Ichnological Patterns at
Hauck, Tyler E.1,
A modern microtidal
barrier island / embayment system in
We found that the shallow lagoon is
heavily bioturbated by a depauperate
assemblage of benthic organisms: the animal activities obscure or eradicate
most primary physical sedimentary structures. Gradually and up to the
fluvial-marine transition the preservation of physical sedimentary structures
is more prevalent. Other trends that are noted up-estuary are: (1) the mean
diameter of burrows is smaller in two species of polychaete;
and, (2) the diversity of benthic organisms decreases gradually in a landward
direction. Contour maps produced from the various measurements of burrow
diameter are used to illustrate the trends in dimunition
and diversity of tracemaking organisms up estuary.
The map shows a gradual decrease in the size-diversity index (burrow diameter x
diversity of burrows locally) up the fluvial-marine transition, and in general
a lower size-diversity index is evident closer to tidal channels and
shorelines. In most respects our efforts at Kouchibouguac
support previous articulations of the brackish-water model. However, they also
aptly demonstrate the potential for high-resolution paleogeographic
studies using ichnofossil measurements to estimate
relative salinities and reveal discrete depositional locales.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California