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global dynamics having to do with the movement of a small number of semirigid sections of Earth's crust, with seismic activity and volcanism occuring primarily at the margins of these sections. this movement has resulted in changes in the geographic positions of continents and the shape and size of ocean basins.
german meteorlogist and geophsicist. first to advance the idea of mobile continents in 1912.
a term applied to early theories supporting the possibility the continents are in motion over Earth's surface
an ancient body of water that seperated Laurasia to the north and Gondwanaland to the south. its location was approximately that of the present Alpine-Himalayan mountain system
an extinct, presumably aquatic reptile that lived about 250 million years ago, and located only in eastern south america and western africa
a condition found in the region around a magnet or an electric current, characterized by the existence of a detectable magnetic force at every point in the region and by the existence of magnetic poles
distortions of the regular pattern of earths magnetic field resulting from the various magnetic properties of local concentrations of ferromagnetic minerals in earths crust
sea floor spreading
a process producing the lithosphere when convective upwelling of magma along the oceanic ridges moves the ocean floor away from the ridge axes at rates between 2 to 12 centimeters per year
continuous underwater mountain range that winds through every ocean basin in the world and resembles the seam of a baseball
the outer layer of earths structure, including the crust and the upper mantle to a depth of about 200 km, major components involved in plate techtonic movement
a plastic layer in the upper mantle 80 to 200 km deep that may allow lateral movement of lithospheric plates and isostatic adjustments
a lithospheric plate boundary where adjacent plates diverge, producing an oceanic ridge or rise
a lithospheric plate boundary where adjacent plates converge, producing ocean trench-island arc systems, ocean trench-continental volcanic arcs, or folded mountain ranges
a deep fracture or break, about 25 to 50 km wide, extending along the crest of mid-ocean ridge
east pacific rise
oceanic rise between pacific and nazca plate. broad, low, gentle swelling of the sea floor with a small, indistinct central rift valley
mid atlantic ridge
oceanic ridge between south american and african plates. tall, steep, rugged oceanic ridge
seismic moment magnitude
earthquake intensity is measured on a scale, which reflects the energy released to create very long period seismic waves
melting in the subduction zone causes an arc shaped row of highly active and explosively erupting volcanoes that parallel the trench
an arc shaped row of active volcanoes produced by subduction that occurs along convergent active continental margins
a linear arrangement of islands, many of which are volcanic, usually curved so that the concave side faces a sea seperating the islands from a continent. the convex side faces the open ocean and is bounded by a deep-ocean trench
movement of one plate past another-produces shallow but often strong earthquakes in the lithosphere
san andres fault
continental transform fault that runs from the gulf of california past san francisco and beyond into northern california
areas of intense volcanic activity that remain in more or less the same location over long periods of geologic time and are unrelated to plate boundaries
a chain of extinct volcanoes that is progressively older as one travels away from a hotspot
intially develop along the margin of a landmass where the temperature, salinity, and turbidity of the water are suitable for reef builiding corals
a ring-shaped coral reef growing upward from a submerged volcanic peak. it may have low-lying islands composed of coral debris
growth or increase in size of a continent by gradual external addition of crustal material
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