Geology Reference
In-Depth Information
Fig. 8.41.
Structure contour maps showing the effect of the angle of fault intersection on the geometry
of sequential dip-slip normal faults. Fault
A
is older and has a pure dip-slip of 100 units; fault
B
is
younger, strikes 335°, and has a slip of 200 units down to the east.
Arrows
give the slip direction of
fault
B
. Structure contours on the displaced marker horizon are
thin solid lines
; contour interval is
50 units.
Dotted contours
are on the fault planes. Note that the strikes of the faults, as shown by the
structure contours, are not the same as the trend of the fault cutoff lines of the marker horizon.
a
Fault
A
strikes 020°.
b
Fault
A
strikes 326°.
c
Fault
A
strikes 276°
(Fig. 8.43b). In the final step, the hangingwall of fault B is displaced up to the west
and the location of the hangingwall cutoff and the contours are drawn as an overlay
on the footwall (Fig. 8.43c). Three fault cuts are present in the vertical zone of com-
bined stratigraphic separation where the older fault is repeated by the younger fault
(Dickinson 1954).
