Geological History

2. scientists that study fossils
3. elements that release particles of energy and they beak down or decay over time. Atoms of one element break down to form atoms of another element.
6. Fossil fossils in which minerals replace all of an organism or part of an organism such as a dinosaur bone - a fossil type
9. a solid copy of the shape of an organism - a fossil type
10. the preserved remains or traces of living things
12. an extremely thin coating of carbon on rock - a fossil type
14. age the age of a rock compared to other rocks, i.e. older or younger than
15. it is the time it takes for a radioactive element for half of the elements to decay

1. the age of a rock compared to other rocks, i.e. older or younger than
4. a fossil that is widely distributed and and in existence for a relatively short period in geologic history. They are useful because they tell tell the relative age of the rock in which they are found.
5. when an organism no longer exists and will never again on earth
7. the number of years that have passed since a rock formed
8. a landmass that existed when all continents were joined, from about 300 to 200 million years ago.
11. a gap in the geological record that shows where rocks are lost due to erosion/ folding, etc...
13. a hollow area in sediment in the shape of an organism or part of an organism - a fossil type