ASBOG FG EXAM PREP 2024/2025 with 100% correct answers
Foot wall and hanging wall - ✔✔Foot wall - block that underlies a non-vertical fault.
Hanging wall - block that overlies a non-vertical fault.
Regressive sequence - ✔✔Regression is the withdrawal of the sea from land. A regressive
sequence is represented by limestone overlain by shale overlain by sandstone.
Order of deposition of evaporites - ✔✔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 included in diagenesis? - ✔✔Compaction, cementation, reworking,
authigenesis, replacement by secondary minerals, crystallization of secondary minerals, leaching,
hydration, bacterial action, formation of concretions.
Bowen's Reaction Series - ✔✔Sequence of minerals that form in the process of fractional
crystallization of a magma.
Transgressive sequence - ✔✔Transgression is the advance of the sea onto land. A transgressive
sequence is represented by sandstone overlain by shale overlain by limestone.
What types of geomorphic features are diagnostic of faulting? - ✔✔Sag ponds, offset ridges,
fault scarps, triangular facets, aligned springs, offset streams, scarplets.
What types of features are indicative of faulting but often are not extensive enough to be
mapped? - ✔✔Slickensides, grooving, drag, gouge, mylonite.
,What would cause a repetition or omission of units in cross section? - ✔✔Faulting - in general, a
reverse fault will cause repetition of beds and normal faults will cause apparently missing beds.
What should be included on a complete geologic map? - ✔✔Scale, north arrow, geologic
symbols, and explanation. The explanation must include all symbols originally on the map or
added (incl. contacts, structure symbols, streams, cross sections) and a stratigraphic column
depicting all units shown on the map and placing them from the oldest units at the bottom to the
youngest at the top. Include lithology, thickness, and names of the units if available.
What type of V will a vertical bed display on a map? - ✔✔A vertical bed will have no V. A
vertical bed crosses all variations of topography with a straight line. This is also true of any
vertical structural feature such as a fault.
Casing - ✔✔A heavy metal pipe lowered into a borehole and cemented in place to prevent cave-
in, loss of drilling fluid, and unwanted fluids from entering the borehole.
Law of Superposition - ✔✔The Law of Superposition states that the oldest layer is on the bottom
and the youngest layer is on top, assuming no overturning. If the beds are overturned or vertical,
stratigraphic succession cannot be determined unless absolute ages of units are known.
How are cross-cutting relationships used to determine relative ages? - ✔✔If cross-cutting
relationships exist, the feature that is cut is older than the feature that cuts across it. Rocks may
be cut by intrusion, faulting, unconformities, or replacement minerals.
Type locality - ✔✔Where a geologic feature (such as a fossil species or geologic formation) was
first recognized and describes. Contains the type section.
Rule of V's - ✔✔The outcrop of a formation as it crosses a valley forms a V shape (as viewed on
a map). The V points in the direction that the formation underlies the valley.
Law of Initial Horizontality - ✔✔The sequence of layers was deposited horizontally or nearly so.
The oldest layer is therefore on the bottom and the youngest layer is on top.
, Similarities and differences of reverse faults and normal faults - ✔✔Normal fault: hanging wall
has moved down relative to foot wall.
Reverse fault: hanging wall has moved up relative to foot wall.
Both: dip-slip faults with a dip between 45 and 90 degrees.
Unconformity - ✔✔A gap in the geologic record, marked by an interruption in the depositional
sequence that implies uplift and erosion have removed part of the geologic record or that non-
deposition has occurred.
Type section - ✔✔The originally described stratigraphic unit to which other parts of the unit
elsewhere may be compared. It is preferable to describe the location where the unit attains its
maximum thickness and where the top and bottom of the unit are exposed.
Tangent equation - ✔✔tan(θ) = Opposite / Adjacent
What is the net slip and where is it measured? - ✔✔Net slip is the distance between two formerly
adjacent points on either side of a fault, measured on the fault surface (in the plane of the fault).
Sine equation - ✔✔sinθ = opposite/hypotenuse
Index fossil - ✔✔An index fossil identifies and dates the strata in which it is found. It combines
a wide geographic range with a narrow stratigraphic occurrence.
General form of the thickness equation and why you wouldn't want to use it - ✔✔thickness (t) =
outcrop width perpendicular to strike (w) sin[dip(δ), slope(σ)]
Generally it is easier to solve a thickness problem graphically because you need to draw a
diagram to scale anyway to get the slope angle (σ) and the perpendicular outcrop width (w).
General equation for calculating the apparent dip and when can't you use it - ✔✔tan(α) =
tan(δ)sin(β)
α = apparent dip
Foot wall and hanging wall - ✔✔Foot wall - block that underlies a non-vertical fault.
Hanging wall - block that overlies a non-vertical fault.
Regressive sequence - ✔✔Regression is the withdrawal of the sea from land. A regressive
sequence is represented by limestone overlain by shale overlain by sandstone.
Order of deposition of evaporites - ✔✔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 included in diagenesis? - ✔✔Compaction, cementation, reworking,
authigenesis, replacement by secondary minerals, crystallization of secondary minerals, leaching,
hydration, bacterial action, formation of concretions.
Bowen's Reaction Series - ✔✔Sequence of minerals that form in the process of fractional
crystallization of a magma.
Transgressive sequence - ✔✔Transgression is the advance of the sea onto land. A transgressive
sequence is represented by sandstone overlain by shale overlain by limestone.
What types of geomorphic features are diagnostic of faulting? - ✔✔Sag ponds, offset ridges,
fault scarps, triangular facets, aligned springs, offset streams, scarplets.
What types of features are indicative of faulting but often are not extensive enough to be
mapped? - ✔✔Slickensides, grooving, drag, gouge, mylonite.
,What would cause a repetition or omission of units in cross section? - ✔✔Faulting - in general, a
reverse fault will cause repetition of beds and normal faults will cause apparently missing beds.
What should be included on a complete geologic map? - ✔✔Scale, north arrow, geologic
symbols, and explanation. The explanation must include all symbols originally on the map or
added (incl. contacts, structure symbols, streams, cross sections) and a stratigraphic column
depicting all units shown on the map and placing them from the oldest units at the bottom to the
youngest at the top. Include lithology, thickness, and names of the units if available.
What type of V will a vertical bed display on a map? - ✔✔A vertical bed will have no V. A
vertical bed crosses all variations of topography with a straight line. This is also true of any
vertical structural feature such as a fault.
Casing - ✔✔A heavy metal pipe lowered into a borehole and cemented in place to prevent cave-
in, loss of drilling fluid, and unwanted fluids from entering the borehole.
Law of Superposition - ✔✔The Law of Superposition states that the oldest layer is on the bottom
and the youngest layer is on top, assuming no overturning. If the beds are overturned or vertical,
stratigraphic succession cannot be determined unless absolute ages of units are known.
How are cross-cutting relationships used to determine relative ages? - ✔✔If cross-cutting
relationships exist, the feature that is cut is older than the feature that cuts across it. Rocks may
be cut by intrusion, faulting, unconformities, or replacement minerals.
Type locality - ✔✔Where a geologic feature (such as a fossil species or geologic formation) was
first recognized and describes. Contains the type section.
Rule of V's - ✔✔The outcrop of a formation as it crosses a valley forms a V shape (as viewed on
a map). The V points in the direction that the formation underlies the valley.
Law of Initial Horizontality - ✔✔The sequence of layers was deposited horizontally or nearly so.
The oldest layer is therefore on the bottom and the youngest layer is on top.
, Similarities and differences of reverse faults and normal faults - ✔✔Normal fault: hanging wall
has moved down relative to foot wall.
Reverse fault: hanging wall has moved up relative to foot wall.
Both: dip-slip faults with a dip between 45 and 90 degrees.
Unconformity - ✔✔A gap in the geologic record, marked by an interruption in the depositional
sequence that implies uplift and erosion have removed part of the geologic record or that non-
deposition has occurred.
Type section - ✔✔The originally described stratigraphic unit to which other parts of the unit
elsewhere may be compared. It is preferable to describe the location where the unit attains its
maximum thickness and where the top and bottom of the unit are exposed.
Tangent equation - ✔✔tan(θ) = Opposite / Adjacent
What is the net slip and where is it measured? - ✔✔Net slip is the distance between two formerly
adjacent points on either side of a fault, measured on the fault surface (in the plane of the fault).
Sine equation - ✔✔sinθ = opposite/hypotenuse
Index fossil - ✔✔An index fossil identifies and dates the strata in which it is found. It combines
a wide geographic range with a narrow stratigraphic occurrence.
General form of the thickness equation and why you wouldn't want to use it - ✔✔thickness (t) =
outcrop width perpendicular to strike (w) sin[dip(δ), slope(σ)]
Generally it is easier to solve a thickness problem graphically because you need to draw a
diagram to scale anyway to get the slope angle (σ) and the perpendicular outcrop width (w).
General equation for calculating the apparent dip and when can't you use it - ✔✔tan(α) =
tan(δ)sin(β)
α = apparent dip
