Environmental Engineering Reference
In-Depth Information
ICHNOCOENOSES
Shallow carbonate sand platform
Deep water
1
1
Coral
patch
reef
b
1
?
?
Bay
a
4
2
5
b
?
4
1
d
5
c
4
5
a
Island
interior
1
Lagoonal mound
3
e
f
a
5
3
4
5
1
4
4
Sea level
Tidal
channel
g
2
2
5
Seaward
4
5
b
Tidal
delta
j
l
Island
interior
h
i
k
a. Callianassid burrows
b.
Skolithos linearis
1
c.
Conichnus conicus
d.
Leeward
Windward
Planolites
e.
Fiddler crab burrrows
Upogebia vasquezi burrows
f.
Psilonichnus upsilon
g.
h.
Cluster burrow
Rhizomorphs
i.
Coral
patch
reef
Coral
bank-barrier
reef
Rocky
headland
Sandy
beach with
dunes
Mangrove
coast
Lagoonal
callianassid
mounds
j. Small, irregular burrows
k. Stellate burrow
l. Coenobichnus currani
FIGURE 9 Hypothetical aerial views of two Bahamian islands and associated coastal environ-
ments. Panel at right illustrates the ichnocoenoses described in this section. Numbers key each
ichnoecoenosis to its environment of occurrence and letters indicate traces present. Modified from
Curran (2007) .
An ichnocoenosis represents an ecologically pure assemblage of traces or
trace fossils derived from collective activities of a single endobenthic community
( Bromley, 1996 ). In Bahamian-style settings, most trace-fossil assemblages are
true ichnocoenoses; the exception is the occurrence of rhizomorphs (or rhizoliths)
formed by plant roots. Rhizomorphs are typically an integral, and sometimes
dominant part of eolian complexes, but they also can result from plant roots pen-
etrating any preexisting lithofacies during an extended period of subaerial
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