A Ahifar; A Kani; H Amiri Bakhtiar
Abstract
Pabdeh Formation has been investigated in three sections viz. the Type Section, Tang-e Hatti and the northern limb of Gurpi Anticline within the ZagrosSedimentaryBasin with emphasis on calcareous nannofossils. Study of microscope slides prepared from the 1508 collected samples resulted in determination ...
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Pabdeh Formation has been investigated in three sections viz. the Type Section, Tang-e Hatti and the northern limb of Gurpi Anticline within the ZagrosSedimentaryBasin with emphasis on calcareous nannofossils. Study of microscope slides prepared from the 1508 collected samples resulted in determination of 256 species belonging to 59 genera from 22 families of nannofossils and biostratigraphic classification was carried out based on their stratigraphic distribution. According to Martini (1971) zonal scheme, presence of NP4-NP23 nannofossil zones at the Type Section, and NP5-NP23 nannofossil zones at both Tang-e Hatti and northern limb sections have been ascertained thus indicating Early Paleocene to Early Oligocene age for the Pabdeh Formation at these three localities. Calcareous nannofossil assemblages reveal sedimentation of Pabdeh Formation occurred in an oligotrophic, warm water environment during Paleocene-Eocene which was later on replaced by a relatively cooler water condition in Oligocene times.
A. Mahanipour; A. Kani; M. H. Adabi; S. N. Raisossadat
Abstract
The Lower Cretaceous sedimentary succession of western Kopet Dagh Basin (Sarcheshmeh and Sanganeh formations) was investigated. Taking into account the considerable thickness of the studied section (1668 m) and the possibility of recording all the important events, determination of calcareous nannofossil ...
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The Lower Cretaceous sedimentary succession of western Kopet Dagh Basin (Sarcheshmeh and Sanganeh formations) was investigated. Taking into account the considerable thickness of the studied section (1668 m) and the possibility of recording all the important events, determination of calcareous nannofossil biostratigraphy was put on the agenda. This resulted in recognition of NC5, NC6 and NC7A nannofossil zones. Accordingly the age of the Sarcheshmeh Formation within the studied section is determined as Late Barremian- Early Aptian while the age of the Sanganeh Formation is late Early Aptian- early Late Aptian. The calcareous nannofossil assemblage of Sarcheshmeh and Sanganeh Formations has a Tethyan affinity with abundant warm-water varieties such as Rhagodiscus spp. and Nannoconus spp. while the cold-water species like Repagulumparvidentatum and Seribiscutum spp. are rare.
