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Chapter 10
Term | Definition |
---|---|
mold | The mineralized impression of the organism left in the sediment |
fossil | he remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock. |
cast | The mineralized sediment that fills the mold recreates the shape of the remains. |
index fossil | represent species that existed on Earth for a short length of time, were abundant, and inhabited many locations |
relative age | the age of rocks and geologic features compared with other rocks and features nearby. |
correlation | matching rocks and fossils from separate locations |
catastrophism | the idea that conditions and organisms on Earth change in quick, violent event |
superposition | the principal that in undistured rock layers, the oldest rocks are on the bottom |
radioactive decay | the process by which an unstable element naturally changes into another element that is stable |
uncomformity | a surface where rock has eroded away, producing a break, or gap, in the the rock record. |
isotope | atoms of the same element that ahve different number of neutrons |
carbon film | the fossilized carbon outline of an organism or part of an organism |
half-life | the time required for half of the parent isotopes to decay into daughter isotopes |
absolute-age | the numerical age, in years, of a rock or object |
uniformitarianism | the theory that changes in the earth's crust during geological history have resulted from the action of continuous and uniform processes. |
trace fossil | a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself. |
paleontologist | a scientist who specializes in the study of life forms that existed in previous geologic periods, as represented by their fossils |
super position | the principle that in undisturbed rock layers, the oldest rocks are on the bottom |