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Why does the ocean floor spread apart at the ridges?

Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.

Why does oceanic crust far from a mid-ocean ridge subside?

Because the plate under the ridge crest is hotter, scientists think that the plate responds to the divergent spreading process more fluidly, and that the ridge behaves like hot taffy being pulled apart. As the sheets of oceanic crust move away from the mid-ocean ridge, the rock is cooled and thus becomes heavier.

Why do plates move away from the mid-ocean ridges?

As the two move apart, mid-ocean ridges are created as magma from the mantle upwells through a crack in the oceanic crust and cools. These continual convection currents, called convection cells, help to move the plates away from each other to allow more crust to be created and the sea floor to grow.

What do you expect to find at a mid ocean ridge?

The massive mid-ocean ridge system is a continuous range of underwater volcanoes that wraps around the globe like seams on a baseball, stretching nearly 65,000 kilometers (40,390 miles). As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.

What type of lava is most common at mid-ocean ridges?

The lava produced at the spreading centers is basalt, and is usually abbreviated MORB (for Mid-Ocean Ridge Basalt). MORB is by far the most common rock type on the Earth’s surface, as the entire ocean floor consists of it.

Do mid-ocean ridges support life?

Within the volcanic upper crust, subterranean chambers and fractures filled with heated water act as incubators for microbes that live in some of the harshest conditions ever discovered to support life. These microbes are the foundation for a rich ecosystem that thrives only at these hydrothermal vents.

Why does the mid-ocean ridge have a zigzag appearance?

The reason the mid-ocean ridge has a zigzag appearance is because: it accommodates spreading of a linear ridge system on a spherical Earth. Turbidity currents are highly erosive and are thought to be responsible for the creation of deep-sea trenches.

Which ocean would you not find a trench?

The Indian Ocean has the fewest trenches of any of the world’s oceans. The narrow (50 miles [80 km]),… Both types of subduction zones are associated with large earthquakes that originate at a depth of as much as 700 km (435 miles).

What is mid-ocean ridge made of?

The material that erupts at spreading centers along the mid-ocean ridge is primarily basalt, the most common rock on Earth. Because this spreading occurs on a sphere, the rate separation along the mid-ocean ridge varies around the globe.

What is beneath the ocean floor?

The ocean floor is called the abyssal plain. Below the ocean floor, there are a few small deeper areas called ocean trenches. Features rising up from the ocean floor include seamounts, volcanic islands and the mid-oceanic ridges and rises.

How are deep sea fish not crushed?

Under pressure Fish living closer to the surface of the ocean may have a swim bladder – that’s a large organ with air in it, which helps them float up or sink down in the water. Deep sea fish don’t have these air sacs in their bodies, which means they don’t get crushed.

Can the ocean pressure crush you?

Human beings can withstand 3 to 4 atmospheres of pressure, or 43.5 to 58 psi. Water weighs 64 pounds per cubic foot, or one atmosphere per 33 feet of depth, and presses in from all sides. The ocean’s pressure can indeed crush you.