Question 1

What type of rock forms from the solidification of molten material?
A)sedimentary
B)metamorphic
C)igneous
D)clastic
E)foliated

Accepted Answer

Igneous rock forms from the solidification of molten material. Sedimentary rock forms from the accumulation of sediment, metamorphic rock forms from the transformation of existing rock due to heat and pressure, clastic rock refers to the type of sedimentary rock that is made up of fragments of pre-existing rocks and minerals, and foliated refers to the texture of metamorphic rock that has a layered or banded appearance due to the alignment of minerals.

Question 2

The major rocks of Earth's crust are classified into principal types based on
A)element composition.
B)mineral composition.
C)the manner in which they formed.
D)relative and absolute locations.
E)age and structure.

Accepted Answer

The major rocks of Earth's crust are classified into principal types based on the manner in which they formed. This includes igneous rocks formed from solidification of magma, sedimentary rocks formed from the accumulation and lithification of sediments, and metamorphic rocks formed from the alteration of pre-existing rocks due to heat and pressure. While element and mineral composition, location, age, and structure may be used as additional criteria for classification, they are not the primary basis for classification.

Question 3

At least 90% of Earth's magnetic field is generated by the
A)inner core.
B)outer core.
C)lower mantle.
D)asthenosphere.
E)Mohorovičić discontinuity.

Accepted Answer

Earth's magnetic field is generated by the motion of molten iron in the outer core. The inner core is solid iron, and while it does contribute to the magnetic field, it is not the primary source. The lower mantle, asthenosphere, and Mohorovičić discontinuity do not have the necessary properties to generate a magnetic field.

Question 4

Which rock type makes up approximately 90% of the Earth's crust?
A)sedimentary
B)metamorphic
C)igneous
D)clastic
E)foliated

Accepted Answer

Igneous rocks are formed from the cooling and solidification of magma or lava, and they make up approximately 90% of the Earth's crust. Sedimentary and metamorphic rocks also contribute to the crust but at a much lower percentage. Clastic and foliated are not types of rocks, but rather terms used to describe certain characteristics of sedimentary and metamorphic rocks, respectively.

Question 5

The rigid crust and uppermost mantle are known collectively as the
A)asthenosphere.
B)lithosphere.
C)Moho.
D)Gutenberg discontinuity.
E)rigid layer.

Accepted Answer

The term used to describe the rigid outermost layer of the Earth is the lithosphere, which includes both the crust and the uppermost mantle. The asthenosphere is a layer in the mantle that is partially molten and more ductile than the lithosphere. The Moho is the boundary between the crust and mantle, and the Gutenberg discontinuity is a zone in the mantle where seismic waves experience a sharp increase in velocity. "Rigid layer" is not a specific scientific term.

Question 6

Molten rock beneath the Earth's surface is known as_____ ,whereas molten rock on the Earth's surface is called ___ .
A)lava;magma
B)intrusive;extrusive
C)magma;lava
D)extrusive;intrusive
E)lava;extrusive

Accepted Answer

Magma is the molten rock beneath the Earth's surface, and lava is the molten rock that flows on the Earth's surface. Choice C correctly identifies these terms.

Question 7

During the past 4 million years,_____geomagnetic reversals have occurred.
A)9
B)25
C)50
D)100
E)1,000

Accepted Answer

The correct answer is A because the Earth's magnetic field has reversed its polarity approximately 9 times during the past 4 million years.

Question 8

Obsidian is an igneous rock with a glassy appearance and minimal crystal growth.What accounts for this?
A)Obsidian is an intrusive igneous rock that cooled slowly beneath the Earth's surface,resulting in little crystal growth.
B)Obsidian is an extrusive igneous rock that cooled slowly on the Earth surface,resulting in little crystal growth.
C)Obsidian is an extrusive igneous rock that cooled very slowly on the Earth surface,resulting in little crystal growth.
D)Obsidian is an intrusive igneous rock that cooled rapidly beneath the Earth's surface,result in little crystal growth.
E)Obsidian has a chemical composition that lends itself to a glassy appearance and minimal crystal growth.

Accepted Answer

The answer of Obsidian is an igneous rock with a...

Question 9

Approximately 95% of the Earth's crust is made up of
A)oxides.
B)phosphates.
C)silicates.
D)carbonates.
E)sulfates.

Accepted Answer

Silicates are the most abundant type of mineral in the Earth's crust, making up approximately 95% of its composition. Silicates are formed from the combination of silicon, oxygen, and various metallic elements. The remaining 5% of the crust is made up of other minerals such as oxides, carbonates, sulfates, and phosphates.

Question 10

The three basic rock types are
A)conglomerates,clastics,and evaporative.
B)intrusive,extrusive,and plutonic.
C)laterite,schist,and basalt.
D)sedimentary,metamorphic,and igneous.
E)felsic,mafic,and ultramafic.

Accepted Answer

The options for rock types given in D are the traditional and commonly recognized divisions of rocks: sedimentary, metamorphic, and igneous. Sedimentary rocks are formed from the accumulation of sediment, usually in layers, over time. Metamorphic rocks are formed from other rocks through heat and pressure. Igneous rocks are formed from the cooling and solidification of magma or lava.

Question 11

Earth's magnetic poles
A)are fixed.
B)are migrating approximately 60 km (37 mi. )per year.
C)are perfectly aligned with Earth's axis.
D)are misaligned from Earth's axis by 23.5 degrees.
E)are no different than Earth's geographic poles.

Accepted Answer

Earth's magnetic poles are not fixed and are constantly moving. Currently, the magnetic north pole is moving approximately 60 km per year towards Siberia, while the magnetic south pole is moving towards Antarctica. This movement is due to changes in the Earth's core and magnetic field.

Question 12

The plastic layer in the mantle from about 70 to 250 km (43 to 155 mi. )in depth is known as the
A)asthenosphere.
B)lithosphere.
C)Moho.
D)Gutenberg discontinuity.
E)plastic layer.

Accepted Answer

The plastic layer in the mantle from about 70 to 250 km (43 to 155 mi.) in depth is known as the asthenosphere.

Question 13

A(n)_____ is an assemblage of minerals bound together,a mass composed of a single mineral,a mass of undifferentiated materials,or a mass of solid organic material.
A)compound
B)mineral
C)molecule
D)rock
E)element

Accepted Answer

A rock is an assemblage of minerals bound together or a mass composed of a single mineral, as well as a mass of undifferentiated materials or a mass of solid organic material. A compound is a substance composed of two or more elements, a mineral is a naturally occurring inorganic substance with a defined chemical composition and crystal structure, a molecule is the smallest unit of a compound, and an element is a substance that cannot be broken down into simpler substances by chemical means.

Question 14

The continuous alteration of Earth materials from one rock type to another is known as the
A)geologic cycle.
B)rock cycle.
C)hydrologic cycle.
D)tectonic cycle.
E)biogeochemical cycle.

Accepted Answer

The continuous alteration of Earth materials from one rock type to another is known as the rock cycle. The other options are not directly related to the process of rock transformation.

Question 15

Which of the following is not a criterion to be classified as a mineral?
A)inorganic
B)anthropogenic
C)solid
D)definable chemical composition
E)crystalline structure

Accepted Answer

Being anthropogenic, or created or influenced by human activity, is not a criterion to be classified as a mineral. The other criteria listed are all necessary for a substance to be classified as a mineral.

Question 16

An element or combination of elements that forms an inorganic,natural compound is called a
A)tectonic rock.
B)granite.
C)mineral.
D)molecule.
E)compound.

Accepted Answer

Minerals are inorganic, naturally occurring compounds formed by geological processes. Tectonic rock and granite are specific types of rocks, which may contain minerals but are not themselves minerals. A molecule is a combination of atoms, which can be either organic or inorganic. A compound is a substance composed of two or more different elements, which can be either organic or inorganic. Only the answer choice C specifically fits the description given in the question.

Question 17

Coarser grained igneous rocks tend to___ be because ____.
A)intrusive;the faster cooling of magma allows more time for crystals to form
B)extrusive;the faster cooling of lava allows more time for crystals to form
C)extrusive;the slower cooling of lava allows more time for crystals to form
D)either intrusive or extrusive;the slower cooling of magma and lava allows more time for crystals to form
E)intrusive;slower cooling of magma allows more time for crystals to form

Accepted Answer

Coarser grained igneous rocks tend to be intrusive, which means they formed from slowly cooling magma beneath the earth's surface. The slower cooling of magma allows more time for crystals to form, resulting in larger crystal size and a coarser texture. Therefore, the correct answer is E - intrusive, slower cooling of magma allows more time for crystals to form.

Question 18

Geomagnetic reversals
A)are rapid events in which the magnetic field "blinks" off and on again.
B)cause in mass species extinctions due to increased cosmic radiation.
C)are predictable events,occurring at set intervals of 100,000 years.
D)are caused by rapid tectonic movement.
E)involve slow diminishments to low intensity and a rapid regaining of full strength.

Accepted Answer

Geomagnetic reversals involve a slow decrease in intensity of the magnetic field, followed by a rapid reversal back to full strength. They are not rapid events or predictable events occurring at set intervals, nor are they caused by tectonic movement or increased cosmic radiation leading to mass extinctions.

Question 19

Felsic igneous rocks,such as granite and rhyolite,
A)have dark coloration.
B)are high in magnesium and iron content.
C)have a high melting temperature.
D)are high in silicate minerals.
E)have a higher density than mafic igneous rocks.

Accepted Answer

Felsic igneous rocks are rich in silicate minerals, such as quartz, feldspar, and mica. They are typically light in color and have a lower density than mafic igneous rocks. They also have a higher melting temperature than mafic igneous rocks.

Question 20

Finer grained igneous rocks tend to be ___because ___ .
A)intrusive;the faster cooling of magma limits time for crystals to form
B)extrusive;the faster cooling of lava limits time for crystals to form
C)extrusive;the slower cooling of lava limits time for crystals to form
D)either intrusive or extrusive;the faster cooling of magma and lava limits time for crystals to form
E)intrusive;slower cooling of magma limits time for crystals to form

Accepted Answer

Finer grained igneous rocks are typically extrusive because they form from lava that cools quickly on the Earth's surface, limiting the time available for crystals to grow.

Quiz 11: The Dynamic Planet

What type of rock forms from the solidification of molten material?

The major rocks of Earth's crust are classified into principal types based on

At least 90% of Earth's magnetic field is generated by the

Which rock type makes up approximately 90% of the Earth's crust?

The rigid crust and uppermost mantle are known collectively as the

Molten rock beneath the Earth's surface is known as___ ,whereas molten rock on the Earth's surface is called _ .

During the past 4 million years,_____geomagnetic reversals have occurred.

Obsidian is an igneous rock with a glassy appearance and minimal crystal growth.What accounts for this?

Approximately 95% of the Earth's crust is made up of

The three basic rock types are

Earth's magnetic poles

The plastic layer in the mantle from about 70 to 250 km (43 to 155 mi. ) in depth is known as the

A(n) _____ is an assemblage of minerals bound together,a mass composed of a single mineral,a mass of undifferentiated materials,or a mass of solid organic material.

The continuous alteration of Earth materials from one rock type to another is known as the

Which of the following is not a criterion to be classified as a mineral?

An element or combination of elements that forms an inorganic,natural compound is called a

Coarser grained igneous rocks tend to_ be because __.

Geomagnetic reversals

Felsic igneous rocks,such as granite and rhyolite,

Finer grained igneous rocks tend to be _because _ .