ASBOG 2025 EXAM with Accurate
Solutions
What does it mean when you have topographic contours on a 1:24,000 scale base map
that are roughly circular and have hachures on the counters? - correct Answer-They
represent a closed depression
You have a base map at a scale of 1:6,000 and you need to represent the information
you obtained during a field investigation of a site that is one square mile, that included
mapping of your site as well as subsurface exploration results. What do you need to do
to the map to make it work? - correct Answer-Use a larger scale map because it covers
a smaller area
If you have a map that is at a scale of 1:24,000 and you want to draw a cross section
with a 10 times exaggeration, what will the vertical scale be? - correct Answer-1" = 200'
What is the approximate exaggerated dip if the vertical scale is exaggerated 10 times
and the true dip is 30*? - correct Answer-80*
What do you do if you have forgotten to research the current magnetic declination
before you go to the field to investigate and map a site for a geologic mapping project? -
correct Answer-Align your map with two planimetric features and measure the
declination with your compasss.
Location and elevation input into your GIS program comes from your GPS system. The
maps generated by this system are based on a reference datum. If the maps were
created in 1972, what do you need to do to use them with the data output from your
GPS system? - correct Answer-Make the conversion from NAD27 to NAD83.
For a strike and dip of N25*E, 15*N, what is the attitude of the bed in terms of the
azimuth? - correct Answer-205, 15
MAP NEEDED PAGE 3: What is the strike and dip of the bed? - correct Answer-N70*W,
38*NE
MAP NEEDED PAGE 3: What apparent dip would you expect to find along a trench that
is perpendicular to cross section A-A'? - correct Answer-26*
The top of Unit A is found at location X at the ground surface and is dipping 40* to the
west. The slope is 20* to the east. Unit B is 75 feet thick, is conformable with and below
Unit A. The slope distance from the outcrop at the top of Unit A at location X to the
, outcrop of the top of Unit B is 173 feet. Unit B is a unit where you would expect a lot of
lost circulation when drilling. The top of unit B is found at a depth of 195 feet. What is
the thickness of Unit A? - correct Answer-150 feet
MAP NEEDED PAGE 4: What geologic law is used to determine the relative ages of the
faults? - correct Answer-Law of Cross-Cutting relationships
MAP NEEDED PAGE 4: There is a synclinal axis downslope of Unit B. Which direction
is the slope facing? Is it steep?. - correct Answer-NW and moderately sloping
MAP NEEDED PAGE 4: What is the youngest continuously deposited bed found on the
map? - correct Answer-Unit D
MAP NEEDED PAGE 4: What type of feature would you expect to see on this map if
you had a plunging anticline? - correct Answer-Closure of the units with the plunge in
the direction of closure
MAP NEEDED PAGE 4: What evidence do you have to determine weather the eastern
fault is normal, reverse or strike-slip? - correct Answer-Normal east side down because
when projected in a cross section Unit A on the west side is higher than its counterpart
on the east side.
MAP NEEDED PAGE 4: If unit A is Permian, what is the most likely age of unit D? -
correct Answer-Cretaceous
Which of the following survey corrections are required for the given geophysical survey
method? - correct Answer-Gravity Survey - Bouguer anomaly
When investigating an active fault that is relatively close to the surface to determine the
impact if would have on a planned structure, it is important to locate it precisely and
determine the recency of activity. In order to accomplish this which of the following field
methods would be the most appropriate? - correct Answer-seismic refraction and
trenching
E-LOG ON PG-6: What is the distinguishing feature that would indicate the presence of
the fresh water-salt water interface in this coastal aquifer? - correct Answer-A change in
the resistivity in Unit D with little corresponding change in the SP log
E-LOG ON PG-6: Where would you install the perforated section in this water supply
well? - correct Answer-620 to 640
When flying to obtain air photos, the flight lines have to be relatively short before they
double back on themselves. Why is this? - correct Answer-If the flight lines are too long
they become less parallel with length making it difficult to line up the photographs to
make them be able to be viewed in stereo.
Solutions
What does it mean when you have topographic contours on a 1:24,000 scale base map
that are roughly circular and have hachures on the counters? - correct Answer-They
represent a closed depression
You have a base map at a scale of 1:6,000 and you need to represent the information
you obtained during a field investigation of a site that is one square mile, that included
mapping of your site as well as subsurface exploration results. What do you need to do
to the map to make it work? - correct Answer-Use a larger scale map because it covers
a smaller area
If you have a map that is at a scale of 1:24,000 and you want to draw a cross section
with a 10 times exaggeration, what will the vertical scale be? - correct Answer-1" = 200'
What is the approximate exaggerated dip if the vertical scale is exaggerated 10 times
and the true dip is 30*? - correct Answer-80*
What do you do if you have forgotten to research the current magnetic declination
before you go to the field to investigate and map a site for a geologic mapping project? -
correct Answer-Align your map with two planimetric features and measure the
declination with your compasss.
Location and elevation input into your GIS program comes from your GPS system. The
maps generated by this system are based on a reference datum. If the maps were
created in 1972, what do you need to do to use them with the data output from your
GPS system? - correct Answer-Make the conversion from NAD27 to NAD83.
For a strike and dip of N25*E, 15*N, what is the attitude of the bed in terms of the
azimuth? - correct Answer-205, 15
MAP NEEDED PAGE 3: What is the strike and dip of the bed? - correct Answer-N70*W,
38*NE
MAP NEEDED PAGE 3: What apparent dip would you expect to find along a trench that
is perpendicular to cross section A-A'? - correct Answer-26*
The top of Unit A is found at location X at the ground surface and is dipping 40* to the
west. The slope is 20* to the east. Unit B is 75 feet thick, is conformable with and below
Unit A. The slope distance from the outcrop at the top of Unit A at location X to the
, outcrop of the top of Unit B is 173 feet. Unit B is a unit where you would expect a lot of
lost circulation when drilling. The top of unit B is found at a depth of 195 feet. What is
the thickness of Unit A? - correct Answer-150 feet
MAP NEEDED PAGE 4: What geologic law is used to determine the relative ages of the
faults? - correct Answer-Law of Cross-Cutting relationships
MAP NEEDED PAGE 4: There is a synclinal axis downslope of Unit B. Which direction
is the slope facing? Is it steep?. - correct Answer-NW and moderately sloping
MAP NEEDED PAGE 4: What is the youngest continuously deposited bed found on the
map? - correct Answer-Unit D
MAP NEEDED PAGE 4: What type of feature would you expect to see on this map if
you had a plunging anticline? - correct Answer-Closure of the units with the plunge in
the direction of closure
MAP NEEDED PAGE 4: What evidence do you have to determine weather the eastern
fault is normal, reverse or strike-slip? - correct Answer-Normal east side down because
when projected in a cross section Unit A on the west side is higher than its counterpart
on the east side.
MAP NEEDED PAGE 4: If unit A is Permian, what is the most likely age of unit D? -
correct Answer-Cretaceous
Which of the following survey corrections are required for the given geophysical survey
method? - correct Answer-Gravity Survey - Bouguer anomaly
When investigating an active fault that is relatively close to the surface to determine the
impact if would have on a planned structure, it is important to locate it precisely and
determine the recency of activity. In order to accomplish this which of the following field
methods would be the most appropriate? - correct Answer-seismic refraction and
trenching
E-LOG ON PG-6: What is the distinguishing feature that would indicate the presence of
the fresh water-salt water interface in this coastal aquifer? - correct Answer-A change in
the resistivity in Unit D with little corresponding change in the SP log
E-LOG ON PG-6: Where would you install the perforated section in this water supply
well? - correct Answer-620 to 640
When flying to obtain air photos, the flight lines have to be relatively short before they
double back on themselves. Why is this? - correct Answer-If the flight lines are too long
they become less parallel with length making it difficult to line up the photographs to
make them be able to be viewed in stereo.
