Here's how it works:
* Fossil Record: Fossils provide a record of life on Earth throughout history. Some fossils are specific to certain time periods, acting as markers for those eras.
* Index Fossils: These are fossils of organisms that lived for a relatively short period of time and were geographically widespread. They are particularly valuable for biostratigraphy.
* Correlation: By comparing the fossil assemblages found in different rock layers, geologists can establish a relative time scale. If the same index fossil is found in two different locations, it indicates that the rocks in both places were deposited during the same period of time.
Important Note: Biostratigraphy determines the relative age of rocks. It tells us which rocks are older or younger than others, but it doesn't provide a specific numerical age in years. For that, we need radiometric dating.
Let me know if you'd like to learn more about radiometric dating!
