Petroleum geology
Nasim Maleki Sadeghi; Ahmad Ahmadi-khalaji; Reza Zarei Sahamieh; Zahra Tahmasbi
Abstract
The study area is a part of Zagros Folded zone and located in the Lorestan sedimentary basin. In this regard, three areas with high bitumen potential were selected, which include the northern area of Kuhdasht, northeast of Poldokhtar and southeast of Sepiddasht. In the study areas, bitumens are exposed ...
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The study area is a part of Zagros Folded zone and located in the Lorestan sedimentary basin. In this regard, three areas with high bitumen potential were selected, which include the northern area of Kuhdasht, northeast of Poldokhtar and southeast of Sepiddasht. In the study areas, bitumens are exposed as veins between the fractures and as interlayers with host rock that the thickness of these veins is between 10 cm to more than 1.5 meters. Field studies showed that the studied bitumens have developed in the shales of Amiran Formation. Based on the results of organic geochemistry, 80.10 to 93.60% of the extractable saturated compounds are in the category of asphalts and have a very good quality in terms of thermal maturity (maturity of organic matter). The studied samples are formed in a reducing to slightly reducing sedimentary environment. Drawing the diagram of C34/C35 Homohopane vs. C29/C30 Hopane for the studied bitumens showed that the generating rocks of the studied samples are carbonate and detrital in nature. This can be explained by the lithology of bituminous formations such as Ilam and Gurpi formations in the study areas. The triangular diagram of regular streams (m/z = 217) for the studied bitumens showed that the source of organic compounds of the studied bitumens is mostly marine with a small amount of entry from dry environments. Severe depletion of the carbon isotope (average -28.83 per mill) indicates organic origin and biomass in these samples. On the other hand, sulfur compounds with depletion (-12.16 per mill) indicate formation in a reduced to semi-regenerated sedimentary environment and oxygen isotope data (+15.03 per mill) indicate the formation of organic matter of sedimentary origin.
P. Rajabi
Abstract
Taleh Zang Formation is shallow carbonate facies of the Paleogene Zagros Basin. According to the area, including depth, tectonic and sedimentary sedimentation rate and other factors of the formation with Kashkan and Shahbazan sometimes with different thicknesses of semi-deep and deep Papdeh facies were ...
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Taleh Zang Formation is shallow carbonate facies of the Paleogene Zagros Basin. According to the area, including depth, tectonic and sedimentary sedimentation rate and other factors of the formation with Kashkan and Shahbazan sometimes with different thicknesses of semi-deep and deep Papdeh facies were deposited locally. According to the study Taleh Zang Formation calcareous stratigraphic section thickness of 185 meters (true thickness) were measured from 15 genera and 10 species of 110 sample benthic foraminifera identified by study and introduced 3 biozones 2 Assemblage zone and a Acrozon, late Paleocene (thanetian) and lower Eocene (ypresian) is intended for the stratigraphic section.
I. Maghfouri Moghaddam
Abstract
Sedimentary setting and paleoecology of the rudist-bearing Upper Cretaceous strata were studied in three sections in Khorram abad. The sections include: Tang Shabi Khone, Cham Sangar (Tarbur Formation) and Pir Shams Eldin (upper part of Amiran Formation). The Tang- E Shabi Khone and Chamsangar ...
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Sedimentary setting and paleoecology of the rudist-bearing Upper Cretaceous strata were studied in three sections in Khorram abad. The sections include: Tang Shabi Khone, Cham Sangar (Tarbur Formation) and Pir Shams Eldin (upper part of Amiran Formation). The Tang- E Shabi Khone and Chamsangar sections are located in Zagros Trust zone while, the Pir Shams Eldin in Lorestan zone. On the basis of the recognized fossils, the three sections are assigned to the Late Cretaceous (Middle to Late Masstrichtian) and are comparable to Omphalocyclus- Loftusia Assemblage Zone. The petrography study showed that the three sections contain nine microfacies that deposited in an open marine, shoal and restricted marine that based on rudist sedimentary models, are comparable to the Inner- shelf basin prograding margin complexes (Tarbur Formation) and the low- angel open shelf margin complexes (Amiran Formation). Probably, Sepid Kuh Fault was detaching the these settings. Augmentation of entering the detrital and silica due to river injection and runoff and consequently to the eurotrophic conditions in the Tnage Shabi Khone and Pir Shams Eldin, frequency of agglutinate foraminifera were increased but in the chamsangar section due to oligotraphy condition , frequency of hyaline foraminifera is increased. Distribution of the foraminifera and algae indicated that the Tarbur Formation is deposited in a photic zone though, some parts of the carbonates of the Amiran Formation were deposited in a aphotic zone.
M Mohammadi; H Amiri Bakhtiar; F Amraee
Abstract
This study aimed to compare Asmari Formation in two sections in Maleh-Kuh and Amiran anticlines based on benthonic foraminifera. In this study, 26 species and 16 genera of benthonic foraminifera from the Maleh-Kuh section yielded 2 biozones of Elphidiumsp. 14 – Peneroplis, farsenensisandBorelismelocurdica ...
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This study aimed to compare Asmari Formation in two sections in Maleh-Kuh and Amiran anticlines based on benthonic foraminifera. In this study, 26 species and 16 genera of benthonic foraminifera from the Maleh-Kuh section yielded 2 biozones of Elphidiumsp. 14 – Peneroplis, farsenensisandBorelismelocurdica – Borelismelomeloweresuggesting an age of Aquitanian – Burdigalian for the formation. In Amiran anticline based on 27 species and 20 genera only the biozone of Borelismelocurdica – Borelismelomelo (Burdigalian)was recorded.Based on this study, the Asmari sequence in Maleh-kuh Section (with a thicknessof 310m) deposited earlier In Aquitanian. But in Amiran section (with a thickness 162m) deposition started in Burdigalian and ended synchronously in both sections. In both sections the Asmari Formation overlain Shahbazan Formation disconformably and is in turn under lain by Ghachsaran Formation concordantly-transitionally in Maleh-Kuh and by a sharp contact in Amiran Section.
M. Abdi; Majid Ghaderi; N. Rashidnejad-Omran; E. Rastad
Abstract
Azna tungsten (copper) ore occurrence is located 2 km west of Azna, in Lorestan province. The region is placed in Sanandaj-Sirjan structural zone of Iran, at the complex deformation sub-zone. In this area, tungsten-copper mineralization occurs as stratiform-stratabound in mylonitic meta-rhyolite and ...
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Azna tungsten (copper) ore occurrence is located 2 km west of Azna, in Lorestan province. The region is placed in Sanandaj-Sirjan structural zone of Iran, at the complex deformation sub-zone. In this area, tungsten-copper mineralization occurs as stratiform-stratabound in mylonitic meta-rhyolite and semi-pelitic country rock within upper Triassic volcano sedimentary sequence. The sequence consists of meta-rhyodacite, amphibolite (basic meta-volcanic), black schist, meta-rhyolite and pelitic schist with a predominance of volcanics over sediments. Ore mineral textures cover a wide variety from laminated, disseminated, choloform, bounded to open space filling. Mineralization occurs in several stages concentrated through regional (medium to high grade facies) metamorphism, folding and mylonitization of shear zone (ductile) and fractures of brittle deformation events. In this ore occurrence, metamorphism and deformations process had confused detection of proximal or distal mineralization. But base of comparison of Azna tungsten mineralization with both typical proximal on Felbertal and Austroalpine and distal on Broken Hill and Kleinarltal tungsten mineralizations has shown that they are more similar to the proximal mineral deposits.
