Geology Reference
In-Depth Information
Fig. 6.47.
Axial surface traces defined
on a vertical slice oblique to
hinge lines (northern section
across Fig. 6.45b);
ast:
axial
surface trace;
hp:
hinge point
Fig. 6.48.
Axial surfaces in the fold of Fig. 6.45.
a
Constructed by linking traces on profiles.
b
Completed
axial surface network superimposed on previous construction
Fig. 6.49.
Completed marker surfaces for map in Fig. 6.45.
a
To p.
b
Middle.
c
Bottom
Some types of information, for example fracture density, may be related to the prox-
imity of the observation point to the fold hinge and so should be projected parallel to
the closest hinge line. 3-D axial surface maps provide essential information for pre-
dicting the deep structure using kinematic models of cross-section geometry (espe-
cially using flexural-slip models Sect. 11.6).
