Methodology and Techniques - Trace Fossils as Indicators of Sedimentary Environments - page 257

assists in behavioral and evolutionary studies ( Koy and Plotnick, 2007 ) and the
reconstruction of burrow geometry as constituent of porous systems ( Bastardie
et al., 2002 ). Hofmann (1990) simulated horizontal trace fossils using algo-
rithms for random patterns to achieve quantitative morphometric data. The frac-
tal geometry of some trace fossils is suitable for distinguishing taxa and thus has
implications for ichnotaxonomy. Further, numerous biological and ecological
studies focus on the simulation of bioturbation for understanding bioirrigation
mechanisms and its environmental impact ( Meysman et al., 2006 ).
Bioturbation may alter sediments with resulting increase or decrease in
porosity and permeability, which again has implications for the characterization
of hydrocarbon reservoirs and aquifers (Cunningham, 2009; Cunningham et al.,
2012; Gingras et al., 2012; Knaust, 2009b; Pemberton and Gingras, 2005 ). Pre-
vious approaches include stochastical simulations of three-dimensional burrow
networks for quantification of bioirrigation ( Koretsky et al., 2002 ), assessing
the anisotropic permeability of burrowed surfaces ( Gingras et al., 1999 ) and
modeling of fluid migration through a two-dimensional bioturbation model
using the software program MPath (Permedia; Spila et al., 2007 ).
The impact of bioturbation on reservoir quality can be simulated together
with high-resolution, process-based models of sedimentary bedding using the
software application SBED (Geomodeling; Ringrose et al., 2005 ), where com-
mon burrow morphologies (e.g., simple shaft, plug-shaped, U-shaped, irregu-
larly branched) are integrated in a range of bedding structures and lithologies
in varying density ( Dabek and Knepp, 2011; Fig. 10 ). After assigning porosity
and permeability values (probe permeameter data) to different host-rock lithol-
ogies (e.g., sandstone, siltstone, and mudstone) and burrow elements (e.g., core
and wall), the upscaled results of the digital rock sample are comparable with
those of the non-bioturbated model.
7. CONCLUSIONS
Numerous techniques and methods are available for supporting ichnological
analysis and help to make paleoenvironmental reconstructions successful. In
the field, the lithology-dependent visibility of bioturbation, trace fossils, and
ichnofabrics can be enhanced by brushing, sectioning, weathering, sawing,
etc. Further, the preparation of peels, molds, and casts can be applied to preserve
a wide range of trace fossil and modern traces. Different kinds of core samplers
(e.g., box-core sampler) are available to obtain subaquatic surface sediment.
Tracks and trackways are imaged and analyzed by utilizing photogrammetry,
anaglyph stereo imaging, high-resolution LiDAR, or laser scanning. Building
stones, as excavated from ichnological sites, offer the opportunity to closely
study various aspects of ichnology. Semiquantification of bioturbation is widely
done with the help of the scale developed by Reineck (1963) , whereas catego-
ries with equal proportions are more applicable for statistical analysis.
In the laboratory, various procedures can help to increase the outcome of
integrated ichnological-sedimentological studies. They include sectioning