Vocabulary - Plate Tectonics - Part 1
Across
- 3. The arrangement of the natural and artificial physical features of an area.
- 4. Contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava underwater, or subaqueous extrusion.
- 5. The rigid outer part of the earth, consisting of the crust and upper mantle.
- 9. Relating to or denoting the depths or bed of the ocean, especially between about 10,000 and 20,000 feet (3,000 and 6,000 m) down.
- 11. The widest layer of the Earth, and it lies between the thin outer layer, the crust, and the super-heated outer core. It’s made of a semi-molten rock called magma.
- 13. A device for determining the depth of the seabed or detecting objects in water by measuring the time taken for sound echoes to return to the listener.
- 15. Extremely hot liquid and semi-liquid rock located under Earth's surface. When it flows onto Earth's surface, it is called lava.
- 17. A supercontinent that formed during the late Neoproterozoic and began to break up, involving the separation of Antarctica from South America and Australia.
- 19. The relatively thick part of the earth's crust that forms the large landmasses. It is generally older and more complex than the oceanic crust.
- 21. A massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.
- 22. The hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago.
- 23. Great flat sediment-covered areas of ocean floor.
- 24. The formation of new areas of oceanic crust, which occurs through the upwelling of magma at midocean ridges and its subsequent outward movement on either side.
- 25. Typically form along the mid-ocean ridges, such as the East Pacific Rise and the Mid-Atlantic Ridge. These are locations where two tectonic plates are diverging, and new crust is being formed.
Down
- 1. The hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed.
- 2. The ancient remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
- 6. The relatively thin part of the Earth's crust which underlies the ocean basins. It is geologically young compared with the continental crust and consists of basaltic rock overlain by sediments.
- 7. Extrusive igneous (volcanic) rock that is low in silica content, dark in color, and comparatively rich in iron and magnesium.
- 8. A hypothetical landmass in the Northern Hemisphere near the end of the Paleozoic Era: split apart to form North America and Eurasia.
- 10. Magma, molten rock, emerging as a liquid onto Earth's surface.
- 12. Where the magnetic north points (roughly) towards the geographic north pole. This is how the magnetic field is aligned today.
- 14. Where the magnetic north points in the opposite direction, and the north end of the magnetic field is close to the present-day south pole.
- 16. An instrument used for measuring magnetic forces, especially the earth's magnetism.
- 18. Zone of Earth's mantle lying beneath the lithosphere and believed to be much hotter and more fluid than the lithosphere.
- 20. A long, seismically active submarine ridge system situated in the middle of an ocean basin and marking the site of the upwelling of magma associated with seafloor spreading.