How do the theories of plate tectonics and continental drift differ?
The difference between continental drift and plate tectonics is that the theory of continental drift states that the world was made up of a single continent. The theory of plate-tectonics, on the other hand, states that earth’s surface is broken into numbers of shifting plates or slabs.
What is below 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.
What made tracks on the ocean floor?
One day, a shark shed a tooth, which drifted hundreds of metres to the ocean floor. Gradually, as metals precipitated out of the sea and water within the sediment, the tooth became coated in minerals. And so began one of the slowest geological phenomena on Earth: the growth of a polymetallic nodule.
What are the features of ocean floor?
Like dry land, the ocean floor has various features including flat plains, sharp mountains, and rugged canyons (Fig. 7.1). However, the lowest point in the world ocean is much deeper than the highest point on land. The ocean floor is continually being formed and destroyed.
What are three major physical features found on the ocean floor?
Features of the ocean floor include the continental shelf and slope, abyssal plain, trenches, seamounts, and the mid-ocean ridge.
What is the floor of the ocean?
The seabed (also known as the seafloor, sea floor, or ocean floor) is the bottom of the ocean, no matter how deep. All floors of the ocean are known as ‘seabeds’.
Where is the ocean floor created?
The Mid-Atlantic Ridge is the longest mountain chain on Earth. These ridges are spreading centers or divergent plate boundaries where the upwelling of magma from the mantle creates new ocean floor.
Are islands connected to the ocean floor?
Islands are not floating at all. They are actually mountains or volcanos that are mostly underwater. Their bases are connected to the sea floor. If an island does disappear under the ocean, it’s because the land underneath has moved or the bottom of the volcano has broken apart.
What force is causing magma to be pushed up in the middle of the ocean?
Ridge push (also known as gravitational sliding) or sliding plate force is a proposed driving force for plate motion in plate tectonics that occurs at mid-ocean ridges as the result of the rigid lithosphere sliding down the hot, raised asthenosphere below mid-ocean ridges.
Where is ocean floor at the greatest water depth?
Mariana Trench
What is the average ocean depth?
The ocean has an average depth of approximately 3.7 kilometres (or 2.3 miles). A calculation from satellite measurements in 2010 put the average depth at 3,682 metres (12,080 feet).
What is the depth of sea?
The average depth of the ocean is 3,700 meters (12,100 feet). But the deepest part ever recorded is located in the western part of the Pacific Ocean, in the Mariana Trench, at a depth of around 11,000 meters (36,200 feet).
Why are trenches so deep?
Ocean trenches are long, narrow depressions on the seafloor. At many convergent plate boundaries, dense lithosphere melts or slides beneath less-dense lithosphere in a process called subduction, creating a trench. Ocean trenches occupy the deepest layer of the ocean, the hadalpelagic zone.
What ocean has no trenches?
Trenches
| Ocean | Area km2 | Number of Trenches |
|---|---|---|
| Arctic Ocean | 0 | 0 |
| Indian Ocean | 166,580 | 9 |
| Mediterranean & Black Sea | 14,970 | 5 |
| North Atlantic Ocean | 116,350 | 3 |
What is the deepest trench in the world?
The Mariana Trench
Where are deep sea trenches found?
Deep-sea trenches generally lie seaward of and parallel to adjacent island arcs or mountain ranges of the continental margins. They are closely associated with and found in subduction zones—that is, locations where a lithospheric plate bearing oceanic crust slides down into the upper mantle under the force of gravity.