Exam 1

Question 1

About ____% of Earth’s water is found in the ocean.

Answer 1

97%

Question 2

On a planetary scale, the ocean comprises about ____% of Earth’s mass.

Answer 2

0.02

Question 3

What comprises the most abundant form of matter in the universe?

Answer 3

hydrogen and helium

Question 4

Stars spend their lives changing its hydrogen and helium to ____.

Answer 4

carbon, oxygen, silicon, and iron

Question 5

What process allows the sun to generate light and heat?

Answer 5

accretion

Question 6

Oxygen first began to accumulate in Earth’s atmosphere as a result of ____.

Answer 6

photosynthesis

Question 7

Earth’s inner core is primarily made of ____.

Answer 7

iron

Question 8

The primary physical process responsible for the formation of Earth’s layers, the inner and outer core, mantle, and crust is ____.

Answer 8

density stratification

Question 9

​Who was the first person to compile a picture of the large-scale wind and current systems?

Answer 9

Matthew Maury

Question 10

The Challenger expedition (1872–1876) was a unique and historic voyage. Why?

Answer 10

​It is the longest continuous scientific oceanographic expedition on record.

Question 11

The ocean provides a variety of resources ranging from food and water to energy, construction materials, and life-saving pharmaceuticals.

Answer 11

True

Question 12

Earlier than 200 million years ago, the continents were joined into one supercontinent called ____.

Answer 12

Pangaea

Question 13

What is the primary reason for the inside of Earth being hot?

Answer 13

The decay of radioactive elements is creating heat in Earth’s inner layers.

Question 14

The rigid outer layer of Earth that comprises the continental crust, oceanic crust, and the uppermost mantle is called the ____.

Answer 14

lithosphere

Question 15

The mid-ocean ridges are ____.

Answer 15

divergent plate boundaries

Question 16

California’s San Andreas fault is which type of plate boundary?

Answer 16

transform plate boundary

Question 17

A “mystery” in our understanding of plate tectonics has been, until recently, the nature of the power source capable of moving the plates and the continents embedded within them. Recent evidence indicates the power source to be ____.

Answer 17

convection currents within Earth’s mantle moving the plates

Question 18

If two oceanic plates collide and one is older and cooler (and therefore, denser) than the other, what will happen?

Answer 18

A deep trench will form

Question 19

Which statement is true with regard to subduction zones?

Answer 19

They are zones where old seafloor descends into the crust and mantle.

Question 20

Which statement about hot spots is true?

Answer 20

Hot spots arise from relatively stationary plumes of magma in the mantle.

Question 21

The transition between the shelf and the deep seafloor is the ____.

Answer 21

continental slope and rise

Question 22

Which statement accurately describes a turbidity current?

Answer 22

a fast, dense current of water and sediment that runs down slopes

Question 23

Which statement accurately describes active continental margins?

Answer 23

They are areas of frequent earthquakes and volcanoes.

Question 24

The deepest places in Earth’s crust are ____.

Answer 24

ocean trenches

Question 25

The deep-ocean basin includes which of the following features?

Answer 25

abyssal plains

Question 26

Which of the following is a major source of terrigenous sediments?

Answer 26

weathering and erosion of rocks

Question 27

Over millions of years, natural gas and oil can be formed from ____.

Answer 27

biogenous sediments

Question 28

Carbonate sediments are rare in deep sea sediments because the ____.

Answer 28

carbonate shells are dissolved in deep water

Question 29

A cross section of Earth reveals a layered structure that has different thicknesses and densities. How do geologists know this?

Answer 29

from observing the transit times through Earth of seismic waves generated by earthquakes

Question 30

The Himalayan Mountains were formed as a result of ____.

Answer 30

continent–continent convergence

Question 31

Where would you look to find an ocean trench? How are these features related to plate tectonics?

Answer 31

Ocean trenches are the result of convergent boundaries. Specifically, they form along subduction zones where oceanic crust sinks under the continental one. Therefore, trenches are typically found in the deep-ocean floor of the Pacific, which is characterized by active margins.

Question 32

What were the contributions of Captain James Cook? Does he deserve to be remembered more as an explorer or as a marine scientist?

Answer 32

James Cook can be considered both and explorer and marine scientist. He was a pioneer of modern oceanography because he described, recorded, and collected specimens of marine life, plants, and animals all around the world. In addition, he first found and charted New Zealand and the West Coast of North America, and mapped Australia’s Great Barrier Reef. He also was able to interpret events in natural history, anthropology, and oceanography.

Question 33

Look again at Figure 2.21. Why do the dates go back only about 200 million years when we know the ocean has been on Earth for billions of years?

Answer 33

The oldest rock only goes back to 200 million years ago because that’s when the Pangaea started to split apart and form continental plates. The interaction between plates at plate boundaries then resulted in the subduction of older oceanic crust under the younger and lighter continental crust or younger oceanic crust.

Question 34

List the four types of marine sediments. Explain the origin of each.

Answer 34

Terrigenous sediments: originate from the erosion of continents or islands, as well as volcanic eruptions and blown dust. It is considered one of the most dominant sediments, especially on continental margins and abyssal plains.
Biogenous sediments: originate from organic matter that comes from the marine organisms such as corals or shells of molluscs. It’s another dominant sediment.
Hydrogenous sediments: originate from the leaching of the crust at oceanic ridges and dissolved minerals coming from submerged rocks.
Cosmogenous sediments: originate from dust from space and meteorite debris. Therefore, it is found in really small proportion, usually mixed in with other, more dominant sediments.