Chapter 2 Internal Energy and Plate Tectonics

Nuclear fusion

The reaction in which two or more atomic muscles collide and join to form a new type element.

Stony meteorites

The rocks of the mantle have a composition similar to that of ____.

plate tectonics

The study of movements and interactions of the plates.

Curie point

The temperature below which a mineral becomes magnetized is called the ____.

Elastic, ductile, and brittle

The three types of strain are

Sequence of lava flows

The timescale of magnetic reversals was developed by measuring the magnetism in ____.

Lengths of time between

The widths of magnetized sea floor stripes correlate well with the ____ reversals of Earth's magnetic field.

Isostasy

This concept explains how mountain ranges float on the denser mantle and will rise up when erosion removes rock material from the mountains.

Increase

Water depths ____ systematically with sea floor age.

Volcanic island arc

What feature forms when one oceanic plate subduction beneath another?

The sinking of a slab of oceanic lithosphere under less-dense lithosphere

What is subduction?

Impact of the young Earth by a Mars-sized object

What is the melt current hypothesis for how the moon was formed?

Subduction zone

What kind of plate boundary is most commonly associated with deep earthquakes?

He noted that natural processes, such as erosion; were very slow.

What led James Hutton to propose the Earth must be extremely old?

Heat

When radioactive isotopes decay, energy is released in the form of

Where the sea floor is oldest

Where are the deepest parts of the ocean found?

Melting of rock; formation of even larger objects; loss of volatiles to space

Which of the following are consequences of collisions of large objects during the formation of the Solar System?

Radioactive decay; gravitational energy; impact energy; differentiation into layers

Which of the following are sources of heat generated during the formation of the Earth?

Immanuel Kant in 1755

Which of the following astronomers introduced the most widely accepted hypothesis regarding the origin of the Solar System?

Magnetic reversals are generated by random changes in the liquid outer core.

Which of the following statements about magnetic reversals is true?

Volcanic continental arc; oceanic trench

Which of these are features that form when an oceanic plate subduction beneath a continental plate?

Impact energy; gravitational energy; radioactive decay

Which of these are the three sources of the energy that flows from the Earth's interior to its surface?

Oceans

Which of these has the lowest density?

Seafloor spreading

The progressive deepening of the oceans away from the mid ocean ridges is evidence for ____.

Half-life

The rate of radioactive decay is measured by the ____ of isotopes.

Rate of human fingernail growth

The rates of tectonic plate movements are comparable to the

Seafloor spreading

The paleomagnetism timescale and the patterns of magnetism on the seafloor provide compelling evidence of ____.

Hot spot

A place on Earth where a plume of magma has risen up from the mantle and through a plate to reach the surface.

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Mantle

A thick layer of dense rock that comprises 83% of the Earth's volume and 67% o its mass.

Actualism

An alternative to the term uniformitarianism. This term is preferred by some scientists because it does not assume that the rate of processes is constant.

Panthalassa

Approximately 220 million years ago, the continents were joined together into one supercontinent known as Pangaea. This supercontinent was surrounded by an ocean named ____.

Thicker

Away from the oceanic ridges the layer of sediment covering the seafloor becomes ____.

200 millions years old

The oldest rocks on the ocean floors are approximately

Subduction

Earthquakes that occur along inclined planes adjacent to deep-ocean trenches are evidence for ____.

Planets

Formed through collisions of particles that fused together, forming larger objects.

1.5

Geologic studies suggest that the outer layers of the Earth were active in the process of plate tectonics by at least ____ billion years ago.

continental drift

The process of the continents moving, spitting, and recombine is known as

Volcanic activity above a hot spot

How did the chain of volcanic islands and seamounts form?

Convection cells

In the mantle form when hit mantle material rises, moves laterally, and then sinks when it becomes cold.

4.4; 3.5

It is likely that oceans and small continents existed on Earth by ____ billion years ago and that life was present by ____ billion years ago.

Collisions of matter within a rotating cloud of gas and dust

It is widely believed that the Solar System formed through

Iron

Minerals that grow as crystals in cooling lava can become magnetized if they contain ____.

Lava

Molten rock erupted from a volcano

The Earth's mantle

Most current hypothesis for how the Moon was formed would suggest that it is mostly made up of material from

At plate boundaries

Most earthquakes occur ____.

65 million years.

Much of the present ocean floor was created during the last

Elastic strain

Occurs when the differences in stress coming from different directions are low.

Yield stress

Permanent strain occurs when the stresses applied to a rock exceed its ____.

Tectonics

Taken from the Greek word meaning "to build," the term describes the building of topography and the deformation and movement within Earth's outer layers.

False

The Earth formed its compositional layers by accretion of first iron-rich materials, followed by rocky materials, and finally by ices.

4.54 billion years

The Earth has existed as a coherent mass for ____.

Iron

The Earth's core is composed mostly of the element ____, which came from meteorites.

Solid; liquid

The Earth's core, which is composed mostly of iron, is divided into the ____ inner core and the ____ outer core.

Hydrogen; helium

The Sun is predominantly composed of the elements ____ and ____.

False

The best fit of the continents to form Pangaea occurs when you match the shorelines.

Strain

The change in shape of a material in response to an applied force is called

5 million years

The collision of Earth with a Mars-sized body that formed our Moon occurred approximately ____ after the Earth is believed to have formed.

Uniformitarianism

The concept that the same laws and processes have been operating on Earth throughout geologic time.

0.1%

The continents make up approximately ____ of Earth's total volume.

Seafloor spreading

The creation of new oceanic lithosphere at an oceanic ridge and its movement away from the ridge is known as ____.

Subduction zones

The deepest parts of the oceans occur in elongate narrow trenches that are associated with ____.

Continental drift

The discovery of sea floor spreading provided the mechanism that was missing in Wegener's hypothesis of ____.

The boundary between low-density continental rocks and higher-density oceanic rocks.

The edge of a continent is found at

Earthquakes

The edges of the tectonic plates can easily be defined by mapping the locations of ____.

Slab pull

The effect of a down-going plate at a subduction zone on the lateral motion of the plates.

Stress

The force per unit area applied to an object.

Mercury; Earth; Mars; Venus

The four inner planets are

Hydrogen, d other frozen materials

The four outer planets of the Solar System are mostly composed of

Spreading centers

The great mountain ranges that extend more than 65,000km across the ocean bottoms are formed at ____.

Impact energy

The heat produced by masses colliding to form the Earth is referred to as

Convection cells

The lateral movement of the tectonic plates occurs as they ride along on top of ____ in the mantle.

Gravitational pull

The lateral spreading of the plates away from the elevated mid ocean ridge is driven in part by ____.

Strengths

The lithosphere, asthenosphere, mesosphere, outer core, and inner core are layers of the Earth that are distinguished from one another by their ____.

The symmetry of the stripes on either side of the volcanic ridge

The most striking feature of the magnetic signature of the sea floor is

Pangaea

The name of the single supercontinent proposed by Wegener.

Grain of Zircon from Australia

The oldest Earth material, dated at 4.37 billion years old, is a

Lavas contain radioactive elements that can be used to date them; lavas become magnetized as they cool below the Curie point

Why are sequences of layered lava flows so useful in the construction of the timescale of magnetic reversals?

The accumulation of sediments over time adds weight to the seafloor; older oceanic crust is denser and thus sits lower on the asthenosphere

Why do ocean water depths increase away from the mid ocean ridge?

Rocks are poor conductors of heat.

Why hasn't all of the heat generated during the formation of the escaped, even after 4.6 billion years of Earth history?

Early Earth rocks are difficult to find due to plate tectonics.

Why is it difficult to study the early history of the Earth?

Early gravitational compaction; great abundance of radioactive isotopes; more frequent meteorite impacts

Why was Earth's Internal Energy higher during its early history?