Aretz et al_2011.pdf - ORBi - Université de Liège

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Kölner Forum Geol. Paläont., 19 (2011)
M. ARETZ, S. DELCULÉE, J. DENAYER & E. POTY (Eds.)
Abstracts, 11th Symposium on Fossil Cnidaria and Sponges, Liège, August 19-29, 2011
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14
Study of Carboniferous Corals in the Ozbak-kuh Mountains (East of
Central Iran)
Mahdi BADPA 1 , Kaveh KHAKSAR 2 & Alireza ASHOURI 1
1 Ferdowsi Universityof Mashhad, Center of excellence for paleontology, Mashhad, Iran;
MahdiBadpa110@gmail.com
2 High Education Center of Jahad Keshavarzi, Karaj, Iran; kavehkhaksar@gmail.com
During Upper Visean-Gzhelian times, marine sedimentation was restricted to the East of Central Iran.
Carbonates of the Ozbak Kuh Mountains are rather unique for the Carboniferous of Iran, which is
commonly represented by sandy-shaly facies. In order to study Carboniferous corals, the Zeludu section in
the Ozbak Kuh Mountains was selected. The Carboniferous strata in this section are 360 meters thick and
are Late Visean to Late Gzhelian in age.
After field studies and sampling, 100 specimens of corals were selected and studied.
In the studied section, 19 species and 1 subspecies belong to 10 genera of rugose and tabulae corals.
These include the following species: Heritschioides pseudosolitarius, Heritschioides vepres, Heritschioides cf.
vepres, Paraheritschiodes antoni antoni, Orygmophyllum sp., Durhamina sp., Fomichevella hoeli, Fomichevella
holtedahli, Fomichevella nevadensis, Fomichevella orientalis, Fomichevella stuckenbergi, Petalaxis sp., Michelinia
sp., Minatoa bulla, Multithecopora sp. 1, Multithecopora sp. 2, Pseudozaphrentoides winsensi, Pseudozaphrentoides
aff. melendezi and Pseudozaphrentoides sp.
In this study, we reviewed the ages of the species Heritschioides vepres, H. pseudosolitarius, H. cf. vepres,
Paraheritschiodes antoni antoni and Pseudozaphrentoides winsensi. Three genera (including Orygmophyllum,
Petalaxis and Durhamina) and six species (Fomichevella hoeli, F. holtedahli, F. nevadensis, F. orientalis, F.
stuckenbergi and Pseudozaphrentoides aff. melendezi,) are reported for the first time from Iran.
The coral abundance in the studied section is heterogeneous. Three limestone members contain coral
faunas.
Member 1 is composed of a one meter thick chertified micritic limestone and contains a coral fauna of
low abundance: Heritschioides, Paraheritschioides, Durhamina, Multithecopora and Orygmophyllum. It is late
Serpokhovian in age.
Member 2 comprises a 5 meter thick package of micritic limestone. Its coral fauna consists of
Fomichevella, Minatoa, Michelinia, Multithecopora and Petalaxis. It is early Bashkirian in age.
Member 3 is 35 m thick. It comprises medium-bedded limestones containg abundant solitary corals.
There are two 20 cm thick coral beds, which merely consist of Pseudozaphrentoides in growth position.
Indeed, these beds represent high abundant, but low diverse coral faunas.
Based on ecological evidences, corallite arrangements and dissepiments thicknesses, three
paleoecological zones in respect to zonations along a shallow carbonate ramp can be differentiated in the
Zeludu section.
Zone 1 consists of fasciculate dendroid and solitary corals, belonging to a quiet and low energy lagoon.
This zone is found in the late Serpokhovian. It should be mentioned that in this zone, paleoecological
factors such as endemism and extinction phases are considered uniquely especially for the Durhaminidae
fauna.
Zone 2 consists of diversified colony builder and predominantly path-like ones, resembling cerioid and
asteroid corals. The mentioned coral assemblage indicates highly agitated water in a shallow setting, and is
Early Bashkirian in age.
Zone 3 consists of large and thick dissepiments corals froming a biostrome. It indicates high energy
shallow water environment and open marine towards a barrier. This zone is Gzhelian in age.