Introduction to Earth Science
Till is an unsorted sediment deposited directly from the melting glacial ice; stream action is not involved.
True
Very fine-grained iron oxide particles account for nearly all red, yellow, and brown soil colors.
True
When a beta particle is emitted, the mass number of the isotope remains unchanged.
True
The minerals gold, silver and mercury are often found in ________.
hydrothermal vein
The Trellis drainage pattern shown below develops ________.
in areas of alternating weak and resistant bedrock
Sediment is neither stored nor produced ________. It is primarily a zone of transport in a river system.
in the trunk stream
The principle of lateral continuity proposes that sedimentary rock layers continue in all directions until they grade into a different rock type or thin out on the edge of a basin is important because ________.
it allowed geologists to correlate sedimentary rock unites over large distances
The term drift ________.
means any sediments of glacial origin
In the television series "Cosmos" the astronomer Carl Sagan used to say, "We are all made of star stuff." What did he mean by that?
All of the chemical elements in our solar system were forged in an ancient star that went supernova.
An important geochronometer is the decay of 147Sm to 143Nd. What type of radioactive decay is involved in this parent-daughter pair?
Alpha decay
The era known as the "age of mammals" is the ________ era.
Cenozoic
Chemically active fluids are ________.
Hot fluids (Hydrothermal) moving through pre-existing rocks. Cause alteration in chemical composition by introducing new ions
A stream begins at an elevation of 200 meters and flows a distance of 400 kilometers to the ocean. What is the average gradient?
0.5 m/km
In the late 20 th century most metal prices were very low but metal prices increased dramatically in the early 21 st century. Simultaneously, the early 21 st century saw extensive "brown fields exploration" in which companies went to old mining areas and extracted old mine wastes or reopened old mine workings. What is the primary explanation for this activity?
The increase of metal prices made mineral resources that were previously uneconomic into ores that could potentially be extracted profitably.
Haiti is a mountainous island nation that has terrible problems with landslides. Which of the following explanations would best explain the problem?
Most of the forests have been cut down for charcoal, leaving barren slopes subject to mass wasting during heavy tropical rainstorms and earthquakes.
When a mineral fractures along a cleavage plane, what does this suggest about the crystal structure of the mineral?
The crystal structure contains planes along which chemical bonding is much weaker than other directions.
A disconformity is an erosional unconformity with parallel beds or strata above and below.
True
Abundant moisture and warm temperatures result in high rates of chemical weathering.
True
Alluvium refers to stream deposits, mainly sand and gravel.
True
Although fluorite and native sulfur are not metallic minerals, deposits of these materials are still called ore deposits.
True
An unconformity involving older metamorphic rocks and younger sedimentary strata is termed a nonconformity.
True
Arêtes, horns, and U-shaped valleys are erosional features carved from bedrock by glaciers.
True
Chemical weathering in bedrock below the land surface often begins along joints and sheeting fractures.
True
Fiords are glacier-cut valleys that flooded as sea level rose in post-glacial times.
True
Internally, the earth consists of spherical shells with different compositions and densities.
True
Particle size is the primary basis for distinguishing among various detrital sedimentary rocks.
True
Quartz is quite resistant to weathering and is an important component of sands in riverbeds and on beaches.
True
Repeated freezing and thawing can be important in soil creep movements.
True
Shields and stable platforms are typically found in the interior regions of a continent.
True
The solum or true soil includes all horizons above the C-horizon.
True
One reason that Catastrophism was popular was ________.
Ussher's estimated age of the earth required catastrophic events to form mountains and canyons
As stream discharge increases ________.
Velocity, width and depth increase
If you want to buy a house in an area and you are worried there may be an earthquake hazard, who would be the best person to ask for advice on this hazard?
a geologist
A mass wasting process that involves slip of solid rock above a distinct sliding surface is called ________.
a slump
If you fall into a crevasse, what is the maximum depth you are likely to fall?
about 150 ft
Which of the following is not a form of artificial flood control?
channel cutoff to form oxbow lakes during a flood
Glacial sediments or tills are characterized by ________.
characterized by ________. wide variations in sizes of clasts
Which of the following would not typically be considered an Earth Science study?
chemical refining of petroleum
Magma differentiation tends to produce deposits of ________ near the base of intrusions.
chromite
The strong tendency of certain minerals to break along smooth, parallel planes is known as ________.
cleavage
The principle of horizontality which states that sediments are usually deposited in relatively flat layers is important because ________.
it provided a way to recognize if rocks had been deformed
A geologist is looking at deposits along a river below a large volcano. She finds large boulders mixed with sand and mud, and all of the material is comprised of volcanic rocks, particularly the mud which is volcanic ash. She quickly realizes these deposits represent an ancient ________.
lahar - a destructive mudflow on the slopes of a volcano.
A soil that has nearly equal amounts of clay, silt and sand is called ________.
loam
Convergent plate boundaries are ________.
locations where lithospheric plates are moving towards one another. The plate collisions that occur in these areas can produce earthquakes, volcanic activity, and crustal deformation.
Deserts and steppes occur at middle latitudes because of ________.
mountains that block the moisture and long distances from the oceans
Which of the following features characterize meandering streams and valleys?
natural levees; broad floodplains
By applying the law of superposition, ________ dates can be determined.
relative
Which of the following best describes sets of fractures in relatively fresh bedrock, such as granite, that are roughly parallel to the land surface?
sheeting fractures
The composition of the earth's inner core is thought to be ________.
solid iron-nickel alloy
What kind of time span is required to produce most mineral deposits?
tens of thousands to millions of years
Basin and Range type region
the Earth's crust (and upper mantle) has been stretched up to 100% of its original width. The entire region has been subjected to extension that thinned and cracked the crust as it was pulled apart, creating large faults. Along these roughly north-south-trending faults mountains were uplifted and valleys down-dropped, producing the distinctive alternating pattern of linear mountain ranges and valleys of the Basin and Range province.
Which of the following did not exist prior to the Quaternary Ice ages?
the Great Lakes
The very large crystals of quartz, feldspar, and muscovite found in pegmatites form from ________.
the final crystallizing parts of a magma
Downcutting (also known as rejuvenation) of a stream may be due to ________. Stream erodes downward through its bed.
uplifted land
The quartz in granite begins to melt at 650°C, so if we find a migmatite where quartz has melted in a granitic rock and we know the temperature in the region increased with depth by about 25°C per kilometer, we could estimate the depth that the rock had been at to be about ________.
26.0 km
________ involves movement on a zone of compressed air and would most likely be triggered by an earthquake
A rock avalanche
Over time as erosion lowers the landscape a river valley will typically ________.
Become broader and lower gradient
Which of the following is not a very long-lived, radioactive isotope?
C-14
________ are erosional features produced by valley/alpine glaciers.
Cirques
Angles are important when looking at which physical properties of minerals?
Cleavages
Which of the following is a renewable resource?
Cotton
Assume that you have just examined several flat-lying sedimentary layers. After much study you determine that there is a considerable span of time for which no sedimentary rock layer exists at this site. You have just discovered a(n) ________.
Disconformity
Which of the following energy sources is thought to drive the lateral motions of Earth's lithospheric plates?
Export of heat from deep on the mantle to the top of the asthenosphere
Nonmetallic minerals like halite and gypsum have no industrial uses.
False
As a stream changes from its headwaters to its mouth, which of the following is not likely to occur?
Flow velocity decreases.
Hurricanes are natural disasters. Which branch of the Earth sciences studies the impact of this phenomenon on coastal environments?
Geology
Which of the following minerals is not a chemical compound?
Graphite (C)
Landslides commonly occur when hurricanes hit steep terrain. Why?
Heavy rain from the tropical system can saturate slopes, triggering mass wasting events like mudslides.
Ice sheets can be ________.
Ice caps generally cover less than 50,000 square kilometers Ice sheets are larger and can cover entire continents and reach thicknesses of over a kilometer
The bond between sodium (Na) and Chlorine (Cl) to form halite (salt) is a(n) ________ bond.
Ionic
What two chemical elements are most abundant in the deep interior of the earth?
Iron and magnesium
Which one of the following mineral groups exhibits a sheet-like silicate structure?
Micas
Hurricanes and tornados are natural disasters. What branch of the Earth sciences studies the origin of these phenomena?
Meteorology
In deserts of southwestern North America developers often build houses in dry stream beds and build only minimal subsurface drainage systems to handle a flow of water comparable to the size of the dry stream channel. Is this a reasonable development model in the interest of public safety?
No, flash floods can produce high viscosity mudflows that would not be captured by the drainage system and could flow out over the valley, destroying everything in its path.
Paleozoic
Paleozoic
What theory dramatically improved geologist's ability to predict where certain ore deposits were formed?
Plate tectonics
Which the following denotes the positively charged particles in an atom's nucleus?
Protons
Sulfates always include ________.
SiO4
Be is to Mg as ________.
Sighh so many options. They have the same amount of valence electrons just swing for a pair with that.
________ make up the suspended loads of most rivers and streams.
Silt and clay-sized, detrital grains
In much of what is now Canada, glaciers covered the land as little as 12,000 years ago and glacial erosion scoured the land surface leaving very thin soil or bare rock over large areas. The Midwestern United States was also covered in ice at this time, yet this area contains some of the richest farm land in the world with thick soils. These soils are formed on glacial sediments and windblown dust deposits from the ice age. Why are the soil conditions between these areas so different when the soils are virtually identical in age?
The Midwestern soils are transported soils with soil development on materials that were already loose, unconsolidated materials.
Which of the following describes radioactive decay by beta particle emission?
The atomic number of the daughter isotope is one more than the parent; the mass numbers are the same.
What does the tendency of micas to produce thin cleavage flakes suggest about its crystal structure?
The atoms are arranged in orderly arrangements that form strongly bonded sheets separated by weak bonds between the sheets
Most insurance companies will not insure property with a known landslide hazard. Why?
The risk is high on human life time scales, and the hazard is difficult to assess.
What is the source of the energy that powers the Earth system?
The sun
Hot springs are most numerous in which region of the United States?
West
A worm would stand a poor chance of being fossilized because ________.
Worms have no hard parts
Chemical sedimentary rocks form from materials ________.
carried in solution
Coal beds originate in ________.
freshwater coastal swamps and bogs
Detrital sedimentary rocks are typically classified on the basis of their ________.
grain size
The continental shelf is located ________.
landward of the continental slope
Long oceanic mountain chains typically are characterized by ________.
layers of igneous rocks
Deserts occur primarily in the Africa, Arabia, and Australia because of ________.
sinking air currents
A ________ is the icicle-like speleothem that grows down from the roof of a cavern.
stalactite
If you were to examine the profile of a typical river, you would probably find that the gradient is _______
steepest near the head
If the glacial budget is balanced (accumulation equals wastage), then ________.
the terminus of the glacier is stationary
An artesian well is one in which ________.
water rises above the top of the aquifer without any pumping
The first step in turning a rock into a sediment is ________.
weathering alters the rock
An atom's mass number is 13 and its atomic number is 6. How many neutrons are in its nucleus?
7 (mass number - atomic number)
At the head of a delta, the major channel splits into smaller channels that follow different paths to the sea. These smaller channels are known as ________.
Distributaries
All of geologic time prior to the beginning of the Paleozoic era is termed the Phanerozoic eon.
False
Chemical compounds retain most of the characteristics of their constituent elements.
False
Deserts are hot, lifeless sand-covered landscapes shaped largely by the forces of wind.
False
Evaporites have a biochemical origin.
False
Lithospheric plates are the tops of convection cells and subduction zones are the downgoing part of the convection cell.
False
Magma is currently forming beneath the Rockies.
False
Oceans cover slightly less than half of the earth's surface.
False
Silicon-oxygen bonds are weak and cause cleavage to be common in silicate minerals.
False
The Colorado River is an example of a large wash.
False
The asthenosphere is a relatively cool and rigid shell that overlies the lithosphere
False
The earth's core is entirely molten iron and convection of this molten mass generates the earth's magnetic field.
False
The waterline where the ocean meets the land is the boundary between oceanic crust and continental crust.
False
Trunk streams are a major region of sediment storage in a river system.
False
Windblown loess, like sand, typically accumulates as mound-like dunes.
False
The Mississippi is only slightly smaller than the Amazon river.
False (Amazon is over 1,000 mi longer)
The Mississippi River today is a classic meandering river. 20,000 years ago the Mississippi River was a major outwash channel for the Laurentide ice sheet, and was characterized by dramatic variations in flow with huge discharge during summer ice melt and a dramatic falloff in discharge during the winter. The river also carried coarser sediment than today, with abundant sand and even gravel in its upper reaches. What does this suggest about the ancient Mississippi?
It probably resembled modern rivers in Alaska with a broad braided stream valley that dried up during the winter months, producing winter dust storms.
Deforestation of rain forests exposes tropical soils that are famous for their low fertility, despite the fact that they had previously hosted a lush tropical forest. Which soil type would describe these soils?
Oxisols—Soils that occur on old land surfaces unless parent materials were strongly weathered before they were deposited. Rich in iron and aluminum oxides, Oxisols are heavily leached, hence are poor soils for agricultural activity
Deposits of which of the following minerals would never be considered an ore?
Quartz
Which of the following is not a dark silicate mineral?
Quartz
Creating artificial cutoffs increases stream velocity.
True
Every metamorphic rock has a parent rock from which it formed.
True
Feldspars commonly decompose during weathering to clay minerals, silica, and soluble constituents.
True
Solifluction (the gradual movement of wet soil or other material down a slope, especially where frozen subsoil acts as a barrier to the percolation of water) occurs during the warmer summer months.
True
Subduction zones are downgoing convection cells in the earth but only carry oceanic material into the mantle.
True
The "Big Bang" is an example of theory
True
The Basin and Range region of the western United States is an excellent example of a mountainous desert landscape.
True
There is geologic evidence that the earth has experienced many episodes of mountain building and erosion.
True
Rare, but complete preservation of fossils occurs in ________.
amber
Continental shields and platforms represent ________.
areas in the interior of continents that have not experienced mountain building for billions of years
Which of the following changes may occur during metamorphism?
certain minerals may recrystallize, the rock becomes more compact, crystals may grow larger
A(n) ________ system is one in which energy moves freely in and out, but no matter enters or leaves the system.
closed
The most unreliable (variable) diagnostic property of minerals such as quartz is ________.
color
When water is pumped from a well, a depression is often produced in the water table. Such a depression is a(n) ________.
cone of depression
The main source of the dissolved load in a stream is ________.
groundwater
Recrystallization during metamorphism causes grains to grow longer in the ________.
direction perpendicular to the compressional stress
The bond between two hydrogen atoms (a covalent bond) is based on the force of attraction between ________.
electrons
The subdivision of the geologic time scale that represents the longest time span is called a(n) ________.
eon
Which of the following denotes the divisions of the geologic time scale in correct order of decreasing lengths of time beginning with the longest time interval and ending with the shortest?
eon, era, period, epoch
A(n) ________ represents a former meltwater channel or tunnel in glacial ice that was filled with sand and gravel.
esker
Which of the following best describes bedded gypsum and rock salt?
evaporates; chemical, sedimentary rocks
Which one of the following is not true of glaciers?
exist only in the Northern Hemisphere
The hydrologic cycle is not balanced right now and, as a result, sea level is rising.
false
Wood floats in water, 1 gram is defined as the mass of 1 cubic centimeter of water, a cubic centimeter of quartz weighs ~2.65 g and a cubic centimeter of galena weighs about 7.5 g. The density of these materials from highest to lowest is ________.
galena, quartz, water, wood
A cubic centimeter of quartz, olivine, and gold weighs 2.5, 3.0, and 19.8 grams, respectively. This indicates that ________.
gold has a greater specific gravity
Which of the following is not considered to be part of a typical ocean basin?
granitic intrusions
In the late 1800's various principles (original horizontality, inclusions, cross cutting relations, etc.) were established and used to ________.
organize the order in which events occurred on Earth
In order to get oil and gas in sufficient quantities to make a profit, an oil trap must exist with ________.
permeability and porosity
Climatologist define a "dry climate" as a climate in which ________.
precipitation is less than expected evaporation
An important tool in understanding the actual numerical dates of past geologic events is ________.
radioactivity
Which one of the following is not related to chemical weathering?
reactions with oxygen
Which of the following mass movements is most likely to occur in a geologic setting where the rock strata are inclined?
rockslide
How is sea ice different from glacial ice?
sea ice forms from salty ocean water, whereas icebergs, glaciers, and lake ice form from fresh water or snow. Sea ice grows, forms, and melts strictly in the ocean. Glaciers are considered land ice, and icebergs are chunks of ice that break off of glaciers and fall into the ocean. Lake ice is made from fresh water and freezes as a smooth layer, unlike sea ice, which develops into various forms and shapes because of the constant turbulence of ocean water. The process by which sea ice forms is also different from that of lake or river ice. Fresh water is unlike most substances because it becomes less dense as it nears the freezing point. This difference in density explains why ice cubes float in a glass of water. Very cold, low-density fresh water stays at the surface of lakes and rivers, forming an ice layer on the top.
Laminar flow, where water moves in approximately straight-line paths, characterizes ________.
slow-moving streams
Soil classifications, like biological classifications, use a taxonomy. The first syllable(s) gives a descriptive term and last syllable is ________.
sol
Which one of the following operates primarily in areas of permafrost (a thick subsurface layer of soil that remains frozen throughout the year, occurring chiefly in polar regions)?
solifluction
A geologist is working in an area with exposed sedimentary rocks and finds a well exposed sequence of stratified rocks. As he works through a thick sequence of limestone, he sees abundant large clam fossils that produce an interlocking texture suggesting a reef, but within the limestone section these clams disappear and the overlying limestone is made up primarily of fragments of corals. He now moves 50 km away and finds limestones interbedded with shales, and the limestones contain the same clam fossils he had seen previously 50 km away. As he continues through this section, the rocks become entirely limestone, and the clams disappear again with coral fossils above forming a reef structure. He concludes ________.
the horizon where the clams disappear occurred at the same time in the two sections when the clams went extinct
You observe a distinct, red sandstone rock body about 50 m thick that is depositionally overlain by a red shale with interbedded gypsum and you follow this boundary in the rock bodies for 1 km until you cross a fault which has displaced the boundary between the two rock bodies. You walk along the fault and see a boundary between a 50 m thick red sandstone and overlying red shale interbedded with gypsum. You conclude ________.
the second exposure of sandstone, shale and gypsum correlates to the first, and the boundary between the sandstone and shale is the same stratigraphic horizon
Intrusive igneous rocks are often characterized as coarse-grained because ________.
the slow cooling depth allows large crystals to grow
Mass wasting, a process that often occurs between weathering and erosion, involves ________.
the transport of material due to gravity
In a dry climate, weathering is significantly less than in a humid climate because ________.
there is a shortage of moisture and organic acids
Why are boulders not a mineral?
they do not have a well-defined chemical composition.
Permanent streams in desert regions are rare, and when they do occur, ________
they originate outside of the desert region and have few tributaries in the desert
Unconformities which represent a break in the geologic record of deposition are important because ________.
they represent a period of major activity.
Deep ocean trenches typically are not located adjacent to ________.
transform plate boundaries
A playa is an intermittent lake on the floor of a desert valley.
true
Arid and semiarid climates cover nearly one-third of Earth's land surface.
true
Basaltic rocks make up most of the sea floor
true
Earthflows and slumps generally involve movement of unconsolidated or weakly consolidated soil and regolith.
true
Flowing water experiences friction when it flows along the sides and bottom of its channel
true
Glassy igneous rocks form when magma cools too fast for mineral grains to grow.
true
Quartz is quite resistant to weathering and is an important component of sands in riverbeds and on beaches.
true
The change from a sediment to a sedimentary rock typically involves burying the sediment.
true
Under the right circumstances, any rock can be transformed into another type of rock in the rock cycle.
true
One of the primary goals of geology is to ___________.
understand the history of the Earth
Centuries ago quarrymen learned that when quarrying granite it was usually easiest to break the rock along a nearly horizontal surface. We now know this arises because ________.
uplift and exhumation of granites produces an unloading, which produces sheeting joints like the quarrymen used