EESA06H3 Lecture 8: Lecture 8
Document Summary
The origin of the earth is 4. 5 ga, and it is not until 500 ma that life becomes so common that we can recognize fossils in rock. Most of the earth"s history, the rocks don"t contain fossils and the importance of fossils is we can use it to correlate it. As life evolves, an organism will chance through time, a specific type of fossil is usually linked to a very specific time period. Correlation= correlate rocks between one era to another. This is a problem in the precambrian era, which is the bulk of the earth"s history and there are no fossils. 500 ma, we have life, the other periods are subdivided based on fossil content. Method by which scientist determine the age of something! Relative age: age that is determines using the sequence of important events, which comes before or after the thing existed. Absolute age: provides a numerical value on how long the thing existed.
