Shorefaces - Trace Fossils as Indicators of Sedimentary Environments - page 547

Increased tidal power

Increased wave power
Wave-
dominated
estuary

Tide-
dominated
estuary

Lagoon

Estuary

Tidal flat

Strand plain

Shoreface

Tide/ocean
current-
dominated
shelf

R

Wave/storm-
dominated
shelf

Shelf

Subtidal

Delta

Intertidal

Supratidal

Tidal flat

Strand plain

River

Boyd 2011
CPH-110797.01

Sand Mud Marsh

FIGURE 1 Siliciclastic marginal-marine and shallow-marine subenvironments of deposition
under varying conditions of tidal power and wave power ( Boyd, 2010 ; courtesy of Ron Boyd).
Figure originally based on Heward (1981) and Boyd et al. (1992) .

A long history of trace-fossil analysis of shoreface systems has generated a
robust ichnological model of their various subenvironments ( Fig. 2 ). This model
builds upon a variety of general models and approaches for using trace fossils in
the identification and interpretation of specific sedimentary environments (e.g.,
Bann et al., 2004; Gingras et al., 1998; Howard and Frey, 1984; MacEachern and
Pemberton, 1992; MacEachern et al., 1999b; Pemberton and Wightman, 1992;
Pemberton et al., 1992a,b,d; Pemberton et al. (1992c) Savrda and Bottjer,
1989; Seilacher, 1967, Taylor et al., 2003; Vossler and Pemberton, 1988,
1989 ; see Fig. 3 ). Animal/sediment interactions are well documented from the
more uniform conditions associated with strandplain shorefaces, and the shore-
face ichnofacies model is robust ( Figs. 2 and 3 ; e.g., Bann and Fielding, 2004;
Bann et al., 2008; Frey, 1990; Howard and Frey, 1984; Howard and Reineck,
1981; MacEachern and Bann, 2008; MacEachern and Pemberton, 1992;
MacEachern et al., 1999a,b; Pemberton and Frey, 1984, Pemberton and
MacEachern, 1995; Vossler and Pemberton, 1988 ). In deltaic settings, the
dynamic interplay of fluvial influx, fluvial discharge types, tidal energy, wave
action, and storms have a strong effect on animal/sediment characteristics
( Tonkin, 2012 ). Such interactions, at least as they affect infaunal diversity,
abundance, feeding strategy, and overall behaviors, are generally poorly