Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Geological Time
| Term | Definition |
|---|---|
| Fossil | The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock. |
| Index Fossil | A fossil that is useful for dating and correlating the strata in which it is found. |
| Permineralized Remains | Permineralization is a process of fossilization in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. |
| Molds and Casts | Organisms buried in sediment may decay or dissolve away leaving a cavity or mold. If the space is subsequently filled with sediment, an external cast can be made. Molds and casts are three dimensional and preserve the surface contours of the organism. |
| Orginal Remains | The evidence in rock of the presence of a plant or an animal from an earlier geological period. |
| Trace Fossils | A fossil of a footprint, trail, burrow, or other trace of an animal rather than of the animal itself. |
| Relative Age | Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. estimated age). |
| Superposition | Superposition is a principle of quantum theory that describes a challenging concept about the nature and behavior of matter and forces at the sub-atomic level. |
| Horizontality | States that layers of sediment are originally deposited horizontally under the action of gravity. |
| Absolute Age | Is the true age of a rock or fossil. Absolute age tells scientists the number of years ago a rock layer formed |
| Half-Life | The time taken for the radioactivity of a specified isotope to fall to half its original value. |
| Isotopes | 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. |
| Radioactive Decay | The spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles. |
| Geologic Time | A system of chronological measurement that relates stratigraphy to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships between events that have occurred throughout Earth's history. |
| Eon | A major division of geological time, subdivided into eras. |
| Era | A geologic era is a subdivision of geologic time that divides an eon into smaller units of time. |
| Period | A geologic period is one of several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. |
| Epoch | A division of time that is a subdivision of a period and is itself subdivided into ages, corresponding to a series in chronostratigraphy. |
| Pangaea | Is 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. |
| Trilobite | An extinct marine arthropod that occurred abundantly during the Paleozoic era, with a carapace over the forepart, and a segmented hind part divided longitudinally into three lobes. |
| Precambrian | Of, relating to, or denoting the earliest eon, preceding the Cambrian period and the Phanerozoic eon. |
| Mesozoic Era | Includes the Triassic, Jurassic, and Cretaceous Periods and is characterized by the development of flying reptiles, birds, and flowering plants and by the appearance and extinction of dinosaurs. |
| Cenozoic Era | Characterized by the formation of modern continents and the diversification of mammals and plants. Grasses also evolved during the Cenozoic. |
Created by:
madisonbarden