Sedimentology
Mahmoud Sharafi; Mahdi Jafarzadeh; Aram Bayet-Goll; Razieh Lak
Abstract
The Urmia Lake, which is a tectonic depression in the northwest of Iran, has received a lot of eroded sediments of the geological records of the lake watershed. Because of the constant drought in the recent years, sediments have been subjected to the wind erosion and thus are an important source for ...
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The Urmia Lake, which is a tectonic depression in the northwest of Iran, has received a lot of eroded sediments of the geological records of the lake watershed. Because of the constant drought in the recent years, sediments have been subjected to the wind erosion and thus are an important source for local and regional emission during dust storms. In this research the south and west sediments of the Urmia playa lake have studied on the parent rock issue. Bivariate plots such as Th/Co versus La/Sc and TiO2 versus Al2O3 and comparison proportion of the trace elements such as La/Sc, Th/Sc, La/Co, Th/Co and Cr/Th display mainly the felsic and partly basic rocks source for the studied sediments. Major and trace spider plots of the studied sediments display their depletion with respect to Sc, V, Cr, Ni and enrichment with respect to Th and Sr, confirm mainly a felsic and partly mafic and ultramafic source rocks. Geochemistry of the major elements shows the dry climatic conditions during deposition of Urmia Lake sediments, suggested by bivariate plots of SiO2 against the sum of Al2O3, K2O and Na2O as well as the amount of chemical index of weathering.
Petroleum geology
Mohammad Javad yousefzadeh; Bijan Maleki; Mir Hassan Moosavi; parviz armani
Abstract
Investigation of probable source rocks in oil fields is very important. In this study, in addition to evaluating the hydrocarbon potential, the kinetic models of Lopatin and Arrhenius were used to more precisely assess the source rock maturity status as well as the percentage of oil generation in the ...
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Investigation of probable source rocks in oil fields is very important. In this study, in addition to evaluating the hydrocarbon potential, the kinetic models of Lopatin and Arrhenius were used to more precisely assess the source rock maturity status as well as the percentage of oil generation in the Solabdar oil field. This field is southeast of Bibi Hakima Square, located in the Dezful embayment. Possible source rocks are scorpions, scorpions, Gurpi and Pabdeh. The samples were also analyzed kinetically and the transformation ratio (TR) of kerogen to the generated hydrocarbon was determined. According to the burial history, the source rock of Kazhdomi formation has reached the highest temperature and depth compared to other source rocks. According to the results of Lopatin method, the transformation rate of organic matter in formations, Gurpi and Pabdeh was determined by 41%, 30% and 30%, respectively. This transformation rate by Arrhenius method was 47%, 15%, and 13%, respectively. This difference is due to the two-factor assumptions that the article discusses.
Sedimentology
Hadi Amin-Rasouli; N. Haghighat jou; Mehdi Moradi
Abstract
Karaftu Cave is located in the 67 km northwest of Divandareh, Kurdistan province. It includes four floors, which the bottom of the second floor, in the bat’s hall, is covered by thick guano deposits. In this study, the distribution of trace elements plus rare earth elements, as well as age determination, ...
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Karaftu Cave is located in the 67 km northwest of Divandareh, Kurdistan province. It includes four floors, which the bottom of the second floor, in the bat’s hall, is covered by thick guano deposits. In this study, the distribution of trace elements plus rare earth elements, as well as age determination, based on 14C, of guano was investigated. Fresh guano decays through bacterial and fungal metabolism and can release organic and inorganic acids. Interactions between these acidic solutions with guano were caused by leaching and changing the distribution and ratios of elements. The rate of leaching is determined by changes in the patterns of distribution of elements and the ratios of Th/U and LREEs/HREEs. The Eu/Eu* and Ce/Ce* ratios are applied to obtain information about the paleoredox conditions of guano deposition. Based on this study, three different climatic conditions, including dry, wet, and dry terms, have been recognized. Geochemical data of guano samples on the La/Th-Hf and Th-Sc diagrams represent intermediate-mafic source rocks. Plot the samples on the Th-Sc-Zr/10 and La/Th-Sc/Ni diagrams, suggesting that their source rocks evolved in a continental island arc tectonic setting. Based on 14C dating, the onset of guano production is about 14260 ± 50 BP after the Last Glacial Maximum recorded worldwide and close to the study area in Zaribar Lake, Zagros Mountains, and Alpine Mountains. The average accumulation rate of guano deposits has been 3.7 mm/year in Karaftu Cave.
Petrology
Leili Bastami; Reza Moussavi; Mahboobeh Hosseini-Barzi; Bahaedin Hamdi Hamdi
Abstract
The sandstones of the Dorud Formation (Early Permian) have been subjected to petrographic and geochemical studies in order to investigate provenance, tectonic setting, source rock and paleoclimate conditions in Khur section, Central Alborz. The Dorud Formation with a thickness of 360 m is mainly composed ...
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The sandstones of the Dorud Formation (Early Permian) have been subjected to petrographic and geochemical studies in order to investigate provenance, tectonic setting, source rock and paleoclimate conditions in Khur section, Central Alborz. The Dorud Formation with a thickness of 360 m is mainly composed of fine to medium grained sandstones with lesser amounts of carbonate and mudstone. In order to achieve the above-mentioned goals, 125 thin sections were subjected to petrographic studies. Modal analysis was performed on 20 thin sections and 13 samples of sandstones were analysed for major and trace elements. Based on petrographic studies the sandstones of the Dorud Formation are classified as quartzarenite with high textural and mineralogical maturity. Plotting point counting data on (Qt99.6, F0.2, L0.2( and (Qm95.9, F0.2, Lt3.9) triangles implies craton interior provenance. Also, major and trace elements based geochemical diagrams indicate that these sandstones deposited in a passive continental margin tectonic setting. According to petrographic and geochemical evidence the sandstones of the Dorud Formation derived from erosion of middle- to high-grade metamorphic, felsic igneous and quartoze sedimentary rocks. High mineralogical maturity, high values of chemical index of weathering (CIW) and chemical index of alteration (CIA) as well as SiO2 (%) versus Al2O3 + K2O + Na2O (%) diagram imply moderate to intense weathering under warm and humid climatic conditions. Passive continental margin tectonic setting and warm and humid paleoclimatic conditions is consistent with paleogeographic position of Iran during the Early Permian.
N. Sarbaz; A. Mahboubi; R. Moussavi-Harami; M. Khanehbad
Abstract
The Koppeh- Dagh Basin in the northeast Iran formed after closure of the Paleotethys in the south of Turan plate. Kashafrud Formation in the Navia Section (west of Bojnourd) with a thickness of 749 m is composed of silici-clastic rocks (conglomerate, sandstone and shale). In order to interpret provenance ...
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The Koppeh- Dagh Basin in the northeast Iran formed after closure of the Paleotethys in the south of Turan plate. Kashafrud Formation in the Navia Section (west of Bojnourd) with a thickness of 749 m is composed of silici-clastic rocks (conglomerate, sandstone and shale). In order to interpret provenance of this formation in the study section, 12 shale samples have been geochemically analyzed. The samples are rich in quartz and clay minerals, with respect to (UCC) depletion in Na2O, CaO, MgO, Cu, Nb and Sr and enrichment in Ni, Co, V, Y and U. Plotting TiO2 versus Al2O3, Zr versus TiO2, as well as ternary diagram (SiO2/20), (k2O+ Na2O), (MgO+ TiO2+ FeO) and diagram Al2O3, (Cao+ Na2O+ K2O), (FeO + MgO) suggest that the original source of this formation was probably from intermediate igneous rocks. Calculated PIA and CIA indicate high chemical weathering and semi- humid climatic condition in the source area. Prepared discrimation diagram using the major oxides (SiO2 versus K2O/Na2O and ternary diagrams SiO2/20, Na2O+ K2O, TiO2+ MgO+ Fe2O3), shows that the shales of this formation were plotted in the passive continental margin. Paleogeographic reconstruction for this formation, during the Middle Jurassic shows that sedimentation of this formation is mainly controlled by intracontinental subsiding basin and the source of these sediments was from the southeast of the Kopph-Dagh Basin.
N Mohammadi Akbari; M.R Kamali
Abstract
Sarvak Formation (with the age span of Cretaceous) is considered as one of the most prominent oil reservoirs in the south of Iran and a significant volume of oil accumulation in the Persian Gulf basin is attributed to this formation. In the present research plan, in order to evaluate the hydrocarbon ...
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Sarvak Formation (with the age span of Cretaceous) is considered as one of the most prominent oil reservoirs in the south of Iran and a significant volume of oil accumulation in the Persian Gulf basin is attributed to this formation. In the present research plan, in order to evaluate the hydrocarbon generation capacity of this formation, cores, cuttings and oil samples collected from fields’ wells located in block D underwent some investigations which were in the Iranian sector of the Persian Gulf. Correlation is defined as the geochemical comparison between hydrocarbons themselves, or also hydrocarbons with source rocks, and furthermore defining the quality of the genetic relation between them. In order to achieve this goal a variety of gadgets and parameters are used, some of them being biomarkers and stable isotopes.
The results obtained from geochemical analyses including primary analyses (pyrolysis rock-eval), bitumen extraction and separation, complementary analyses (gas chromatography), gas chromatography-mass spectrometry and stable isotope studies on samples indicate that kerogen of studied samples is a combination of types II and III and it implies that most organic matter generating hydrocarbon were formed in a marine environment along with a little entering from land. The hydrocarbons existing in Sarvak Formation were generated from a semi carbonated clastic source rock and were sedimented under a reduced or semi-reduced environment. The saturate sections of the Chromatograms samples indicate the lack of environmental biodegradation in the studied samples. The Oil and inter bed shaly-marl samples of the Sarvak Formation show a fair to good hydrocarbon potential. The set of under study samples are located in the beginning of the oil generation window (late diagenesis) and early catagenesis in terms of their maturity degree. Furthermore, hydrocarbons show a paraffinic-naphthenic characteristic. It seems the shaly-marl layers existing in some parts of the Sarvak Formation (Ahmadi member), in Block D, in the Persian Gulf, have been the cause for the generation of hydrocarbons available in the Sarvak reservoir.
D Raeisi; S Dargahi; S.H Moeinzadeh; M Arvin; B Bahrambeigi
Abstract
Gandom-Berian area, located on southern part of the Kavir-e Lut, covers an area around 480 km2 and morphologically is a covered messa by very dark basaltic lava flows. Their major minerals are olivine and clinopyroxene phenocrysts along with plagioclase microlites and their main textures are microlitic ...
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Gandom-Berian area, located on southern part of the Kavir-e Lut, covers an area around 480 km2 and morphologically is a covered messa by very dark basaltic lava flows. Their major minerals are olivine and clinopyroxene phenocrysts along with plagioclase microlites and their main textures are microlitic porphyry to glomeroporphiry with interestal to intergranular groundmass. The in line position of volcanic cones along the line of movements of Nayband fault show its effect on the formation of Gandom-Berian basaltic magma. The genetic realationship of these lava flows with deep seated lithospheric fractures as a result of Nayband fault, the presence of mantle xenoliths and alkaline nature of basalt all reveal a fast deep ascending of magmas. Based on geochemical analysis and occurrence of nepheline in the norm composition the Gandom-Berian basaltic lava flows belong to basanite-tephrite group. The investigation on Gandom-beriyan alkali basalts clearly shows their relationships to an intera-continental extensional environment. Low ratio of Ce/Nb, Th /Nb, U/Nb, Ba/Nb and High levels Zr with mean 234.81 indicate a none depleted asthenospheric mantle source the origin of Gandom-Berian basaltic lava flows. Enrichment and depletion of light and heavy rare earth elements respectively indicate the existence of garnet in the source rock.
A. Rajabi-Harsini; M. Memariani
Abstract
In this study, in order to evaluate the geochemical characterization of Kangan Formation in well B in South Pars Gas Field, geochemical analysis (including preliminary and complementary analysis such as Rock-Eval Pyrolysis, extraction of organic matter (EOM), bitumen fractionation, Gas chromatography ...
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In this study, in order to evaluate the geochemical characterization of Kangan Formation in well B in South Pars Gas Field, geochemical analysis (including preliminary and complementary analysis such as Rock-Eval Pyrolysis, extraction of organic matter (EOM), bitumen fractionation, Gas chromatography and Gas chromatography-Mass Spectrometry) were carried out on core samples. Geochemical results reveal that these samples have kerogen type III and II, indicating a marine organic matter with a little terrestrial input. The organic matter of these samples was derived from source rock(s), with clastic-carbonate lithology which deposited under anoxic to subanoxic conditions. In addition, the above samples exhibt poor to moderate genetic potential with kerogen maturity at the beginning of oil generation (late diagenesis to early catagsnesis). Also, based on column chromatography, the above samples are mainly composed of paraffinic-naphthenic and paraffinic hydrocarbons. A negligible amount of hydrocarbons seems to have been generated locally from Kangan Formation.
D. Esmaeily; A. Esna Ashari; H. Rahimpour Bonab
Abstract
Study of source rock materials in Jajarm bauxite deposit is the main subject of this study to show its origin. From bottom to top, this deposit consists of lower argillaceous layer, argillaceous bauxite, hard bauxite and upper kaolinite units. Correlation coefficients and scatter ...
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Study of source rock materials in Jajarm bauxite deposit is the main subject of this study to show its origin. From bottom to top, this deposit consists of lower argillaceous layer, argillaceous bauxite, hard bauxite and upper kaolinite units. Correlation coefficients and scatter diagrams of immobile elements in these four layers, demonstrate an early homogenous origin at the beginning of the bauxite formation. Accordingly, source materials were separated slowly due to the different conditions dominated in different parts of the deposit. Difference in drainage conditions and leaching of some elements from upper part and their re-deposition in lower parts of the deposit are the main reasons for hard bauxite separation from argillaceous one. Formation of the lower argillaceous layer, located between argillaceous bauxite and carbonate footwall is due to the direct contact of the argillaceous bauxite and carbonate footwall and also difference in drainage rate in contact area of the two layers. Geochemical evidence also depicts that upper kaolinite formation is the result of the silica leaching from upper horizons and its re-deposition in hard bauxites. Compositional comparison of studied samples with chondrite and upper continental crust demonstrates the effect of both of the basic and sedimentary rocks in evolution of the Jajarm bauxite. Formation of this deposit can be considered as a result of the alteration of the primitive laterite in an area close to the current location of the deposit. During alteration and transportation bauxite is deposited on the karstic topography and then some continental sediment was added to it.
M. H. Karimpour; A. Malekzadeh Shafaroudi
Abstract
Sangan Iron ore deposit is located 300 km southeast of Mashhad (Eastern Iran). Based on the high grade, low P- content and big ore reserve, Sangan is an important Iron mine in Iran. It is a magnetite skarn and can be classified as iron-oxide type deposit. Based on the surface exposure, the western magnetite ...
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Sangan Iron ore deposit is located 300 km southeast of Mashhad (Eastern Iran). Based on the high grade, low P- content and big ore reserve, Sangan is an important Iron mine in Iran. It is a magnetite skarn and can be classified as iron-oxide type deposit. Based on the surface exposure, the western magnetite skarn (A´), a Ca-rich type skarn, was formed at the contact of intrusive. Eastward, the skarn gradually becomes distal and Mg-type. The A´ magnetite skarn contains andradite, magnetite, K-rich amphibole, hedenbergite and calcite. Magnetite skarn in A, B, and C- south contain magnetite, repidolite, ferro-actinolite, siderite and minor pyrite. Baghak and C- north magnetite skarn comprise Mg-rich- magnetite, phlogopite, chinochlore, talc, dolomite, forsterite, dolomite, pyrite ± chalcopyrite ± arsenopyrite ± pyrrhotite. High S-content is found mainly in Baghak and C-north deposits. In this research, the igneous source rock is found in A´ deposit and identified as ultra-potassic type (K2O> %9). Sarnowsar granite which used to be the source rock for Iron, contains less than %5 K2O, therefore it cannot be the source. The K2O content of Sarnowsar granite increases near the magnetite skarn due to alteration. The Fe-ore bearing solution moved along the contact between Sarnowsar granite and the limestone. Sarnowsar granite was altered and skarn formed in the limestone.
The source rock is quartz biotite-hornblende alkali syenite to quartz hornblende syenite porphyry. The younger intrusive rocks are biotite granite, biotite-hornblende quartz monzonite porphyry and quartz syenite porphyry. Potassium within the ore bearing solution controlled the mineralogy of skarn. Contact skarn in A´ magnetite deposit comprises K-rich amphibole and distal skarn (Baghak and C-north) contains phlogopite.
Comparison of trace elements from source rocks with Sarnowsar granite indicates that the Nb, Zr, Zn and Rb contents are high in the former rocks and Cu and Sr ones are higher in the latter rock. Furthermore, comparison of some trace elements from source rocks with younger intrusive rocks indicate that Cr, Ni, Zr, Ce, Cu, Sr, and La contents are higher in younger intrusive and Rb content is higher in source rocks.
M. Paryab
Abstract
Hydrocarbon source rocks, the subject of various analyses and investigations, are well appreciated because of their capacity for oil generation. In the present study, attempts were made to evaluate source rock using a leap cost analytical method. For this purpose, some samples from these formations were ...
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Hydrocarbon source rocks, the subject of various analyses and investigations, are well appreciated because of their capacity for oil generation. In the present study, attempts were made to evaluate source rock using a leap cost analytical method. For this purpose, some samples from these formations were analyzed by Rock- Eval. CO2 generated from these samples at 350ºС are calculated as mgHy/gr rock or Kg Hy/Ton rock. As this method requires more time and is relatively expensive, we offered a new method in which by calibration of data, obtained from analyzed samples, the result could be attributed to the whole interval of a formation. By calculation of S2, Tmax and TOC of analyzed samples collected from wells A and B for both Pabdeh and Gurpi formations in accordance with ∆LogR method, rescaling of Resistivity-sonic logs, Resistivity-Density logs and Resistivity-Neutron logs, TOC content of these formations were estimated. Comparison between these data and data obtained from direct sample measurements in lab and extrapolation of an equation that relates these data to S2 and TOC of sample analysis, TOC and S2 content of whole intervals of these formations were calculated through ∆LogR method. Then hydrocarbon generation potential of the Pabdeh and Gurpi formations were finally evaluated. These data were processed in a neural network method with forward back propagation capability designed as try and error structure within Matlab software. Final results are in good agreement with those data obtained from direct measurements.
