EARTH’S OCEANS

The Ocean Floor

OCEAN FLOOR

OCEAN FLOOR

WHAT DOES THE OCEAN FLOOR LOOK LIKE? Have you ever heard of topography?

What is a topography? What is the topography of the ocean floor?

Is the topography of the ocean floor similar to the topography of the continents?

WHAT IS A TOPOGRAPHY? Topography is the shape of Earth’s structure

Now, What is the topography of the ocean floor?

OCEAN FLOOR’S TOPOGRAPHY The topography of the ocean floor is a description of the shape of the ocean floor, its characteristics and major features.

OCEAN FLOOR VS CONTINENTS Has higher mountains Deeper canyons, and larger Flatter plains More volcanoes Greater frequency of Earthquakes

Rocks Thinner crust

EDGES OF THE CONTINENTS On a continent, there is a boundary where the land and ocean meet. (Shoreline)

A shoreline doesn’t mark the end of the continent. It marks the average position of sea level

EDGES OF THE CONTINENTS The area where the underwater edge of a continent meets the ocean floor is called a continental margin.

Is it part of the Ocean floor or the land?

EDGES OF THE CONTINENTS Although a continental margin forms part of the ocean floor, it is more a part of the land than it is a part of the ocean.

It consists of:A continental shelfA continental slopeA continental rise

CONTINENTAL MARGIN

CONTINENTAL SHELF The relatively flat part of a continental margin that is cover by shallow water

Usually slopes very gently downward from the shoreline (less than 1.2 m for every 100 m from the shoreline).

CONTINENTAL SHELF It can be beneficial to us (humans)The best fishing areaLarge mineral depositsLarge deposits of oil and natural gas

CONTINENTAL SLOPE At the edge of a continental shelf, the ocean floor plunges steeply 4 to 5 kilometers

It marks the boundary between the continental crust and the oceanic crust

CONTINENTAL RISE It is made of large sediments (small pieces of rocks, remains of animals and plants)The sediments are carried down the slope turbidity currents (underwater avalanche)

It separates a continental slope from the ocean floor.

FEATURES OF THE OCEAN FLOOR Scientists have identified several major features of the ocean floor (ocean basin)

These features includes:Abyssal plains, seamounts, guyots, trenches, midocean ridges, reefs….

ABYSSAL PLAINS The large flat areas on the ocean

They are larger in the Atlantic and Indian oceans than in the Pacific Ocean.Two reasons:

The world greatest rivers

The floor of the pacific contains cracks

SEAMOUNTS AND GUYOTS Seamounts are underwater volcanic mountains that rise more than 1000 meter above the surrounding ocean floor.

They have steep sides that lead to a narrow top

SEAMOUNTS AND GUYOTS Guyots are flat-topped seamounts

The flat tops are the result of wave erosion.

SEAMOUNTS AND GUYOTS

TRENCHES The greatest depths of the ocean are found in trenches along the edges of the ocean as oppose to the middle of the ocean floor.

They are long, narrow cracks that can be more than 11,000 meters deep.

MIDOCEAN RIDGES The larger mountain ranges on Earth located under the oceans

They are areas where molten material from deep within the Earth flows up to the surface

VIDEO TO CONSIDER http://www.youtube.com/watch?v=W2qdlYkl2HY