Deck 8: Geologic Time

Question 1

Of the choices listed below, which would make the best aquifer for water content and delivery?

A) clay
B) basalt
C) granite
D) sand

Answer 1

D

Question 2

Which one of the following statements is true for an artesian aquifer?

A) In deep, stream- cut valleys, many springs are fed from artesian aquifers.
B) Upward flow from a permeable aquitard is prevented by a confining aquifer.
C) The water table in the recharge area is at a higher elevation than the top of the aquifer in the subsurface.
D) The pressure at any point in the aquifer is considerably less than the weight of the water column between the point and the top of the aquifer.

Answer 2

C

Question 3

When water is quickly produced from a well, locally the water table and aquifer experience

A) drawdown
B) artificial insemination
C) decreased flow velocity towards the well
D) artesian flow

Answer 3

A

Question 4

Which statement concerning the water table is false?

A) In humid regions, it is generally higher than lake or stream level.
B) Wetlands (swamps) occur where the water table is at the surface.
C) Its elevation is constant and does not fluctuate seasonally.
D) Its shape is a subdued replica of the overlying surface topography.

Question 5

After ice sheets and glaciers, contains the next highest percentage of Earth's freshwater that is readily accessible to humans.

A) Dasani/Coca- cola Ltd.
B) the atmosphere
C) lakes and rivers
D) groundwater

Question 6

account for the largest usage of groundwater in North America.

A) Industrial uses
B) Water for livestock and poultry
C) Agriculture and irrigation
D) Domestic and municipal supplies

Question 7

From the typical hydrologic properties of materials, which would make the best aquifer considering just the water delivery, not its turbidity or chemistry?

A) granite, limestone, sandstone
B) clay, sand, soil
C) basalt, granite, sandstone
D) basalt, gravel, limestone

Question 8

The mechanical removal or diminution of unwanted substances such as bacteria, viruses, or mineral turbidity from groundwater is termed .

A) dolomitization
B) aqua- cleansing
C) filtration
D) derriereation

Question 9

What proportion of the world's water for industrial use (cooling, solvation, transport, manufacturing etc.) is supplied by groundwater aquifers?

A) 87%
B) 40%
C) 25%
D) 50%

Question 10

Suppose a well has become contaminated by harmful bacteria such as E. coli. How can this be removed from an aquifer by natural subsurface processes?

A) dissolution, diagenesis, and fossilization
B) mechanical filtration, chemical oxidation, or assimilation by other organisms
C) overpumping for a few days until the well tests clean
D) asymptotic expansion

Question 11

What proportion of the world's water for agriculture (irrigation, greenhouses, golf courses) is supplied by groundwater aquifers?

A) 50%
B) 87%
C) 25%
D) 40%

Question 12

Which one of the following concerning artesian wells is false?

A) The aquifer is generally inclined, and it is saturated to an elevation above the point where the well penetrates the aquifer.
B) When the well penetrates the aquifer, the water rises to the bottom of the aquitard above the aquifer.
C) The well penetrates an aquifer underlain by an impermeable bed.
D) The well penetrates an aquifer overlain by an aquitard.

Question 13

Which one of the following is not a speleothem?

A) dripstone
B) geyserite
C) stalactite
D) stalagmite

Question 14

Under most conditions, groundwater moves .

A) only between rainstorms by drainage
B) very little as most of it is stagnant and all at a single level
C) very quickly as it flows predominantly in open cavernous underground rivers
D) at slow but variable rates generally less than a few metres per day

Question 15

Where are the most famous geyser in the world?

A) Yellowstone National Park, U.S.
B) Banff Hot Springs in the Canadian Rockies
C) Iceland's Groundwater Preserve
D) Ottawa's famous bombastic effluent

Question 16

The longest known cave system in the world is with more than 540 km of passages.

A) Mammoth Cave, Kentucky
B) Carlsbad Caverns, New Mexico
C) Lechuguilla Cave, New Mexico
D) Castleguard Cave, Alberta

Question 17

In Darcy's Law for flow velocity written as: V = (K/n) × (h/l), what does h/l stand for?

A) porosity
B) capacity
C) permeability
D) hydraulic gradient

Question 18

Which of the following describes the configuration of an unconfined water table around a pumping well?

A) a bad impression
B) cone of depression
C) inverted cone head
D) depression withdrawal

Question 19

Groundwater is tightly held by surface tension to mineral grains or other soil particles in the

A) zone of saturation
B) aquiclude
C) gitchee gumee
D) capillary fringe

Question 20

In general, how do we know where the water table is located?

A) Just look at a regional map; it is the same elevation everywhere.
B) By drilling wells, measuring the water levels, and contouring those elevations.
C) It is always at the base of the soil zone; just measure the soil thickness.
D) Look at the regional streams and measure their depths; that's where the water table is.

Question 21

In Jules Verne's classic tale "Journey to the Centre of the Earth", how did the explorers return to the surface?

A) by riding up in a geyser
B) by riding on the back of a pterodactyl
C) by climbing up a volcano's vent
D) by riding up an artesian well

Question 22

What geo- environmental condition did not contribute to the May 2000 Walkerton tragedy?

A) a nearby unsealed test well
B) a fast delivery fractured bedrock aquifer
C) a shallow overburden with little filtration capacity
D) a buried artesian aquifer

Question 23

Excessive groundwater withdrawals can cause .

A) porosity in the aquifer to increase as the water is removed
B) the cone of depression to invert
C) the water table to decline in elevation and land to subside
D) uplift through expansion of the dewatered aquifer

Question 24

Most hot springs that are just a little warmer than mean annual temperature (6°- 9°C) acquire their heat .

A) because most of the groundwater is millions of years old from when the Earth's climate was warmer
B) because there are young intrusions everywhere at depth, always warming up the crust
C) by deep circulation through progressively warmer rocks at depth (~2°C per 100 m)
D) because most of the recharge from rainfall is in the warmer summer months

Question 25

Which of the following is not a general characteristic of groundwater?

A) constant temperature year round
B) rarely contains dissolved constituents
C) supply is independent of short droughts
D) rarely contains suspended sediment

Question 26

Where does the majority of groundwater originate?

A) by primordial outgassing from magmatic intrusions
B) by infiltration from precipitation that falls on the land
C) released from minerals undergoing diagenetic and metamorphic dehydration reactions
D) it was deposited along with the sediments that contain it

Question 27

Which reservoir of the hydrosphere would you describe as containing only a small fraction of Earth's freshwater that is well mixed and exchanged continually?

A) the atmosphere
B) groundwater
C) lakes and reservoirs
D) soil moisture

Question 28

An artesian well is one in which .

A) the well is horizontal and the water table is perched
B) water rises above the top of the aquifer without any pumping
C) pressurized groundwater rises from a deep, unsaturated aquifer
D) the water is warm, fairly saline, and recharged by an affluent stream

Question 29

Which of the following best describes how geysers erupt?

A) Expansion from heating forces some warm water out the top of the geyser system; with this reduction in pressure, superheated water in a saturated, natural conduit suddenly boils, sending a plume of steam and hot water into the air above the vent.
B) Water below the water table slowly boils causing a plume of condensed water vapour in a vertical crack or natural conduit to rise above the vent.
C) Water suddenly boils in disconnected voids and cracks above the water table, causing the aquifer to explosively fragment.
D) All of the water in the geyser chamber slowly heats until it reaches the boiling point, whereupon it starts erupting until it boils dry.

Question 30

Which would have the highest porosity?

A) a mixture of well rounded sand and gravel particles
B) unfractured crystalline limestone
C) angular gravel of variable sizes
D) a uniform sized, well rounded sand

Question 31

A perched water table develops when .

A) an aquitard below the regional water table lies above a horizontal aquifer
B) an aquifer above the regional water table is overlain by a horizontal aquitard
C) an aquifer below the regional water table is underlain by a horizontal aquitard
D) a horizontal aquitard above the regional water table lies below an aquifer

Question 32

The fastest groundwater flows would be expected for an aquifer with .

A) high porosity and many small pores
B) high specific retention and low permeability
C) low gradients and low permeability with a few very large pores
D) high gradients (hydraulic head) and high permeability

Question 33

Which would be the most prone to surface contamination from runoff and infiltration?

A) wells a few hundred metres uphill from septic systems in rugged mountainous terrain
B) deep confined aquifers directly below contaminated sites
C) shallow aquifers with thin soils or unconsolidated coarse overburden
D) an aquifer with a thick, overlying, unsaturated vadose zone

Question 34

Considering their relative density and solubility in water, how would hazardous substances behave that accidentally entered a groundwater system?

A) Sulphuric and nitric acids would sink to the bottom of the aquifer; kerosene would accumulate as a layer just below the water table.
B) Gasoline and kerosene would float on the water table; ethyl alcohol would dissolve and disperse in the groundwater.
C) E- coli bacteria may build up in groundwater but can be diluted or rinsed away with sufficient input of natural surface waters such as farm runoff.
D) Gasoline and kerosene would float on the water table, but most pesticides break down chemically when they reach the water table.

Question 35

For unconfined aquifers, what hydrologic factor is approximated by the slope of the water table?

A) porosity head
B) hydraulic competency
C) hydraulic gradient
D) affluent decline

Question 36

Of the choices listed on flow characteristics alone, if the following aquifers became contaminated, which would remain contaminated for the longest time?

A) sand
B) clay
C) gravel
D) limestone

Question 37

is a measure of the connectedness of pore spaces, which controls the ease (or difficulty) of groundwater transmission through a porous material.

A) Permeosity
B) Portability
C) Permeability
D) Potability

Question 38

Which of the following can logically be concluded by speleothems/dripstone hanging from a cave roof?

A) The cave roof was below the water table when the speleothems formed.
B) The cave roof was below the water table sometime after the speleothems had formed.
C) The cave floor was above the water table, and the roof was below the water table when the speleothems formed.
D) The cave roof was above the water table when the speleothems formed.

Question 39

The zone of aeration .

A) lies below the capillary fringe
B) lies above the water table
C) has pore spaces which are filled with water
D) is a well- oxygenated, shallow aquifer

Question 40

Which of the following geologic materials would have the highest groundwater velocities and be least effective in removing unwanted pollutants from the water?

A) limestone with numerous solution channels and fractures widened by dissolution
B) sandstone; well- cemented with a few, widely spaced vertical fractures
C) a sandy loam soil with high organic carbon content
D) lakebeds consisting of unconsolidated very fine- grained sand and silt

Question 41

In Darcy's Law for flow velocity written as: V = (K/n) × (h/l), what does K stand for?

A) porosity
B) capacity
C) hydraulic gradient
D) permeability

Question 42

The term karst topography was first used in .

A) eastern Canada in areas of fractured igneous and metamorphic rocks
B) India near the southern foothills of the Himalayan Mountains
C) Australia for the extremely dry interior area near Alice Springs
D) the Republic of Slovenia

Question 43

Geysers periodically boil and erupt because .

A) new groundwater flows in to replace that lost in the prior eruption, this takes time
B) each injection of hot magma at depth triggers another episode of boiling in groundwater
C) the god Vulcan is at work at his subterranean forge
D) great pressures from deep water- filled chambers prevent water from boiling until higher temperatures are reached; eventually enough heat is supplied by the hot (volcanic) rocks to expand the water and let it boil anyway

Question 44

Which one of the following concerning stalactites and stalagmites is false?

A) Stalagmites form on the floors of caves below the water table.
B) Both are composed of calcium carbonate.
C) Both are forms of dripstone; stalactites hang from the ceiling, stalagmites grow upward from the cavern floor.
D) Stalactites are deposited from water dripping from the ceiling of an aerated cavern.

Question 45

Of the choices listed below, which would make the best aquitard?

A) granite
B) clay
C) sand
D) basalt

Question 46

Which common, rock- forming mineral or mineral group is most readily dissolved by groundwater?

A) calcite
B) feldspars
C) clay minerals
D) quartz

Question 47

The water table is .

A) a flat underground layer of partly saturated rock
B) a boundary between unsaturated bedrock below and saturated bedrock above
C) a boundary between saturated soil/rock below and unsaturated soil/rock above
D) a boundary between unsaturated bedrock and an underground river

Question 48

How are travertine or silica deposits formed from boiling geysers and related hydrothermal systems?

A) As pressures increase less mineral matter is soluble.
B) By introduction of cold fresh recharge water which quenches the system.
C) Boiling off steam forces the remaining hot solution to be saturated or supersaturated as the same mineral content is now concentrated in less water and it precipitates.
D) More gases enter the system once boiling starts forcing precipitation.

Question 49

are specific features of karst topography.

A) Streams flowing into depressions and continuing underground
B) Perched water table springs on hillsides
C) Perennial streams fed by large springs
D) Numerous artesian wells in a given area

Question 50

The direct energy causing groundwater flow from one place to the other is .

A) solar power driving wind and evapotranspiration
B) surface tension and capillary forces between water molecules and mineral surfaces
C) gravity due to the weight of water and elevation differences
D) precipitation differences between localities (groundwater flows towards drier areas)

Question 51

are characteristics found in all good aquifers.

A) High porosity and high permeability
B) High potability and high portability
C) Low porosity and low permeability
D) Low permeability and high potability

Question 52

Other than increased pressure, geysers and hot springs tend to get superheated because of dissolved mineral matter which builds deposits of as some of the water boils away leaving supersaturated brines.

A) calcareous tufa (travertine) and siliceous sinter (geyserite)
B) halite and gypsum
C) corundum and feldspar
D) sponge reefs

Question 53

How do we know which direction ground water will flow?

A) It is generally the same as the prevailing wind direction.
B) It flows perpendicular to the water table contours, in a downhill direction.
C) It is parallel to local stream flow, just slower.
D) Dye or chemical tracer tests are required, often requiring multiple wells and months.

Question 54

What force pushes groundwater from pore to pore below the water table?

A) permeability steepness
B) surface tension
C) hydraulic gradient
D) integrated saturation impulse

Question 55

Which one of the following logically explains why parts of some cavern systems are aerated?

A) The main water table is perched above the cavern roofs, allowing air to enter.
B) A nearby, downcutting stream lowered the water table after the caves had formed.
C) The caves formed and later the water table rose.
D) Streams formerly flowing on the surface were diverted into the groundwater system through sinkholes.

Question 56

is the volume of voids or open space in a rock or unconsolidated material.

A) Saturation index
B) Porosity
C) Capillarity
D) Permeability

Question 57

What is the belt of soil moisture?

A) at shallow depth, a surface film of water retained on soil, sediment, or organic particles
B) where permafrost has melted leaving completely saturated soils
C) the layer in the ground with the largest roots, just beneath the zone of saturation
D) a viable farming region across southern Alberta and Saskatchewan without rain

Question 58

What is the relationship between drawdown and the cone of depression associated with a pumping well?

A) Drawdown is dealing from the bottom of the deck in a crooked poker game.
B) The drawdown is the diameter of the cone of depression measured at the elevation of the original water table.
C) The drawdown is the percentage of available water in the aquifer that has already been used.
D) Drawdown is the distance between the original water table and the water level in the well.

Question 59

Which of the following statements is false for an area subsiding because of excessive pumping of groundwater?

A) The aquifer is consolidated bedrock.
B) Water table is substantially lowered.
C) Dewatered aquifer material compacts.
D) Effluent streams may dry up.

Question 60

The porosity of typical unconsolidated sediments and sedimentary rocks is .

A) <0.1%
B) 1- 5%
C) 6- 9%
D) 10- 50%

Question 61

A is the icicle- like speleothem that grows down from the roof of a cavern.

A) slagmite
B) stalagmite
C) dingleberry
D) stalactite

Question 62

Where does the majority of fresh groundwater reside?

A) flowing in large underground rivers
B) as superheated steam in vast hotspring and geyser fields
C) in pores within soils and sediments or in fractures in rocks
D) as large stationary bodies in enormous underground caverns

Question 63

Henry Darcy was .

A) a hydrogeologist who built caissons on the floor of the Fraser River to provide the first filtered water for the city of Richmond, BC
B) an Oxford educated English aristocrat who studied water flow while designing canals in the Midlands for Charles II
C) a French engineer who studied the flow of water in pipes and filter beds to provide a municipal water supply for Dijon, France
D) an engineer for the Hershey Co. who studied the flow of molten chocolate through beds of crushed peanuts (and for whom the Oh Henry candy bar was named)

Question 64

An artesian well is one in which .

A) water has enough head to rise above the top of the aquifer without any pumping
B) pressurized groundwater rises from a deep, unsaturated aquifer
C) the well is horizontal and the water table is perched
D) the water is warm, fairly saline, and recharged by a stream

Question 65

An aquifer is .

A) a saturated, porous, and permeable layer or stratum that has high water flow
B) the best place to dispose of soluble toxic waste
C) a layer or stratum in which groundwater flows downward to the water table
D) an unsaturated bed or stratum below a spring

Question 66

What proportion of the world's drinking water is supplied by groundwater aquifers?

A) 25%
B) 50%
C) 87%
D) 40%

Question 67

An area exhibiting tower karst features would likely have .

A) isolated steep sided hills that are riddled with cave passages
B) cave formations stacked up throughout a series of different limestone beds
C) caves with open bullet shaped rooms reaching up several stories
D) intricate three dimensional lacework of interlocking soda straws reaching up from the cave floor

Question 68

The travertine hot spring deposits at Mammoth Hot Springs, Yellowstone National Park, are more spectacular than most. Around the immediate area are either unconsolidated glacial deposits or Tertiary volcanics. What rock probably lies deeper beneath the hot springs to account for all the travertine deposits?

A) shale
B) quartzite
C) limestone
D) rhyolite

Question 69

A water table is the .

A) boundary between the zone of saturation above and partly saturated zone below
B) boundary between the zone of aeration above and zone of saturation below
C) bottom boundary surface of the zone of saturation above an aquitard
D) boundary between the zones of aeration and superposition

Question 70

Which reservoir of the hydrosphere would you describe as containing the largest fraction of Earth's liquid freshwater?

A) lakes and reservoirs
B) glaciers and ice sheets
C) groundwater
D) soil moisture

Question 71

Two ways that sink holes can form are by and .

Question 72

Sinkholes can form .

A) in humid regions underlain by carbonates, salts, or gypsum
B) in any calcium bearing bedrock
C) only in limestones
D) only in high elevation areas with sufficient gradient to carry away dissolved materials

Question 73

In a uniformly porous and permeable material, groundwater tends to flow along curved paths

A) as a compromise between the downwards pull of gravity and movement towards areas of lower pressure
B) because this is the shape of the overlying land
C) because this is the shape of most sedimentary bodies
D) because this is the shortest distance between recharge and discharge

Question 74

In three words, describe the shape of the water table around a pumping well.

Question 75

Given the right kind of bedrock, cave formation occurs most readily .

A) in temperate to high latitude settings where seasonal freeze- thaw fractures the bedrock
B) beneath the ocean
C) in tropical areas with high rainfall and abundant vegetation
D) in arid and semi- arid regions with strongly alkaline surface waters

Question 76

What proportion of groundwater in the US and western Canada is used for agricultural irrigation (center- spot, commercial greenhouses, golf courses)?

A) 0- 5%
B) > 65%
C) 15- 25%
D) 45- 55%

Question 77

would be the best medium to naturally remove sewage pollutants.

A) Well- sorted, coarse gravel
B) Slightly clayey sand
C) Fractured granite
D) Limestone with solution channels and caverns

Question 78

A stream flowing into a sinkhole is called a .