Stratigraphy and Palaeontology
elahe zarei
Abstract
The Dalichai Formation in Ahvanu section in the north of Damghan city with a thickness of 78 meters consisting of an alternation of bluish-gray marls and limestone, was studied. Based on the presence and stratigraphic distribution of miospore, Klukisporites variegatus and Callialasporites dampieri of ...
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The Dalichai Formation in Ahvanu section in the north of Damghan city with a thickness of 78 meters consisting of an alternation of bluish-gray marls and limestone, was studied. Based on the presence and stratigraphic distribution of miospore, Klukisporites variegatus and Callialasporites dampieri of pollen are identified (Middle Jurassic) and presence of some index dinoflagellate species led to the identification of three biozones in the Dalichai Formation. These include in ascending order, Cribroperidinium crispum Total Range Biozone (late Bajocian), Dichadogonyaulax sellwoodii Interval Biozone (Bathonian - early Callovian), Ctenididinium continuum Interval Biozone (early to middle Callovian). Also, this Formation was divided into two biozone on the basis of Lenticulina varians-Ophtalmidium Assemblage zone and Globigerina bathoniana Taxon range zone. The close similarities of fauna assemblages of Dalichai Formation in this region (eastern Alborz ((dinoflagellate cyst, foraminifera, posidonia and radiolar) with assemblages recorded from different parts of Iran (such as central and eastern, western Alborz and Binalud and south of Iran) and other parts of world (northwest of Europe, and the northwestern Tethys and …) confirm the marine connection and faunal exchange between the mentioned basins during Middle Jurassic.
F Hosseinipour; M.J Hassani; M Dastanpour
Abstract
The Guri limestone member of the Mishan formation in SE of Zagros Basin (N of Bandar-e-Abbas) consists of the thick bedded limestone bearing oyster shells. Seven species of Ostreidae and Gryphaeidae belonging to four genera of Crassostrea, Cubitostrea, Ostrea and Hyotissa were identified as: Cubitostrea ...
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The Guri limestone member of the Mishan formation in SE of Zagros Basin (N of Bandar-e-Abbas) consists of the thick bedded limestone bearing oyster shells. Seven species of Ostreidae and Gryphaeidae belonging to four genera of Crassostrea, Cubitostrea, Ostrea and Hyotissa were identified as: Cubitostrea frondosa, Ostrea (cubitostrea) dubertreti, Cubitostrea digitalina, Crassostrea gryphoides, Hyotissa virleti, Ostrea vesitata and Ostrea plicatula. These fossils are reported from the Zagros Basin for the first time. These deposits assign to a Burdigalian age based on the presence of Borelis melo curdica. The reclining mode of life, adjacent right and left valves and rare erosion traces on shells indicate an in situ buried in hyper saline shallow and near shore water with moderate to low sedimentation rate. The early Miocene oyster assemblages similar to this studied assemblage have been reported from the other parts of Tethys showing a seaway connected to Tethys during the early Miocene. Therefore, the oysters can be used for the Paleogeographical correlation in the early Miocene deposits.
