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Fossils and Unconfor
Vocabulary
| Question | Answer |
|---|---|
| Absolute Age | The exact age of a rock layer or fossil |
| Angular Unconformity | When there is movement of the earth that turns the rock layers at an angle. |
| Anticline | An upward fold of rock |
| Crosscutting | Intrusive magma or lava is always younger than the existing rock. |
| Extrusion | Lava that hardens on the surface |
| Folding | When heat and pressure bends rock |
| Fossil | The preserved remains or traces of an organism |
| Index Fossils | Useful fossils that help determine the age of other fossils or rock layers. They must 1) have lived and died in a relatively short period of time and 2) They need to be widely distributed. |
| Intrusion | Magma cooled and hardened into a mass of igneous rock. |
| Lava | Flow from the mantle that is on top of the crust |
| Law of Inclusion | When rock layers have bits of the rock layer below it, it must be younger than the one below it. |
| Magma | Flow from the mantle that is inside the crust |
| Relative Dating | Determining the relative age of rock layers or order of past geologic events |
| Relative Age | The approximate age of a rock layer or fossil |
| Syncline | A downward fold of rock |
| Strata | Rock layers |
| The Law of Superposition | In an undisturbed horizontal sequence of rocks, the oldest rock layers will be on the bottom. |
| Unconformity | Represent gaps in the geologic record; periods of time that are not represented by any rocks. |
| Geyser | A hot spring in which water intermittently boils, sending a tall column of water and steam into the air. |