Geol 3000
Lab 6 – Folds and Geologic Map Patterns
Name ___________________________
1) For figures a - d, show fold patterns of the strata in the front section based on the order of younging
(bed 1 is oldest) and the strike and dip of layers. Also, using a dashed line, show the trace of the axial
plane on the map view and the front section. Show appropriate arrow labels for anticline and synclines on
the map view. (4 pts)
For Figure f, show the map view pattern
for a fold with no plunge. Also show
the axial trace (with dashed line) on the
front and map views with the
appropriate symbol.
(1 pt)
2) On the geologic map below:
A) Mark the axial trace of anticlines and synclines with proper symbols and showing the direction of
plunge. Note how the unit contacts V into the streams to determine the direction of dip. All map
units dip at steeper angles than the topography. (3 pts)
7
6
5
4
3
2
1
B) What is the oldest unit: ________(.5 pt )
3) For Figures g & h, fill in the blank panels for the dome and basin structures. (2 pts)
4) For Figures i-l, show the folded strata in the blank panels given the information provided (unit 1 is
oldest in i and unit x is oldest in l). Mark the axial trace (use dashed line) with the appropriate
symbol. Be sure to show the direction of plunge. (4 pts)
5) The figures below from Lisle (2004) show types of non-cylindrical folds and structural contours
typical of non-cylindrical folds.
The numbers on the map below give the depths in meters (below sea level) to the top of the Wittkalk
Limestone. (6pts)
A) Sketch (and label) structure contours (10m intervals 120, 110, 100, 90, 80, 70) for the top of the
limestone in pencil.
B) Show the axial traces of antiforms (crest lines) and synforms (trough lines) with colored dashed lines.
C) Label the types of non-cylindrical folds evident on the map.
D) Determine the strike and dip of the top of the limestone at points Q ________________________ and
P________________________.
6) The map below shows the geology of an area in the province of Namur in Belgium. The relie in this
area is negligible. All bedding is upward facing (i.e., not overturned)
A) Deduce what are anticlines and synclines from the closure on the folds and the age relationships
and mark the axial traces of the folds using dashed colored lines and appropriate symbols. Note
that fold axes can merge. (3pts)
B) Deduce the direction of plunge of the fold axes and show with arrows on the axial traces. (1pt)
7) The map below is from the Derbyshire region of England.
A) Identify and mark with a blue dot, the locations of fold hinge lines. (1 pt)
B) Draw the axial traces of antiforms and synforms with colored dashed lines (1 pt)
C) Show the direction of plunge of the folds with arrows on the axial traces. (1 pt)
D) Why do the sandstone units (stippled pattern) vary so much in the width of outcrop? (1 pt)
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8) For the map below:
A) Mark hinge points (blue dots) and axial traces of folds (colored dashed line), types of folds (with
arrow symbols), and plunge directions (with arrows). (3 pts)
B) Deduce the general orientation (dip direction and angle) of the axial planes of the folds. ________
(1pt)
C) On a separate piece of graph paper, construct a geological cross section with topographic
expression along line X-Y. Does this section show true or apparent dip?
_____________________ (3pts)