The specification states that you need to be able
to:
describe trace fossils:
Tracks
Trails
Burrows
and outline their use in interpreting
palaeoenvironments.
Trace fossils are traces left behind by an
animals activity but the remains of the animal
are not necessarily preserved.
Excellent Environmental
Indicators
This is because behaviour is often influenced by
environmental factors, trace fossils provide
important clues to the original conditions of
ancient environments.
Environmental factors reflected by trace fossils
include:
Salinity
Oxygen levels
Energy
Organismal interactions??????
Food supplies
Tracks
Footprints:
Can indicate
reptile/amphibian/bird or
mammal activity formed in
land/swamps or beach
environment.
The distance between
footprints combined with
finding out the length of the
leg (from fossils) can allow
you to work out the speed.
The depth of the footprint can
give a hint at the mass of the
animal.
Tracks
Cruziana
These are trails left behind by
trilobites (which are
arthropods with jointed
limbs).
As the trilobite moves along
each pair of llimbs leaves a
mark (like a centipede would
if it walked over wet mud).
Rusophycus
This is the correct term for a
“resting” trace formed as the
trilobite settled into the
sediment when resting.
Trails (Feeding Trails)
These include the
burrows of sediment
feeders usually with a
distinct threedimensional shape.
They may be dendritic or
multibranched.
Other feeding traces
consist of large vertical
and horizontal branching
tubes.
Burrows
Many fossils burrow into
sediment (infaunal) and will
leave a trace.
Often these are soft bodied
organisms that otherwise
would not be known.
They may be single burrows.
U-shaped (can indicate wayup).
Or complicated 3D shapes.
Fossil Poo
Additionally, trace
fossils inductive of
feeding behavior (and
diet) include predatory
borings and fossilized
excrement (called
coprolites).
Smaller fecal pellets
(microcoprolites) are
a common constituent
in many sediments.