ASBOG

Question 1

A description of a particular ground motion shown on a graph of spectral acceleration versus period (in seconds)

Answer 1

Response Spectrum

Question 2

According to the Unified Soil Classification System, gravels have a grain size greater than what diameter?

Answer 2

No. 4 Sieve or 4.75 mm

Question 3

are layers that have been deposited simultaneously over large areas. Good examples are
volcanic ash, beds rich in fish scales, oysters or corals; serves to facilitate correlation in field mapping or subsurface studies

Answer 3

Key Bed

Question 4

Below _____ of oil saturation, the reservoir will produce mostly water.

Answer 4

60%

Question 5

According to the Unified Soil Classification System, clay or silt would contain particles less than what diameter?

Answer 5

Sieve No. 200 (0.075 mm)

Question 6

Is now used as an industrial substitute for asbestos
a. Wollastonite
b. Wolframite
c. Wurtzite
d. Wulfenite

Answer 6

Wollastonite

Question 7

A braided stream usually indicates that the stream
a. is old
b. is at grade
c. has greater competency than capacity
d. has greater load than capacity

Answer 7

has greater load than capacity

Question 8

Which of the following soils classified by USCS would be the best aquitard?
a. SP
b. ML
c. CL
d. SW

Answer 8

Lean Clay (CL)

Question 9

Which deposit is most closely associated with rare earths?
a. a titaniferous magnetite deposit
b. a fissure vein gold-quartz
c. a strata-bound uranium deposit
d. a shallow, low temperature hydrothermal deposit

Answer 9

a fissure vein gold-quartz

Question 10

Given 0.65 ft3 of a soil sample weighing 36.2 lbs, with a moisture content of 15%, what is the dry density of the soil? Show solution.

Answer 10

The moisture content is given as 15%, which means that 15% of the weight of the dry soil is water.

W total = W dry + W water
36.2 = W dry + 0.15 (W dry)
W dry = 36.2/1.15 = 31.48 lbs

density (p) = weight/volume
p = 31.48/0.65 = 48.4 lbs/ft3

Question 11

What geophysical technique would you use to investigate a skarn?
a. gravity
b. seismic reflection
c. seismic refraction
d. magnetics

Answer 11

magnetics

Question 12

Caves found within limestone result from
a. groundwater which remains in one place and does not circulate
b. water moving off speleothems
c. slowly circulating water below the water table
d. artesian conditions

Answer 12

slowly circulating water below the water table

Question 13

Plagioclase, quartz, biotite and hornblende would most likely be found in a
a. andesite
b. dacite
c. syenite
d. trachite

Answer 13

Answer: Dacite

a. andesite - is also an intermediate volcanic rock but generally contains less quartz than dacite. It typically features more plagioclase and less biotite and hornblende compared to dacite.
c. syenite - is an intrusive igneous rock primarily composed of alkali feldspar with minor amounts of plagioclase and very little to no quartz (usually less than 5%).
d. trachyte - is a volcanic rock that primarily consists of alkali feldspar with little to no quartz.

Question 14

Convergent plate margins are characterized by
a. thin shelf deposits, thick clastic slope and rise deposits
b. interlocking faulted crustal blocks with small depositional basins
c. melanges of feldspathic sandstone, siltstone and shale
d. quartzose sandstones associated with aluminous clay-rich shales

Answer 14

melanges of feldspathic sandstone, siltstone and shale

Question 15

How does “sandy limestone” be depicted in a lithologic log drawing?
a. sandstone symbols with scattered limestone symbols
b. addition of sand symbol within the blocks of the limestone symbol
c. addition of layers of sandy symbol in the typical limestone symbol
d. limestone symbol with a descriptive modifier

Answer 15

addition of sand symbol within the blocks of the limestone symbol

Question 16

This ratio states that for every meter of fresh water in an unconfined aquifer above sea level, there will be forty meters of fresh water in the aquifer below sea level.

Answer 16

Ghyben-Herzberg Theory

Question 17

The storage coefficient and transmissivity are two important parameters calculated by using the

Answer 17

Theis equation

Question 18

Name three main physical properties of rocks logged by wirelines:
a. electrical, nuclear, acoustic
b. electrical, nuclear, water content
c. shear wave velocity, strength, water content
d. shear wave velocity, fracture patterns, strength

Answer 18

electrical, nuclear, water content

Question 19

Which of the following rocks make poor aggregate for use with Portland Cement?
a. chert
b. basalt
c. quartz
d. pumice

Answer 19

chert

Question 20

Storage coefficient or storativity in an unconfined aquifer is equal to
a. specific storage
b. specific yield
c. field capacity
d. specific retention

Answer 20

Specific yield

Question 21

Soft sediments are best sampled with a ______ to obtain undisturbed samples.
a. Split Spoon
b. Shelby Tube
c. Modified California sampler
d. Sieve

Answer 21

Shelby Tube

Question 22

Which geophysical technique would not be used to investigate a massive sulfide ore body?
a. seismic refraction
b. gravity
c. induced polarization
d. resistivity

Answer 22

Answer: Seismic refraction - primarily used to determine subsurface geological structures.

b. gravity - Gravity surveys can detect massive sulfide deposits due to their density differences compared to surrounding rocks
c. induced polarization - it measures the electrical chargeability of the ground, which is often high in areas with sulfide minerals.
d. resistivity - Similar to induced polarization, resistivity surveys can identify conductive zones associated with massive sulfides

Question 23

What does a slug test measure?

Answer 23

Localized values of permeability

Question 24

Groundwater that flows through different pores at different rates and flow paths that vary in length is caused by?

Answer 24

Dispersion

Question 25

Which mineral family produces the most clay minerals during weathering processes?

Answer 25

Feldspar

Question 26

What is a krotovina?

Answer 26

A tunnel-like structure created by a burrowing animal and filled with soild material from another horizon.

Question 27

A type of trace fossil that represents root structures preserved in sediment. These structures can indicate past vegetation and soil conditions, similar to how krotovinas indicate animal activity in the soil.

Answer 27

Rhizolith

Question 28

Marks left on substrates as a result of predation, such as drill holes in shells caused by predators.

Answer 28

Predation Traces (Praedichnia)

Question 29

Structures formed as organisms flee from predators or unfavorable conditions, often leading to new habitats.

Answer 29

Escape Traces (Fugichnia)

Question 30

In which soil horizon would you find hardpan?

Answer 30

B

Question 31

If you create a cross section at a scale of 1” = 2000’ from a 1:24,000 scale map, what is the exaggeration?

Answer 31

1 in (map) = 24,000 in (real life)

24000in (1ft /12in)= 2000 ft

Note: (“) is inch, (‘) is foot
Exag = VS/HS = 2000’/2000’
Exaggeration is 1x

Question 32

A stratigraphic sequence that is composed, from the bottom of the column up, of limestone, gypsum and halite would indicate what type of environment?
a. Dry temperate
b. Humid tropical
c. Dry tropical
d. Humid temperate

Answer 32

Answer: Dry Tropical Environment

Limestone typically forms in warm, shallow marine environments where calcium carbonate precipitates, often indicating a tropical or subtropical climate.
Gypsum is an evaporite mineral that forms in arid conditions where water evaporates, concentrating sulfate and calcium ions. Its presence suggests a transition to drier conditions.
Halite also forms through evaporation in very arid environments. It usually precipitates after gypsum as the salinity of the remaining water increases.

Question 33

How does the thickness of the aquifer affect the storage?
a. The thicker the aquifer the greater the storage
b. The thinner the aquifer the greater the specific storage
c. It is not affected by the quifer thickness
d. You use the specific capacity to determine the specific storage

Answer 33

The thicker the aquifer the greater the storage

Question 34

A clay whose shear strength is decreased to a fraction of its former value be remolding is called

Answer 34

Sensitive clay

Sensitivity measures the loss in strength of soils as a result of remolding, and it is defined as the ratio of the unconfined compressive strength of the clay in its undisturbed state to that in its remolded state.

Question 35

In a stratigraphic section that has, from bottom up, cross-bedded sandstone, ripple-marked sandstone, claystone and siltstone interbedded with thin sand lenses, the probable depositional environment was
a. delta
b. meandering stream
c. a dune to lagoon transition
d. alluvial fan

Answer 35

a dune to lagoon transition

Question 36

Magnetic declination is constantly changing; therefore, if you have an old map on which you will be placing data obtained in the field you will need to ascertain the correct declination before measuring any orientations. What is the best way to obtain a local magnetic declination?
a. By orienting the map along a straight road and measuring the orientation with a compass
b. By checking references to establish the polar wandering since the date was established
c. By contacting the USGS
d. By applying an annual correction constant to the published declination

Answer 36

By orienting the map along a straight road and measuring the orientation with a compass

Question 37

What would be the best way to establish the depth to the contact between two soil materials with similar drilling characteristics?
a, Downhole e-logging
b. Watch cuttings and drilling fluids
c. Split the unsampled interval in half and draw the contact with a dashed line

Answer 37

Answer: Watch cuttings and drilling fluids - The characteristics of the cuttings (such as color, texture, and composition) can indicate when one soil type transitions to another. Additionally, changes in the properties of the drilling fluid can also signal a change in soil material.

Downhole e-logging- is useful for obtaining continuous data about subsurface conditions but may not be as effective.
Splitting the unsampled interval in half and drawing the contact with a dashed line- is not a reliable method, as it does not provide empirical evidence of the actual contact.

Question 38

You are investigating a site in which the aquifer water is contaminated at depths of 200 to 300 feet. What drilling method would result in the best quality groundwater data if expense is not a concern?
a. Rotary Wash
b. Cable Tool
c. Hollow-stem Auger
d. Jet Drilling

Answer 38

Answer: Cable Tool- does not use circulating fluids, which can spread contamination

Rotary Wash: This method uses circulating fluids that can introduce contaminants and may not provide as clean a sample as cable tool drilling.
Hollow-Stem Auger: While also effective for environmental work, it may still involve some fluid usage and might not be as effective as cable tool drilling in certain contexts.
Jet Drilling: Similar to rotary methods, jet drilling can also introduce contaminants into the groundwater.

Question 39

Lab analyses of a soil reveal that 75% of soil is smaller than the No. 4 sieve, 61% passes through the No. 200 sieve, the liquid limit is 62, and the dry strength and toughness are high. What would be the likely origin of this material?
a. Aeolian deposits
b. Fluvial deposits
c. Lake bed deposits
d. Shallow marine deposits

Answer 39

Answer: Lake bed deposits

More than 50% passes through No. 200 sieve (clay or silt), high liquid limit (moisture content)

Question 40

What mining method would be appropriate for a disseminated ore that is in relatively weak and fractured rock?
a. strip mining
b. room and pillar
c. square-set stoping
d. block caving

Answer 40

Answer: Block Caving

Strip Mining: Typically used for horizontal, shallow deposits and not ideal for weak, fractured rock.
Room and Pillar: More suited for thicker, more competent deposits where pillars can support the roof.
Square-Set Stoping: Generally used in steeply dipping, high-grade deposits where support is needed to prevent collapse.

Question 41

A coal bed in downhole geophysical logs are characterized by _____ gamma, _____ density, _____neutron, and _____ resistivity log

Answer 41

Answer: Low gamma, Low density, Low or High neutron, High resistivity

Gamma Log: Coal generally has low radioactivity, resulting in low gamma readings compared to surrounding rock types like shale.
Density Log: Coal is less dense than many other sedimentary rocks, leading to lower density values on the log.
Neutron Log: Coal contains organic material with high hydrogen content, which results in high neutron readings. But it can be low because coal has a lower hydrogen content than water-saturated rocks.
Resistivity Log: Coal is a poor conductor of electricity, so it typically shows high resistivity values compared to more conductive materials like water-saturated rocks.

Question 42

Which of the following soil types is most appropriate as roadbed subgrade?
a. GP
b. SP
c. SC
d. MH

Answer 42

GP (Poorly-graded Gravel)

Question 43

What is the minimum size for a reliable RQD calculation?

Answer 43

NX (Core diameter: 2.15 in) which is slightly larger than NQ (Core diameter: 1.88 in)

Question 44

Horizontal drains are used for:
a. pumping wells
b. sumps
c. stabilization of hillslopes
d. dewatering a slurry trench

Answer 44

Answer: Stabilization of hillslopes

Pumping wells: These typically require pumps to extract water, whereas horizontal drains function passively without pumps.
Sumps: Sumps collect water but do not actively drain it; horizontal drains facilitate drainage away from slopes.
Dewatering a slurry trench: This often involves vertical systems or vacuum pumps to manage groundwater, unlike horizontal drains which rely on gravity

Question 45

What type of soil sampler would you use to obtain an undisturbed sample of very stiff clay?
a. SPT
b. Pitcher barrel sampler
c. piston sampler
d. core barrel

Answer 45

Answer: Pitcher barrel sampler- Utilizes a thin-walled tube pushed into the soil without driving, maintaining sample integrity by preventing fluid contamination

Standard Penetration Test- Involves dropping a weight on a split-barrel sampler to penetrate the soil, which disturbs the sample significantly
Piston Sampler- Employs a piston mechanism to seal the sample but is less effective in very stiff soils due to high insertion forces
Core Barrel- A rotating outer barrel cuts through soil while an inner stationary tube collects samples, primarily used for softer materials, but it can disturb stiff clays

Question 46

The geologic hazard which could cause catastrophic damage to low density residential development built to current building codes
a. potentially unstable slopes
b. high water table area
c. faults
d. debris flows

Answer 46

Answer: Debris Flows

Potentially unstable slopes- While they can lead to landslides, debris flows are often more destructive due to their speed and volume.
High water table area- This can cause flooding or foundation issues but typically poses less immediate risk than debris flows.
Faults- While earthquakes can cause significant damage, buildings designed to code can often withstand seismic impacts.

Question 47

Which type of soil is best for dam embankment shells?
a. OL
b. MH
c. GW
d. SW

Answer 47

Answer: GW- provide excellent drainage and stability

OL- Unstable because it’s organic
MH- Low shear strength and more susceptible to erosion
SW- Excellent drainage but does not provide good stability

Question 48

Which of the following geophysical logs allows the direct measurement of porosity?
a. gamma-gamma
b. neutron
c. none
d. resistivity

Answer 48

Answer: None

Gamma-gamma logs measure density but not porosity directly.
Neutron logs estimate porosity based on hydrogen content in pore fluids, but they are calibrated to specific lithologies.
Resistivity logs measure the electrical resistance of formations, which can infer porosity indirectly but do not provide a direct measurement.

Question 49

What type of tunnel support would be best for squeezing ground conditions?
a. rock bolting
b. invert struts
c. none
d. precast concrete liners

Answer 49

Answer: Invert Struts are horizontal supports placed at the tunnel’s invert (bottom) to resist upward heave and manage lateral pressures. They help distribute loads and stabilize the tunnel during ground deformation, making them particularly effective in squeezing conditions where ground movement is significant

Rock bolting: While useful for general support, it may not adequately address the dynamic pressures in squeezing conditions.
Precast concrete liners provide a rigid support structure but may not accommodate the continuous deformation typical in squeezing ground conditions, potentially leading to cracking or failure.

Question 50

Young’s modulus is also known as

Answer 50

Modulus of Elasticity

Question 51

Point load tests are commonly used
a. to empirically obtain uniaxial compressive strength
b. to test the level of weathering
c. to measure in-situ strengths
d. on core that is one inch in diameter

Answer 51

Answer: To empirically obtain uniaxial compressive strength. Point load tests measure the load required to break a rock specimen. The results can be correlated with UCS through empirical relationships

To test the level of weathering- Point load tests do not specifically measure weathering levels; they focus on strength characteristics of intact rock.
To measure in-situ strengths- While point load tests can give an indication of rock strength, they are typically performed on prepared samples rather than directly in situ.
On core that is one inch in diameter- Point load tests are not limited to one-inch cores.

Question 52

What are rippable rocks?

Answer 52

Rippable Rocks are those that can be mechanically excavated using ripping equipment, typically due to their physical properties such as strength, weathering, and fracturing. Non-rippable rocks have higher seismic velocities (>3000m/s) generally indicate harder and more competent rock types, necessitating alternative excavation methods such as blasting.

Question 53

If a fresh water aquifer has a hydraulic conductivity (K_w) of 1000 ft/day, what is its conductivity (K) to a solvent with a density (ρ_s) of 1.65 grams per cubic cm and a viscosity (μ_s) of 0.07 grams per cm-sec? Density of freshwater (ρ_w) 1 g/cm3. Viscosity of freshwater (μ_w) 0.01 g/cm-sec.

Answer 53

K = K_w • (ρ_s/ρ_w) • (μ_w/μ_s)

No need to convert metric to english, because metrics are cancelled out

K = 235.8 ft/day

Question 54

How long will a solvent traveling at 235 ft/day to be detected at a site 5 miles away in the downgradient direction?

Answer 54

Time = Distance/Velocity
5 miles = 26,400 ft
Time = 26,400/235

Time = 112 days

Question 55

When investigating an active fault that is relatively close to the surface to determine the impact it would have on planned structure, it is important to locate it precisely and determine recency of activity. In order to accomplish this which of the following field methods would be most appropriate?
a. GPR and electrical resistivity survey
b. seismic refraction and trenching
c. drilling/sampling and GPR
d. GPR and seismic refraction

Answer 55

Answer: Seismic Refraction (This method uses seismic waves to identify subsurface structures, including faults. It helps determine the depth, geometry, and potential impact of the fault on structures) and trenching (allows for direct observation of the fault’s characteristics and provides evidence of recent activity by exposing the fault plane and any associated displacements or features)

Ground Penetrating Radar (GPR) may struggle with depth penetration in certain geological conditions
Resistivity Surveys are more suited for mapping broader geological features rather than precise fault analysis.
Drilling/Sampling- While drilling can provide samples for laboratory analysis, it does not directly visualize fault activity or structure like trenching does

Question 56

High altitude vertical photos would be good for mapping regional scale geologic features in an arid environment such as Basin and Range Province because there is little to no vegetation. What method would work best in the northeastern US?
a. High-altitude color infrared
b. LIDAR
c. SRTM
d. Side-looking airborne radar (SLAR)

Answer 56

Northeastern US- mountainous area, glaciers
Answer: LIDAR (Light Detection and Ranging) - provides detailed topographic data over large area that can reveal subtle geological features such as fault lines, erosion patterns, and glacial landforms. LIDAR can penetrate tree canopies, allowing for accurate mapping of ground features in forested areas.

High-altitude color infrared: This method is useful for vegetation analysis and land use mapping, but not for geological features
SRTM (Shuttle Radar Topography Mission): While SRTM provides elevation data globally, its resolution is coarser compared to LIDAR. It may not capture the fine details needed to identify specific geological features or recent fault activity.
Side-looking airborne radar (SLAR): SLAR can be effective for mapping large-scale features but may not offer the same level of detail as LIDAR in detecting small-scale geological variations or faults.

Question 57

SP logs are widely used for logging wells because:
a. their interpretation is quite simple for freshwater aquifers
b. they provide information on lithology and salinity of interstitial water
c. the salinity of the borehole fluid does not affect them
d. they are usually run with a nuclear log

Answer 57

Spontaneous Potential (SP) Logs, commonly referred to as SP logs, are a type of well logging measurement used primarily in the oil and gas industry to characterize rock formations. They measure the natural electrical potential difference between a movable electrode in the borehole and a reference electrode at the surface. The SP log is particularly useful for identifying permeable formations (that correlate with differences in salinity), determining formation water resistivity, and correlating geological layers across different wells.

Question 58

What defines “hardness” in water?

Answer 58

Concentration of dissolved minerals, mainly calcium and magnesium

Question 59

What is the optimum hardness range for domestic use of water?
a. <50 mg/L
b. 50-150 mg/L
c. 150-300 mg/L
d. >300 mg/L

Answer 59

Answer: 60-120 mg/L (closest is B)

Question 60

What is the best reason why we need to keep the optimum level of hardness in domestic water?
a. energy efficiency to pump light water
b. scaling in pipes and appliances, affecting efficiency and longevity
c. adverse health effects of hard water
d. enhance taste and improve health

Answer 60

Scaling in pipes and appliances, affecting efficiency and longevity

Minor reason: Enhance taste and improve health (too low hardness value would be not palatable)

Question 61

Thiobacillus ferroxidans is a bacteria that
a. can solubilize phosphorus and produce enzymes that contribute to mineral weathering
b. are involved in the bioremediation of contaminated environments and can reduce heavy metals (like uranium) and minerals through electron transfer processes
c. oxidizes sulfur and is crucial in bioleaching processes, where metals are extracted from ores. It produces sulfuric acid as a byproduct, which can enhance the solubility of metal ions, facilitating their extraction.
d. accelerates the process of acid mine drainage development when pH drops
e. are important in the sulfur cycle and can convert sulfate into sulfide.

Answer 61

Answer: Accelerates the process of acid mine drainage development when pH drops

a. Bacillus species
b. Geobacter species
c. Acidithiobacillus thiooxidans
e. Desulfovibrio species

Question 62

The effectiveness of the remediation methods that would reduce the impact of acid mine drainage from an abandoned mine for metallic sulfides would be influenced most by
a. rainfall
b. the presence of deep soils
c. the presence of bacteria
d. controlling the pH

Answer 62

controlling the pH

Question 63

What remote sensing method would you use to investigate a region to obtain detailed high resolution images of the ground surface for modeling flood-prone areas where elevation data is critical?
a. LIDAR
b. SLAR
c. NOAA
d. Multispectral Remote Sensing

Answer 63

Answer: LIDAR (Light Detection and Ranging) due to its high resolution, ability to penetrate vegetation, rapid data collection capabilities, and compatibility with hydrodynamic models.

SLAR (Side-Looking Airborne Radar): While SLAR can provide valuable information about surface conditions, it typically lacks the resolution
NOAA (National Oceanic and Atmospheric Administration): NOAA provides valuable data related to weather and ocean conditions but is not a remote sensing method itself
Multispectral Remote Sensing: This method captures data across various wavelengths to analyze land cover and vegetation but does not provide the precise elevation data needed for flood modeling.

Question 64

What happens to a tall high-rise building underlain by poorly consolidated deep soils with a period of 1 second and a large earthquake occurred?

Answer 64

The potential for liquefaction, increased ground shaking, differential settlement, and structural damage poses serious challenges for safety and stability

Question 65

If an aquifer has a storativity of 0.04, is it confined or unconfined?

Answer 65

Unconfined because S is greater than 0.005 ( Confined if lower)

Question 66

The porosity of a bed is 0.35, the volume of voids is 15 cubic-in. What is the void ratio?

Answer 66

• Void Ratio = Pore Volume / Solids Volume
• Volume of the bed (Total Volume) = Pore Volume + Solids Volume
• Porosity = Pore Volume / Total Volume

Void Ratio = Pore Volume / [(Pore Volume/Porosity) - Pore Volume]

Void Ratio = 15 / [(15/0.35) -15]
Void Ratio = 0.54

Question 67

Smoky quartz and purple fluorite are commonly found in association with _____ deposits.

Answer 67

Uranium

Question 68

Clay mineral that originates from the weathering of biotite or phlogopite.

Answer 68

Vermiculite

Question 69

Clay mineral that occured in areas with volcanic activity where ash deposits are subjected to alteration by water.

Answer 69

Bentonite (Montmorillonite)

Question 70

What geologic condition would produce slow drainage within the cone of depression of an unconfined aquifer?
a. glacial drift
b. stream gravels
c. turbidite
d. cross-bedded sands

Answer 70

Answer: Glacial Drift - Composed of unsorted sediments deposited by glaciers, glacial drift often includes a mix of clay, silt, sand, and gravel. The presence of fine-grained materials like clay can significantly reduce permeability, leading to slow drainage.

Stream gravels are typically well-sorted and have high permeability, allowing for rapid drainage.
Turbidites consist of sediments deposited by underwater landslides and can vary in grain size. While they may contain finer materials that could slow drainage, they are generally more permeable than glacial drift due to their layered structure.
Cross-Bedded Sands are typically well-sorted and highly permeable

Question 71

What type of slope failure would you expect to find in a well-cemented conglomerate overlying a shale in an area of high ground water levels?
a. Rock fall
b. Translational slide
c. Rotational slide
d. Topple

Answer 71

Answer: Translational slide - the well-cemented conglomerate provides a relatively strong and stable layer above the weaker shale. When groundwater levels rise, increased pore water pressure can reduce the effective stress acting on the slope, leading to a decrease in shear strength at the interface between

Rock Fall: This type involves vertical or near-vertical movement of rock fragments and is not applicable here due to the horizontal layering of materials and groundwater influence
Rotational Slide: While rotational slides (slumps) involve movement along a curved failure surface and are common in homogeneous fine-grained materials, they are less likely in this case because the well-cemented conglomerate’s stability under high pore pressures would favor translational movement along a planar interface instead of rotational failure
Topple: Toppling involves forward rotation about a point near the base of the slope and typically occurs in steeply inclined rock layers

Question 72

A good index fossil is characterized by a restricted _____ and a wide _____.

Answer 72

Restricted stratigraphic range and a wide geographic range.

Question 73

Why is till classified as GM-GC using USCS?

Answer 73

Till is classified as GM-GC in the USCS because it typically contains a significant proportion of gravel along with fines (silt and clay), meeting the criteria for both silty gravel and clayey gravel classifications. Till is often called Boulder Clay.

Question 74

Your base map has been developed from aerial photographs that were shot at an elevation of 3000 feet and using a focal length of 6 inches. What is the scale of the map?

Answer 74

Scale = Focal length/Height

Scale = 6 in/ 36000 in
Scale = 1:6000

Question 75

Which of the following is a formally named formation in a proper stratigraphic reference?
a. Kaibab Limestone of the late Permian
b. Late Permian Kaibab limestone
c. Kaibab Limestone (Late Permian)

Answer 75

Kaibab Limestone (Late Permian)

Question 76

Basins and domes have similar outcrop patterns in map view. What distinguishing characteristics would you look for to determine one from the other in the map view given a map with no legend or strike and dip symbols?
a. Circular or ring drainage pattern
b. V’s at the streams/valleys pointing outward for the dome and inward for the basin
c. If there is a clue to the ages of the units, the older will be in the center in a basin and younger in the center in a dome
d. V’s at the streams/valleys pointing inward for the dome and outward for the basin

Answer 76

Answer: V’s at the streams/valleys pointing outward for the dome and inward for the basin (Not the Rule of V’s but the V created when two rivers join)

Question 77

Atterberg Limits tests define:
a. Degree of adhesion
b. Compressibility
c. Water content at the different states of consistency
d. Grain size

Answer 77

Water content at the different states of consistency

Question 78

If you have a map that is at a scale of 1:62,500 and you want to draw a cross section with a 10 times exaggeration, what will the vertical scale be?
a. 1” : 520’
b. 1” : 5208’
c. 1” : 6250’
d. 1” : 625’

Answer 78

Answer: 1” : 520’

62,500”= 5200’
5200’/10 = 520’
(“) inch, (‘) foot

Question 79

In USCS, well graded also means _____ sorted

Answer 79

poorly

Question 80

The base map provided for a project involving the mapping of surface outcrops of a series of coal beds for the purposes of determining the thickness and lateral extent over a 50,000 acre site is at a scale of 1:250,000. Is this an appropriate scale for plotting the field data? Why or why not?
a. Yes, because it fits nicely in the report.
b. Yes, because it covers a large area.
c. No, because there is not adequate detail to accurately locate the coal beds.
d. No, because it doesn’t cover a large enough area.

Answer 80

No, because it is a small scale map and there is not adequate detail to accurately locate the coal beds.

Question 81

In exploring to establish the lateral extent of a 2000-foot deep metallic sulfide deposit containing Pb, Zn, and Ag which of the following methods would be most effective?
a. IP
b. Magnetic Survey
c. Seismic Reflection
d. Gravity Survey

Answer 81

Answer: Induced Polarization - particularly effective in detecting metallic sulfide deposits because it measures the chargeability of the ground

Magnetic Survey: are less effective for identifying non-magnetic metallic sulfides like galena or sphalerite.
Seismic Reflection: This method is primarily used for mapping subsurface geological structures and may not provide sufficient detail for identifying specific mineral deposits, especially at depths of 2000 feet.
*Gravity Survey: Gravity surveys measure variations in density.

Question 82

What type of sampler would be the best to use to get an undisturbed sample of a uniform soft saturated clay from a depth of 75 feet?
a. SPT Sampler
b. Pitcher Barrel
c. Shelby Tube
d. Split-spoon Sampler

Answer 82

75 feet (23 meters) depth presents unique challenges (< 50 ft or 15 m is considered shallow), such as increased soil pressure and potential disturbance during extraction. At greater depths, maintaining sample integrity becomes critical, particularly in soft saturated clay, which can easily deform or lose cohesion.

Answer: Shelby Tube - most effective for undisturbed sampling of cohesive soils, it minimizes disturbance due to its thin-walled structure.

Pitcher Barrel - effective for soft soils, it can provide good samples while managing drilling fluid contamination, but not as effective as Shelby Tube
SPT Sampler (Standard Penetration Test) - Primarily used for disturbed sampling and assessing soil density, not ideal for undisturbed samples
Split-spoon Sampler* - involves driving a thick-walled sampler into the soil using a hammer, and the number of blows required to penetrate specific intervals (typically 6 inches) is recorded. This blow count, known as the “N-value,” provides an indication of soil resistance and is primarily used for disturbed sampling

Question 83

In order to get stereo-paired aerial photographs at a scale of 1:12,000 using a camera with a focal length of 3 inches, how high does the plane have to fly?

Answer 83

Answer: 3000 feet

1:12,000
3 in : 36,000 in
3 in : 3,000 ft

Question 84

As measured in drilled core samples the RQD is determined by
a. the ratio of natural fractures over the whole core run
b. the ratio of man induced fractures over the whole core run
c. the ratio of natural fractures over the recovered core
d. the orientation of the fractures with respect to the axis of the core

Answer 84

The ratio of natural fractures over the whole core run

Question 85

In order to obtain aerial photographs at a scale of 1” = 100,’ how high must the plane fly using a camera with a focal length of 0.5 feet?

Answer 85

Answer: 600 ft

1” : 100’ is same as
1 : 1,200 so…
0.5’ : 600’

(“) inch, (‘) foot

Question 86

In examining a topographic map you will be using for mapping the geology of a site in a moderately hilly area you note several unusual features including aligned saddles in a series of ridges several of which contain small water filled depressions and a couple of deflected and beheaded streams. What should you look for during your mapping expedition?
a. Evidence of strike-slip faulting
b. Evidence of landslides
c. Strikes and dips that would indicate regional folding
d. Evidence of past volcanic activity

Answer 86

Answer: Evidence of strike-slip faulting

Evidence of landslides: While landslides can occur in hilly areas, they typically do not create the specific features noted.
Strikes and dips indicating regional folding: This would be more relevant if there were clear signs of folding rather than the linear features observed.
Evidence of past volcanic activity: Volcanic features would present differently and are not indicated by the features described.

Question 87

What is Mohr’s Circle used for?
a. Representing the state of stress.
b. Determining the shear strength.
c. Establishing maximum compaction.
d. Determination of compressibility.

Answer 87

State of Stress Representation: Mohr’s Circle provides a graphical method to visualize and calculate the normal and shear stresses acting on various planes within a material. It helps determine principal stresses and maximum shear stresses, essential for understanding material behavior under load

Question 88

A prominent feature often seen as a result of erosion along an emergent coastline is
a. a sequence of terraces consisting of a headland or cliff topped by a flat bench.
b. beaches that migrate onshore during times of calm and offshore during storms.
c. long sand spits produced by shore drift.
d. lagoons.

Answer 88

Answer: a sequence of terraces consisting of a headland or cliff topped by a flat bench. These coastlines typically exhibit features such as sea cliffs and wave-cut platforms, which form due to the erosion of rock by wave action. As sea levels drop or land rises, these platforms can become elevated, creating terraces.

Beaches that migrate onshore during times of calm and offshore during storms: This describes depositional processes rather than erosion.
Long sand spits produced by shore drift: Spits are formed through sediment deposition, not primarily through erosion.
Lagoons: These are typically associated with submergent coastlines and are formed by sedimentation, not erosion.

Question 89

A split-spoon sampler is used to obtain
a. the number of blows required to drive the sampler into the ground in 6-inch increments.
b. an undisturbed sample which can be tested in the lab for shear analysis.
c. samples from which downhole strikes and dips can be analyzed.
d. None of the above

Answer 89

The Split-spoon sampler - involves driving a thick-walled sampler into the soil using a hammer, and the number of blows required to penetrate specific intervals (typically 6 inches) is recorded. This blow count, known as the “N-value,” provides an indication of soil resistance and is primarily used for disturbed sampling

Question 90

The base map provided for a project involving a series of 1000-foot seismic refraction lines is at a scale
of 1:62,500. Is this an appropriate scale for plotting the field data? Why or why not?
a. Yes, because it fits nicely in the report.
b. Yes, because it covers a large area.
c. No, because there is not adequate detail to accurately locate the refraction lines.
d. No, because it doesn’t cover a large enough area.

Answer 90

No, because there is not adequate detail to accurately locate the refraction lines.

Question 91

What type of drilling method would you use to collect undisturbed samples of the unconsolidated soils that are below the water table to determine the geotechnical characteristics of the materials at a proposed tunnel depth of 175 feet?
a. Rotary wash
b. Hollow-stem auger
c. Bucket Auger
d. Standard Penetration

Answer 91

The specification of 175 feet or 53 meters (< 50 ft or < 15 m is considered shallow) indicates that the drilling will occur at a significant depth where soil conditions can vary widely. At this depth, maintaining borehole stability and obtaining high-quality samples becomes increasingly challenging.

Answer: Rotary Wash - this method can effectively maintain borehole stability and minimize disturbance to the soil structure and is suitable for deeper boreholes, allowing for effective penetration through unconsolidated soils while managing water and soil interactions.

Hollow-stem auger: While it can be used for sampling, it has limitations in saturated loose sands and may not provide the best results at greater depths due to potential caving issues.
Bucket Auger: This method is generally not suitable for deep drilling below the water table as it can cause significant disturbance and is less effective in saturated conditions.
Standard Penetration Test: This method primarily provides disturbed samples and is not designed for collecting undisturbed samples from deeper depths.

Question 92

Well screen slot sizes are based on the subsurface materials. The thickness and depths of the
subsurface units have been determined accurately and consist of a 15-foot section of fine grained sand overlying a 50-foot section of coarser grained sandy gravel. The well is going to be naturally
developed. How would you configure the slots in a multi-slot screen?
a. The finer screen should extend into the underlying coarser material at least 3 ft.
b. A screen appropriate for the finer material should be used throughout the screened interval.
c. The finer screen should end at the contact between the finer and coarser material.
d. Since the water is drawn down in the aquifer from the lower section, you need only one slot size
that is appropriate for the thicker coarse-grained materials.

Answer 92

Answer: The finer screen should extend into the underlying coarser material at least 3 ft. Extending the finer screen into the coarser material which acts as a buffer helps prevent the migration of coarser particles into the finer screen, which could lead to clogging and reduced water flow. This configuration allows for better filtration and ensures that the screen can effectively draw water from both soil types.

A screen appropriate for the finer material should be used throughout the screened interval: Using only a finer screen throughout would not accommodate the coarser material below, potentially leading to issues with water flow and efficiency.
The finer screen should end at the contact between the finer and coarser material: This would limit the well’s ability to draw from both layers effectively and could lead to sediment issues.
Since the water is drawn down in the aquifer from the lower section, you need only one slot size that is appropriate for the thicker coarse-grained materials: This ignores the presence of fine-grained sand above, which requires consideration to avoid clogging and ensure effective water extraction.

Question 93

What is the primary purpose of a bailer test?
a) To measure the rate of water absorption in soil
b) To assess the recovery of water levels after removing a specific volume of water
c) To evaluate the performance of a well under varying pumping rates
d) To determine the hydraulic conductivity of an aquifer

Answer 93

To assess the recovery of water levels after removing a specific volume of water

Question 94

A step-drawdown test is used to:
a) Measure soil permeability for septic system suitability
b) Quickly remove a known volume of water from a well
c) Analyze the change in water levels as pumping rates are increased
d) Collect groundwater samples from monitoring wells

Answer 94

Analyze the change in water levels as pumping rates are increased

Question 95

What does a percolation test primarily assess?
a) The recovery rate of groundwater levels in a well
b) The hydraulic conductivity of an aquifer
c) The yield of a well under different pumping conditions
d) The suitability of soil for wastewater drainage systems

Answer 95

The suitability of soil for wastewater drainage systems

Question 96

What does a percolation test primarily assess?
a) The recovery rate of groundwater levels in a well
b) The hydraulic conductivity of an aquifer
c) The yield of a well under different pumping conditions
d) The suitability of soil for wastewater drainage systems

Answer 96

The suitability of soil for wastewater drainage systems

Question 97

A slug test is performed to:
a) Measure the rate at which water is absorbed into soil
b) Determine how quickly water levels recover after a disturbance in a well
c) Collect undisturbed samples from groundwater
d) Evaluate the performance of a well under continuous pumping

Answer 97

Determine how quickly water levels recover after a disturbance in a well

Question 98

To see surficial expression of geologic conditions in low-altitude stereo-paired aerial photographs, the time of day when photos are taken is
a. important because the land surface is exposed better when the sun is high in the sky.
b. important because when the sun is lower in the sky it provides shadows.
c. not important, it is only important not to have cloud cover when flying.
d. not important because the vegetative cover mimics the ground surface.

Answer 98

Answer: Important because when the sun is lower in the sky it provides shadows. When the sun is lower in the sky, it creates shadows that enhance the texture and depth of the landscape, making geological features more visible and easier to interpret.

Important because the land surface is exposed better when the sun is high in the sky: While a high sun angle can illuminate surfaces, it often flattens features and reduces contrast, making it harder to discern details.

Question 99

What is the best foundation condition for the construction of a dam?
a. Jointed rock
b. Horizontal beds
c. Synformal folded rocks
d. Angled beds with a fault running perpendicular through

Answer 99

Answer: Jointed rock - characterized by natural fractures that can enhance drainage and provide a stable foundation. The joints allow for some flexibility in load distribution, which can help accommodate any minor movements without compromising the dam’s integrity.

While horizontal beds can offer stability, they may be less effective in managing water seepage compared to jointed rock.
Synformal folded rocks present complex geometries that can lead to uneven loading conditions.
Angled beds with a fault running perpendicular through poses significant risks due to the presence of a fault, which can weaken the foundation substantially

Question 100

“The fossils’ range that have been found in the Franciscan Formation give a range in age from Upper Jurassic to Upper Cretaceous. These fossils include locally abundant Foraminifera in limestone and Radiolaria in chert indicating a submarine environment until at least the Late Cretaceous.”

What edits would you make to correct what is being said?
a. Change “Upper Jurassic to Upper Cretaceous” to read upper Jurassic to upper Cretaceous
b. Change “Upper Jurassic to Upper Cretaceous” to read late Jurassic to late Cretaceous
c. Change “Upper Jurassic to Upper Cretaceous” to read Late Jurassic to Late Cretaceous
d. Change “Late Cretaceous” to read Upper Cretaceous

Answer 100

Change “Upper Jurassic to Upper Cretaceous” to read late Jurassic to late Cretaceous