Methodology and Techniques - Trace Fossils as Indicators of Sedimentary Environments - page 254

There are not many published examples where ichnological information has
been incorporated into the conventional interpretation of borehole image logs
(e.g., Cunningham et al., 2009, 2012; Salimullah and Stow, 1995 ), probably
because of the image resolution, which is just about the size of typical burrows.
Prosser et al. (1999) provide an overview of applications and methodologies
of borehole images with special reference to integrated sedimentological-
ichnological studies.
5. STATISTICAL ANALYSIS
An introduction to statistical methods for earth scientists is given by McKillup
and Dyar (2010) , whereas Harper (1999) reviews computer-based techniques
available for the analysis and modeling of paleontological data. Statistical
methods can be applied in various ways to analyze ichnological data, and var-
ious text books cover different aspects of this topic: (1) Trace fossils can be
described and named on the basis of their morphological features (morphomet-
rics) which may be captured by a statistical analysis if sufficient material is
available ( Orr, 1999; Platt et al., 2010 ). (2) Distribution analysis and modeling
of trace fossils in time and space can provide important clues for paleoecologi-
cal and taphonomic reconstructions ( Kowalewski, 2002 ). (3) Benthic commu-
nities can be numerically analyzed to delineate population densities,
subenvironments, changes in substrate, or stress factors. This is a common pro-
cedure in neoichnological investigations, but can also be applied to trace-fossil
assemblages with some restrictions ( Martin, 1993; Pemberton and Frey, 1984 ).
(4) Changes in trace-fossil composition and amount of bioturbation can be
detected through the stratigraphic record, which may help in the identification
of ecological and evolutionary trends ( Uchman, 2004 ). This is particularly cru-
cial in the recognition of significant changes (e.g., ichnodiversity) across mass
extinctions ( Knaust, 2010a ). (5) Statistical analysis can contribute to quantify-
ing bioturbation, mapping trace-fossil distributions, or to the testing of lateral
persistence of ichnofabrics ( McIlroy, 2007 ).
A common technique for statistical data analysis is a multivariate analysis
(cluster analysis), which can be used in ichnology, for instance, for finding sim-
ilarities in trace-fossil assemblages and for defining environmental gradients
expressed by trace fossils ( Bjerstedt, 1988; Minter and Braddy, 2009 ). Dia-
grams containing the extent of bioturbation (ichnograms) can be used in basin
analysis ( Bottjer and Droser, 1991 ) but also have a great potential in the char-
acterization and interwell correlation of hydrocarbon reservoirs ( Fig. 9 ).
6. COMPUTER MODELING
Computer simulation of trace fossils and bioturbation has a great potential in
different fields of neo- and paleoichnology. Artificial life methods and neural
networks are employed to create virtual trace fossils, whereas the computer-
based study of the morphogenesis of the spatial distribution of complex traces