Fossil age dating
One outcrop shows layers from one geologic time period, while the other outcrop represents a different time. Can he put the pieces together to make the story more complete? Let's find out how scientists deal with this common problem by using the fossils inside the rocks.
Obviously, the fossil assemblages change from period to period.Organisms usually need to be covered by mud, sand, tar or some other sediment as soon as possible or frozen or dessicated (dried out) for fossilization to occur.Fossils, by definition, are the remains or traces of organisms that lived at least 10,000 years ago.Scientists are still finding a few new sites where they live today but they were quite abundant on earth some 2 billion years ago, and perhaps earlier.
Geologists credit stromatolite activity for creating the earth's first atmospheric oxygen and making animal life possible.
These isotopes aren’t found in the fossils themselves, but in the rock encasing the fossils Geologists in the International Commission on Stratigraphy make proposals based on the most recent studies to constantly update the geologic time scale of the world’s rocks.