Sequence Stratigraphy - Trace Fossils as Indicators of Sedimentary Environments - page 166

FIGURE 4 Incised shoreface deposits of the falling stage systems tract (FSST). Core box photo
(A) and close-up photo (B) of a forced regressive incised shoreface produced during a relative sea-
level fall. The locality corresponds to a more proximal position in the forced regressive shoreface,
wherein proximal upper offshore sandy mudstones of the underlying highstand systems tract (HST)
are erosionally overlain by bioturbated proximal lower shoreface sandstones of the FSST. The dis-
continuity (arrow) is a regressive surface of marine erosion (RSME). The contact shows palimpsest
softground Skolithos ( Sk ) marking the omission suite. Core box photo (C) and close-up photo (D) of
the same forced regressive incised shoreface shown in photos A and B, but lying in a more seaward
position. Here, the RSME is cut into lower offshore mudstones of the underlying HST normal regres-
sive parasequences and is overlain by bioturbated muddy sandstones of the incised lower shoreface.
The discontinuity is demarcated by firmground Thalassinoides ( Th ) of the Glossifungites Ichno-
facies. Early Cretaceous Viking Formation, Kaybob-Fox Creek Field, Alberta. Scale bars ¼ 15 cm
(A and C) and 3 cm (D).

sandy mudstones of the upper offshore and into thoroughly burrowed (BI 4-5)

muddy sandstones of the distal lower shoreface (cf. Pemberton et al., 2012 ).
In proximal positions ( Fig. 4 A and B), the RSME tends to be incised into
lower shoreface sandstones, and omission suites are generally represented by
palimpsest softground associations dominated by Skolithos ( Fig. 4 B) and Diplo-
craterion . In slightly more distal positions, the RSME is incised into upper off-
shore and lower offshore deposits of the earlier highstand. Omission suites are
generally characterized by firmground Thalassinoides ( Fig. 4 C and D), Spon-
geliomorpha , and rare Diplocraterion . The BSFR is not preserved within the
Kaybob-Fox Creek area. Additional RSL falls led to removal of the BSFR
by overlying RSME associated with younger, downstepping forced regressive
shorefaces that terminate at the Judy Creek Field lying to the northeast.
The forced regressive shoreface deposits in the area are coarser-grained than
the underlying highstand succession, form generally thinner coarsening-upward

¼