sequence. Paleoecological interpretations of the Turritella-
dominated gastropod fauna suggest a shallow to moder-
ately deep sublittoral environment for this part of the
section (Harzhauser
2004
). The upsection loss of sand, and
the solitary coral assemblage in marls with abundant
plankton, documents a new rise of relative sea-level during
the
second
depositional
sequence.
Associated
erect
branching bryozoans suggest low water energy conditions
in a deeper habitat (e.g., Smith
1995
), as is also indicated
by the co-occurring lepidocyclinids, which are represented
by large discoid forms that are typical for deeper, low light
environments (Hallock
1985
; Hallock and Glenn
1986
;
Pedley
1998
). Accompanying Leptoseris build-ups (20)
also point to a relatively deep environment (Kahng and
Maragos
2006
). Argillaceous limestones with sandy inter-
calations (23–27) preluded a shallowing succession.
Nummulites tests in Callianassa burrows of bed 25 point to
relocation and represent relictic, storm generated deposits
that are trapped in the burrows (Wanless et al.
1988
;
Beavington-Penny et al.
2006
). Sustained shallowing is
documented by the coral-bearing succession above (28–
32). The presence of sparsely distributed, large, hemi-
spherical colonial corals in life position (Perrin et al.
1995
),
and the high content of clay in limestones, indicate a
moderately deep environment below the fair-weather wave
base. Upsection, colony size and frequency of corals
increase and the non-constructional coral assemblage shifts
into a patch reef facies for which Schuster and Wielandt
(
1999
) discuss a water depth between 5 and 20 m. Mi-
croatolls on some coral colonies (Fig.
5
b) document that
vertical reef growth was limited by the sea-surface, and
that corals on top of the patch reefs became exposed at
lowest tides (Woodroffe and Gagan
2000
). The gastropod
fauna from the inter-reef areas is characterized by herbi-
vorous taxa pointing to the presence of seagrasses
(Harzhauser
2004
). Upsection the shallowing trend con-
tinued and a restricted lagoonal milieu established, as
indicated by the dominance of porcellaneous foraminifers
(Sen Gupta
1999
) in the marl on top of the patch reef facies
(34). The second sequence terminates with an erosional
surface that reflects emersion.
The third sequence is initiated by a fluvial conglomerate
(35) that was deposited during a sea-level lowstand and
which is followed by a thin succession of coastal clastics.
The latter contain intercalated, low-diversity, potamidid-
neritid gastropod coquinas (Fig.
10
a) that suggest a littoral
environment with fluctuating salinities in the vicinity of
mangroves (Harzhauser
2004
). Highly diverse mollusk
faunas from the overlying bioturbated marls (41–48) point
to a shallow subtidal and restricted lagoonal environment
with seagrass meadows (Mandic
2000
; Harzhauser
2004
).
The associated benthic foraminiferal fauna supports the
assumption of seagrass with the occurrence of soritids and
peneroplids (Sen Gupta
1999
). A coral reef sequence fol-
lows above (49–52), which indicates a minimal rise of
relative sea-level that provided the necessary accommo-
dation space. The reef facies is formed by massive
hemispherical and crustose corals as well as by coralline
red algae that form a rigid framework with a high resis-
tance against wave damage in a shallow exposed position.
The large discoid tests of lepidocyclinids, abundant deli-
cate branching bryozoans, planktic foraminifers, and
articulated pectinids in marls above the reef limestone (53–
54; Fig.
10
e) point to a low energy, turbid and low light
environment (Hallock
1985
; Hallock and Glenn
1986
). It
established during maximum flooding after drowning of the
reef.
The thick package of skeletal limestones above (55–61)
is mainly composed of remains of light-dependent biota
(corallinaceans, larger foraminifers, corals). It therefore
suggests a formation in the shallower photic zone during a
relative sea-level fall. At the base of the skeletal limestone
succession floatstones dominate. These were deposited in
relatively deep settings below the fair-weather wave base,
as indicated by their high content of fine-grained matrix.
Upsection, increasing fragmentation of the bioclasts caused
by an increase in water energy, and loss of matrix due to
winnowing is noticed. The corallinacean-foraminiferal rud-
and grainstones (Fig.
10
c) are indicative of a shallow
subtidal setting. Because the density in coral cover
decreases with depth (Perrin et al.
1995
), the shift from an
in situ, non-constructional coral community with large
hemispherical colonies (55–57) to an in situ patch reef
assemblage (58) displays shallowing. The limestones
above the patch reef facies suggest an increase in water
energy and shallowing since they exclusively contain top-
pled coral colonies and coral rubble. Abundant soritids and
peneroplids point to seagrass meadows (Sen Gupta
1999
).
Zefreh sections
In the Zefreh sections (Figs.
5
,
6
) four depositional
sequences (Zefreh A: three sequences, Zefreh B: one
sequence) are recognized in the Qom Fm., which trans-
grade over continental siliciclastics of the Lower Red Fm.
(A1–3). The beginning of the first sequence is a thin
alternation of marl and siliciclastics (A4–10) with a marine
fauna for which a shallow nearshore environment is indi-
cated by cross-bedding texture. Subsequently, marls
developed (A11) for which abundant plankton indicates
increasing water depths and a deeper offshore environment.
A package of bryozoan rud- and grainstones (A13), and
siltstones (A12, 14) initiate the onset of the second
sequence. For their formation, the high amount of terrige-
nous quartz and the rudstone texture suggest a shallow
Int J Earth Sci (Geol Rundsch)
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