Plate Tectonics Crossword

2. another word for divergent plate boundary
5. along the creat of some ridge segments is a deep canyonlike structure called
7. seed fern
8. arc a chain of volcanic islands generally located a few hundred km from a trench where there is active subduction of one oceanic plate beneath another
9. how many plates account for 94% of Earth’s surface area?
10. elevated areas of the seafloor characterized by high heat flow and volcanism
13. boundary a boundary in which two plates move together
15. small aquatic freshwater reptile
18. supercontinent containing all existing continents
19. a hypothesis which suggested all present continents once existed as a single supercontinent.
20. a continuous elevated zone on the floor of all major ocean basins and varying in width from 500 to 5,000 km

1. book written by Alfred Wegener in 1915
3. German meteorologist and geophysicist who created the continental drift hypothesis
4. a narrow, elongated depression of the seafloor
6. a boundary in which two plates move apart, resulting in upwelling of material from the mantle to create new seafloor
11. a hypothesis, first proposed in the 1960s by Harry Hess, which suggested that new oceanic crust is produced at the crests of mid-ocean ridges, which are the sites of divergence
12. primary driving force for movement of tectonic plates
14. largest plate
16. processes that deform Earth’s crust to create major structural features, such as mountains, continents, and ocean basins
17. inventor of seafloor spreading hypothesis