Word Entries containing the term:
geological age, geologic age
1. Any great time period in the earth's history marked by special phases of physical conditions or organic development.
2. A formal geologic unit of time which corresponds to a stage.
3. An informal geologic time unit that corresponds to any stratigraphic unit.
4. The fourth-order division of geologic time, which establishes the limits or boundaries of by very minor changes; usually, in sea level and/or climate or in the biota, and usually local.
This is limited to a single continent or a part of it.
geological assurance, geologic assurance
The relative degree of certainty with which the existence, abundance, and quantity of a given resource can be determined; such as, coal or oil.
geological chronology, geologic chronology
Specifically, the dating of archaeological data in association with a geological deposit or formation; such as, the dating of Pleistocene human remains in the context of glacial advances and retreats.
Disasters caused by movements and deformation of the earth's crust.
geological erosion, geologic erosion; normal erosion
Erosion which is caused by prevailing agencies of the natural environment; including, running water, rain, wind, waves, and organic weathering.
Such erosion is primarily responsible for the present modifications of the land surfaces.
geological horizon, geologic horizon
1. A layer of rock with a particular composition; especially, of fossils, used for dating the stratum.
2. A specific layer, or stratum, of soil or subsoil in a vertical cross section of land.
3. A term used to describe an artifact, art style, or other such cultural trait which has extensive geographical distribution but a limited time span.
4. A thin bed or surface within a sedimentary sequence which represents a particular portion of geologic time and that is characterized by its distinctive fossil content or lithology.
geological log, geologic log
A graphic presentation of the lithologic or stratigraphic units or both traversed by a borehole.
Used in petroleum and mining engineering as well as geological surveys.
geological map, geologic map
1. A map on which geological information; such as, distribution, composition, and occurrences of bedrock, is recorded for a geographical region.
2. The representation of geological surfaces or subsurface features by means of signs and symbols and with indicated means of orientation.
It includes nature and distribution of rock units, and the occurrence of structural features, mineral deposits, and fossil localities.
geological oceanography; marine geology; submarine geology
The study of the features of the floors and margins of the oceans, including descriptions of topography, composition of bottom materials, interaction of sediments and rocks with air and sea water, the effects of movements in the mantle on the sea floor, and action of wave energy in the submarine crust of the earth.
Dynamic actions or events that occur at the earth's surface as a result of the application of natural forces resulting from gravity, temperature changes, freezing and thawing, chemical reactions, seismic shaking, and the agencies of wind and moving water, ice and snow.
Where and when a force exceeds the strength of the earth's material, that material is changed by deformations, translocations, or chemical reactions.
geological province, geologic province
An extensive region that is characterized by a similar geological history, or by particular structural or physiographical features throughout; such as, a basin or a delta.
geological repository, deep geological repository
A mined facility for the disposal of radioactive waste, using waste packages and the natural geological formations as barriers to provide waste isolation.
The deep geological repository idea involves the encapsulation of used nuclear fuel in long-term engineered casks which are placed and sealed within excavated rooms in a geological formation at a determined depth of 500 to 1000 meters below the earth's surface.
It involves the construction of a vault within a stable, low permeability bedrock, using conventional mining techniques. The bedrock and other engineered barriers are supposed to provide ecological safety over an extended time.
geological storage, geologic storage; geological sequestration, geologic sequestration (s) (noun)
; geological storages, geologic storages; geological sequestrations, geologic sequestrations (pl)
The long-term accumulation of a substance; such as, carbon dioxide or radioactive waste, in a natural geologic formation; for example, a sedimentary basin, seabed, or underground cavern: Jack and the geologists were exploring the possibilities of having a geological sequestration
in the mountains.
A major demonstration of carbon dioxide injection into a saline formation for sequestration is under way at an offshore gas platform in the North Sea near Norway. Results from this project (and others) suggest that such formations will be reliable, long-term geologic sequestration (storage) sites or carbon dioxide reservoirs.
There are numerous natural carbon dioxide reservoirs throughout the Rocky Mountain states of the United States in geologic "domes" and "traps", suggesting these geological storage formations will be excellent for keeping carbon dioxide captured from industrial facilities.
geological survey (s) (noun)
, geological surveys (pl)
The research of the earth in order to compile maps, and to perform reconnaissance work and comprehensive analytical work: A geological survey is a systematic study of the distribution, structure, composition, and history of land features of a selected region of the world.
geological thermometer, geologic thermometer
1. A mineral or aggregate of minerals the presence of which defines the temperature ranges or limits within which the minerals were formed.
2. A thermometer constructed to measure temperatures in boreholes to provide information about the temperature range within which minerals were developed.
This entry is located in the following units:
geo-, ge- +
thermo-, therm-, thermi-, -thermia, -therm, -thermal, -thermic, -thermias, -thermies, -thermous, -thermy
geological time scale
A system of measuring the history of the earth by studying the rocks of the earth's crust.
Since new rocks are generally deposited on top of existing material, those lower down are oldest.
The strata of rock are classified according to their age, and a time scale corresponding to this can be constructed.
The main divisions (eras) are the Paleozoid, Mesozoic, and Cenozoic. These are further subdivided into periods and epochs.
geological time scale, geologic time scale
An arbitrary chronological arrangement of geological events; usually represented, in the form of a chart, showing the names of various rock layers and indicating the estimated period of each geological unit of geological time.
geological time, geologic time
1. The period of time from the end of the formation of the earth as a separate planet to the beginning of written history, as recorded and illustrated by the succession of rocks.
2. The period of time that extends from the beginning of the world to the present day.
3. An interval of time occupied by the earth's geologic history, extending from about 3.9 billion years ago (corresponding to the age of the oldest known rocks) to the present day.
In other words, the part of the earth's history that is recorded in rock strata.
The geological time scale is classified in intervals distinguished by characteristic geological and biological features; as indicated by the following longest to the shortest durations: eon (one thousand million years), era (divided into several periods), period (unit of geological time during which a system of rocks is formed), and epoch (geologic time that is a subdivision of a period).