Geo Chapter 1
Terms
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- Trench
- (deep ocean) A very deep, long depression in the sea floor marking a subduction zone.
- Accreted terrane:
- A portion of a plate added to a larger block of crust along a convergent plate boundary.
- .Displacement:
- The separation of formerly continues features across a fault.
- Displacement:
- The separation of formerly continues features across a fault.
- Passive continental margins:
- A continental edge far from active plate boundaries.
- Asthenosphere:
- The region of the mantle about 100 to 250 km beneath EarthÂ’s surface where rocks are plastic and easily deformed. Mushy and flows.
- Lithosphere:
- The earthÂ’s rigid outer 100 kilometers, including crust and outer mantle.
- Convection currents:
- The movement of liquid and gas in which hot, less dense materials rise and colder, denser materials sink.
- Deformation:
- A general term for folding, faulting, and other changes in rocks, sediments, and the land surface that take place in response to stress.
- Compression:
- Stress resulting from forces directed toward each other.
- Reverse fault:
- A fault along with one side is moved up over the other side as a result of compression.
- Thrust fault:
- A type of reverse fault in which the fault surface is only slightly inclined.
- Extension:
- Stretching that occurs in response to stresses directed away from each other.
- Normal faults:
- A fault that drops one side down relative to the other as a result of extension.
- Shear stress:
- Forces causing two blocks of rock or other material to move past each other.
- Transpression:
- combination of compression and transform movement.
- Plate Tectonics:
- The concept that the EarthÂ’s lithosphere consists of a number or rigid, mobile pieces (plates) riding over the more plastic asthenosphere.
- Crust:
- The thin, outer layer of the Earth, composed mostly of silicate minerals; upper part of EarthÂ’s lithosphere.
- Mantle:
- The thickest of EarthÂ’s layers, between the crust and the core, composed of more dense silicate minerals than the crust.
- Divergent Plate Boundary
- The line where two plates meet as they move apart from each other.
- Seafloor spreading:
- The divergent motion and creation of oceanic crust caused by rising magmas along divergent plate boundaries.
- Convergent plate boundary:
- The lines where two plates meet as they move towards each other.
- Subduction:
- The process by which an oceanic plate is driven beneath another plate into the mantle along a convergent boundary.