268
rE
F
LOG SEQUENCES
-,
LS to
LS 8
The Stratigraphic Architecture of Fluvial Depositional Systems
OR
OEN
IN�!:.FWAL AES
g•em->
TRANSIT
Ul$ 2 9S TIME
O�ms
Fig. 9.21. Example of a subsurface wireline-log
record through Triassic nonmarine deposits in the
Snorre field area of the northern North Sea, showing three categories of nonmarine sequence. The
high-order sequences correspond to third-order
cycles of Vail et al. (1977) and are allogenic in
origin. (Nysteun et al. 1989)
Nystuen et al. (1989) indicated that their high-order
cycles have durations of 4-12 million years. Steel and
Ryseth (1990) suggested a duration of 10-15 million
years for their megasequences.
Nested sequences on two scales occur in the
Castlegate Sandstone of Utah (Fig. 9.18), as noted
above. The main Castlegate sequence in proximal
areas had an estimated duration of about 5 million
rE
F
LOG SEQUENCES
-,
LS to
LS 8
The Stratigraphic Architecture of Fluvial Depositional Systems
OR
OEN
IN�!:.FWAL AES
g•em->
TRANSIT
Ul$ 2 9S TIME
O�ms
Fig. 9.21. Example of a subsurface wireline-log
record through Triassic nonmarine deposits in the
Snorre field area of the northern North Sea, showing three categories of nonmarine sequence. The
high-order sequences correspond to third-order
cycles of Vail et al. (1977) and are allogenic in
origin. (Nysteun et al. 1989)
Nystuen et al. (1989) indicated that their high-order
cycles have durations of 4-12 million years. Steel and
Ryseth (1990) suggested a duration of 10-15 million
years for their megasequences.
Nested sequences on two scales occur in the
Castlegate Sandstone of Utah (Fig. 9.18), as noted
above. The main Castlegate sequence in proximal
areas had an estimated duration of about 5 million