Fishes of the Marianas

Sea Floor Spreading

1. What is sea floor spreading?
* sea floor spreading is the process by which new ocean floor is formed by lava erupting from a rift valley, pushing the existent floor outward from the rift.

2. What are some of the major land forms that are created from plate movement?

* Volcanoes, mountains, rift valleys, and oceans trenches.

3.How were the Mariana Islands formed?
* The southern islands are composed of volcanic rocks that have been overlain with coral-derived limestone. Subsequent tectonic movements and changing sea levels have raised many of the islands in the south considerable heights above sea level forming terraces and high cliffs.

4. What evidence exists today that the plates are still moving and that the islands are ancient volcanoes?
* Earthquakes and volcanoe activities that are still active.

5. What is an atoll?
* A coral island consisting of a ring of coral surrounding a central lagoon. Atolls are common in the Indian and Pacific Oceans.

6. Why are atolls mainly found on the Pacific?

* Because the Pacific Ocean floor has the most volcanic activities.