Chapter 9 Plate Tectonics
Terms in this set (20)
a hypothesis that originally proposed that continents had once been joined to form a singlesupercontinent
The name of the single landmass that broke apart 200 million years ago and gave rise to today's continents
an electronic depth-sounding mechanism; calculates the depth by recording the time it takes for an energy pulse to reach the ocean floor and return
a surface feature in the seafloor produced by the descending plate during subduction
an undersea mountain chain where new ocean floor is produced; a divergent plate boundary
deep faulted strucutre found alon the axes of diveregent plate boundaries.
the process by which plate tectonics produces new oceanic lithosphere at ocean ridge
the process by which oceanic crust sinks beneath a trench and back into the mantle at a colliding plate boundary.
The study of changes in Earths magnetic field, as shown by patterns of magnetism in rocks that have formed over time.
one of numerous ridig sections of the lithosphere that moves as a unit over the material of the asthenosphere
the theory that proposes that Earths outer shell consists of individual plates that interact in various ways and thereby produce earthquakes, Volcanoes, mountains, and the crust itself
a region where the ridig plates are moving apart, typified by the oceanic ridges
a boundary wher two plates go together
a boundary in which two plates slide past each other without creating or destroying lithosphere
continental volcanic arc
mountain formed formed in part by volcanic activity caused by the subduction of oceanic lithosphere beneath a continent
volcanic island arc
a chain of volcanic islands generally located a few hundred kilometers from a trench where subduction of one oceanic slab beneath another is occurring
the motion of matter resulting from changes in themperature. moves the tectonic plates
a mass of hotter-than -normal mantle material that ascends toward the surface, where it may lead to igneous activity
a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and pulls the trailing lithosphere along
a mechanism that may contribute to plate motion; it involves the oceanic lithosphere slideing down the oceanic ridge under the pull of gravity.