Why is potassium argon dating useful for dating hominids Swingerschat no regi

28 Mar

Each volcanic eruption has a unique "fingerprint" and sometimes they scatter ash over a vast area.

In analyzing the other fossils found around the newly discovered hominid bones.

Potassium-Argon Dating Potassium-Argon dating is the only viable technique for dating very old archaeological materials.

Geologists have used this method to date rocks as much as 4 billion years old.

With 18 protons and 22 neutrons, the atom has become Argon-40 (Ar-40), an inert gas.

For every 100 K-40 atoms that decay, 11 become Ar-40.

Volcanic material is the ideal subject of potassium-argon dating because it is a closed system - there is none of the daughter element present when the material is formed to contaminate measurements.

Potassium (K) is one of the most abundant elements in the Earth's crust (2.4% by mass).

One out of every 10,000 Potassium atoms is radioactive Potassium-40 (K-40).

The half-life of potassium40 is roughly 1.25 billion years, so four half-lives are about five billion years, or older than the earth.

Other radiometric techniques, like carbon14, are useful for much more recent dates.