Question 1

Earth's magnetic field
A) is variable, and it has phased to zero some nine times during the past 4 million years.
B) is constant in its intensity.
C) remains a mystery as to its cause.
D) is principally generated in the inner core.

Accepted Answer

Earth's magnetic field is not constant and has phased to zero nine times in the past 4 million years, which is known as magnetic reversals. The cause of the magnetic field is generated by a dynamo effect in the outer core of the Earth, which is thought to be driven by the motion of molten iron.

Question 2

The shape of Earth's surface results from
A) gravity.
B) the action of wind, water and ice.
C) the radioactive decay of atoms.
D) all of the above
E) gravity, wind, water, and ice only

Accepted Answer

The shape of Earth's surface results from the combined effects of gravity, wind, water, and ice. Gravity pulls the Earth's mass into a spherical shape, while wind, water, and ice erode and deposit material on the Earth's surface, creating mountains, valleys, and other landforms.

Question 3

Which of the following lists is in the correct sequence from youngest to oldest?
A) Holocene, Pleistocene, Pliocene, Miocene
B) Holocene, Precambrian, Cenozoic
C) Paleozoic, Cenozoic, Mesozoic
D) Tertiary, Quaternary, Cretaceous

Accepted Answer

The correct chronological sequence from youngest to oldest is: Holocene, Pleistocene, Pliocene, Miocene.

Question 4

When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time." This fact is based on the principle of ________.
A) uniformitarianism
B) superposition
C) catastrophism

Accepted Answer

Superposition states that in undisturbed layers of rock or sediment, the oldest layer is at the bottom and each layer above it is progressively younger. Therefore, by digging downward, geologists and archaeologists are moving through progressively older layers and uncovering objects that are progressively older.

Question 5

Knowledge of Earth's interior is derived from
A) direct sampling of the interior using deep-test wells.
B) work in Earth's deepest caverns and caves.
C) indirect evidence involving the analysis of seismic waves.
D) historic and prehistoric records.

Accepted Answer

Indirect evidence involving the analysis of seismic waves is the primary method for gaining knowledge of Earth's interior. Direct sampling of the interior using deep-test wells is not possible due to the extreme depth and pressure of the Earth's interior. Work in Earth's deepest caverns and caves would not provide information on the structure or composition of the interior. Historic and prehistoric records may provide some information on surface geology and past events but are not a reliable source for understanding Earth's interior.

Question 6

Which of the following statements about Earth's core is false?
A) It is composed primarily of iron.
B) The inner core is believed to be liquid and the outer core solid.
C) Temperatures in the core reach several thousand degrees.
D) Temperatures and pressures are higher in the inner core than in the outer core.

Accepted Answer

The inner core of the Earth is believed to be solid due to the extreme pressure causing the iron to be compressed into a solid state, while the outer core is believed to be liquid.

Question 7

Earth's interior is
A) evenly mixed throughout.
B) not subject to internal differentiation.
C) heated unevenly by the heat of radioactive decay.
D) arranged with lighter elements toward the center and heavier elements toward the crust.

Accepted Answer

The heat of radioactive decay is not evenly distributed throughout Earth's interior, leading to uneven heating. This contributes to processes such as mantle convection, which cause internal differentiation and the separation of different types of materials. There is also evidence that heavier elements are more concentrated towards the center of the planet, with lighter elements being more abundant in the crust.

Question 8

Which of the following is incorrectly matched?
A) endogenic - internal processes
B) exogenic - external processes
C) radioactive decay heat - exogenic energy source
D) weathering - exogenic breaking and dissolving the crust

Accepted Answer

Radioactive decay heat is an endogenic energy source, as it is generated internally within the Earth's crust.

Question 9

Tectonic forces
A) erode the surface of Earth.
B) warp, fold, and uplift rock.
C) control soil formation processes.
D) form sedimentary rock.

Accepted Answer

Tectonic forces, such as plate movements and collisions, cause the deformation of rock resulting in warping, folding, and uplift.

Question 10

Approximately 90 percent of Earth's magnetic field is generated in the
A) inner core.
B) outer core.
C) lower mantle.
D) upper mantle.

Accepted Answer

The Earth's magnetic field is generated in the outer core, which is composed of liquid iron and nickel. As the outer core rotates at a different speed than the rest of the planet, it creates convection currents in the molten metal which generate electrical currents, producing the magnetic field. The inner core is solid iron and nickel, therefore not capable of generating a magnetic field. The lower and upper mantle are composed of solid rock and cannot generate a magnetic field.

Question 11

The heat that melted the early Earth was derived from
A) nuclear fusion.
B) radioactive decay.
C) chemical reactions.
D) sunlight.

Accepted Answer

The heat that melted the early Earth was derived from radioactive decay, specifically from the decay of isotopes like uranium, thorium, and potassium. This process released a significant amount of heat, which contributed to the melting and differentiation of the Earth's interior.

Question 12

The idea that Earth formed only a few thousand years ago is
A) basically accepted today by science.
B) based on little physical evidence and is more appropriately considered a belief.
C) referred to as uniformitarianism.
D) the basis of the geologic time scale.

Accepted Answer

The idea that Earth formed only a few thousand years ago is not accepted by mainstream science because there is overwhelming physical evidence that Earth is around 4.5 billion years old. The belief that Earth is young is more appropriately considered a religious or cultural belief rather than a scientific theory.

Question 13

Which of the following is true regarding the geologic time scale?
A) The bulk of Earth's history has occurred during the Cenozoic era.
B) Over 87 percent of Earth's history has elapsed during the more recent Cenozoic, Mesozoic, and Paleozoic eras.
C) Both relative and absolute dating methods are used in determining the sequence of the time scale.
D) We live in the Tertiary period.

Accepted Answer

The geologic time scale is determined by both relative and absolute dating methods, with relative dating determining the sequence of events, and absolute dating assigning numerical ages to those events. Option A is incorrect as the Cenozoic era only comprises the last 66 million years of Earth's history. Option B is incorrect as the three aforementioned eras only make up about 25% of Earth's history. Option D is incorrect as the Tertiary period is no longer recognized in the current geologic time scale, having been replaced by the Paleogene and Neogene periods.

Question 14

Which of the following is $\underline {\text { exogenic }}$in nature?
A) earthquakes
B) volcanism
C) flows of heat and materials in the mantle
D) weathering

Accepted Answer

Exogenic processes are external processes that occur on the Earth's surface, such as weathering, which involves the breakdown of rocks by atmospheric and environmental factors.

Question 15

Which of the following can occur when seismic waves encounter a layer in Earth's interior?
A) They can be reflected or refracted.
B) They can be absorbed.
C) Their speed can change.
D) All of the above can occur, depending upon the nature of the layer.
E) None of the above-seismic waves cannot penetrate below the crust of Earth.

Accepted Answer

All of the above can occur, depending upon the nature of the layer. Seismic waves can be reflected or refracted, absorbed or their speed can change when they encounter a layer in Earth's interior. The specific behavior of the waves depends on the physical properties of the layer they encounter, such as its composition, density, and temperature.

Question 16

Uniformitarianism assumes that
A) Earth is quite young and is shaped by dramatic events.
B) catastrophic episodes have regularly occurred.
C) the same physical processes we see today are a key to understanding the processes that have been operating throughout geologic time.
D) mountains, plains, and canyons formed by catastrophic events.

Accepted Answer

Uniformitarianism assumes that the same physical processes we see today are a key to understanding the processes that have been operating throughout geologic time. This principle is based on the idea that the laws of nature have remained constant throughout time, and therefore the processes that we observe today can be used to explain events that occurred in the past. It does not assume that Earth is young or that catastrophic episodes have regularly occurred.

Question 17

Which of the following is $\underline {\text { endogenic } }$ in nature?
A) weathering
B) stream deposition
C) volcanism
D) glacial erosion

Accepted Answer

Endogenic processes are those that originate from within the Earth's interior, such as volcanism, earthquakes, and mountain building. Out of the given options, only volcanism is endogenic in nature. Weathering, stream deposition, and glacial erosion are exogenic processes that are driven by external factors such as climate, water, and wind.

Question 18

Which of the following gives the correct sequence of layers in Earth, from the surface to the center?
A) crust, core, lower mantle, aesthenosphere
B) aesthenosphere, lower mantle, crust, core
C) crust, lower mantle, aesthenosphere, core
D) crust, aesthenosphere, lower mantle, core

Accepted Answer

The correct sequence from the surface to the center of the Earth is crust, asthenosphere, lower mantle, and core. The crust is the outermost layer, followed by the asthenosphere (part of the upper mantle), then the lower mantle, and finally the core.

Question 19

Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest?
A) era, eon, epoch, period
B) eon, era, period, epoch
C) epoch, era, eon, period
D) period, eon, era, epoch

Accepted Answer

The correct sequence of divisions in the geologic time scale is eon, era, period, epoch. This sequence goes from largest to smallest in terms of time intervals.

Question 20

Which of the following is an example of an age-relationship based on relative dating?
A) The oldest known rocks on Earth are 3.96 billion years old.
B) The Vishnu schist at the bottom of the Grand Canyon is 2 billion years old.
C) The dinosaurs became extinct 65 million years ago.
D) The Coconino formation in the Grand Canyon is older than the Kaibab formation.

Accepted Answer

Relative dating determines the age of a geological feature in relation to other features. Choice D states that one formation is older than another, making it an example of relative dating. Choices A, B, and C all give specific numerical ages, so they are not examples of relative dating.

Quiz 8: The Dynamic Planet

Earth's magnetic field

The shape of Earth's surface results from

Which of the following lists is in the correct sequence from youngest to oldest?

When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time." This fact is based on the principle of ________.

Knowledge of Earth's interior is derived from

Which of the following statements about Earth's core is false?

Earth's interior is

Which of the following is incorrectly matched?

Tectonic forces

Approximately 90 percent of Earth's magnetic field is generated in the

The heat that melted the early Earth was derived from

The idea that Earth formed only a few thousand years ago is

Which of the following is true regarding the geologic time scale?

Which of the following is $\underline {\text { exogenic }}$ in nature?

Which of the following can occur when seismic waves encounter a layer in Earth's interior?

Uniformitarianism assumes that

Which of the following is $\underline {\text { endogenic } }$ in nature?

Which of the following gives the correct sequence of layers in Earth, from the surface to the center?

Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest?

Which of the following is an example of an age-relationship based on relative dating?