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Geology Timeline
Term | Definition |
---|---|
amber | hard translucent fossilized resin produced by extinct coniferous trees of the Tertiary period, typically yellowish in colo |
fossil | the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock |
cast | throw forcefully in a specified direction |
index fossil | a fossil that is useful for dating and correlating the strata in which it is found |
mold | a hollow container used to give shape to molten or hot liquid material when it cools and hardens |
permineralization | a process of fossilization in which mineral deposits form internal casts of organisms |
tace fossil | a fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itsel |
cross cutting relationships | an igneous intrusion is always younger than the rock it cuts across |
geologic time | the long period of time occupied by the earth's geologic history. |
lateral continuity | ayers of sediment initially extend laterally in all directions; in other words, they are laterally continuous |
original horizontality | layers of sediment are originally deposited horizontally under the action of gravity |
superostition | a principle of quantum theory that describes a challenging concept about the nature and behavior of matter and forces at the sub-atomic level |
unconformity | a surface of contact between two groups of unconformable strata |
uniformitrianism | the theory that changes in the earth's crust during geological history have resulted from the action of continuous and uniform processes |
absolute aga | the true age of a rock or fossi |
half life | he time taken for the radioactivity of a specified isotope to fall to half its original value. |
ice core | a core sample that is typically removed from an ice sheet |
isotope | each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element |
radiometric dating | a method of dating geological or archeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample |
differentiation | the action or process of differentiating |
outgassing | release or give off as a gas or vapo |
supercontient | each of several large landmasses thought to have divided to form the present continents in the geological past |
pangaea | a hypothetical supercontinent that included all current land masses, believed to have been in existence before the continents broke apart during the Triassic and Jurassic Periods |
orogeny | a process in which a section of the earth's crust is folded and deformed by lateral compression to form a mountain range |
evolution | the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth |
natural selection |