| A | B |
|---|
| uniformitarianism | current geologic processes are the same as have been going in the past |
| James Hutton | British scientist that first theorized the age of the Earth |
| earth's age | 4.6 Billion Years old |
| relative age | one layer of rock being older or younger, but not specific years |
| beds | compressed sediment layers |
| bedding plane | the boundary between two beds |
| law of superposition | an undeformed sedimentary rock layer is older than the layers above it and younger than the layers below it |
| principle of original horizontality | sedimentary rocks left undisturbed will remain horizontal |
| graded bedding | the arrangement of layers in which heavier layers are on the bottom |
| cross-beds | when layers are formed at an angle to the bedding plane |
| ripple marks | waves that form in sand or silt in response to water or wind |
| unconformity | a break in the geologic record because of erosion or because sediment is not deposited |
| non-conformity | when igneous rock is eroded and filled in with sedimentary rock |
| angular unconformity | when rock deposited horizontally is tilted and eroded |
| disconformity | When layers of sediment are uplifted without tilting and then eroded |
| fault | a break or crack in the Earth's Crust |
| intrusion | when magma is injected into existing rock and then cools |
| law of cross cutting relationships | a fault or igneous intrusion is always younger than the rock it cuts through |
