Volcanoes and Plate Tectonics
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Created by:
NinaRose123 on May 31, 2011
Subjects:
earth science, science, geology
Description:
TU Geology 836
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67 terms
Terms | Definitions |
|---|---|
 mafic | basaltic rocks that contain a high percentage of ferromagnesian minerals are called this |
| felsic | Describes magma or igneous rock that is rich in feldspars and silica and that is generally light in color. |
| andesite | Intermediate in composition between mafic basalt and felsic rhyolite, |
| rhyolite | A fine-grained, felsic, igneous rock made up mostly of feldspar and quartz. |
| basaltic | dense, dark-colored igneous rock formed from magma; rich in magnesium and iron and poor in silica |
| Convergent Boundary | A tectonic plate boundary where two plates collide, come together, or crash into each other. |
| Divergent Boundary | the boundary between two tectonic plates that are moving away from each other |
| Transform Boundary | a plate boundary where two plates move past each other in opposite directions |
| Gradualism | The theory that evolution occurs slowly but steadily |
| James Hutton | Scottish geologist who described the processes that have shaped the surface of the earth (1726-1797) |
| Inner Core | a dense sphere of solid iron and nickel at the center of Earth |
| Outer Core | a layer of molten iron and nickel that surrounds the inner core of Earth |
| Mantle | the layer of the earth between the crust and the core |
| Lithosphere | the solid part of the earth consisting of the crust and outer mantle |
| olivine | a mineral consisting of magnesium iron silicate |
| Asthenosphere | The solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it |
| Subduction Zone | the region where an oceanic plate sinks down into the asthenosphere at a convergent boundary, usually between continental and oceanic plates |
| Uniformitarianism | is the idea that the geologic processes that operate today also operated in the past |
| Oceanic Plate | denser plate made mostly of basalt |
| Continental Plate | tectonic plate that lies under a continent |
| Continental Volcanic Arc | mountains formed by igneous activity associated with the subduction of oceanic lithosphere beneath a continent |
| Pyroclastic Eruption | these eruptions produce clouds and avalanches of pyroclastic debris and happen when gas expands in the rising magma but cannot escape, eventually the pressure becomes so great that it blasts the lava out of the volcano |
| Magma Chamber | The pocket beneath a volcano where magma collects. |
| Silica | a material found in magma that is formed from the elements oxygen and silicon |
| VEI | indicates the destructiveness of a volcano |
| Stratocone Volcano | Thick, high viscosity, rubble-like lava. - Explosive activity - Intermediate (60%) silica content. |
| Cinder-Cone Volcano | Steep-sided, loosely packed volcano formed when tephra falls to the ground |
| Tephra | bits of rock or solidified lava dropped from the air |
| Lava | magma that reaches the Earth's surface |
| Shield Volcano | a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions |
| Lapilli | pebble like bits of magma that cool in the air |
| Volcanic Ash | Extremely small fragments, usually of glass, that form when escaping gases force a fine spray of magma from a volcano. |
| Volcanic Bombs | A projectile of hot magma or rock that is blown from the vent during a volcanic eruption. These solidify in flight and frequently form an elongated rock of streamlined shape. |
| Volcanic Blocks | Large pieces of pyroclastic material that is made up of rock. |
| EAGLET | Volcanic Hazards: Explosives, Ash, Gas, Lava, Earthquakes, Tsunamis |
| Recurrence Interval | how frequently a flood of 'x' severity occurs in average for that particular stream |
| Plinian Eruption | a volcanic eruption in which a stream of gas and ash is violently ejected to a height of several miles |
| Peleean Eruption | Mainly associated with felsic magmas, marked by glowing clouds- downslope |
| Caldera | a large crater caused by the violent explosion of a volcano that collapses into a depression |
| Hot Spot | an area where magma from deep within the mantle melts through the crust above it |
| Lahar | A mudflow composed of water and volcanic ash. Lahars can be triggered by the flash melting of the snow cap of a volcanic mountain or from heavy rain. Lahars are very dangerous because they can occur suddenly and travel at great speeds. |
| Nuee Ardent | Fiery pyroclastic flow made of hot gases infused with ash and other debris. Move down the slopes of a volcano at speeds up to 200 km per hour (125 ish miles per hour) |
| mid Ocean Ridge | An undersea mountain chain where new ocean floor is produced |
| Iron Catastrophe | The process that created the Earth's magnetic field. The Earth got so hot that the molten iron got stuck as the planet's core because of density. |
| Nebular Hypothesis | (cosmology) the theory that the solar system evolved from a hot gaseous nebula |
| Lava Fountain | a vertical geyser of lava which shoots dozens of yards up into the air from a narrow conduit |
| Fumarole | a vent in a volcanic area from which fumes or gases escape |
| Ring of Fire | Collection of volcanoes rimming the Pacific Ocean, really a ring of subduction zones |
| Conditional Probability | the probability that an event will occur given that oneor more other events have occurred |
| Frequency v Magnitude | The greater the magnitude of a disaster, the lower the frequency |
| Catastrophism | a principle that states that geologic change occurs suddenly |
| Moho | the boundary between the earth's mantle and crust |
| Continental Drift | the hypothesis that the continents slowly move across Earth's surface |
| Rift Valley | a valley formed when the block of land between two normal faults slides downward |
| Fissure Eruption | A volcanic eruption emanating from an elongated fissure rather than a central vent. |
| San Andreas Fault | a huge crack that runs through most of California that separates the North American and Pacific plates |
| Volcanic Dome | a mound of felsic lava which may form inside a crater; a kind of cap over the vent. |
| Decompression Melting | Partial melting of hot mantle rock when it moves upward and the pressure is reduced to the extent that the melting point drops to the temperature of the body. |
| Lateral Blast | An explosion in which the energy released is directed horizontally instead of vertically as in a regular eruption. |
| Pyroclastic Deposit | vast, sheetlike deposit of felsic pyroclastic materials erupted from fissures |
| Aa | a slow-moving type of lava that hardens to form rough chunks; cooler that pahoehoe |
| Pahoehoe | a hot, fast-moving type of lava that hardens to form smooth, ropelike coils |
| Silica Content | high content is more viscous (thick, andesitic/rhyolitic) low content is less (thin, basaltic) |
| Predictions Based on Precursors | Tilt Meters/GPS, Earthquakes, Temperature changes, Changes in Gas Composition, other geophysical methods |
| Age of the Earth | 4.5-5 billion years |
| Strombolian | lava and cinders, moderate magma volume, moderate violence, composite or cinder cone, sporatic violence |
| Volcanian | *type of eruption -dense cloud of ash-laden gas explodes from the crater and rises above the peak -steaming ash forms a whitish cloud near the upper level -Paricutin Volcano in 1947 |
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