List of Articles Palaeoecology

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  1 - Biostratigraphy and paleoecology of the e Member of the Qom Formation based on Ostracoda at Cheshmeh Boroun section, West of Qom
   Daneshian مسعود گودرزی
  The aim of this study is determining systematics and identification of ostracods genera and species of the e Member of the Qom Formation at the studied section (Cheshmeh Boroun) for biostratigraphy and age determination, and palaeoecological investigations considering t More

  The aim of this study is determining systematics and identification of ostracods genera and species of the e Member of the Qom Formation at the studied section (Cheshmeh Boroun) for biostratigraphy and age determination, and palaeoecological investigations considering the abundance and diversity changes of ostracods based on the collected data. The abundance and diversity of the ostracods taxa such as Paracypris، Aurila ،Ruggieria ،Loxochoncha ، Krithe، Xestoleberis, Cytherella mostly suggest a marine environment with normal salinity and warm climate from ecological point of view. However, the increase and decrease of these taxa in the studied section indicate the diversity and abundance changes is related to environmental changes. In fact, this shows the instability of the environmental conditions which seems to be affected by the changes of food and oxygen values, and water turbulence. Based on ostracods assemblages, an Early Miocene age ( Aquitanian- Burdigalian) is exclusively suggested for the e Member of the Qom Formation at Cheshmeh Boroun stratigraphic section. Manuscript profile
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  2 - Palynostratigraphy and palaeoecology of the Middle Jurassic strata, Tapal, west of Shahrood, eastern Alborz
  F. Sajjadi Firoozeh Hashemi Yazdi Hossain Hashemi
  Palynological data are used for palynostratigraphy and reconstruction of some environmental parameters of the Middle Jurassic (Bajocian - Callovian) deposits at the Tapal stratigraphic section, west of Shahrood, eastern Alborz. The studied strata (Dalichai Formation) co More

  Palynological data are used for palynostratigraphy and reconstruction of some environmental parameters of the Middle Jurassic (Bajocian - Callovian) deposits at the Tapal stratigraphic section, west of Shahrood, eastern Alborz. The studied strata (Dalichai Formation) contain diverse, relatively well-preserved palynofloras, including miospores (spores and pollens), dinoflagellates cysts, fungal spores, foraminiferal test linings, acritarchs and Tasmanites. The palynofloras include 22 species of spores (belonging to 18 genera), 15 species of pollen (attributed to 9 genera) and 28 species of dinoflagellate cysts (assigned to 15 genera). Based on the stratigraphic distribution of miospores, the Klukisporites variegatus-Araucariacites australis-Cerebropollenites macroverrucosus Assemblage Zone is recognized in the sequence examined, Presence of some index dinoflagellate species led to the identification of three successive biozones including, in an ascending order, Cribroperidinium crispum Total Range Zone (late Bajocian), Dichadogonyaulax sellwoodii Interval Zone (Bathonian – early Callovian) and Ctenidodinum continuum Interval Biozone (early - middle Callovian). To reconstruct some parameters of the sedimentary environments of the studied strata, evidences such as frequency and diversity of spores attributable to ferns, relative abundance of drier/wetter and warmer/cooler elements in different plant communities, ratio of palynological elements and palynofacies, presence of index shallow water dinoflagellate cysts for instance Dichadogonyaulax sellwoodii, Ctenidodinium spp., Valensiella ovulum, Pareodinia spp., Nannoceratopsis gracilis, abundance of proximate dinocysts forms, presence of fungal spores and warm - temperate water dinoflagellate (Gonyaulacysta centriconnata, Nannoceratopsis pellucida, Gonyaulacysta jurassica, Pareodinia ceratophora) are utilized. Based on the above criteria, the material examined seems to have been deposited in a marine margin, low oxygen environment, with low rate sedimentation, under hot and humid climate conditions, where the surrounding terrestrial vegetation was dominated by ferns. Manuscript profile
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  3 - Biostratigraphy and palaeoecology of Qom formation in the Ghamsr section (SW of the Kashan)
  tayyeb binazadeh Amrollah  Safari Hosyen Vaziri moghadam
  In order to study the biostratigraphy and palaeoecology, the Qom Formation has been studied in the Ghamsar section of Kashan. The studied section, with a thickness of 314 m, consists of medium to thick-bedded to massive limestones and shale. The Qom Formation overlies t More

  In order to study the biostratigraphy and palaeoecology, the Qom Formation has been studied in the Ghamsar section of Kashan. The studied section, with a thickness of 314 m, consists of medium to thick-bedded to massive limestones and shale. The Qom Formation overlies the Eocene volcanic rocks in the Ghamsar section and is covered by the Recent alluvial sediments. A total of 21 genera and 9 species of benthic foraminifera were identified in this section and the results indicated the age of Rupelian-Chattian. According to the above palaeoecological conditions, in the lower parts of this section (Rupelian), light conditions are euphotic and nutrient conditions are first eutrophic and then Meso-oligotrophic with mainly normal sea salinity. During Chattian, the trophic state was mainly meso-oligotrophic with normal salinity, and salinity varied between 40 and 50 PSU. Light conditions also were between aphotic and mainly meso-oligophotic. Large benthic foraminifera with hyaline walls, such as Amphistegina, Lepidocyclinide and Nummulitide, in shallow environments with high energy, have thicker shells and smaller shell size, and in deep environments, due to reduced light intensity and low water circulation, they have thinner and more elongated shells. The results of the morphometry of 186 samples of Amphistegina show that the seawater depth in Ghamsar section (Rupelian-Chattian) fluctuated from less than 11 meters to less than 44 meters. Manuscript profile