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Geology: Topic Page
Geology is the study of the solid, nonliving earth, including earth’s materials, structure, processes, and history. Earth’s nonliving materials and features are the result of geologic processes.
Catastrophism: Topic Page
In The Dictionary of Physical Geography
Any major, normally short-lived and sudden event leading to widespread undesirable or disruptive change, as might be triggered by storm surges, floods and hurricanes.
Continental Drift: Topic Page
Geological theory that the relative positions of the continents on the earth's surface have changed considerably through geologic time.
Geomorphology: Topic Page
Branch of geology developed in the late 19th century, dealing with the morphology, or form, of the Earth's surface; nowadays it is also considered to be an integral part of physical geography.
Plate Tectonics: Topic Page
A geological theory according to which the Earth’s crust is composed of a small number of large plates of solid rock, whose movements in relation to each other are responsible for continental drift.
Uniformitarianism: Topic Page
In geology, doctrine holding that changes in the earth's surface that occurred in past geologic time are referable to the same causes as changes now being produced upon the earth's surface.
Rock Cycle: Topic Page
The recycling of the Earth's outer layers. Rocks are continually being formed, destroyed, and re-formed in an endless cycle of change that takes millions of years. The processes involved include the formation of igneous rock from magma (molten rock); surface weathering and erosion; the compaction and cementation of sediments into sedimentary rock; and metamorphism, chemical and physical changes brought about by heat and pressure, producing metamorphic rock.
Chaos Theory: Topic Page
Chaos theory derives from physics and mathematics, and is a form of systems theory that seeks to describe highly complex and disordered systems, such as the atmosphere.
Astronomy: Topic Page
Branch of science that studies the motions and natures of celestial bodies, such as planets, stars, and galaxies.
Geography: Topic Page
The term Geography formally applies to an academic discipline (and a human construct) that encompasses study of the Earth’s surface (Physical Geography), its inhabitants (Human Geography), and, more recently, its environment (Environmental Geography).
Meteorology: Topic Page
Scientific observation and study of the atmosphere, so that weather can be accurately forecast.
Paleontology: Topic Page
[Gr.,= study of early beings], science of the life of past geologic periods based on fossil remains.
Seismology: Topic Page
Scientific study of earthquakes and related phenomena, including the propagation of waves and shocks on or within the earth by natural or artificially generated seismic signals.
Atmosphere: Topic Page
Mixture of gases surrounding a planet. Planetary atmospheres are prevented from escaping by the pull of gravity.
Big Bang: Topic Page
In astronomy, the explosive event that marked the origin of the universe as we know it.
Climate: Topic Page
Combination of weather conditions at a particular place over a period of time - usually a minimum of 30 years.
Climate Change: Topic Page
Increase in average global temperature, amounting to approximately 0.74°C/1.3°F from 1906 to 2005.
Erosion: Topic Page
General term for the processes by which the surface of the earth is constantly being worn away.
Greenhouse Effect: Topic Page
Phenomenon of the Earth's atmosphere by which solar radiation, trapped by the Earth and re-emitted from the surface as long-wave infrared radiation, is prevented from escaping by various gases (the ‘greenhouse gases’) in the air.
Ice Age: Topic Page
Any of several periods in the Earth’s history when the average temperature of the atmosphere decreased to such an extent that ice sheets and glaciers covered large areas of the Earth that previously had a temperate climate.
Mantle: Topic Page
Intermediate zone of the Earth between the crust and the core, accounting for 82% of the Earth's volume.
Ozone Layer: Topic Page
Or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. <
Seafloor Spreading: Topic Page
A theory of lithospheric evolution that holds that the ocean floors are spreading outward from vast underwater ridges. First proposed in the early 1960s by the American geologist Harry H. Hess, its major tenets gave great support to the theory of continental drift and provided a conceptual base for the development of plate tectonics.
Sea Level: Topic Page
The level of the sea, which serves as the datum used for measurement of land elevations and ocean depths.