Stratigraphy and Palaeontology
Nasrollah Abbassi; Safoora Shakeri; Javad Rabbani
Abstract
Numerous Proboscidean footprints have been discovered in the outcrop (135 m) of lower rock unit of the Upper Red Formation (Middle-Late Miocene) in the north Avaj (Qazvin province), central Iran. These footprints are preserved as circular concave epi-relief in the upper bedding planes with smooth or ...
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Numerous Proboscidean footprints have been discovered in the outcrop (135 m) of lower rock unit of the Upper Red Formation (Middle-Late Miocene) in the north Avaj (Qazvin province), central Iran. These footprints are preserved as circular concave epi-relief in the upper bedding planes with smooth or levee rims or with sediment accumulation in the front of the footprints. Five digit imprints present in some of the footprints. The frequency of footprints is considerable the most of the upper surface of layers which was resulted by movement of proboscis herds. Ichnotaxonomically these footprints identified as Proboscipedaen igmatica. The footprints are classified as two sizes as small (15 cm) and large (25 cm) categories, and based on the geometric relationships, the height of shoulder was estimated as 140-170 cm for adult and 76-106 cm immature individuals. According to reports of Miocene Proboscidean body fossils from Iran, and based on the distributions of the Proboscidean in this time, it seems that the Choerolophodon (Gomphotheriidae) is candidate as track-maker of the Avaj footprints. Among the Proboscidean footprints, there are crocodile and fish swimming imprints which were left in the shallow pools.
Stratigraphy and Palaeontology
Abdolvahab Kazemi; Nasrollah Abbassi
Abstract
Agha Jari Formation (Miocene-Pliocene, 788 m) comprises alternations of sandstone, siltstone, and marl in red to brown color layers in the east Gotvand, north Khuzestan province, southwest Iran. Numerous vertebrate footprints have been found in the middle part of the Formation, which includes footprints ...
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Agha Jari Formation (Miocene-Pliocene, 788 m) comprises alternations of sandstone, siltstone, and marl in red to brown color layers in the east Gotvand, north Khuzestan province, southwest Iran. Numerous vertebrate footprints have been found in the middle part of the Formation, which includes footprints of wetland small bird (Aviadactyla media, Gruipeda dominguensis), artiodactyls (Lamaichnum alfi, Lamaichnum isp., Pecoripeda satyri, Pecoripeda isp.), canids (Canipeda isp.) and large reptiles (Hatcherichnus sanjuanensis). Frequency of artiodactyl imprints are more than the other footprints. These footprints proof the living of camels and crocodiles in the Zagros basin for the first time. The ichnotaxa diversity of the footprints in the studied section is more than the other reports of Agha Jari Formation in Iran and its stratigraphic equivalent in the adjacent countries.
Enayatallah Haghfarshi; Peyman Rezaee; Seyed Reza Moosavi Harami; Mohammad Faridi
Abstract
Lignite Beds of Tabriz are among of the Neogene formations in the northwestern area of the Iran, which is spread in the eastern suburb of Tabriz. Its sedimentary facies includes facies groups of fine grains clastics, sandstones, limestones and facies of lignite, tuff and microfacies and petrofacies under ...
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Lignite Beds of Tabriz are among of the Neogene formations in the northwestern area of the Iran, which is spread in the eastern suburb of Tabriz. Its sedimentary facies includes facies groups of fine grains clastics, sandstones, limestones and facies of lignite, tuff and microfacies and petrofacies under them. In this study, two stratigraphic sections of these sediments in the eastern part of Tabriz were studied and 171 samples and 42 thin sections were collected and studied. XRD analysis for mineralogy and SEM electron microscopy for 3-dimensional studies were used to identify microfossils. Identified fossils include the genera and species of gastropods, Pelecypods, ostracods, fish, diatoms, charophyte algae, and foraminifera. The studied fossil assemblages includes species from freshwater to euryhaline and marine. The identified sedimentary environments include the lake basin environment, the shallow coastal environment and the marshy lake environment. In the studied sedimentary strata, strong fossil evidence and sedimentological evidence of the marine environment are not observed, at least during its lifetime. Therefore, it is concluded that the marine taxis in these deposits remain and are adapted from a former marine environment.
Sedimentology
Mahmoud sharafi; Arsalan Zeinalzadeh; Aram Bayet-Goll; Bijan Biranvand; Mehran Moradpour; Farid Taati
Abstract
Miocene siliciclastic sediments with 338m thick are studied in the southern Neka of Northern Alborz flank. Detailed sedimentology study allows recognition four facies associations consist of delta plain, distributary channel, delta front and pro-delta. Delta plain and tidal flat include heterolithic ...
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Miocene siliciclastic sediments with 338m thick are studied in the southern Neka of Northern Alborz flank. Detailed sedimentology study allows recognition four facies associations consist of delta plain, distributary channel, delta front and pro-delta. Delta plain and tidal flat include heterolithic shale-silt-sand and limestone with fenestral fabric. Distributary channel and delta front associations consist of thin to thick channel shape sandstone, which display coarsening-thickening upward cycles with pro-delta/offshore association. Scares Ophiomorpha nodosa and Thalassinoides in these sandstones indicate a stressful condition such as sandy mobile substrate, turbidity and highly salinity fluctuation in the sedimentary environment. Shale-silty sediments of the pro-delta association with abundant framboidal and chamber filling pyrite and organic material display anoxic condition of the sedimentary substrate. Introducing Miocene hydrocarbon sediments in the neighboring region like Turkmenistan and Russia and sedimentary characteristics of the pro-delta/offshore shale of the studied succession allow us to introduce those as high potential candidate for hydrocarbon source.
Stratigraphy and Palaeontology
shahram navavajary; Iraj Maghfouri Moghaddam; Ali Reza Shahidi; Hamid Nazari
Abstract
Oligo-Miocene rocks are deposited between Pyrenean and Pasadenian orogenic phases. This rocks in central Iran back arc deposits are named Qom formation. There are well developed outcrops of Qom formation at the North of Central Iran zone. In order to study microbiostratigraphy of the formation, Three ...
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Oligo-Miocene rocks are deposited between Pyrenean and Pasadenian orogenic phases. This rocks in central Iran back arc deposits are named Qom formation. There are well developed outcrops of Qom formation at the North of Central Iran zone. In order to study microbiostratigraphy of the formation, Three sections, north west of Darjazin town , Bonak mount and Arvaneh were selected. In these sections Qom formation with discontinuity overlays the Lower Red formation and with the same quality under the Late Miocene Conglomerate with intercalations of Sandstone, which is equivalent to the Upper Red Formation is placed. The main lithological composition of the Qom Formation in the study area alternates between layers of limestone and Marl with intercalations of siliciclastic rocks. Members and submembers of the Qom formation type area are not visible in this area and can only based on the lithological characteristics divide to local units. Based on bentic foraminifera and other microbiostratigraphical data, Qom Formation age in north west-west of Semnan (Darjazin-After zone), which is located in the Central Alborz structural- sedimentary zone, is early Miocene epoch and Burdigalian stage, which is the equivalent of Borelis melo curdica-Borelis melo biozone.
A. Zohdi; S. A. Moallemi; M. A. Salehi
Abstract
In the Zagros sedimentary basin, the maximum thickness of the Guri Member carbonates is belonging to the eastern parts of the Bandar-Abbas region. In this research, the Guri Member in five outcrops at the Bandar-Abbas region has been sedimentological and stratigraphic studied. The Guri Member mainly ...
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In the Zagros sedimentary basin, the maximum thickness of the Guri Member carbonates is belonging to the eastern parts of the Bandar-Abbas region. In this research, the Guri Member in five outcrops at the Bandar-Abbas region has been sedimentological and stratigraphic studied. The Guri Member mainly consists of limestone with interbedded marl with a variable thickness from 540 m at the Handun outcrop to 52 m at the Nakh outcrop. According to facies study and using the 87Sr/86 Sr isotopic ratio (amounts 0.708522 and 0.708790 values) of the basal carbonate layers of this member, the beginning sedimentation of these deposits occur during the Burdigalian and Langian times within the five carbonate facies. Fieldwork observations and facies distribution suggested a shelf carbonate platform for deposition of the Guri Member at the Bandar-Abbas region. Petrographic investigation in addition to trace elements (Sr, Mn and Fe) and isotopic (oxygen and carbon) geochemical analyses, also indicate the main influence of the marine to shallow-burial diagenetic process with the marine fluids after primary deposition of the Guri Member. The comparison of the oxygen and carbon isotope values of the Guri samples with the least-altered oxygen and carbon range for the early to middle Miocene marine calcite and also the more variations of the oxygen isotope values (between -1.19‰ to -5.39‰ PDB), and lees variations of carbon isotope values (between -1.05‰ to 2.2‰ PDB), indicate the effects of shallow-burial fluids (marine-phreatic) on the carbonate of the Guri Member.
I Maghfouri Moghaddam; S Yasboulaghi
Abstract
The Qom Formation is well exposed in Ashtian area (Central Iran). Pelecypoda of the formation in a stratigraphic section of west of Ashtian were examined in terms of paleontological and paleoecological criteria. In this section, the Qom Formation overlies the Lower Red Formation with a gradual contact ...
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The Qom Formation is well exposed in Ashtian area (Central Iran). Pelecypoda of the formation in a stratigraphic section of west of Ashtian were examined in terms of paleontological and paleoecological criteria. In this section, the Qom Formation overlies the Lower Red Formation with a gradual contact and is disconformably overlain by Upper Red Formation. For the first time, the systematic studies of the fauna yielded four genera and two species of small pelecypoda. Common stratigraphic ranges of determinatedpelecypoda with the presence of coexistence foraminifera, give the age of Early Miocene (Aqitanian) for these layers.The distribution of the foraminifera in the studied area indicates that carbonate containing small pelecypoda of the Qom Formation were deposited in an aphotic zone of tropical to subtropical region.
Z.K. Mossadegh; M.H. Adabi; A. Sadeghi
Abstract
We studied the geochemistry of the Asmari Formation in two outcrop sections: Tang-e-Sapou a 260 m section near Dehdasht City (Kohgiluyeh va Bouyer Ahmad Province) and Tang-e-Ban a 214 m section near Behbahan City (Khozestan Province). Sampling included the complete Asmari Formation and the top of the ...
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We studied the geochemistry of the Asmari Formation in two outcrop sections: Tang-e-Sapou a 260 m section near Dehdasht City (Kohgiluyeh va Bouyer Ahmad Province) and Tang-e-Ban a 214 m section near Behbahan City (Khozestan Province). Sampling included the complete Asmari Formation and the top of the Pabdeh Formation. The Late Oligocene to Early Miocene Asmari Formation lies above the Pabdeh Formation and is overlain by the Gachsaran Formation. Elemental geochemistry (Fe, Mg, Na, Sr, Mn, Ca), and Oxygen and Carbon isotope analyses indicate that meteoric diagenesis affected carbonates of the Asmari Formation. The δ18O/δ13C data plots in an inverted J-trend suggesting that meteoric diagensis occurred in a closed to semi-closed system. The geochemistry also suggests that the original mineralogy was Aragonite. The boundary between the Pabdeh and Asmari Formations can be recognized by changes in the δ 18O and δ 13C. In the Pabdeh Formation the δ 18O and δ 13C values are mostly negative, but in the Asmari Formation values range from positive to negative. Strontium is much higher in the Pabdeh Formation than in the Asmari Formation. Changes in isotope and elemental geochemistry clearly show the Chattian-Aquitanian and Aquitanian-Burgidalian boundaries.
A.H. Kokabi Nezhad; Z. Purabrishami; Kh. Tehrani
Abstract
One of Hipparion species which has complete characters of cranium and maxillary with teeth found during excavation is H.primignium. Since this sample is the only complete one in the world, (of course without mandible) with special species characters we can call it Homeotype. Because of finding this species, ...
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One of Hipparion species which has complete characters of cranium and maxillary with teeth found during excavation is H.primignium. Since this sample is the only complete one in the world, (of course without mandible) with special species characters we can call it Homeotype. Because of finding this species, pyroclastic sediments of Maragheh would be dated upper Astracian, so Maragheh informal formation which in the past was thought to be as old as vallencian- Trulain, seems a bit older. Because the mentioned samples were also found in Samus and Pikermi in Greece, so we can say these two regions have vertebrate familiarities in fossils fauna and other characters like paleogeography, biochronology and biogeography in late Miocene- early Pliocene.
N. Abbassi; A. H. Amini
Abstract
The Upper Miocene Upper Red Formation in the Evan-e-Key Section is composed of conglomerates, sandstones, mudstones, and thin lenses of evaporates (gypsum). The formation is dominated by gypsiferous mudstones and characterized by fining-up cycles in this area. The whole ...
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The Upper Miocene Upper Red Formation in the Evan-e-Key Section is composed of conglomerates, sandstones, mudstones, and thin lenses of evaporates (gypsum). The formation is dominated by gypsiferous mudstones and characterized by fining-up cycles in this area. The whole formation occurs as a fining upward megasequence, in which the sandy facies dominate the lower half and muddy facies the upper half. Gypsum layers, up to 10 meters thick, are locally observed in the basal part. The formation has suffered an extensive weathering in the region, as a result of which primary features (e.g. sedimentary structures, trace fossils) are partially obscured. In the sandy units of the middle part of the formation some vertebrate footprints are observed, which are locally deformed due to intensive weathering of the rocks. Two types of Carnivoripedida footprints however, are distinguished and described here, so that well preserved Chelipus isp. is related to Felidae. Depositional environments including alluvial fans with abundant debris flows, gravelly bed load braided systems with wide flood plains and local swamps provided a good opportunity for development of the track makers. The transverse and longitudinal bars within the channels, levees, and over-bank sub-environments were found more suitable for development and preservation of the footprints. Comparing with other sections of the formation (e.g. Qum area), desirable climate was found a major control on development of the vertebrate track maker in the Evan-e-key area.
Z. A. Pur-Abrishami; A. H. Kokabi-Nezhad; G. R. Zare; O. Dabiri
Abstract
Maragheh informal Formation is widely extended on the Sahand hillside and Maragheh city. Based on lithology and sedimentary facies, Maragheh Formation is divided into two members: lower member in the studied area (Mordagh area - Aghajery) consists of marl, tuff, tuffaceous ...
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Maragheh informal Formation is widely extended on the Sahand hillside and Maragheh city. Based on lithology and sedimentary facies, Maragheh Formation is divided into two members: lower member in the studied area (Mordagh area - Aghajery) consists of marl, tuff, tuffaceous sandstone with several fossiliferous layers. Upper member has more extent and thickness than the lower member and the facies variation are accompanied by increase of tuffaceous layers with diatomit and fish debries. In the Gorg Darreh –Mordagh area four geologic sites were excavated and investigated for vertebrate fossils. The samples obtained in this study from above mentioned sites consist of Ivory of mastodont, Ivory of phiomia, Monkey teeth, radius and ulana bones of elephant, cervid, gazelle and hipparions. The sequence of Maragheh Formation mostly consists of fluvial deposits, therefore its dating is difficult. However, it displays different ages from 7Ma to 12.5Ma respectively based on the vertebrate fossils such as hipparion sp. ,.
