subunits of the c-Member exhibit the same larger forami-
niferal assemblage. The main contributors are Operculina
(O. complanata, O. sp.), heterosteginids [Heterostegina
(Vlerkina) assilinoides, H. cf. pusillumbonata, Planoste-
gina aff. giganteoformis], Amphistegina cf. lessonii, and
Lepidocyclina (Eulepidina) dilatata. Smaller nephrolepid-
inids (of morgani-type) are less frequent. Additionally,
miogypsinids were detected in the middle subunit.
Above, a siliciclastic-dominated unit occurs, made up of
marls, sandstones, silts, gypsum and carbonates (d-Mem-
ber: 33–37). The lower gypsum bed (33) is partly banded
and contains gypsum nodules of 0.5 cm in diameter. Red
and green siltstones cover the gypsum (34), showing wave
ripples and bioturbations at their base, while the upper part
exhibits a fine lamination. The siltstones are overlain by
ooid grainstones and a series of bryozoan packstones,
composed of cm-sized fragments of mostly erect folia-
ceous, framework-forming bryozoan colonies (35). The
bryozoans are accompanied by oysters, pectinids and
irregular echinoids. Higher in the section green marls (36)
and a package of laminated gypsum appear (37; Fig.
5
e).
The gypsum is covered by green and gray marls (e-
Member: 38–52) with ostracods and a rich foraminiferal
fauna including benthic and planktic forms. Textularia,
Spirorutilis, Baggina, Siphotextularia, Heterolepa, and
Fontbotia are characteristic benthic foraminifers at the base
of the e-Member (38), while benthic foraminifers dominated
by Cibicidoides, Uvigerina, and Heterolepa together with
Textularia, Spirorutilus, Cylindroclavulina, Pullenia, Mel-
onis, Praeglobobulimina, Gyroidinoides occur higher in the
e-Member marl sequence (48–52). Planktic foraminifers are
represented by Globigerina ottnangiensis, Gg. lentiana, Gg.
cf. ciperoensis, Gg. cf. officinalis, Globigerinella obesa,
Globigerinoides ruber, Gs. quadrilobatus, Gs. primordius,
Gs. trilobus, Globigerinella obesa, Globorotalia woodi,
Paragloborotalia?
inaequiconica,
Paragloborotalia?
pseudocontinuosa, Globorotaloides suteri, and Cassigeri-
nella chipolensis. The nannoplankton flora consists of
Reticulofenestra abisecta, R. floridana, Sphenolithus mori-
formis, S. cf. umbrellus, S. cf. pseudoradians, Helicosphaera
bramletti, H. cf. intermedia, H. cf. compacta, H. cf. carteri,
Coccolithus pelagicus, C. cf. micropelagicus, Coronocyclus
cf. nitescens, and Pontosphaera sp. Ostracods and burrow-
ing echinoids (Schizaster, 51) are also common. Some layers
are strongly bioturbated, others contain a high amount of
terrigenous quartz (52). Float- and packstone intercalations
contain echinoids, rhodolites, and mollusks (Harzhauser
2004
). Conspicuous are monospecific coquinas with artic-
ulated shells of the pectinid bivalve Costellamussiopecten
pasini (44–51).
The e-Member marls grade into a carbonate package (f-
Member: 53–132), which can be subdivided into three
subunits. In the lower one (53–75), marls are still interca-
lated
between
bioclastic
corallinacean-echinoderm
floatstones with dominating Lithothamnion, Neogonioli-
thon, and Spongites among corallinaceans. At the top of
this subunit isolated Porites corals with massive hemi-
spherical growth forms occur in situ (73). The lower
subunit is terminated by an erosional surface.
The middle part of the f-Member (76–101) is mainly
composed of packstones. Some beds contain accumulations
of mollusks, larger foraminifers, echinoids (Clypeaster, in
89 and 101) or isolated colonial corals (Porites). In bed 96
corals are associated with the thick-shelled bivalves Gi-
gantopecten
holgeri,
Modiolus
escheri,
Periglypta
miocaenica, and Megacardita crassa taurovata. Chert
concretions are enriched in some layers (76, 83, 88–87).
Upsection follows a subunit with a higher pelitic content
(102–132), including marls and corallinacean limestones
(floatstone, rudstone, packstone, grainstone). In marly in-
terbeds
(102–108)
benthic
foraminifers
(Ammonia,
nonionids) are common, while planktic foraminifers
(Globigerina praebulloides, Gg. postcretacea, Gg. dubia,
Gg. lentiana, Gg. ottnangiensis, Cassigerinella chipolensis,
C. boudecensis, Turborotalia quinqueloba, Tenuitella?
brevispira, Tenuitellinata angustiumbilicata) rarely occur.
Corals (Schuster and Wielandt
1999
), bivalves (Mandic
2000
), and gastropods (Harzhauser
2004
) are abundant.
Usually, corals occur as isolated dome-shaped and
branching colonies up to 70 cm in diameter and only spo-
radically form small (3–4 m width, 1.5 m thick) patch reefs
constructed mainly by faviids and Caulastraea (120–121).
The coralline algal flora is relatively diverse and comprises
encrusting growth forms as well as rhodolites both of
Spongites, Neogoniolithon, Lithothamnion, Sporolithon,
and Lithoporella species. The patch reefs interfinger with
grain- to packstones with a typical miliolid-soritid-Borelis
foraminiferal assemblage (Fig.
10
b), comprising Borelis
melo curdica, B. melo melo, B. haueri, Dendritina rangi,
Archaias hensoni, A. asmaricus, Peneroplis armorica, P.
laevigatus, P. evolutus, and Spirolina sp. The pectinid fauna
comprises Gigantopecten holgeri, Amussiopecten expansus,
Manupecten puymoriae, and Pecten subarcutus.
The transition of the Qom Fm. into the Upper Red Fm.
(133–145) is gradual and characterized by a drastic
increase of siliciclastics. Fossiliferous [echinoids, gastro-
pods (e.g., Ficus, Strombus), bivalves (Gigantopecten
holgeri and Manupecten puymoriae)] red marls, siltstones
and fine-grained sandstones prevail. Intercalated are
monotypic coquinas of the clam Polymesoda aff. brogni-
arti. Reddish, fine-grained sandstones with wave ripples,
laminated siltstones with plant debris, and conglomerates
of the Upper Red Fm. terminate the Qom section.
Fig. 9
Chalheghareh section; lithological succession, texture, water
depth trend, litho- and chronostratigraphy; see Fig.
4
for legend
b
Int J Earth Sci (Geol Rundsch)
123