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E
Observations
I
E
Single colonization with
clearly visible primary
structures
Initial colonization of, for
example, an event bed by
a low diversity biota
Most likely an unstable
high sedimentation rate
environment, e.g.
estuarine
1
Successive colonization
without an increase in
biotic diversity
Gradual/moderate
sedimentation in stressed
environments
Possibly longer intervals
between events than in
examples 1 or 3 but with
low diversity biota
2
Simple tiering by
increasingly diverse biota
A wide range of
environments associated
with event beds
Moderate sedimentation
rates, but perhaps longer
intervals between events
than in example 1
3
Complex tiering
Gradual aggradation
Stable environment with
low sedimentation rates
4
Gradual overlap
Low sedimentation
Gradual environmental
change
5
Omission and possible
truncation of burrows
Sudden facies change,
perhaps with the
development of a
firmground or even
hardground
Period of non-deposition
and condensation
6
Figure A5.4 Examples of tiering of burrows and their implications. (Modifi ed after Goldring 1991.)
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