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Geological Evolution
Evolution of the Earth
Term | Definition |
---|---|
relative dating | The age of a rock or fossil described in comparison to that of another rock or fossil. |
absolute dating | The actual age of a rock or fossil or how long ago it formed. |
radioactive dating | A means of measuring the age of a material by comparing the amount of a radioactive form of an element with the amount of its decay product. |
half life | The time required for any specified property to decrease by half. |
fossils | Imprints or the remains of organisms that were once alive |
paleontology | The branch of science concerned with fossil animals and plants. |
superposition | Older layers of rock lie beneath younger rock layers. |
faults | A break or crack in Earth's surface along which movement occurs. |
intrusions | The action or process of forcing a body of igneous rock between or through existing formations, without reaching the surface. |
erosion | A process by which weathered rock is picked up and moved to new places. |
ice cores | A long tube shaped sample of ice taken from a glacier that helps give us data about the composition of the Earth's atmosphere during long periods of time. |
geological time | The time line that organizes Earth's history over the last 4.6 billion years. |
continental drift | The theory that explains how the continents were once together, Pangaea, and then have steadily drifted apart. First proposed by Alfred Wegener. |
pangaea | The hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago. |
plate tectonics | A scientific theory that the Earth's surface is made of very large sections that move very slowly. |
index fossil | A fossil that is useful for dating and correlating the strata in which it is found. |
trace fossil | A fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself. |
unconformity | A mixture of material in a rock. |
extinction | No longer found living on Earth. |
strata | A layer or a series of layers of rock in the ground. |