| Definition | Word |
|---|
| A mass of hotter-than-normal mantle material that ascends toward the surface, where it may lead to igneous activity. These plumes of solid yet mobile material may originate as deep | |
| A coherent unit of Earth’s rigid outer layer that includes the crust and upper mantle. | |
| A long, narrow zone where one lithospheric plate descends beneath another. | |
| A region where the rigid plates are moving apart, typified by the mid-oceanic ridges. | |
| A continuous elevated zone on the floor of all the major ocean basins and varying in width from 500 to 5,000 km. The rifts at the crests of ridges represent divergent plate bounda | |
| A magnetic field that is the same as that which exists at present. | |
| A large landmass that contains all, or nearly all, of the existing continents. | |
| A mechanism that may contribute to plate motion. It involves the oceanic lithosphere sliding down the oceanic ridge under the pull of gravity. | |
| A magnetic field opposite to that which exists at present. | |
| | Definition | Word |
|---|
| The theory that proposes that Earth's outer shell consists of individual plates that interact in various ways and thereby produce earthquakes volcanoes, mountains, and the crust it | |
| A boundary in which two plates slide past one another without creating or destroying the lithosphere. | |
| The natural remnant magnetism in rock bodies. The permanent magnetization acquired by rock that can be used to determine the location of the magnetic poles and the latitude of the | |
| A chain of volcanic islands generally located a few hundred km from a trench where active subduction of one oceanic slab beneath another is occurring. | |
| A long, narrow trough bounded by normal faults. It represents a region where divergence is taking place. | |
| A mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and “pulls” the trailing lithosphere along. | |
| The process by which most igneous rocks melt. Since individual minerals have different melting points, most igneous rocks melt over a temperature range of a few hundred degrees. If | |
| The process of producing new seafloor between two diverging plates. | |
| The proposed supercontinent that 200 million years ago began to break apart and form the present landmasses. | |
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Planets from the Sun
Digits of Pi
Minute Math (Addition)
