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Fig. 4.6 Examples of mud
stowage by animals in tidal
settings. ( a ) Cylindrichnus (Cy)
and Siphonichnus (Si) where
mud has been reamed/packed
into the burrow lining (x-ray
negative: white is sand rich, dark
is mud rich). Modern subtidal
point-bar, 1-m depth Willapa
Bay, Washington, USA.
Box core is 20 cm wide.
( b ) Cylindrichnus (Cy) with
concentric, iterative mud linings,
indicating temporal fluctuation
of mud availability. Slabbed
core is 10 cm wide. Cretaceous
Centenario Fm, Argentina.
( c ) Thickly lined Cylindrichnus
(Cy). Slabbed core is 10 cm
wide. Cretaceous, McMurray
Formation, Alberta, Canada
viewed from as many scales as possible. Hand-sample,
core-, and outcrop-scale observations include the
types of ichnogenera present, the nature of their lin-
ings and infill (if present), and the distribution of trace
fossils in beds and bed-sets. Mappable data, such as
the distribution of key ichnogenera and their sizes,
and diversity trends within genetically linked strata
also stand to enhance a tidal interpretation: it should
be emphasized that very few studies of this nature
presently exist, and that a full understanding of ichno-
fossil distributions in various tidal settings is still
forthcoming.
The general framework for identifying tidal influ-
ence from ichnological data depends upon the ability
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