earth science

Oceanic plateau

Oceanic plateau is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Oceanic plateau rather than just read about it. In short: An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides. There are 184 oceanic plateaus in the world, covering an area of 18,486,600 km2 (7,137,700 sq mi) or about 5.11% of the oceans.

Key takeaways

Oceanic plateau belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Oceanic plateau to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Oceanic plateau from memory before moving on to harder problems.

Reference excerpt

An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides. There are 184 oceanic plateaus in the world, covering an area of 18,486,600 km2 (7,137,700 sq mi) or about 5.11% of the oceans. The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus (see map). Oceanic plateaus produced by large igneous provinces are often associated with hotspots, mantle plumes, and volcanic islands — such as Iceland, Hawaii, Cape Verde, and Kerguelen. The three largest plateaus, the Caribbean, Ontong Java, and Mid-Pacific Mountains, are located on thermal swells. Other oceanic plateaus, however, are made of rifted continental crust, for example the Falkland Plateau, Lord Howe Rise, and parts of Kerguelen, Seychelles, and Arctic ridges. Plateaus formed by large igneous provinces were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snake River Plain in the United States. In contrast to continental flood basalts, most igneous oceanic plateaus erupt through young and thin (6–7 km (3.7–4.3 mi)) mafic or ultra-mafic crust and are therefore uncontaminated by felsic crust and representative for their mantle sources. These plateaus often rise 2–3 km (1.2–1.9 mi) above the surrounding ocean floor and are more buoyant than oceanic crust. They therefore tend to withstand subduction, more-so when thick and when reaching subduction zones shortly after their formations. As a consequence, they tend to "dock" to continental margins and be preserved as accreted terranes. Such terranes are often better preserved than the exposed parts of continental flood basalts and are therefore a better record of large-scale volcanic eruptions throughout Earth's history. This "docking" also means that oceanic plateaus are important contributors to the growth of continental crust. Their formations often had a dramatic impact on global climate, such as the most recent plateaus formed, the three, large, Cretaceous oceanic plateaus in the Pacific and Indian Ocean: Ontong Java, Kerguelen, and Caribbean.

Role in crust–mantle recycling Geologists believe that igneous oceanic plateaus may well represent a stage in the development of continental crust as they are generally less dense than oceanic crust while still being denser than normal continental crust. Density differences in crustal material largely arise from different ratios of various elements, especially silicon. Continental crust has the highest amount of silicon (such rock is called felsic). Oceanic crust has a smaller amount of silicon (mafic rock). Igneous oceanic plateaus have a ratio intermediate between continental and oceanic crust, although they are more mafic than felsic. However, when a plate carrying oceanic crust subducts under a plate carrying an igneous oceanic plateau, the volcanism which erupts on the plateau as the oceanic crust heats up on its descent into the mantle erupts material which is more felsic than the material which makes up the plateau. This represents a step toward creating crust which is increasingly continental in character, being less dense and more buoyant. If an igneous oceanic plateau is subducted underneath another one, or under existing continental crust, the eruptions produced thereby produce material that is yet more felsic, and so on through geologic time.

List of oceanic plateaus

Continental oceanic plateaus Campbell Plateau (South Pacific) Challenger Plateau (South Pacific) Exmouth Plateau (Indian) Falkland Plateau (South Atlantic) Lord Howe Rise (South Pacific) Rockall Plateau (North Atlantic)

Igneous oceanic plateaus Agulhas Plateau (Southwest Indian) Azores Plateau (North Atlantic) Broken Plateau (Indian) Caribbean-Colombian Plateau (Caribbean) Exmouth Plateau (Indian) Hikurangi Plateau (Southwest Pacific) Iceland Plateau (North Atlantic) Kerguelen Plateau (Indian) Magellan Rise (Pacific) Manihiki Plateau (Southwest Pacific) Mascarene Plateau (Indian) Naturaliste Plateau (Indian) Ontong Java Plateau (Southwest Pacific) Shatsky Rise (North Pacific) Vøring Plateau (North Atlantic) Wrangellia Terrane (Northeast Pacific) Yermak Plateau (Arctic)

Illustrations

Worked examples

Example 1 — a first encounter with Oceanic plateau

Start with the simplest possible case. Write down what Oceanic plateau claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Oceanic plateau before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Oceanic plateau ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Oceanic plateau

In research: Oceanic plateau appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Oceanic plateau in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Oceanic plateau is common in secondary-school and first-year university syllabi. It links to neighbouring topics Abyssal plains, Aquatic ecology, Coastal and oceanic landforms, so understanding it makes those chapters shorter.
In everyday life: Look for Oceanic plateau outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Oceanic plateau in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Oceanic plateau means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Oceanic plateau out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Oceanic plateau in simple terms?

Why does Oceanic plateau matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Oceanic plateau?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Oceanic plateau.