Ocean Floor 13.2

1. Ocean Floor 13.2

3. Shoreline • Where water and land meet.

4. Continental Shelf • Begins at the shoreline and slopes gently toward the open ocean • It continues until the ocean floor begins to slope more steeply downward

5. Continental Slope • Begins at the edge of the continental shelf • It continues steeply downward to the flattest part of the ocean floor.

6. Continental Rise • The base of the continental slope • Made of large piles of sediment from mud slides. • The boundary between the continental margin and the deep-ocean basin lies underneath the continental rise.

7. Abyssal Plain • The broad flat part of the deep-ocean basin • Covered by mud and the remains of tiny marine organisms • Average depth is about 4000m

8. Mid-ocean Ridges • Are under water mountain chains that form where tectonic plates pull apart. • Rifts form, magma rises to fill the spaces • Heat convection cells in the magma cause the crust on either side to spread apart.

9. Rift Valley • The pulling motion creates cracks in the ocean floor called rift zones. • As mountains on either side build, a valley forms in the rift zone.

10. Sea Mounts • Tall, narrow individual volcanic cones generally forming at hot spots or plate boundaries • If it gets tall enough to break the surface of the water, it will become a volcanic island.

11. Ocean Trenches • Huge cracks in the deep-ocean basin which are abnormally deep. • Trenches form where one oceanic plate is pushed beneath another plate.