mohammad parandavar | G.S.I - Academia.edu (original) (raw)

Papers by mohammad parandavar

Research paper thumbnail of Stratigraphy of the Alveolina elliptica group from the Middle Eocene of Iran: Calibration with calcareous nannofossils biozones and description of Alveolina ozcani n. sp

Journal of Palaeogeography

Research paper thumbnail of Integrated biostratigraphy (orbitolinids and calcareous nannofossils) of the Lower Cretaceous Taft Formation in Isfahan, Central Iran

Cretaceous Research, Oct 1, 2021

Abstract The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological... more Abstract The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological unit of the Taft Formation, cropping out in Central Iran, that is known for its orbitolinid inventory. An integrated biostratigraphy based on agglutinated benthic foraminifera (mainly orbitolinids) and calcareous nannofossils was carried out for the unit. This upper part of the Taft Formation is dated here as early to middle Aptian on the basis of orbitolinids such as Iraqia simplex Henson, Dictyoconus? pachymarginalis Schroeder, Paleodictyoconus cuvillieri (Foury), Mesorbitolina lotzei (Schroeder), and Mesorbitolina parva (Douglass). Calcareous nannofossil index taxa appearing in the upper part of the “Upper Orbitolina Limestone” and also in the underlying shaly unit, including Percivalia fenestrata (Worsley), Percivalia sp., Hayesites irregularis Thierstein, Watznaueria barnesiae Perch-Nielsen, ?Phosterolithus prossii Aguado, ?Rhagodiscus achlyostaurion Hill, R. angustus Stander, Micrantholithus sp., and Eprolithus floralis Stander, support the assigned age by orbitolinids. Based on the discovery of lower Aptian deposits from the “Upper Orbitolina Limestone” (previously assigned to the upper Aptian), the Lower Cretaceous stratigraphy of the Isfahan area is revised.

Research paper thumbnail of Extending the stratigraphic range of Nummulites bormidiensis Tellini in the Neo-Tethys (Zagros basin, SE Iran) through biometry and calcareous nannofossil biostratigraphy

Micropaleontology

A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Format... more A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22-NP23 (=CNO2-CNO3) Zones.We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 um. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelianwhere classically just N. fichteli is reported so far. The stratig...

Research paper thumbnail of Biostratigraphy of Oligo-Miocene marine deposits of Central Iran basin based on calcareous nannoplanktons

Journal of Oceanography

Background and Objectives: The Oligo-Miocene marine deposits (Qom Formation) have been widely spr... more Background and Objectives: The Oligo-Miocene marine deposits (Qom Formation) have been widely spread in the Central Iran Zone. According to economic value of these marine deposits, this Formation studied by several researchers. While there are many differences opinion among researchers. For this reason, to solve the existing ambiguities, it is necessary to study with new tools and techniques. Therefore, the present study is the first study aimed at biostratigraphy based on calcareous nannoplankton that has been performed on all succession exposed from the Oligo-Miocene marine deposits (members a to f of the Qom Formation). Methods: The studied deposits are located in the middle part of the Central Iran Zone and more precisely in the Navab anticline (northeast of Kashan city), which has a thickness of 417 meters. Due to the location and expansion of all members in this section, it has been a very suitable area for biostratigraphic assessments comparable to world standard models. In this study, a total of 370 microscopic slides prepared from rock samples were studied to the determination of the calcareous nannoplankton and accurately separate world standard biological zones. Findings: The present study led to the identification of 72 species belonging to 18 genera of this valuable group of the planktonic microorganisms. According to the identified index species, standard nannoplankton biozones of the NP25 and NN1-NN4 were separated from this surface section of the Qom Formation. In addition, the equivalent biozones such as CNO5-6, CNM1-CNM6 as well as zones and subzones CP19b, CN1a, b, c, CN2-CN3, which belonging to the newest biozonation patterns, were also separated in this study. Conclusion: Therefore, based on the geological time value of the separated biozones, the age of late Chattian to late Burdigalian-early Langhian was proposed for the Qom Formation in the Navab anticline section. In this study, for the first time, the important chronostratigraphic boundaries such as the Paleogene-Neogene system boundary (or Chattian-Aquitanian stage boundary) in the upper parts of sub-member "c1", the Aquitanian-Burdigalian stage boundary at the base of member "e" and Burdigalian-Langhian in the upper part of member "f", were disaggregated based on biostratigraphic criteria.

Research paper thumbnail of Calcareous nannofossil biostratigraphy of the Qom Formation in Central Iran

Journal of Nannoplankton Research, Sep 12, 2017

Research paper thumbnail of Ypresian Alveolina and calcareous nannofossils from the south Sabzevar area (Central Iran): biostratigraphic, taxonomic and paleobiogeographic implications

Micropaleontology

The Eocene carbonates of the south Sabzevar region in central Iran hold a rich Alveolina assembla... more The Eocene carbonates of the south Sabzevar region in central Iran hold a rich Alveolina assemblage.Nine species including A. globula, Alveolina sp. 1, Alveolina aff. globula, A. regularis, A. globosa, A. pasticillata, A. laxa, A. pisiformis and A. cf. decipiens are identified through detailed analysis in thin section. The biostratigraphy obtained points to the early Ypresian Shallow Benthic Zones SBZ6 and partly SBZ7, indicating the occurrence of a lower Eocene carbonate system. The Alveolina biostratigraphy is correlated to the calcareous nannofossil biostratigraphy, and is assignable to the middle part of the NP10 Zone and especially with the CNE2 biozones. The evolutionary trends of A. globula and its dispersal through thewestern and central Neo-Tethys Ocean during theYpresian is here considered in relation with the occurrence of Alveolina sp. 1.

Research paper thumbnail of Biostratigraphic analysis of Assilina and calcareous nannofossil assemblages from the lower part of the Jahrum Formation (Zagros zone, Iran): insight into systematic of Assilina d'Orbigny

The present research is a study on the Assilina assemblages which are recorded from the lower par... more The present research is a study on the Assilina assemblages which are recorded from the lower part of the Jarum Formation in the Buldaji section, exposed in the Zagros region, southwest Iran. Studies on the systematic analysis and biostratigraphy of these assemblages resulted in diagnosis of three Assilina taxa: A. ex. interc. cuvillieri Schaub, 1981-tenuimarginata Heim, 1908, A. aspera Doncieux, 1948, and A. aff. aspera (Doncieux, 1948), associated with calcareous nannofossil assemblage. Biostratigraphically, we present new data assignable the SBZ13 and NP15/ CNE9-10 zones from the lower part of the Jahrum Formation (Zagros region) pertaining to the central Tethys. This integrated study indicates a precise correlation between Assilina and calcareous nannofossils zonations of the studied interval at a local stratigraphical scale, enabling us to make possible projections for future stratigraphic studies in the vicinity of Tethyan regions.

Research paper thumbnail of Calcareous nannofossils biostratigraphy of Late Maastrichtian- Early Paleocene in Sheikh Makan section (North-East of Kabir kuh)

Ui Journals System, Jun 15, 2013

Research paper thumbnail of Nummulitids of the shallow-marine middle Eocene limestones from the central Iran region: taxonomic and biostratigraphic implications

Micropaleontology

Nummulitid tests are recorded for the first time from an upper Lutetian limestone outcrop of the ... more Nummulitid tests are recorded for the first time from an upper Lutetian limestone outcrop of the Tihoieyeh section, exposed in the southwestern Jiroft region of central Iran. Detailed studies on their systematics and biostratigraphy resulted in the diagnosis of three nummulitid taxa as Assilina exponens Sowerby 1840, Nummulites deshayesi D’Archiac and Haime 1853 and Nummulites sp. cf. N. praelyelli. These larger benthic foraminifera are associated with calcareous nannofossil assemblages assignable to the SBZ16, NP16/CNE14 biozones.

Research paper thumbnail of The first marine record of the Bartonian Nummulites and Calcareous nannofossils at the Tihoiyeh section of the Jiroft area (Central Iran)

Research paper thumbnail of Integrated bio- and chemostratigraphy of the Cretaceous – Paleogene boundary interval in the Zagros Basin (Iran, eastern Tethys)

Palaeogeography, Palaeoclimatology, Palaeoecology

Research paper thumbnail of Integrated biostratigraphy (orbitolinids and calcareous nannofossils) of the Lower Cretaceous Taft Formation in Isfahan, Central Iran

The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological unit of ... more The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological unit of the Taft Formation, cropping out in Central Iran, that is known for its orbitolinid inventory. An integrated biostratigraphy based on agglutinated benthic foraminifera (mainly orbitolinids) and calcareous nannofossils was carried out for the unit. This upper part of the Taft Formation is dated here as early to middle Aptian on the basis of orbitolinids such as Iraqia simplex Henson, Dictyoconus? pachymarginalis Schroeder, Paleodictyoconus cuvillieri (Foury), Mesorbitolina lotzei (Schroeder), and Mesorbitolina parva (Douglass). Calcareous nannofossil index taxa appearing in the upper part of the “Upper Orbitolina Limestone” and also in the underlying shaly unit, including Percivalia fenestrata (Worsley), Percivalia sp., Hayesites irregularis Thierstein, Watznaueria barnesiae Perch-Nielsen, ?Phosterolithus prossii Aguado, ?Rhagodiscus achlyostaurion Hill, R. angustus Stander, Micrantholith...

Research paper thumbnail of Biostratigraphical investigation of calcareous nannofossils: The middle Paleogene to early Neogene strata from the eastern parts of Iran (Median Tethys sea-way)

Russian Journal of Earth Sciences

Research paper thumbnail of Evaluation of Organic Matter Richness of Eocene Strata Based on Calcareous Nannofossils and Rock-Eval Analysis in North Dezful, Iran

Journal of Earth Science

Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic ge... more Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic geochemistry and distribution of calcareous nannofossils. Based on the results, an Eocene-aged organic matter (OM)-rich interval was identified and traced across different parts of the North Dezful zone and partly Abadan Plain. In order to characterize the OM quality and richness of the studied intervals, Rock-Eval pyrolysis and nannofossils evaluation were performed, and the geochemical data collected along selected wells were correlated to capture the variations of thickness and source potential of the OM-rich interval. Accordingly, remarkable variations were identified within the depth ranges of 2 480–2 552 m and also 2 200–2 210 m, which were attributed to the maximum increase in the rate of growth R-selected species. This increase in the productivity rate was found to be well correlated to high Rock-Eval total organic carbon (TOC) and hydrogen index (HI) values. Given that the maturity of Pabdeh Formation in the studied area was found to have reached the oil window, we expect significant hydrocarbon generation (Type II kerogen), making the play economically highly promising.

Research paper thumbnail of Identification of the Oligocene-Miocene boundary in the Central Iran Basin (Qom Formation): calcareous nannofossil evidences

Geological Quarterly, May 23, 2019

As so ci ate Ed i tor-Wojciech Granoszewski A di verse Late Oligocene to Early Mio cene cal car e... more As so ci ate Ed i tor-Wojciech Granoszewski A di verse Late Oligocene to Early Mio cene cal car e ous nannofossil as sem blage was ex am ined from the Qom For ma tion in the Cen tral Iran Ba sin, and the Oligocene-Mio cene bound ary was iden ti fied based on the quan ti ta tive anal y sis of the as semblages in 303 smear slides. Eleven well-es tab lished cal car e ous nannofossil bio-events are de lin eated in the Up per Oligocene through Lower Mio cene. The re sults clearly show that the High est Oc cur rence (HO) of Sphenolithus delphix is the clos est bio-event to the bound ary as tra di tion ally de lin eated on the lithostratigraphic cri te ria, and pro vides a dis tinct biohorizon be low it. The Low est Oc cur rence (LO) of the spe cies Discoaster druggii is the old est Mio cene bio-event that is observed shortly af ter the HO of S. delphix, show ing that cal car e ous nannofossils are well suited for ap prox i mat ing the Oligocene-Mio cene bound ary in the Qom For ma tion. The Oligocene-Mio cene bound ary is placed in the up per part of Sub-mem ber "c1" in all three sec tions stud ied here and it is trace able through out the Cen tral Iran Ba sin, which makes a poten tially re li able marker ho ri zon for se quence strati graphic and hy dro car bon stud ies in the area.

Research paper thumbnail of Calcareous nannofossil biostratigraphy of the Late Cretaceous‒early Paleocene interval in the Zagros basin (southeastern Tethys), Iran

Alcheringa: An Australasian Journal of Palaeontology

Research paper thumbnail of Stratigraphy of the Alveolina elliptica group from the Middle Eocene of Iran: Calibration with calcareous nannofossils biozones and description of Alveolina ozcani n. sp

Journal of Palaeogeography

Research paper thumbnail of Integrated biostratigraphy (orbitolinids and calcareous nannofossils) of the Lower Cretaceous Taft Formation in Isfahan, Central Iran

Cretaceous Research, Oct 1, 2021

Abstract The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological... more Abstract The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological unit of the Taft Formation, cropping out in Central Iran, that is known for its orbitolinid inventory. An integrated biostratigraphy based on agglutinated benthic foraminifera (mainly orbitolinids) and calcareous nannofossils was carried out for the unit. This upper part of the Taft Formation is dated here as early to middle Aptian on the basis of orbitolinids such as Iraqia simplex Henson, Dictyoconus? pachymarginalis Schroeder, Paleodictyoconus cuvillieri (Foury), Mesorbitolina lotzei (Schroeder), and Mesorbitolina parva (Douglass). Calcareous nannofossil index taxa appearing in the upper part of the “Upper Orbitolina Limestone” and also in the underlying shaly unit, including Percivalia fenestrata (Worsley), Percivalia sp., Hayesites irregularis Thierstein, Watznaueria barnesiae Perch-Nielsen, ?Phosterolithus prossii Aguado, ?Rhagodiscus achlyostaurion Hill, R. angustus Stander, Micrantholithus sp., and Eprolithus floralis Stander, support the assigned age by orbitolinids. Based on the discovery of lower Aptian deposits from the “Upper Orbitolina Limestone” (previously assigned to the upper Aptian), the Lower Cretaceous stratigraphy of the Isfahan area is revised.

Research paper thumbnail of Extending the stratigraphic range of Nummulites bormidiensis Tellini in the Neo-Tethys (Zagros basin, SE Iran) through biometry and calcareous nannofossil biostratigraphy

Micropaleontology

A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Format... more A biometrical study on four reticulate Nummulites populations from the lower part ofAsmari Formation of the Vazag section (Zagros zone) is carried out. The biostratigraphy obtained by studing the succession points to the Early Oligocene (Rupelian), indicating shallow benthic zones SBZ21 and SBZ22A by the occurrence of Operculina cf. complanata, Eulepidina formosoides, Nephrolepidina sp. The age assignment is calibrated with calcareous nannofossils biostratigraphy indicating the NP22-NP23 (=CNO2-CNO3) Zones.We have observed a stratigraphic trend related to Nummulites bormidiensis Tellini 1888 that results to be characterized by two populations composed of transitional Nummulites fichteli/bormidiensis with values of mean inner proloculus that exceeds by very little the boundary commonly established at 300 um. Such a populations, indicated as Nummulites ex interc. bormidiensis et fichteli, span through the lower Rupelianwhere classically just N. fichteli is reported so far. The stratig...

Research paper thumbnail of Biostratigraphy of Oligo-Miocene marine deposits of Central Iran basin based on calcareous nannoplanktons

Journal of Oceanography

Background and Objectives: The Oligo-Miocene marine deposits (Qom Formation) have been widely spr... more Background and Objectives: The Oligo-Miocene marine deposits (Qom Formation) have been widely spread in the Central Iran Zone. According to economic value of these marine deposits, this Formation studied by several researchers. While there are many differences opinion among researchers. For this reason, to solve the existing ambiguities, it is necessary to study with new tools and techniques. Therefore, the present study is the first study aimed at biostratigraphy based on calcareous nannoplankton that has been performed on all succession exposed from the Oligo-Miocene marine deposits (members a to f of the Qom Formation). Methods: The studied deposits are located in the middle part of the Central Iran Zone and more precisely in the Navab anticline (northeast of Kashan city), which has a thickness of 417 meters. Due to the location and expansion of all members in this section, it has been a very suitable area for biostratigraphic assessments comparable to world standard models. In this study, a total of 370 microscopic slides prepared from rock samples were studied to the determination of the calcareous nannoplankton and accurately separate world standard biological zones. Findings: The present study led to the identification of 72 species belonging to 18 genera of this valuable group of the planktonic microorganisms. According to the identified index species, standard nannoplankton biozones of the NP25 and NN1-NN4 were separated from this surface section of the Qom Formation. In addition, the equivalent biozones such as CNO5-6, CNM1-CNM6 as well as zones and subzones CP19b, CN1a, b, c, CN2-CN3, which belonging to the newest biozonation patterns, were also separated in this study. Conclusion: Therefore, based on the geological time value of the separated biozones, the age of late Chattian to late Burdigalian-early Langhian was proposed for the Qom Formation in the Navab anticline section. In this study, for the first time, the important chronostratigraphic boundaries such as the Paleogene-Neogene system boundary (or Chattian-Aquitanian stage boundary) in the upper parts of sub-member "c1", the Aquitanian-Burdigalian stage boundary at the base of member "e" and Burdigalian-Langhian in the upper part of member "f", were disaggregated based on biostratigraphic criteria.

Research paper thumbnail of Calcareous nannofossil biostratigraphy of the Qom Formation in Central Iran

Journal of Nannoplankton Research, Sep 12, 2017

Research paper thumbnail of Ypresian Alveolina and calcareous nannofossils from the south Sabzevar area (Central Iran): biostratigraphic, taxonomic and paleobiogeographic implications

Micropaleontology

The Eocene carbonates of the south Sabzevar region in central Iran hold a rich Alveolina assembla... more The Eocene carbonates of the south Sabzevar region in central Iran hold a rich Alveolina assemblage.Nine species including A. globula, Alveolina sp. 1, Alveolina aff. globula, A. regularis, A. globosa, A. pasticillata, A. laxa, A. pisiformis and A. cf. decipiens are identified through detailed analysis in thin section. The biostratigraphy obtained points to the early Ypresian Shallow Benthic Zones SBZ6 and partly SBZ7, indicating the occurrence of a lower Eocene carbonate system. The Alveolina biostratigraphy is correlated to the calcareous nannofossil biostratigraphy, and is assignable to the middle part of the NP10 Zone and especially with the CNE2 biozones. The evolutionary trends of A. globula and its dispersal through thewestern and central Neo-Tethys Ocean during theYpresian is here considered in relation with the occurrence of Alveolina sp. 1.

Research paper thumbnail of Biostratigraphic analysis of Assilina and calcareous nannofossil assemblages from the lower part of the Jahrum Formation (Zagros zone, Iran): insight into systematic of Assilina d'Orbigny

The present research is a study on the Assilina assemblages which are recorded from the lower par... more The present research is a study on the Assilina assemblages which are recorded from the lower part of the Jarum Formation in the Buldaji section, exposed in the Zagros region, southwest Iran. Studies on the systematic analysis and biostratigraphy of these assemblages resulted in diagnosis of three Assilina taxa: A. ex. interc. cuvillieri Schaub, 1981-tenuimarginata Heim, 1908, A. aspera Doncieux, 1948, and A. aff. aspera (Doncieux, 1948), associated with calcareous nannofossil assemblage. Biostratigraphically, we present new data assignable the SBZ13 and NP15/ CNE9-10 zones from the lower part of the Jahrum Formation (Zagros region) pertaining to the central Tethys. This integrated study indicates a precise correlation between Assilina and calcareous nannofossils zonations of the studied interval at a local stratigraphical scale, enabling us to make possible projections for future stratigraphic studies in the vicinity of Tethyan regions.

Research paper thumbnail of Calcareous nannofossils biostratigraphy of Late Maastrichtian- Early Paleocene in Sheikh Makan section (North-East of Kabir kuh)

Ui Journals System, Jun 15, 2013

Research paper thumbnail of Nummulitids of the shallow-marine middle Eocene limestones from the central Iran region: taxonomic and biostratigraphic implications

Micropaleontology

Nummulitid tests are recorded for the first time from an upper Lutetian limestone outcrop of the ... more Nummulitid tests are recorded for the first time from an upper Lutetian limestone outcrop of the Tihoieyeh section, exposed in the southwestern Jiroft region of central Iran. Detailed studies on their systematics and biostratigraphy resulted in the diagnosis of three nummulitid taxa as Assilina exponens Sowerby 1840, Nummulites deshayesi D’Archiac and Haime 1853 and Nummulites sp. cf. N. praelyelli. These larger benthic foraminifera are associated with calcareous nannofossil assemblages assignable to the SBZ16, NP16/CNE14 biozones.

Research paper thumbnail of The first marine record of the Bartonian Nummulites and Calcareous nannofossils at the Tihoiyeh section of the Jiroft area (Central Iran)

Research paper thumbnail of Integrated bio- and chemostratigraphy of the Cretaceous – Paleogene boundary interval in the Zagros Basin (Iran, eastern Tethys)

Palaeogeography, Palaeoclimatology, Palaeoecology

Research paper thumbnail of Integrated biostratigraphy (orbitolinids and calcareous nannofossils) of the Lower Cretaceous Taft Formation in Isfahan, Central Iran

The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological unit of ... more The so-called “Upper Orbitolina Limestone” of Isfahan is a relatively thick lithological unit of the Taft Formation, cropping out in Central Iran, that is known for its orbitolinid inventory. An integrated biostratigraphy based on agglutinated benthic foraminifera (mainly orbitolinids) and calcareous nannofossils was carried out for the unit. This upper part of the Taft Formation is dated here as early to middle Aptian on the basis of orbitolinids such as Iraqia simplex Henson, Dictyoconus? pachymarginalis Schroeder, Paleodictyoconus cuvillieri (Foury), Mesorbitolina lotzei (Schroeder), and Mesorbitolina parva (Douglass). Calcareous nannofossil index taxa appearing in the upper part of the “Upper Orbitolina Limestone” and also in the underlying shaly unit, including Percivalia fenestrata (Worsley), Percivalia sp., Hayesites irregularis Thierstein, Watznaueria barnesiae Perch-Nielsen, ?Phosterolithus prossii Aguado, ?Rhagodiscus achlyostaurion Hill, R. angustus Stander, Micrantholith...

Research paper thumbnail of Biostratigraphical investigation of calcareous nannofossils: The middle Paleogene to early Neogene strata from the eastern parts of Iran (Median Tethys sea-way)

Russian Journal of Earth Sciences

Research paper thumbnail of Evaluation of Organic Matter Richness of Eocene Strata Based on Calcareous Nannofossils and Rock-Eval Analysis in North Dezful, Iran

Journal of Earth Science

Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic ge... more Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic geochemistry and distribution of calcareous nannofossils. Based on the results, an Eocene-aged organic matter (OM)-rich interval was identified and traced across different parts of the North Dezful zone and partly Abadan Plain. In order to characterize the OM quality and richness of the studied intervals, Rock-Eval pyrolysis and nannofossils evaluation were performed, and the geochemical data collected along selected wells were correlated to capture the variations of thickness and source potential of the OM-rich interval. Accordingly, remarkable variations were identified within the depth ranges of 2 480–2 552 m and also 2 200–2 210 m, which were attributed to the maximum increase in the rate of growth R-selected species. This increase in the productivity rate was found to be well correlated to high Rock-Eval total organic carbon (TOC) and hydrogen index (HI) values. Given that the maturity of Pabdeh Formation in the studied area was found to have reached the oil window, we expect significant hydrocarbon generation (Type II kerogen), making the play economically highly promising.

Research paper thumbnail of Identification of the Oligocene-Miocene boundary in the Central Iran Basin (Qom Formation): calcareous nannofossil evidences

Geological Quarterly, May 23, 2019

As so ci ate Ed i tor-Wojciech Granoszewski A di verse Late Oligocene to Early Mio cene cal car e... more As so ci ate Ed i tor-Wojciech Granoszewski A di verse Late Oligocene to Early Mio cene cal car e ous nannofossil as sem blage was ex am ined from the Qom For ma tion in the Cen tral Iran Ba sin, and the Oligocene-Mio cene bound ary was iden ti fied based on the quan ti ta tive anal y sis of the as semblages in 303 smear slides. Eleven well-es tab lished cal car e ous nannofossil bio-events are de lin eated in the Up per Oligocene through Lower Mio cene. The re sults clearly show that the High est Oc cur rence (HO) of Sphenolithus delphix is the clos est bio-event to the bound ary as tra di tion ally de lin eated on the lithostratigraphic cri te ria, and pro vides a dis tinct biohorizon be low it. The Low est Oc cur rence (LO) of the spe cies Discoaster druggii is the old est Mio cene bio-event that is observed shortly af ter the HO of S. delphix, show ing that cal car e ous nannofossils are well suited for ap prox i mat ing the Oligocene-Mio cene bound ary in the Qom For ma tion. The Oligocene-Mio cene bound ary is placed in the up per part of Sub-mem ber "c1" in all three sec tions stud ied here and it is trace able through out the Cen tral Iran Ba sin, which makes a poten tially re li able marker ho ri zon for se quence strati graphic and hy dro car bon stud ies in the area.

Research paper thumbnail of Calcareous nannofossil biostratigraphy of the Late Cretaceous‒early Paleocene interval in the Zagros basin (southeastern Tethys), Iran

Alcheringa: An Australasian Journal of Palaeontology