These techniques are accurate only for material ranging from a few thousand to 500,000 years old — some researchers argue the accuracy diminishes significantly after 100,000 years.

How accurate is isotope dating?

Absolutely. It is an accurate way to date specific geologic events. This is an enormous branch of geochemistry called Geochronology. There are many radiometric clocks and when applied to appropriate materials, the dating can be very accurate.

What dating methods do scientists use?

To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

Why is U 238 used to date very old rocks?

The more lead the rock contains, the older it is. The long half-life of uranium-238 makes it possible to date only the oldest rocks. Also, the half-life of potassium-40 is only 1.3 billion years, so it can be used to date rocks as young as 50,000 years old.

Can objects over 50000 60000 years old be dated using carbon?

Geologists do not use carbon-based radiometric dating to determine the age of rocks. Carbon dating only works for objects that are younger than about 50,000 years, and most rocks of interest are older than that. Over time, carbon-14 decays radioactively and turns into nitrogen.

Which isotope would be best to date the oldest rock on Earth?

In comparison, the half-life of the radioactive uranium 238 isotope is 4.5 billion years, which makes it useful for dating extremely old materials.

What are the limitations of uranium-238 dating?

The more lead the rock contains, the older it is. The long half-life of uranium-238 makes it possible to date only the oldest rocks. This method is not reliable for measuring the age of rocks less than 10 million years old because so little of the uranium will have decayed within that period of time.