Ichnology,classification& significance of trace fossil Most trace fossils are largely facies dependant. No secondary displacement or transport. Trace fossils are common in rocks that otherwise are unfossiliferous. (siliciclastics, shorelines) Non-preservation of the causative organism. Multiple architects may produce a single structure. The same individual can produce different structures corresponding to different behavior. The same individual may produce different structures corresponding with identical behavior but in different substrates. Identical structures may be produced by the activity of systematically different organisms where behavior is similar. Abundance - one animal, especially if mobile, can make many traces during its lifetime, whereas it may or may not have its body preserved in the fossil record.

1. I C H N O L O G Y,
C L A S S I F I C AT I O N
&
S I G N I F I C A N C E O F
T R A C E F O S S I L
B Y
U J J A V A L P A T E L
G E L 4 0 8

2. INTRODUCTION TO ICHNOLOGY
THE USE OF TRACE FOSSILS IN PALEONTOLOGY AND RELATED GEOSCIENCES.

3. THE CONCEPTUAL FRAMEWORK AND
PRINCIPLES OF ICHNOLOGY
• Most trace fossils are largely facies dependant.
• No secondary displacement or transport.
• Trace fossils are common in rocks that otherwise are unfossiliferous. (siliciclastics,
shorelines)
• Non-preservation of the causative organism.
• Multiple architects may produce a single structure.
• The same individual can produce different structures corresponding to different behavior.
• The same individual may produce different structures corresponding with identical behavior
but in different substrates.
• Identical structures may be produced by the activity of systematically different organisms
where behavior is similar.
• Abundance - one animal, especially if mobile, can make many traces during its lifetime,
whereas it may or may not have its body preserved in the fossil record.

6. TRACE FOSSIL CLASSIFICATION
• Trace fossils are classified in various ways for different purposes.
• Trace fossils have three distinct and significant aspects, to each of which a unique
classification attaches:
(1) The preservational (stratinomic), which treats of the origin of the fossil in the rocks
(2) The behavioral (ethological), which treats of the biological function represented in the
fossil.
(3) The phylogenetic (taxonomic), which is concerned with the identity of the organism that
produced the fossil.

8. • Trace fossils provide very useful in situ records for palaeoenvironmental interpretation
based on factors that influence the individual and the community. In a certain
stratigraphic succession the ecological information provided by trace fossils can be
pieced together to restore the local history of environmental change and basin
evolution.
• Trace fossils are largely facies-controlled and there are only few cases when they have
a real biostratigraphic value. For instance, the Precambrian - Phanerozoic boundary,
generally marked at the first occurrence of trilobite body fossils, could be better
defined by the study of the traces produced by trilobites. Recently the Proterozoic -
Cambrian boundary was defined on the basis of the first appearance of complex
feeding burrows, coelenterate impressions and arthropod traces, between
the Harlaniella podolica and the Phycodes pedum trace fossil zones.
• A correct interpretation of the preservational and deformational patterns of the trace
fossils found in tectonically deformed structures, can provide very useful information
about the type of folds (considering the preservational patterns) and deformation of
the original strata.

9. THE IMPORTANCE OF TRACE FOSSILS IN
GEOLOGY RESIDES ON THE FOLLOWING
CONCEPTS:
• Long time range - similar taxa occur in present day environments as they did early in
Phanerozoic, a useful concept for palaeoecological interpretations, although the long
time range restricts the value of trace fossils in biostratigraphy.
• Narrow facies range - certain traces are found in close association with certain
substrate (facies type).
• No reworking - traces themselves are a part of the fabric of a sedimentary rock, so
that they are destroyed by erosion, rather than released and reworked as the body
fossils.
• Occurrence in nonfossiliferous rocks - is usually of a great help for palaeoecological
and stratigraphical studies in hostile, poorly populated environments.
• Creation by soft-bodied taxa - trace fossils could give the only information about
organisms which are not otherwise found within the sedimentary record, by
demonstrating their presence (for instance the existence of soft-body metazoans prior
to evolution of hard body parts in Precambrian), or function through the interaction
with the sediment.

10. • In Structurally complicated areas where inverted beds may be expected to occurs
burrows & trails may be useful for distinguishing top & bottom of strata.
• By observing vertical & horizontal burrows that originally had tunnels with circular
cross section & elliptical the amount of lateral & vertical compression may be
quantitatively determined each rocks are especially favorable for the preservation of
trace fossils.
• Also many marine epicontinental sediments of all lebensspuren. However, these trace
fossil association are different composition & show less diversity than those in flysch
facies.
• In sediments not entirely marine in region, for example, the Lower Triassic Buntsand-
stein, which was deposited under essentially continental condition trace fossils are also
present.
• However, in contrast to the ichnocoenosess of marine environments, the number of
different types of nonmarine trace fossil is considerably use.
• Sediments without lebensspuren are rare. There are also sediments in which some
exogenic traces are preserved whereas endogenic burrows are absent, due to
ecologically unfavorable substrates.
• Homogeneous sediments may appear completely devoid of lebensspuren but this

11. • Lebensspuren usually have little importance in stratigraphy. In restricated areas,
however, they may attain the rank of index fossils.
• A long time range is one of the characteristics of most biogenic structures, the majority
of which remain unchanged through out geologic time.

12. REFERENCE
• Bromley, R. C. 1970. Borings as trace fossils and Entobia cretacea Portlock, as an example. In
T. P. Crimes and J. C. Harper (eds.), Trace fossils. Ceoi. Jour., Spec. Issue 3:49- 90.
• Ager, D. V. and P. Wallace. 1970. The distribution and significance of trace fossils in the
uppermost Jurassic rocks of the Boulonnais, northern France. In T. P. Crimes and J. C.
Harper (eds.), Trace fossils. Geol. Jour., Spec. Issue 3:1–18.