Chapter 2 - HW (Internal Energy and Plate Tectonics)

In the _______, evidence abounded, mechanisms seemed plausible, and the plate-tectonic theory was developed and widely accepted.

mid-1960s

After lava cools below the Curie point, which is about __________, atoms in iron-bearing minerals become magnetized in the direction of Earth's magnetic field at that time and place.

550°C

After lava cools below the __________ point atoms in iron-bearing minerals become magnetized in the direction of Earth's magnetic field at that time and place.

Curie

If sea floor spreading occurs at a constant rate, the widths of magnetized seafloor strips have__________ ratios as the lengths of time between successive reversals of Earth's magnetic field.

the same

The oldest rocks on the ocean floors are about __________ years in age.

200 million

The hot-spot-melting-through-lithosphere process forms lines of extinct volcanoes on the ocean floor, from youngest to oldest, __________.

pointing in the direction of plate movement

The blanket of sediment on the sea floor is ___________ toward the ocean margins.

very thin at the volcanic ridges and thickens

Moving progressively away from the ridges, the ocean water depths increase systematically with seafloor age due to all but which of the following?

Erosion of the older ocean floor by deep ocean currents

When oceanic lithosphere collides with another plate, the ________ in the process of subduction.

older, colder plate turns downward beneath the younger, warmer plate

The principle of uniformitarianism, developed by James Hutton, implies that __________.

natural laws are uniform through time and space

Earth is about __________ years old.

4.5 billion

Which of the following accurately describes the state of the continents and ocean 65 million years ago?

Seafloor spreading had opened and connected the North and South Atlantic Ocean but North America and Eurasia were still partially connected.

Choose the most likely outcome if the large ice sheet on Greenland was to completely melt.

Greenland would slowly rise over thousands of years as isostatic rebound occurs.

Which of the following concepts best explains why a mass of low-density material in the mantle rises?

Buoyancy

Our solar system formed __________.

through collisions of matter within a rotating cloud of gas, ice, dust, and other solid debris

Which statement accurately describes the planets of our solar system?

The four inner planets are smaller and rocky and the four outer planets are giant icy bodies composed mostly of hydrogen and helium.

The solar radiation we receive on Earth is the result of __________.

the nuclear fusion of hydrogen into helium

The Moon is thought to have formed __________.

from material that coalesced after an impact between Earth and a Mars-sized object

Which of the following correctly lists the order the layers from the surface of Earth toward the center?

Lithosphere, asthenosphere, mesosphere, and the core

A rock subjected to higher temperatures would be expected to behave __________.

in a more ductile manner

A rock smashed into many pieces by a scientist using a hammer is undergoing ______ deformation.

brittle

The heat that transformed Earth early in its history came primarily from all but which of the following?

dark energy

An isotope's half-life is equal to the time it takes __________.

half of the parent atoms to decay into daughter atoms

A rock with only 25% of the parent isotope left has been decaying for time equal to __________ half-lives.

two

If an oceanic trench formed along the East Coast of North America, the deepest earthquakes related to the subduction of the oceanic plate beneath North America would occur __________ the eastern coastline.

west of

During a __________ year period starting at about 4.5 billion years ago, bits and pieces of metal-rich particles, rocks, and ices accumulated to form the Earth.

Correct!

30-100 million

The large ocean that existed ~220 million years ago, forming about 60% of the Earth's surface was known as __________.

Panthalassa

Earth's magnetic pole and rotational pole coincide.

false

The grand recycling of the upper few hundred kilometers of Earth is called the tectonic cycle.

true

The gigantic pieces of lithospheric plates diverging, sliding past, or colliding with each other are directly responsible for most of the earthquakes, volcanic eruptions, and mountains on Earth.

true

In 1620, Francis Bacon of England noted the parallelism of the Atlantic coastlines of South America and Africa and suggested that these continents had once been joined.

true

When data from the Earth's magnetic field locked inside seafloor rocks became widely understood, most skeptics around the world were convinced that seafloor spreading occurs and that the concept of plate tectonics is valid.

true

The early differentiation of Earth into a mantle and a core was created by ________________.

the buildup of heat and the melting of iron, which was pulled by gravity to the center of Earth

The processes that reverse the polarity of the magnetic field are likely related to changes in the flow of the iron-rich liquid in the outer core.

true

Parallel bands of magnetized rock that show alternating polarities stripe the floor of the Atlantic Ocean;the pattern is symmetrical and parallel with the spreading center.

true

Subducted slabs completely melt in the mantle and mix with the surrounding mantle.

false

The greatest mountain ranges on Earth lie on the ocean bottoms and extend more than 65,000 km.

true

Hot spots have active volcanoes above them on Earth's surface and moving plates carry the volcanoes away from their hot-spot source.

true

The ages of former volcanoes decrease with their distance from their parent hot spot.

false

Above the oceanic ridges, the ocean water depthsare relatively deep in comparison to depths farther away from the ridges.

false

Gravitational pull on a dense, down-going plate at a subduction zone (slab pull) is one of the forces that keeps the lithospheric plates moving.

true

The rates of plate movement are comparable to those of human fingernail growth.

true

The leading theory on the origin of the moon leads to the idea that the moon is composed of mantle.

true

Earth's inner core is a 2,450-km diameter _________ mass with temperatures up to 4,300°C (7,770°F).

solid

The Chernobyl disaster initially resulted from a 3.0 magnitude earthquake ~12km (7mi) away.

true

As radioactive atoms decay, heat energy is _________.

released

All of the continents were once combined into a single supercontinent called ________________.

Pangaea

Which of the following is not a basic tenet of plate tectonics?

The slab pulled into the asthenosphere begins the process of melting and moves into the liquid core.

The time needed for a typical atom in an oceanic plate to complete a plate-tectonic cycle is ____________ years.

in excess of 250 million

The most famous and outspoken of the early proponents of continental drift was ______________.

Alfred Wegener