Methods of Structural Geology
Methods of Structural Geology
Methods of Structural Geology
Methods of
Structural Geology
1. Cross sections
Why?
Fundamental understanding of our planet(s)
Exploration (hydrocarbons, ore, etc.)
Nuclear waste disposal & CO2-sequestration
1
Field-based research
Theory-based research
How do structures form?
How do rocks deform?
Methods of
Structural Geology
1. Cross sections
Why?
Fundamental understanding of our planet(s)
Exploration (hydrocarbons, ore, etc.)
Nuclear waste disposal & CO2-sequestration
1
Field-based research
Theory-based research
How do structures form?
How do rocks deform?
This course
Practical info
Constructing cross-sections
Strain analysis
Fry method, Centre-to-centre method,
Using stretch and rotation of lines & planes
Mohr circle for strain!
http://www.structural-geology.info
This lecture
Orientation data
Sedimentary bedding
Faults
Fold axes and axial planes
tan(")=300/500
-> " = 31
090/31
500
400
300
200
300
400
500
600
600
300
400
500
500
400
300
700
600
31
31
tan(")=300/500
-> " = 31
270/31
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. .. . . .
..
?
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12
Construct axial
planes
Between domain A
and B : 40 to E
B: 80
C: 40
Assumption
Chevron fold
Fold panels or
domains
Axial plane
bisects limbs in
middle
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A: 20
A: 20 B: 80
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We know
Orientations
Stratigraphy
Fold type?
C: 40
With stratigraphic
column we can
extend further down
Between domain B
and C: 70 to E
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A: 20
B: 80
C: 40
?
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Exercise
B: 80
An EW-profile
Draw dip domains
Draw profile with all units
C: 40
One fold
Determine axial
plane between A & C:
80 to W
A: 20
C: 40
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20
Dip domains
Different dip
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Profile with
Centre of arc
3 dip measurements
One lithological boundary A-B
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Centre of arc
For each arc centre, find the arc for layer boundary A-B
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X
Y
P
31
Y
Q
Draw the arc with centre Z for the section from points Q to Y
Insert a straight section from points P to Y
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Exercise
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Exercise
Draw profiles for this section
- One with the dip domain method
- One with the circular arc method
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