Rider Structural Geology 310 2012 GCHERMAN
FoldsFolds
“Horizontal fold”
“Mushroom fold”
Rider Structural Geology 310 2012 GCHERMAN
Rider Structural Geology 310 2012 GCHERMAN
Rider Structural Geology 310 2012 GCHERMAN
Rider Structural Geology 310 2012 GCHERMAN
A’
A
Rider Structural Geology 310 2012 GCHERMAN
A’
A’
A
Rider Structural Geology 310 2012 GCHERMAN
Object grouped and scaled 95% in the vertical dimension
Fold plunges about 18o, therefore, cos 18 = .95
A
Vertical, cross-section plane
Fold-profile plane
18o
The profile view of the fold is looking down the fold plunge into
the profile plane (90o to the plunge)
This view of the fold is the vertical cross-section
Fold axis
A’A
60
Symbols:Name:
Rider Structural Geology 310 2012 GCHERMAN
60
Symbols:Name:
Rider Structural Geology 310 2012 GCHERMAN
0.6
1.8
0.6
1.818o
18
60o
75o
Tight, steeply-inclined,gently-plunging anticline
0.8
1.2
Width of unit A = 0.8 @ 52o
Actual thickness : sin 52 = x / 0.8 = 0.63
Plunge: TAN X = 0.63 / 1.2 = 28o
28
Open, upright, gently-plunging syncline
ILA = 76o
90o
ILA = 30o
Profile
Profile
Rider Structural Geology 310 2012 GCHERMAN
Rider Structural Geology 310 2012 GCHERMAN
O
O
I
D
C
C
EXPLANATION:
Anticline
Syncline
O - outlier
I - inlier
D – depression
C - culmination
Rider Structural Geology 310 2012 GCHERMAN
Explanation:
Rider Structural Geology 310 2012 GCHERMAN
Structure contours for a limb
Use the structure contours to figure out the limb dip, which is the same dip value for all limbs,
Hinge point
Name:
Rider Structural Geology 310 2012 GCHERMAN
Name:
260
YX
z
150
22o
WISP FELL
Open, steeply inclined, horizontal anticline
Thickness: SIN 22 = z / 150 = 56 m
44
20
Dip: TAN X = 20 / 40 = 26o
z
Open, steeply inclined, horizontal syncline