Stratigraphy and Palaeontology
Mahmoud sharafi; Nasim Mousavi; Mehran Moradpour; Bijan Biranvand; ebrahin Abdollahi; Hossein Soltani
Abstract
Based on lithostratigraphy analysis, Cheleken Formation in the studied section of the Gorgan plain, subdivided into lower sandstone and upper mudstone/marl units. Based on petrographic analysis, the sandstone sediments include low textural and compositional maturity litharenite and sublitharenite. Conglomerates ...
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Based on lithostratigraphy analysis, Cheleken Formation in the studied section of the Gorgan plain, subdivided into lower sandstone and upper mudstone/marl units. Based on petrographic analysis, the sandstone sediments include low textural and compositional maturity litharenite and sublitharenite. Conglomerates are polymictite orthoconglomerate with variables carbonate and chert grains. High percentage of the porosity as vuggy, channels and fractures in the sandstone and conglomerates and even mudstone deposits displays high reservoir potentional for the studied sediments and hence necessitates the exploration studies in the Iranian part of the SCB. Based on the youngest nannofossil species, a late Miocene to middle Pliocene (?) age is defined for the Cheleken Fm. in the studied area. Nannofossils distribution of the studied succession displays the SCB was connected to the Black Sea and Mediterranean Basin in the late Miocene- early Pliocene and the Pleistocene and was isolated in the main part of the Pliocene.
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.
