7.2 Basic Concepts
307
a
o
b
c
o
LOW- TO MEDIUM-FREOUENCY SEA- OR BASE-LEVEL CHANGE
( 1 st to 3rd order sequences)
, Il:
0C!l
01~(I)
~(I)
IW
I-Z
ACC
TIME
- + 4
_ _ _ _ _ _ ...1
t
W
~
i=
ISOCHRO
Il:~
IIU(I)
MEDIUM-FREQUENCY SEA- OR BASE-LEVEL CHANGE
(3rd order sequences)
NO EROSION
I
ER ..r---,~
~--'oC'.:~ BYP
SLF>SUB
HIGH-FREOUENCY SEA-LEVEL CHANGE
(4th and 5th order sequences)
B~
_ __ 1- __ _
I
I
I
I
~~
HIATUS AND fOR INCISED VALLEYS
CHRONOSTRATIGRAPHY
THICKNESS
1
<2
<3
<4
ISOCHRONES
SED2-4
SAME
THICKNESS
8
HIATUS
THICKNESS
/ \
ALTERNATIVE
EROSIONAL
UNCONFORMITY
c. 6-8
\
INCISION