What is the deepest part of the ocean?

Challenger Deep in the Mariana Trench

Why is ocean crust younger than continental crust?

It is recycled at subduction zones

Ocean Floor Quiz: Can You Get 8 Out of 10?

This ocean floor quiz covers the continental shelf and slope, abyssal plains, mid-ocean ridges, deep trenches, seamounts, hydrothermal vents and Marie Tharp's pioneering maps. Can you get 8 out of 10 on the landscape hidden beneath the sea?

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🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Shelf
What is the shallow area around continents called?
Plains
What are the vast flat areas of the deep ocean floor called?
Ridge
What runs through the middle of the Atlantic?
Tharp
Who mapped the ocean floor and revealed the rift valley in the Mid-Atlantic Ridge?
Trench
What is the deepest part of the ocean?
Seamount
What is a seamount?
Guyot
What is a flat-topped seamount called?
Age
Why is ocean crust younger than continental crust?
Mapped
Roughly how much of the seafloor has been mapped in high resolution?
Sediment
What covers much of the deep seafloor?

Explanations: answer key for all 10 questions

Q1: What is the shallow area around continents called?
Answer: Continental shelf
It is rich in marine life and resources.
Q2: What are the vast flat areas of the deep ocean floor called?
Answer: Abyssal plains
They are among the flattest places on Earth.
Q3: What runs through the middle of the Atlantic?
Answer: Mid-Atlantic Ridge
New seafloor forms there.
Q4: Who mapped the ocean floor and revealed the rift valley in the Mid-Atlantic Ridge?
Answer: Marie Tharp
She worked with Bruce Heezen in the 1950s.
Q5: What is the deepest part of the ocean?
Answer: Challenger Deep in the Mariana Trench
It is nearly 11 kilometers deep.
Q6: What is a seamount?
Answer: An underwater mountain
Most are extinct volcanoes.
Q7: What is a flat-topped seamount called?
Answer: Guyot
Waves once eroded its top.
Q8: Why is ocean crust younger than continental crust?
Answer: It is recycled at subduction zones
Most is under 200 million years old.
Q9: Roughly how much of the seafloor has been mapped in high resolution?
Answer: About a quarter
Seabed 2030 aims to finish it.
Q10: What covers much of the deep seafloor?
Answer: Fine sediment and ooze
Ooze includes tiny shells.

Ocean Floor Quiz – The Hidden Landscape

The ocean floor has mountains, valleys, plains and trenches, many larger than those on land. Near the coasts, the continental shelf slopes gently before dropping down the continental slope to vast abyssal plains.

Mid-ocean ridges wind around the planet where plates spread apart, forming the longest mountain range on Earth. Deep trenches form where plates subduct, and the Mariana Trench's Challenger Deep reaches nearly 11 kilometers down.

Marie Tharp's maps in the 1950s helped prove plate tectonics. Today ships with sonar and autonomous vehicles map the seafloor, but much remains unexplored, and the Seabed 2030 project aims to map it all.

What This Quiz Teaches

This quiz is for students exploring the ocean floor.

What the continental shelf is
What abyssal plains are
What mid-ocean ridges are
Who mapped the seafloor
What seamounts are

Did You Know?

Underwater canyons can rival the Grand Canyon.
Manganese nodules lie on the seafloor.
Hydrothermal vents host unique life.
Ocean crust is mostly basalt.
Sonar uses sound echoes to map depth.