Earth

3. the time taken for radioactivity of a specified isotope to fall to half its original value.
5. states that layers of sediment are originally deposited horizontally under the action of gravity .
8. sample that is typically removed from an ice sheet
9. is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.
10. A crack in the earths crust.
11. the branch of science concerned with fossil animals and plants.
13. the underlying geological material in which soil horizons form.

1. States layers of rocks above are younger than the ones they are on top of.
2. ordering events or objects in time without assigning actual ages or dates.
4. determining an actual age for an object or a date of occurence for an event.
6. emitting or relating to the emission of ionizing radiation or particles.
7. Lived in a particular geologic age, and can be used to identify or date the rock or rock layer in which it is found.
12. is a method for determining the age of an object containing organic material by using the properties of radiocarbon.