What substances do geologists use in radiocarbon dating?

1 Answer
Jan 19, 2017

Potassium 40 to Argon 40: Uranium 238 to lead 206 :Uranium 235 to lead 207 Rubidium 87 to strontium 87 are some of the most common.

Explanation:

First geologist do not use Carbon 14. Carbon 14 has a half life of only 5,730 years. This makes the effective useful dating age of Carbon 14 only about 50,000 years.
The radioactive materials are used to obtain a ratio of the mother to daughter materials. The half life of the material is than multiplied by the ratio. This method assumes that the original material was 100% of the mother material when the sample was formed. It also assumes that none of the mother materials or the daughter materials has been lost or eroded away.

Radioactive dates are rarely used in isolation. The geologist usually has a target date based on fossils and strata that the geologist wants to confirm or support with radioactive measurements.