ASBOG FG Exam UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
A plunging anticline will show closure in an outcrop pattern. In which direction does the
anticline plunge with respect to the closure? - CORRECT ANSWER A plunging
anticline is plunging in ht direction of closure.
What can be inferred from a borehole log indicating a repetition of beds? - CORRECT
ANSWER A repetition of beds in cross section indicates fault movement in which the
hanging wall has moved up with respect to the foot wall (reserve faulting).
Are slickensides indicative of faulting? - CORRECT ANSWER The presence of
slickensides may indicate faulting but this feature also results from non-fault related
movement in clays, such as shrinking and swelling.
What type of geologic feature might you expect from a mapped outcrop pattern that consists
of a series of series of concentric circular shapes? - CORRECT ANSWER 1.
Horizontal beds mapped on a rounded hilltop. 2. Horizontal beds mapped in an enclosed
basin. 3. An intrusion with bands of contact metamorphism of varying degrees.
Chert is found commonly in the Coast Ranges Province of California. What is its depositional
environment and how is it formed? - CORRECT ANSWER Chert originates in shallow
sea water. Some cherts result from the enrichment of silica in the sea water from volcanic
rocks. They also may form by the accumulation of silicious skeletons of silica secreting
organisms.
According to the Unified Soil Classification System, gravels have a grain size greater than
what diameter? - CORRECT ANSWER gravel: >No. 4 sieve or 4.76 mm
When observing cross-bedded sandstones, how do you know where the top of the beds are? -
CORRECT ANSWER Unit is right side up when cross-bedding is concave up.
,What type of geologic units would constitute a "key bed"? - CORRECT ANSWER Key
beds are layers that have been deposited simultaneously over large areas. Volcanic ash, beds
rich in fish scales, oysters or corals.
What type of fault might be represented by juxtaposition in map view of noncontiguous
sedimentary formations. - CORRECT ANSWER Sedimentary formations that do not
occur next to each other may be moved laterally by strike slip faults.
Name and define the 4 various different types of unconformities? - CORRECT
ANSWER Angular unconformity: strata below the unconformity are cut off and
overlain at an angle by the beds above.
Nonconformity: sedimentary deposits rest upon older igneous or metamorphic rocks.
Disconformity: beds above and below unconformity are parallel, but unconformity not
parallel to bedding.
Paraconformity: unconformity is parallel to the strata above and below it.
How can the "rules of V's" be used on a map with no topography? - CORRECT
ANSWER In using the rule of V's to interpret direction of dip on a map with no
topography you must first look at the V's downstream, since V downstream is always dip
downstream. When interpreting V's upstream you must observe the quality of the V. Shallow
V's mean dip upstream and ac the V's get deeper it passes from horizontal bedding to a dip
downstream less than the valley gradient.
Define foot wall and hanging wall - CORRECT ANSWER Foot wall - block that
underlies a non-vertical fault.
Hanging wall - block that overlies a non-vertical fault
What is a regressive sequence? - CORRECT ANSWER Regression is the withdrawal
of the sea from land. A regression is represented by limestone overlain by shale overlain by
sandstone.
What is the order of deposition of evaporites? - CORRECT ANSWER Order of
Deposition
calcium carbonate - calcite
, calcium sulfate - gypsum or anhydrite
sodium chloride - halite
magnesium sulfates and chlorates
sodium bromide and potassium chloride
What are the processes of diagenesis? - CORRECT ANSWER Diagenetic processes
include: compaction, cementation, reworking, authigenesis, replacement by secondary
minerals, crystallization of secondary minerals, leaching, hydration, bacterial action, or
formation of concretions.
Give three examples of magmatic segregation deposits - CORRECT ANSWER 1.
Layered magic intrusions (chromite)
2. Kimberlite pipes (diamonds)
3. Ophiolites (asbestos)
What is the importance of knowing water saturation in a oil reservoir? - CORRECT
ANSWER Below 60% of oil saturation, the reservoir will produce mostly water.
Define aquifer - CORRECT ANSWER A geologic unit that is saturated and sufficiently
permeable to transmit significant economic quantities of water to wells and springs
A poorly-sorted (or well-graded) sediment or sedimentary rock contains how many grain
sizes? - CORRECT ANSWER Poorly-sorted (well graded) sediment has a wide range
of grain sizes present.
A plunging syncline may show closure in an outcrop pattern. In which direction does the
syncline plunge with respect to the closure? - CORRECT ANSWER A plunging
syncline is plunging away from the closure.
According to the Unified Soil Classification System, a clay or silt would contain particles less
than what diameter? - CORRECT ANSWER clay or silt - <No. 200 sieve or 0.074 mm
QUESTIONS AND CORRECT ANSWERS
A plunging anticline will show closure in an outcrop pattern. In which direction does the
anticline plunge with respect to the closure? - CORRECT ANSWER A plunging
anticline is plunging in ht direction of closure.
What can be inferred from a borehole log indicating a repetition of beds? - CORRECT
ANSWER A repetition of beds in cross section indicates fault movement in which the
hanging wall has moved up with respect to the foot wall (reserve faulting).
Are slickensides indicative of faulting? - CORRECT ANSWER The presence of
slickensides may indicate faulting but this feature also results from non-fault related
movement in clays, such as shrinking and swelling.
What type of geologic feature might you expect from a mapped outcrop pattern that consists
of a series of series of concentric circular shapes? - CORRECT ANSWER 1.
Horizontal beds mapped on a rounded hilltop. 2. Horizontal beds mapped in an enclosed
basin. 3. An intrusion with bands of contact metamorphism of varying degrees.
Chert is found commonly in the Coast Ranges Province of California. What is its depositional
environment and how is it formed? - CORRECT ANSWER Chert originates in shallow
sea water. Some cherts result from the enrichment of silica in the sea water from volcanic
rocks. They also may form by the accumulation of silicious skeletons of silica secreting
organisms.
According to the Unified Soil Classification System, gravels have a grain size greater than
what diameter? - CORRECT ANSWER gravel: >No. 4 sieve or 4.76 mm
When observing cross-bedded sandstones, how do you know where the top of the beds are? -
CORRECT ANSWER Unit is right side up when cross-bedding is concave up.
,What type of geologic units would constitute a "key bed"? - CORRECT ANSWER Key
beds are layers that have been deposited simultaneously over large areas. Volcanic ash, beds
rich in fish scales, oysters or corals.
What type of fault might be represented by juxtaposition in map view of noncontiguous
sedimentary formations. - CORRECT ANSWER Sedimentary formations that do not
occur next to each other may be moved laterally by strike slip faults.
Name and define the 4 various different types of unconformities? - CORRECT
ANSWER Angular unconformity: strata below the unconformity are cut off and
overlain at an angle by the beds above.
Nonconformity: sedimentary deposits rest upon older igneous or metamorphic rocks.
Disconformity: beds above and below unconformity are parallel, but unconformity not
parallel to bedding.
Paraconformity: unconformity is parallel to the strata above and below it.
How can the "rules of V's" be used on a map with no topography? - CORRECT
ANSWER In using the rule of V's to interpret direction of dip on a map with no
topography you must first look at the V's downstream, since V downstream is always dip
downstream. When interpreting V's upstream you must observe the quality of the V. Shallow
V's mean dip upstream and ac the V's get deeper it passes from horizontal bedding to a dip
downstream less than the valley gradient.
Define foot wall and hanging wall - CORRECT ANSWER Foot wall - block that
underlies a non-vertical fault.
Hanging wall - block that overlies a non-vertical fault
What is a regressive sequence? - CORRECT ANSWER Regression is the withdrawal
of the sea from land. A regression is represented by limestone overlain by shale overlain by
sandstone.
What is the order of deposition of evaporites? - CORRECT ANSWER Order of
Deposition
calcium carbonate - calcite
, calcium sulfate - gypsum or anhydrite
sodium chloride - halite
magnesium sulfates and chlorates
sodium bromide and potassium chloride
What are the processes of diagenesis? - CORRECT ANSWER Diagenetic processes
include: compaction, cementation, reworking, authigenesis, replacement by secondary
minerals, crystallization of secondary minerals, leaching, hydration, bacterial action, or
formation of concretions.
Give three examples of magmatic segregation deposits - CORRECT ANSWER 1.
Layered magic intrusions (chromite)
2. Kimberlite pipes (diamonds)
3. Ophiolites (asbestos)
What is the importance of knowing water saturation in a oil reservoir? - CORRECT
ANSWER Below 60% of oil saturation, the reservoir will produce mostly water.
Define aquifer - CORRECT ANSWER A geologic unit that is saturated and sufficiently
permeable to transmit significant economic quantities of water to wells and springs
A poorly-sorted (or well-graded) sediment or sedimentary rock contains how many grain
sizes? - CORRECT ANSWER Poorly-sorted (well graded) sediment has a wide range
of grain sizes present.
A plunging syncline may show closure in an outcrop pattern. In which direction does the
syncline plunge with respect to the closure? - CORRECT ANSWER A plunging
syncline is plunging away from the closure.
According to the Unified Soil Classification System, a clay or silt would contain particles less
than what diameter? - CORRECT ANSWER clay or silt - <No. 200 sieve or 0.074 mm
