chapter 1-3
Lithospheric plates move at an average rate of ________ per year.
2 to 3 centimeters
Plate-tectonic processes on earth have been active for at least
3 billion years.
The silicate tetrahedron is composed of
4 oxygen and 1 silicon atoms.
The width of the Atlantic Ocean grows by about 7 cm per year due to spreading along the mid-Atlantic ridge. Assuming this spreading rate has been continuous, how much wider is the Atlantic Ocean today compared to when the Mayflower brought the first Pilgrims from Europe in 1620?
About 28 meters
Pre-drift reassembly of the continents can be assisted by
All of the choices are correct.
Sedimentary rocks include
All of the choices are correct.
The strength of a rock
All of the choices are correct.
Which of the following are minerals that comprise a native element?
All of the choices are correct.
Which of the following statements about asbestos is true?
Asbestos is a generic term for any mineral crystal that is a fiber (i.e. thin and flexible).
Brittle behavior in rocks leads to formation of folds.
False
Chemical sedimentary rocks are those precipitated from a silicate melt.
False
Continental lithosphere is similar in density to that of the asthenosphere.
False
Earthquakes occur at subduction zones, but volcanoes do not because the subducted lithosphere is pushed deep into the mantle.
False
In order for continental drift to occur, the continental lithosphere must behave plastically.
False
It is not possible to estimate rates of plate movement because new rocks are constantly being created from old.
False
Plutonic rocks are typically fine grained owing to a faster rate of cooling than volcanic rocks.
False
Polar-wander curves prove that the magnetic poles have meandered over the earth's surface with time.
False
Rifting occurs at oceanic spreading ridges, but not within continents, because continents are so thick and strong.
False
Rubber bands show elastic behavior until their elastic limit is exceeded; rocks are always brittle.
False
Seafloor rocks get progressively younger the farther they are from of an ocean ridge.
False
Stress is the deformation resulting from the application of strain to a rock.
False
The landmass that eventually split up into South America, Africa, India, Antarctica, and Australia was
Gondwanaland.
These are areas not connected with plate boundaries but are regions of volcanic activities and are used to monitor the direction and movement of plates:
Hotspots
Pure ice is a mineral while pure liquid water is not. Why?
Liquid water does not have an orderly internal arrangement of atoms.
The Appalachian Mountains of eastern North America were formed by continent-continent collision. Today, these mountains are still being uplifted by the same type of collision:
The Himalaya Mountains of Asia.
Satellite data now allow direct measurement of the rates of plate movement, even though it is slow.
True
Earth's early atmosphere
contained little or no oxygen.
No subduction occurs during
continent-continent convergence.
A possible "driving force" for plate motions is
convection in the asthenosphere.
The collision of the following plates: continent-ocean; continent-continent; ocean-ocean is best referred to as the
convergent plate boundary.
Where are rocks most likely to strain in a plastic fashion?
crust
Which layers make up the Earth's lithosphere?
crust and upper part of the mantle, which behave rigidly
As population increases,
demand for resources will tend to increase.
New lithosphere is created at
divergent plate boundaries.
The study of paleomagnetism has revealed that
earth's magnetic field has reversed many times.
All of the following have been used to determine the rates and directions of plate movements except
earthquake locations.
The origin of earth's magnetic field is probably due to
electric currents in the fluid outer core.
The earth's polarity has remained the same since its existence.
false
The idea of continental drift was not proposed until the 1960s, when the first evidence to support it was discovered.
false
World population has now stabilized because of limitations imposed by resource shortages.
false
Which mineral subgroup is the most abundant in Earth's crust?
feldspars
Silicates rich in iron and/or magnesium are termed
ferromagnesian.
The theory of continental drift was initially rejected by many scientists because
few scientists believed it possible for the continents to move over a solid earth.
The Himalayan Mountains
formed by India drifting north and colliding with the Asian continent.
The planets
formed from the same cloud of gas and dust as the sun.
Of the following rocks, the one that is metamorphic is
garnet schist.
Which of the following is an igneous rock?
granite
At a convergent plate boundary,
high mountains may be built during continent-continent collision.
A "polar-wander" curve shows
how continents have moved or drifted, relative to the magnetic poles.
Sea floor is formed at spreading ridges and destroyed
in subduction zones.
The shape of mineral crystals depends most on
internal atomic arrangement.
Earth's core is composed mostly of
iron
The earth's inner core is composed mostly
iron
The lithosphere
is thickest under the continents, thinnest beneath the oceans.
Magma that is erupted at the earth's surface is
lava.
All of the following are examples of clastic sedimentary rocks except
limestone
An example of a chemical sedimentary rock is
limestone.
According to plate-tectonic theory, plates of rigid, elastic __________ move over a weak plastic layer below.
lithosphere
A rock's Curie temperature is the temperature above which it
loses its magnetism.
Divergent plate boundaries
may result in rifts on continents, but may also "fail" or stop, resulting in topographically low areas.
Which of the following is a silicate mineral?
micas
Which of the following would not be considered a characteristic of a hot spot?
move along with plates.
Which of the following rock is an example of an extremely rapid rate of cooling?
obsidian
Native elements are those elements that
occur as minerals consisting of a single element.
Island arcs are associated with
ocean-ocean convergences.
Which layer within the earth is molten (liquid)?
outer core
The two most abundant elements in the crust are
oxygen and silicon.
The Himalaya and Appalachian Mountains were formed by
plate convergence.
Which of the following is a member of the sulfide mineral group?
pyrite
A ductile material is one that
readily undergoes plastic deformation.
Oceanic lithosphere
records magnetic "stripes" of normally and reversely magnetized rocks.
Which of the following was not a consequence of the early heating of the earth?
release of abundant, free oxygen into the atmosphere
For most solids, sufficiently increased stress results in
rupture
Divergent plate boundaries around the world are indicated by
seafloor spreading.
An example of a clastic sedimentary rock is
shale
Examples of foliated metamorphic rocks are
slate and schist.
Ocean floor rocks on opposite sides of an ocean ridge show
symmetrical and alternating bands of normal and reverse magnetization.
Stress tending to pull objects apart is __________ stress.
tensile
The natural satellite of the earth is answer
the moon
The theory of plate tectonics can be used to explain all of the following EXCEPT:
the origin of the Earth's core.
The locations and ages of islands in the Hawaiian Island chain can be used to show
the rate and direction of movement of the Pacific Plate.
The magnetic dip preserved in a rock indicates
the rock's magnetic latitude at the time that it crystallized.
With increasing distance from an oceanic ridge,
the rocks become older.
Most of the mass of the solar system is concentrated in answer
the sun
The asthenosphere lies entirely within
the upper mantle.
The San Andreas fault is a good example of a
transform plate boundary.
About 200 million years ago, most of the continents were together, forming a "super continent" called Pangaea.
true
Although convection in the asthenosphere is widely accepted as the cause of plate movements, it may be that the weight of down-going lithosphere in subduction zones pulls the trailing plate behind it.
true
An island arc comprising of volcanic islands forms as a result of ocean-ocean convergence.
true
Continental drift may explain evidence of past glaciation in regions now located in the tropics, because local climate is strongly controlled by latitude.
true
Deep in the crust, at elevated temperatures, rocks may behave plastically and undergo folding or flow.
true
Diamond and graphite have the same chemical composition.
true
Differences in magma composition account for the fact that some volcanoes erupt quietly, others explosively.
true
Obsidian (volcanic glass) is an example of a clastic rock.
true
Part of western California is attached to the Pacific Plate, while most of North America belongs to a separate plate.
true
Rocks may behave differently over the long spans of geologic time than they do in short-term laboratory experiments.
true
Seawater interacting with hot sea floor at spreading ridges may produce mineral deposits.
true
The Hawaiian Islands were formed by repeated volcanic eruptions over a hot spot.
true
The asthenosphere is a weak, locally partly molten layer over which lithospheric plates can move.
true
The best explanation for the distribution of Glossopteris and Mesosaurus is that they lived when continents on which their fossils are now found were once connected then later were rifted and drifted apart.
true
The grain size of an igneous rock is generally related to how quickly the melt cooled: the slower the cooling, the coarser the crystals.
true
The particle grain size of conglomerate is greater than that of sandstone.
true
The physical properties of a mineral are often closely related to its internal atomic arrangement or crystal structure.
true
The remnant magnetism in the rocks is called paleomagnetism.
true
The sulfide mineral group includes many valuable ores.
true
The term cleavage refers to a mineral's tendency to break preferentially in certain directions of the crystal structure.
true
Transform faults that offset segments of a spreading ridge are formed because rates of spreading are not constant along any one rift zone so shearing develops when one segment grows faster than another.
true
Volcanoes and earthquakes are concentrated along the margins of lithospheric plates.
true
Which of the following statements is not true?
Certain problems, such as resource shortages, will become less severe when other planets or the moon are colonized in the next few decades.
Metamorphic rocks are formed at extremely high temperatures, above those required to form plutonic rocks.
False
The basic "building blocks" of the silicate minerals are tetrahedra of silicon and carbon.
False
Human beings, as the species Homo sapiens, have existed on earth for approximately
0.00012 (0.12 thousandths) of the earth's history.
The average global population growth rate is answer
1 percent per year
The Big Bang occurred
12 to 14 billion years ago.
An atom that has 20 protons and 20 neutrons in its nucleus has this atomic number
20
The age of the earth is estimated to be ____ billion years.
4.5
The Earth and the rest of our solar system formed
4.5 billion years ago.
The number of naturally occurring chemical elements is approximately
90
In which of the following areas is population growth at present most rapid?
Africa
The population size changes by the difference between the birth rate and death rate of individuals. What factors influence these rates?
All of the choices are correct
Considerations that complicate our understanding of geologic processes include
All of the choices are correct.
Sources of heat in the early earth included
All of the choices are correct.
Atoms of the same element that have different numbers of neutrons are ___________ of that element.
Isotopes
The process by which sediments are converted to sedimentary rocks is called
Lithification
Which of the following has existed unchanged from the time of the earth's formation to the present?
None of the choices are correct.
Which of the following statements is not true?
People are unevenly distributed around the world, but resources are uniformly distributed among nations.
A scientific hypothesis that holds up through numerous experiments or repeatedly through observation becomes.
a theory
Which is not part of the definition of a mineral?
aggregate of elements
Contact metamorphic rocks
are formed next to igneous intrusions.
An element's chemical identity is determined by its
atomic number.
The maximum population of a species that an ecosystem can sustain is called
carrying capacity.
The two fundamental characteristics that distinguish a mineral from all other minerals are its
chemical composition and crystal structure.
Rock salt and limestone are examples of
chemical sedimentary rocks.
A subgroup of silicates that includes minerals used in ceramics, construction, and drilling for oil is the
clay subgroup
Which of the following was an important heat source for melting of the primitive earth?
collisions of infalling particles
Which of the following physical properties are unreliable and not unique to a particular mineral and so must be used only cautiously when identifying minerals in the absence of scientific instruments?
color
Which of the following physical properties is not a reliable guide to mineral identification in hand specimens?
color
Continental crust differs from oceanic crust in that
contains more light minerals than oceanic crust.
Earth's internal layers, in order from outermost to innermost, are
crust, mantle, core
The internal regular arrangement of ions or atoms in a material makes it
crystalline
The presence of free oxygen in the atmosphere is attributed mainly to which of the following?
development of blue-green algae
Which of the following is not a member of the silicate group of minerals?
diamond
Expansive clays
expand when wet, shrink when dried out.
All crystalline materials show well-developed crystal faces.
false
Earth's population will be stabilized when its growth rate becomes constant.
false
Geologic processes can be described in a series of distinct and independent cycles of air, water and rock.
false
Isotopes are atomic nuclei that are radioactive.
false
It is impossible to estimate the age of the universe.
false
It is impossible to know the internal composition or structure of the earth because geologists cannot sample the interior.
false
Land—both to live on and to grow food on—is in abundant supply on earth, though other resources are limited.
false
Once internal differentiation was complete, the earth's surface remained essentially unchanged to the present.
false
Population growth rates are very non-uniform worldwide, with the fastest rates of increase in the technologically advanced countries.
false
Quartz is the most abundant mineral in the crust.
false
The least dense minerals are found in earth's core
false
The massive size of continents contributes to their permanence; they have remained stable and virtually unchanged since they formed.
false
The scientific method cannot be applied to the study of the earth, because we cannot experiment on the earth.
false
Clastic sedimentary rocks are formed
from the broken-up fragments of preexisting rocks.
Isotopes of the same element
have different atomic mass numbers.
Rocks that crystallize from magma are
igneous
In general, consumption of resources has
increased faster than population growth.
By weight percent, the most common chemical element in the whole earth is
iron
A population's doubling time
is the length of time required for that population to double in size.
The earth's outer core is answer
liquid.
Rocks that are formed by the crystallization of new minerals in the solid state (i.e. without melting) due to heat and/or pressure are
metamorphic.
Single-celled blue-green algae of the early earth enriched the atmosphere with oxygen through the life process of
photosynthesis
Which of the following would not be considered a mineral?
possibly an organic chemical compound
The concept of the rock cycle is that
rocks are continually undergoing change, being transformed into new rocks.
The most common minerals in the crust are
silicates
All of the following statements concerning minerals are correct except
some minerals are produced by biological processes.
Humans have caused
the amount of carbon dioxide in the atmosphere to increase.
In an electrically neutral atom,
the number of protons and the number of electrons are the same.
Evidence that the universe originated in a "big bang" includes answer
the observation that stars are all moving apart.
______ are supported by numerous experiments over time and are widely accepted to explain a set of data and/or observations.
theories
A scientific hypothesis that is subsequently extensively tested and continues to appear valid may be called an
theory
Anions are negatively charged and cations are positively charged.
true
At present (2016) growth rates, the doubling time of the world's population is about 70 years.
true
Clastic sedimentary rocks are classified or named on the basis of the size of the fragments that form the rock.
true
Different isotopes of one element are chemically indistinguishable.
true
Exporting U.S. agricultural production methods to the rest of the world might increase food production but would also increase energy demands.
true
Foliation, referring to a preferential parallel orientation of mineral crystals, is a texture that is referred for metamorphic rocks.
true
Human ancestral remains appear quite late in the geologic record, within only the last 3 to 4 million years.
true
Humans can, to some extent, control their surroundings, disease and other factors, so human populations are subject to fewer checks than animal populations.
true
Many compositional features of the earth, including its abundant surface water, are unique in the solar system.
true
The best records of ancient life are those for the last 600 million years, when organisms with hard parts became widespread.
true
The carrying capacity for humans is not known.
true
The seriousness of many environmental problems is a direct result of the large number of humans interacting with the environment
true
The starting composition of the solar nebula can be inferred from studies of stars.
true
When a population is growing exponentially, it is increasing by a fixed percentage per unit time
true
World population has been growing more and more rapidly over the past several millennia.
true
The compositions of the planets
were determined by the distance from the sun at which each formed, except for the largest planets.