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30 Cards in this Set
- Front
- Back
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Lithosphere
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earth’s crust and that portion of the upper-most mantle directly below the crust, extending down to about 70km. some sources use this term to refer to the entire earth..
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Astenosphere:
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region of the upper most mantle just below the lithosphere; the least rigid portion of Earth’s interior and known as the plastic layer, flowing very slowly under extreme pressure and heat.
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Mantle:
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An area within the planet representing about 80% of Earth’s total volume, with densities increasing with depth and averaging 4.5g/cm3; occurs between the core and the crust; is rich in iron and magnesium oxides and silicates.
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Crust:
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Earth’s outer shell of crystalline surface rock, ranging from 5-60km in thickness from oceanic crust to mountain ranges. Average density of continental crust is 2.7g/cm3, whereas oceanic crust is 3.0g/cm3.
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Isostasy:
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A state of equilibrium in Earth’s crust formed by the interplay between proportions of the lithosphere and the asthenosphere and the principle of buoyancy. The crust depresses under weight and recovers with its removal, for example, the melting of glacial ice. The uplift is known as isostatic rebound.
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Magnetic reversal:
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A polarity change in Earth’s magnetic field. With uneven regularity, the magnetic field fades to zero, then returns to full strength but with the magnetic poles reversed. Reversals have been recorded 9 times during the past 4 million years.
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Elastic Rebound:
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A concept describing the faulting process in Earth’s crust, in which the two sides of a fault appear locked despite the motion of adjoining pieces of crust, but w/the accumulating strain they rupture suddenly, snapping to new positions relative to each other, generating an earthquake.
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Lahar:
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A lahar is a type of mudflow composed of pyroclastic material and water that flows down from a volcano, typically along a river valley.
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pyroclastic flow:
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are a common and devastating result of some volcanic eruptions. They are fast-moving fluidized bodies of hot gas, ash and rock (collectively known as tephra) which can travel away from the vent at up to 150 km/h.
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Composite Volcano:
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A volcano formed by a sequence of explosive volcanic eruptions; steep-sided, conical shape.
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Shield Volcano:
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A symmetrical mountain landform built from effusive eruptions. Typical of the Hawaiian volcanoes.
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Caldera:
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An interior sunken portion of a composite volcanoes crater, usually steep sided and circular.
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Continental Crust
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is granite, high in silica, low density, 2.7g/cm3
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Oceaninc Crust
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is basalt, denser than contental crust, 3.0g/cm3
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Three kinds of rocks
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igneous, sedimentary, and metamorphic
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Igneous Rock
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molten state, granite, basalt, rhyolite, from magma, 90% earths crust
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Sedimentary Rock
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involves lithofication, cementation, compaction and hardening, sandstone, shale, limestone, and coal
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Metamorphic rock
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from parent material, foliated, non-foliated texture
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Earth's Age
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4.567 billion years
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Outer Core
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molten metallic minerals, w/light density
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Plate Tectonics
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include upwelling of magma, lithosphere plate movements, sea floor spreading, earthquakes, volcanic activity
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seafloor spreading
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builds suboceanic mountain ranges
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midoceanic ridges
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submarine mnt ranges, upwelling flows of magma, intense hypothermal activity
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Divergent Boundaries:
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sea floor spreading, occur at mid ocean ridges, spreading apart.
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convergent boundaries
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collision zones, continental and oceanic lithosphere collide.
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transform boundaries
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plates slide past one another
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Normal Fault
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forces pull rocks apart
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Reverse fault
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rocks move upward
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strike slip fault
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transform fault, right lateral or left lateral.
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Location of volcanos
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along subduction zones, sea-floor spreading, hot spots.
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