphere. After death 14^c starts to decay in 14^n. Times it takes one half of a radioactive isotopes to decay chemically into another isotope (5,730 years) To date something with a radiocarbon dating it have to be organic. Only good for 50,000 years ago to the present. Potassium- argon dating (k-ar): compares the ratio of radioactive potassium to stable argon gas. K/ar has a half-life of 1. 25 billion years; best sample include rocks heated extremely high, e. g. by volcanic activities.
