Earth Science Honors Ch. 12
Terms
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- ABSOLUTE AGE
- Actual age of an object
- AMBER
- Hardened tree sap in which fossils may be preserved
- ANGULAR UNCONFORMITY
- Boundary between horizontal and tilted layers of rock
- BEDDING PLANE
- Boundary between two sedimentary rock layers
- COPROLITE
- Fossilized waste material from an animal
- DISCONFORMITY
- Boundary between layers of rock that have not been deposited continuously
- EVOLUTION
- Change of living things over time
- GASTROLITH
- Fossilized stone found within the digestive system of a dinosaur or other reptile
- HALF-LIFE
- Time required for half the mass of a radioactive element to decay into its daughter elements
- INDEX FOSSIL
- Guide fossil; fossil found in the rock layers of only one geologic age and is used to establish the age of the rock layers
- LAW OF CROSSCUTTING PRINCIPLE
- Principle that a fault or intrusion is always younger than the rock layers it cuts through
- LAW OF SUPERPOSITION
- Principle that a sedimentary rock layer is older than the layers above it and younger than the layers below it
- MUMMIFICATION
- Preservation of a dead organism by drying
- NONCONFORMITY
- Unconformity in which stratified rock rests on unstratified rock
- PALEONTOLOGIST
- Scientist who studies fossils
- PALEONTOLOGY
- Study of fossils
- PETRIFICATION
- Process in which organic materials are replaced by new materials
- PRINCIPLE OF UNIFORMITARIANISM
- Theory that geologic processes at work in the present were also at work in the past
- RELATIVE AGE
- Age of an object compared with the ages of other objects
- TRACE FOSSIL
- Fossil trace left by an ancient organism, such as a track, footprint, boring, or burrow
- UNCONFORMITY
- Break in the geologic record created when rock layers are removed by erosion
- VARVE
- Annual layer of sedimentary deposit on a lake bed
- CENOZOIC ERA
- The most recent geologic era, beginning 65 million years ago; the Age of Mammals
- EPOCH
- Subdivision of a geologic period
- ERA
- Largest unit of geologic time
- GEOLOGIC COLUMN
- Arrangement of rock layers based on the ages of the rocks
- INVERTEBRATE
- Animal without a backbone
- ION
- Atom or group of atoms that carries an electrical charge
- MESOZOIC ERA
- Geologic era that lasted from 248 to 65 million years ago, prior to the Cenozoic; the Age of Reptiles
- PALEOZOIC ERA
- Geologic era that followed Precambrian time, lasting from 540 million to 248 million years ago
- PERIOD
- Subdivision of geologic era
- PRECAMBRIAN TIME
- Earliest and longest geologic era, lasting from 4.6 billion to 540 million years ago
- THEORY OF EVOLUTION
- Theory that organisms change over time and that new organisms are derived from ancestral types
- VERTEBRATE
- Animal with a backbone