Geology and the OceanBy: Luc & Rebecca

What is Geology?

Geology is the study of the solid earth, like rocks, and the process through which is evolves and changes.

The Ocean floor is divided into 3 major parts. These parts include the Continental shelf, the continental Slope and the deep ocean floor.

The Ocean

Continental ShelfThe continental shelf is the submerged part of the continents. It has

physical features the same as you would find above land, including hills, ridges and canyons. The continental shelf can extend anywhere from being virtually nonexistant to up to 1500 km wide in Antarctica. The average width of the shelf is about 80 km.

The continental slope extends from the edge of the continental shelf to the floor of the ocean. It constitutes for about 20% of the total ocean floor.

The Ocean FloorThe ocean floor is the very bottom of the ocean, usually around 3700 meters in depth but can go up to 11 033 meters or 36 201 feet deep. The deepest part of the ocean floor is known as the abyssal plain. It is a huge flat surface that takes up about 50% of the total surface of the earth. This is also the flattest, smoothest and most unexplored part of the earth.

Pacific Ring of Fire

The Pacific ring of fire is an area bordering the shores of nearly all the country's surrounding the Pacific ocean, The Ring of fire is about 40 000km long and it is responsible for about 90% of the earthquakes that happen around the world, It is also home to 75% of the earths volcanoes, hence the name "ring of fire"

One very important geological components of the ocean is the movement of the lithosphere, which is the crust of the earth, or more commonlyknown as the movement of the tectonic plates. Every bit of land we see is moving and constantly changing because of the plates. Actually the Ring of fire has been created by the tectonic plates because they are pushing outwards from the pacific ocean. But as these plates are moving outward they are leaving gaps between them where lava is seeping through the ground and re-hardening within the water and actually creating the largest mountain range on earth, known as the Mid-Ocean Ridge.

Lithospehere

The mid Ocean Ridge is the worlds largest and longest mountain range, It covers about 80% of the oceanfloor and with its length of 60 000km it is long enough to circle the globe one and a half times. It hasa height that goes up to 1500m, and yet the peak only comes to about 6km from the surface of the water.

Mid Ocean Ridge

Vents And VolcanoesHydrothermal vents are when super heated water shoots into the ocean.

These are created when the tectonic plates move leaving gaps in the ocean floor which fill with water and become super heated from the magma below and then the pressure forces them to shoot back into the ocean.

As the plates continue to move further away from each other magma will shoot into the ocean faster than the water can fill the gap and cause the eruptions of underwater volcanoes. As the magma hardens and the plates continue to move apart new seafloor is created, this process is known as seafloor spreading.

When the plates move towards each other they slam into each other and cause earthquakes which can kill thousands of people. Like the earthquake in Tohoko, Japan which was the result of the Pacific plate slamming into the plate lying below Honshu, Japan. This earthquake was rated 9.8 on the richter scale and ended up causing 15 822 deaths.

Earthquakes can also cause other disasters as well, When the plates move towards each other one is forced to either move above or below the other. This can result in underwater mountains or trenches. But the also displaces a massive amount of seawater and causes tsunamis. Tsunamis are large tidal waves that can move up to speeds of 800km/h and the largest recorded was 63m (210 ft) in height.

Earthquakes

http://www.ceoe.udel.edu/deepsea/level-1/geology/geology.html

http://en.wikipedia.org/wiki/Continental_shelf

http://en.wikipedia.org/wiki/Abyssal_plain

http://en.wikipedia.org/wiki/Ocean_floor

http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire

http://en.wikipedia.org/wiki/Lithosphere

http://www.sciencedaily.com/articles/m/mid-ocean_ridge.htm

http://en.wikipedia.org/wiki/Hydrothermal_vent

http://en.wikipedia.org/wiki/Tectonic_plate

http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami

http://en.wikipedia.org/wiki/Earthquake

http://www.ceoe.udel.edu/deepsea/level-2/geology/vents.html

Bibliography