Sequence Stratigraphy - Trace Fossils as Indicators of Sedimentary Environments - page 176

FIGURE 11 WRS, TS/SU, and WRS/SU associated with wave-dominated estuarine valleys. Core
box photo (A) and close-ups (B and C) show bioturbated upper offshore sandy mudstones of
the underlying marine parasequences cross-cut by late-stage central-basin heterolithic facies.
The discontinuity (white arrow and photo B) represents a TS/SU, reflecting a bay-line flooding sur-
face draped onto the subaerial unconformity. The surface is demarcated by palimpsest softground
Diplocraterion ( D ). The uppermost discontinuity (outlined arrow and photo C) corresponds to a
WRS cut across central-basin deposits near the valley margin. The surface is marked by firmground
Diplocraterion habichi ( D ) of the Glossifungites Ichnofacies, capped by a transgressive lag and shelf
mudstones. Crystal Field, Alberta. Core box photo (D) and close-up (E) from an off-valley (inter-
fluve) position. The discontinuity, marked by firmground Skolithos ( Sk ) of the Glossifungites Ich-
nofacies, corresponds to the WRS/SU and separates underlying lower offshore mudstones from
overlying upper offshore mudstones. Gilby Field, adjacent to the Willesden Green valley, Alberta.
See Fig. 3 for sequence-stratigraphic surface names. Scale bar ¼ 15 cm (A and D) and 3 cm (B).