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Internal Structures
Term | Definition |
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lithosphere | the rigid outer part of the earth, consisting of the crust and upper mantle. |
asthenosphere | highly viscous, mechanically weak and ductilely deforming region of the upper mantle of the Earth. It lies below the lithosphere, at depths between approximately 80 and 200 km (50 and 120 miles) below the surface. |
magnetic field | A magnetic field is the magnetic effect of electric currents and magnetic materials |
Hydrosphere | The hydrosphere in physical geography describes the combined mass of water found on, under, and over the surface of a planet |
Magnetosphere | A magnetosphere is the region of space surrounding an astronomical object in which charged particles are controlled by that object's magnetic field |
Atmosphere | the envelope of gases surrounding the earth or another planet |
dynamo effect | The Earth's magnetic field is attributed to a dynamo effect of circulating electric current, but it is not constant in direction. Rock specimens of different age in similar locations have different directions of permanent magnetization |
continental drift hypothesis | Continental drift is the movement of the Earth's continents relative to each other, thus appearing to "drift" across the ocean bed. The speculation that continents might have 'drifted' was first put forward by Abraham Ortelius in 1596. |
subduction zone | Geometry of a subduction zone-insets to show accretionary prism and partial melting of hydrated asthenosphere |
lamproites | Lamproites are ultrapotassic mantle-derived volcanic and subvolcanic rocks.They have low CaO, Al2O3, Na2O, high K2O/Al2O3, a relatively high MgO content and extreme enrichment in incompatible elements. |
transform plate boundaries | A transform fault or transform boundary, is a type of fault whose relative motion is predominantly horizontal, in either a sinistral or dextral direction. |
divergent plate boundaries | In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. |
convergent plate boundaries | In plate tectonics, a convergent boundary, also known as a destructive plate boundary (because of subduction), is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide |
conduction | the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material. |
convection | the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat |
radiation | In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium |
plasma | an ionized gas consisting of positive ions and free electrons in proportions resulting in more or less no overall electric charge, typically at low pressures (as in the upper atmosphere and in fluorescent lamps) or at very high temperatures. |
Geomagnetic reversals | A geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged, while geographic north and geographic south remain the same. |
Coriolis effect | an effect whereby a mass moving in a rotating system experiences a force (the Coriolis force) acting perpendicular to the direction of motion and to the axis of rotation |
ophiolite | is a section of the Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. |
Global warming | Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects. |
plate tectonics | Plate tectonics is a scientific theory that describes the large-scale motion of Earth's lithosphere. |
Doppler Effect | The Doppler effect (or Doppler shift) is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source |
Greenhouse Effect | The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere |
Mantle | The mantle is a layer inside a terrestrial planet and some other rocky planetary bodies |
seismograph | Seismometers are instruments that measure motion of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources |
seismic waves | The two main types of waves are body waves and surface waves. Body waves can travel through the earth's inner layers, but surface waves can only move along the surface of the planet like ripples on water |
sea-floor spreading | a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. |
xenolith | a rock fragment which becomes enveloped in a larger rock during the latter's development and hardening. |