Question

Scientists found a layer of rock with a very old trilobite fossil. They tested the rock layer and found that there was only 12.5% of the original Uranium-235 in it. How old is this trilobite?

Answer 1

I think it should be: 2,130 million years

Step-by-step explanation:

In the chart it says that Uranium 253 takes 710 million years for one half life. If 50% percent is 710 million years and then you half 50% again you will add on another 710 million years, getting 1,420 million years. However, it says that there is 12.5% of the original Uranium 253, so you need to add one more half life on, because 12.5% is half of 25%. In the end when you add three half lives together you get 2,130 million years.

Answer 2

The oldest trilobite (ancient marine arthropods) fossils are about 525 million – 500 million years old. They are known as Redlichiida and they first appear in the fossil record in the Lower Cambrian period. The earliest Redlichiida are considered the ancestors of all other trilobite species.

Step-by-step explanation: