What is a type of relative dating of fossils

Absolute Dating Absolute dating is used to determine a precise age of a fossil through radiometric methods.This uses radioactive minerals in the rocks and fossils almost like a geological clock.While there is no defined date, typically something must be older than 10,000 years to be considered a fossil.The oldest fossils in the fossil record date from 3.5 billion years ago, however it wasn't until around 600 million years ago that complex, multi-cellular life began was first preserved in the fossil record.Replacement and Recrystallization - Replacement occurs when the shell, bone or other tissue is replaced with another mineral.A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.Index fossils are fossils that only occurred during a specific time frame.Typically commonly occurring fossils that had a widespread geographic distribution such as brachiopods, trilobites, and ammonites make the best index fossils.

In cases of rapid fosssilization, very fine details can be preserved.

For example if you have a fossil trilobite and it was found in the Wheeler Formation which has been dated to approximately 507 million years old, you know the fossil in it is approximately 507 million years old.

Scientists use certain types of fossils referred to as index fossils to assist in relative dating via correlation.

Very rare, and typically found in very recent fossils.

Some examples include freezing (woolly mammoths in the permafrost), mummification, fossilization in amber.

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