Geology Reference
In-Depth Information
Fig. 3.21.
Cross sections showing direc-
tions of constant thickness.
The dips are identical in each
cross section.
a
Constant bed
thickness (
t
).
b
Constant verti-
cal thickness (
v
).
c
Constant
apparent thickness (
t
') in an
inclined direction
thickness remain constant and the units unfaulted over the projection distance. The
most definitive check on the validity of a projected or composite surface is to construct
a cross section that shows all the horizons from which data have been obtained (Chap. 6),
as in Figs. 3.21 and 3.22. Any projection problems should be reasonably obvious on the
cross section.
Folding may produce thickness changes that are a function of position within the
fold and the mechanical stratigraphy. Equation 3.1 is based on the assumption that
