Marine Invertebrate Neoichnology - Trace Fossils as Indicators of Sedimentary Environments - page 266

Chapter 10
Marine Invertebrate
Neoichnology
Shahin E. Dashtgard * ,1 and Murray K. Gingras †
*Applied Research in Ichnology and Sedimentology (ARISE) Group, Department of Earth Sciences,
Simon Fraser University, Burnaby, British Columbia, Canada, † Ichnology Research Group,
Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada
1 Corresponding author: e-mail: [e-mail]
1. INTRODUCTION
Ichnology draws heavily on the linkage between the burrowing behaviors and dis-
tributions of modern animals, and the trace fossils that are commonly observed in
sedimentary strata. In contrast with sedimentary structures, which record the
hydrodynamic conditions under which sediments are deposited, ichnology is a
proxy for the physical and chemical (physico-chemical) stresses at the time of
sediment deposition. Neoichnology (studies of modern animal burrows, track-
ways, and trails) details the linkage between physico-chemical stress and animal
response, where animal response to various environmental factors can be assessed
and the resultant trace assemblage determined. Taken further, quantification of
environmental factors and burrow distributions in modern settings may enable
semiquantification of paleoenvironmental conditions. Through semiquantitative
analysis, it may be possible to constrain subaerial exposure times, sedimentation
rates, substrate consistencies, and salinity at the time of sediment colonization.
A fundamental principle of ichnology is the interpretation of burrowmorphol-
ogy as a function of animal behavior. With few exceptions, these behaviors are
consistent through the Phanerozoic ( Buatois et al., 2005 ), reflecting the necessity
for animals to employ specific burrowing strategies in response to similar envi-
ronmental conditions ( Ginsburg et al., 1966; MacEachern et al., 2007; Pemberton
et al., 2001; Seilacher, 1953, 1964 ). By studying animal response, and specifically
animal burrowing behavior under varying environmental conditions, neoichnol-
ogists can associate depositional parameters and organism response to the envi-
ronment ( Clifton and Thompson, 1978; Dafoe et al., 2008; Dashtgard, 2011a,b;
Dashtgard and Gingras, 2005; Dashtgard et al., 2008; Gingras et al., 1999,
2008b; Howard and Frey, 1975; Howard et al., 1975 ).