Andrew Wright

2. is the portion of motion of a tectonic plate that can be accounted for by its subduction.
3. large elongated depression with steep walls formed by the downward displacement of a block of the earth's surface between nearly parallel faults or fault systems.
4. the gradual movement of the continents across the earth's surface through geological time.
5. Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle
7. an instrument used for measuring magnetic forces, especially the earth's magnetism.
8. is a linear feature that exists between two tectonic plates that are moving away from each other.
9. Changes in direction or orientation of the magnetic field of the Earth that have occurred from time to time.
11. a line on a diagram or map connecting points relating to the same time or equal times.
12. the study of the magnetic record in rock is called

1. these magnetic reversals led scientists to the idea of
4. is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.
5. is where two of the floats - two tectonic plates - side alongside each other. When this happens, the scraping of the two plates causes earthquakes.
6. the hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago.
10. is a proposed mechanism for plate motion in plate tectonics.
13. the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.