Dating by radioisotopes Free sex chating without any ragistration
Scientists can use certain types of fossils referred to as index fossils to assist in relative dating via correlation.Index fossils are fossils that are known to only occur within a very specific age range.The same rock formation also contains a type of trilobite that was known to live 415 to 425 million years ago.
The total number of neutrons and protons (symbol A), or mass number, of the nucleus gives approximately the mass measured on the so-called atomic- mass-unit (amu) scale.
Potassium-40 on the other hand has a half like of 1.25 billion years and is common in rocks and minerals.
This makes it ideal for dating much older rocks and fossils.
The Wheeler Formation has been previously dated to approximately 507 million year old, so we know the trilobite is also about 507 million years old.
But, how can we determine how old a rock formation is, if it hasn’t previously been dated?