Ocean Shapes Earth
The Ocean is vital in global geological cycling which includes elements like carbon, nitrogen, silica and carbonate. It is because of carbon that scientists are able to age fossils. Because the ocean holds the most life, it is the largest reservoir of ‘rapidly’ cycling carbon. Unless it is deposited on a beach, eaten, or taken at the surface, most ocean life ends up eventually sinking to the bottom. Where the carbon is in it's life cycle tells scientists how old their sample is. By coring into the ocean bottom, geologists can read the past like a book.
The ocean is just as important to forming land as the life that inhabits it. The ocean has the power to build, shape, and break down the land, forming the earth as we know it today. It is the interaction between the ocean, also called the hydrosphere, and the land, known as the geosphere, that causes these changes on the earth. The ocean wears down rock and land with waves, currents, erosion, and tectonic activity. It can also build up rock and land with waves, currents, deposits, volcanic activity, and tectonic activity.
Many of earth's materials and geochemical cycles originate in the ocean. Sedimentary rocks now exposed on land were formed in the ocean. Ocean life laid down the vast volume of siliceous and carbonate rocks as well. The land is the way it is because of the influence from the ocean. Sea level changes and force of waves, tectonic activity, and erosion influence the physical structure and land forms of the coast.
The surface of the Earth is in a constant state of change. The surface of the earth is separated into different plates that move over the molten upper portion of the mantle called the asthenosphere. Oceanic and continental plates diverge, converge, and interact at boundaries all over the planet.
The type of movement depends on the type of plate.
At divergent boundaries, the plates separate to form a narrow rift valley. Here, geysers release of water, magma, or molten rock to solidify and form new crust. It is at these boundaries that oceanic crust is created. For example, the mid-ocean range is the world's longest mountain range at 65,000 kilometers long. The Mid-Atlantic ridge can be observed as the ridge rises above sea levels in Iceland, where the North American and Eurasian plates diverge.
Convergent boundaries are were plates collide into each other. At these boundaries one, or both, of the plates' edge buckle under the other. This may create a mountain range or subducting, or a deep seafloor trench if both plate edges collapse. The Himalayas were formed 55 millions years ago when the Eurasian and Indo-Australian continental plates converged. The Marianas trench was created when the Pacific Plate subducted beneath the smaller Mariana Plate in the Pacific Ocean. All of these changes occurred on the ocean floor.
The movement of tectonic oceanic plates hugely impacts life on the land. As the dense oceanic tectonic plates slowly slide under lighter continental plates they reshape the ocean basins, continental shelves, inland seas, and the continents. When large earthquakes happen near the coast, the ocean can restructure the surface of coastal lands with shaking, sea level change, landslides, and tsunami wave force.
Erosion is another processes that demonstrates how the ocean has influenced the structure of the land. Erosion is the break down of material, caused by air flow or water movement. On the coastal line it is extremely common for rock formations to experience a break down from various forms of erosion. Wave pounding is where the energy of the waves breaks pieces of the rocks away. Abrasion occurs when waves launch material from the sea at the rocks. this is an effective and rapid form of shoreline erosion. Corrosion can also occur when rock is exposed for long periods of time to the carbonic acid in sea water. The coastline has been, and is still, being shaped by erosion from the ocean.
Eventually, sediment falls to the bottom of the ocean or is thrown up on land with the waves. These piles of sediment can collect at the edges of rivers or at the ocean's coast. This is where sand comes from. Sand consists of tiny bits of animals, plants, rocks, and minerals. Most beach sand is eroded from land sources and carried to the coast by rivers but sand is also eroded from coastal sources by surf. Sand is redistributed by waves and coastal currents seasonally.
Just as materials can be broken down to make sand, they can also be pushed together to form rock. There are 3 main types of rocks that are important to know:
Igneous Rock: is formed when magma (liquid rock) from underneath the earth's crust cools and hardens to form a rock.
Sedimentary Rock: is formed at the earths surface when fragments of rocks, minerals, and organisms are compacted and hardened together under pressure. Rather than staying in broken pieces like sand, these sediments fuse together to form rock.
Metamorphic rock: is formed when other types of rocks, like igneous or sedimentary rock, are fused together to form a new kind of rock.
Just as new rocks can be formed or broken down in the ocean, entire new land forms can also be created.
Just as erosion breaks down the land, geological movement in the ocean can also build it up again. Dense tectonic oceanic plates slowly slide under lighter continental plates which reshapes the ocean basins, continental shelves, inland seas, and the continents.
Volcanoes are underwater mountains that release hot molten rock, or lava, from underneath the earth's crust. When these rocks harden, they can create new land forms called Islands. It is through this release of material from under the earth's crust at the bottom of the ocean that forms new rocks and materials.
The geological movement in the ocean shapes and impacts the earth in many different ways. The land is not only influenced by the ocean, it is physically shaped and moved by it.
When large earthquakes happen near the coast, the ocean can restructure the surface of coastal lands with shaking, sea level changes, landslides, and tsunami wave force. The incredible force of the ocean and the tectonic plates in the ocean play a huge role in the creation of the land on earth. The land is not only connected to the ocean, it is physically shaped and moved by it.
Continue to Fundamental Principle Content »