| A | B |
|---|
| relative age | the age of something comaired to something else |
| absolute age | the date that the event occured or rock was formed |
| uniformitarianism | the things that have happened in the past directly relate to happings of the future |
| catastrophes | sudden major chages |
| superposition | principal that states the oldest rocks are on the bottom and tthe youngest are on the top |
| original horizontality | sedimentary rocks mostly form in horizontal layers |
| intrusion | magma comes up through the sedimentary layers alterating them not reach the surface |
| extrusion | the magam comes up all the wa to the surface alterating the layers of rock |
| joint | crack in the rock |
| correlation | showing that rocks or geololic events that occured in different places are the same age |
| index fossils | fossils that are used to date layers of sedematary rock |
| unconformity | a buried erosinal surface |
| Isotopes | different formes of the sme element |
| radiation | alpha, betta, gamma |
| half life | time need for half of a raidoactive substance to decay |
| age of the earth | 4.5 billion years |
| half life of carbon | 5770 |
