Iranian Journal of Earth Sciences: 5 (2)

Open Access Article

1 - Tectonic Setting of Metabasites of the Neo-Tethyan Oceanic Remains in Sanandaj-Sirjan Structural Zone West of Isfahan, Central Iran
Ali-Khan Nasr-Esfahani

The study area is located in the western portion of Isfahan, in Shahrekord-Dehsard Terrene. This area is part of the Sanandaj- Sirjan structural Zone. In this area, metamorphosed igneous outcrops contain greenschist and metabasite rocks. These rocks have metamorphed int More

The study area is located in the western portion of Isfahan, in Shahrekord-Dehsard Terrene. This area is part of the Sanandaj- Sirjan structural Zone. In this area, metamorphosed igneous outcrops contain greenschist and metabasite rocks. These rocks have metamorphed into greenschist facies and belong to the Triassic-Jurassic age. The etabasite is mainly composed of plagioclase, amphibole, epidote and chlorite. Geochemical data shows that the parent rocks are of basalt to andesitic basalt composition with sub alkaline and tholeiitic trends. In the REE and trace elements spider diagrams, these are similar to MORB and adapted with E-MORB. These results indicate a metabasite enerated back arc basin volcanic subduction environment. The Metabasite in Sahrekord - Dehsard terrene shows remnants of a Neo-Tethyan oceanic lithosphere with a back arc basin environment that was subducted and uplifted to the surface. Manuscript profile

Open Access Article

2 - Remote Sensing and Land Use Extraction for Kernel Functions Analysis by Support Vector Machines with ASTER Multispectral Imagery
E. Akbari N. Amiri H. Azizi

Land use is being considered as an element in determining land change studies, environmental planning and natural resource applications. The Earth’s surface Study by remote sensing has many benefits such as, continuous acquisition of data, broad regional coverage, More

Land use is being considered as an element in determining land change studies, environmental planning and natural resource applications. The Earth’s surface Study by remote sensing has many benefits such as, continuous acquisition of data, broad regional coverage, cost effective data, map accurate data, and large archives of historical data. To study land use / cover, remote sensing as an efficient technology, is always desired by experts. In this case, classification could be considered as one of the most important methods of extracting information from digital satellite images. Selecting the best classification method and applying the proper values for parameters extremely influence the trust level of extracted land use maps. This research is an applied study which attempts to introduce Support Vector Machines (SVM) classification method, a recent development from the machine learning community. Moreover, we prove its potential for structure–activity relationship analysis on Aster multispectral data of central county of Kabodar-Ahang region in Hamedan, Iran. Accuracy of SVMs method is varied by the type of kernel functions and its parameters. The purpose of this research is to find the accuracy of Land use extraction by SVM method by Polynomial and radial basis functions kernel with their estimated optimum parameters in addition to compare the results with Maximum Likelihood method. Most of the scientists imply that Maximum Likelihood method is suitable for classification. Therefore, we try to compare SVM with ML method and to deliberate the efficiency of this new method in classification progress on Aster multispectral data. The accuracy of SVM method by Polynomial and radial basis functions kernel with optimum parameters and ML classification methods achieved 93.18%, 91.77% and 88.35 % respectively as an overall accuracy. By comparing the accuracy of these methods, SVM method by Polynomial kernel was evaluated as suitable. Therefore, we can suggest using SVM method especially with the use of Polynomial kernel to determine land use. In general, the results of this research are very practical in natural resources conservation planning and studies. Also, this study verifies the effectiveness and robustness of SVMs in the classification of remotely sensed images. Manuscript profile

Open Access Article

3 - Relations between Deep and Shallow Stratigraphic Units of Northern Iraq during Cretaceous
Kamal H Karim Rabea K Al-Hamadani Sirwan H. Ahmad

The studied area includes Sulaimani, Erbil and Dohuk Governorates where Cretaceous rocks are well exposed in the High Folded Zone of North and Northeastern Iraq. This area is part of the northwestern boundary of Arabian platform near to Iranian border. In these governor More

The studied area includes Sulaimani, Erbil and Dohuk Governorates where Cretaceous rocks are well exposed in the High Folded Zone of North and Northeastern Iraq. This area is part of the northwestern boundary of Arabian platform near to Iranian border. In these governorates, the study tries to clarify the relations between deep and shallow stratigraphic units (formation or facies) during Cretaceous. The result of the present study is mainly depended on the field lateral tracing of the lithologic changes and paleontological evidences for indicating the new age termination of the units. The result showed as a generalized and simple model of temporal and special relations between Cretaceous deep and shallow water formations. The Balambo (Kazhdumi in Iran), Kometan (Ilam), Shiranish-Tanjero (Gurpi) Formations (as deep facies) are indicated as lateral equivalent of shallow facies of Qamchuqa (Sarvak and Dariyian), Bekhme (has not equivalent in Iran yet) and Aqra Formation (Seymare or Tarbur) respectively. On the model, the transition zone is indicated where the deep facies, from the east, change to shallow ones at the west. The shallow facies consist of coarse grain limestone with fossils skeletons, bioclasts and intraclasts. The deep facieses are fine grain pelagic limestone with microfossils (panktonic forams and nanofossils) whiles the transitional facies (zones) generally consist mixture of the two as interfigering relation between the deep and shallow facies. As the changes of the lithology of transitional zones are relatively sudden, therefore, they are not designated as formation and not defined previously. Manuscript profile

Open Access Article

4 - Evaluation of the Paleocene-Eocene deposits, Jahrum Formation, base on 2-D seismic data, Central Persian Gulf
Naser Abdi Hossain Rahimpour-Bonab Sayyed Reza Moussavi-Harami Iraj Abdollahi Fard Davood Jahani Ali Chehrazi

The Persian Gulf is part of an asymmetric foreland basin related to the Zagros Orogen. It has been episodically flooded for much of its history which are reflected in sedimentary successions. The evaluation of this succession from depositional trend view, in central Per More

The Persian Gulf is part of an asymmetric foreland basin related to the Zagros Orogen. It has been episodically flooded for much of its history which are reflected in sedimentary successions. The evaluation of this succession from depositional trend view, in central Persian Gulf during Paleocene-Eocene, is the aim of this article. The sedimentary rocks physical characteristics effects on seismic data, gives an appearance to the data, which can be a key factor for their evaluation. The reflectors geometry and terminations have been used for their interpretation. The current study the uses seismic data beside drilling wells data, including cutting description and logs. The study result shows progradation toward northeast, the direction in which the accommodation space is increasing. The sedimentary environments changes to lagoon, platform and basin which affect the deposits. These environments demonstrate suitable condition for carbonates and evaporites precipitation, in Jahrum Formation, which are approved by cutting ription. The sediments extension and its trend show high thickness of Paleocene-Eocene deposits in north west of the study area, where the basin is deeper. In some intervals the thickness of sediments is decreased in deep basin, due to sediment starvation. Manuscript profile

Open Access Article

5 - Geochemistry, Paleoclimatology and paleogeography of the Northeast Region of the Persian Gulf( Case Study from outhern Hormuzgan, Iran)
Mojtaba Taghizade Khosro Khosrotehrani Razieh Lak Seyed Ali Aghanabati Hamidreza Peyrowan

The Wisconsin glaciation was started a approximately 125,000 years ago and reached its lowest extend between 20,000 to 21,000 years ago during which the sea level fell 120 to 130 meter. At the end of the ice age, about 18,000 years ago, the sea level increased and reach More

The Wisconsin glaciation was started a approximately 125,000 years ago and reached its lowest extend between 20,000 to 21,000 years ago during which the sea level fell 120 to 130 meter. At the end of the ice age, about 18,000 years ago, the sea level increased and reached its present level about 5,000 years ago. The Persian Gulf was exposed in the last glacial moment (LGM). After this moment, the sea level prograted toward the Persian Gulf Basin and reached 1 to 3 meters higher than present levels 4,000 to 6,000 years ago. This study was focused on paleoecology, sedimentation and sea level changes in the northeastern portion of the Persian Gulf and shallow marine area in southern Hormuzgan, Iran near the ports of Bandar Abbas and Shahid Rajaee. Hormuzgan Province is located to the north of Strait of Hormuz. In this study, a core with a length of 10 meters was taken from late Holocene sediments in the northeast marine region of the Persian Gulf using a rotary drilling system. Then different sedimentary types were studied and separated and samples were sent for ICP and XRD elementary analysis and dating. As is already known, increasing and decrease of sea levels are related to moist weather and arid conditions respectively. Additionally, it is proved that variation of elements such as Al, Cr, Fe, K, Mg, Mn, Ti, and Zn have a direct relation to sea level changes. It is shown that the variations of Sr and Ca having a reverse relation to sea level changes. Geochemical study and dating on sediments shows that although the sea level rose 10,000 years ago in the studied region, 3,700 to 6,800 and 7,900 to 9,300 years ago, the sea level and rate of precipitation in this area was higher than the mean. This illustrates an increase in rain and humidity during these two periods Manuscript profile

Open Access Article

6 - Fistulipora Microparallela (Yang and Lu, 1962) from Lower Permian Bryozoans of Lut Block, Central Iran
H. Yarahmadzahi A. Ernst M.N. Gorgij

The Fistulipora microparallela (Yang and Lu, 1962) species is described for the first time from the Sakmarian deposits of the Sarab section in Lut Block, Central Iran. This species has been reported only from the Permian (Cisuralian-Guadalupian) of the Qilianshan and Ka More

The Fistulipora microparallela (Yang and Lu, 1962) species is described for the first time from the Sakmarian deposits of the Sarab section in Lut Block, Central Iran. This species has been reported only from the Permian (Cisuralian-Guadalupian) of the Qilianshan and Kankerin formations, and the Baliqliq Group (Upper Carboniferous to Lower Permian) of Western Xinjiang, China. Manuscript profile

Open Access Article

7 - Constraints on the Petrogenesis of Nosrat-Abad Ophiolite Extrusives, SE Iran
Mohammad Elyas Moslempour Morteza Khalatbari-Jafari Rahim Dabiri Sara Shahdadi

Nosrat-Abad ophiolitic extrusive sequence, located in the Sistan Suture Zone, in south eastern Iran. The extrusive sequence, contains pillow lava, sheet flow and related volcanic-clastic breccias which have undergone low-grade metamorphism. This association shows calc a More

Nosrat-Abad ophiolitic extrusive sequence, located in the Sistan Suture Zone, in south eastern Iran. The extrusive sequence, contains pillow lava, sheet flow and related volcanic-clastic breccias which have undergone low-grade metamorphism. This association shows calc alkaline to tholeiitic affinities. Interpretation of the geochemical data and behavior of the elements in different diagrams reveals two distinct domains in the Nosrat-abad ophiolitic extrusive sequence. The sheet flows are depleted in HFSE similar to those of SSZ. However, the enrichment of the pillow lavas in LILE could be attributed to an enriched mantle source or melting of metasomatized sediments above the subducted slab. It appears that two subduction components (fluids-melt), caused the diversity seen in the chemical composition of the study rocks. The MORB to subduction chemical characteristics of the Nosrat-Abad ophiolitic extrusive sequence could be explained by a shift in the tectonic settings from the mid-ocean ridge to the marginal basin in Sistan during the Late Cretaceous period. Manuscript profile

Open Access Article

8 - An Algorithm for Modeling and Interpretation of Seismoelectric Data
Ehsan Golmakani Torghabeh Mohammad Ebrahimi Dabbagh Hooman Latifi

Generally speaking, seismoelectric modeling is a prospecting method based on seismic and electromagnetic waves, in which waves generated by a seismic source at the boundary of the two environments generate a relative fluid-solid motion formed as a result of antagonism b More

Generally speaking, seismoelectric modeling is a prospecting method based on seismic and electromagnetic waves, in which waves generated by a seismic source at the boundary of the two environments generate a relative fluid-solid motion formed as a result of antagonism between the elastic properties of the environment with the saturated fluid. This research has as its objective, a study of the effect of an electric field due to DC current on the propagation of seismic waves by pseudo spectral time domain method, or the more general concept of seismoelectric coupling effect. In this research, poroelastic equations were used for seismic waves and Maxwell’s equations for lectromagnetic waves. Additionally, the seismoelectric effect or charge density, electrical conductivity, dielectric permittivity function, fluid viscosity and zeta potential were determined. DC electric field variations were compared with results of a physical experiment conducted in a modeled environment. The results revealed that DC electric significantly affected the propagation of elastic energy through seismoelectric coupling in a wide range of seismic frequency widths. Additionally, the boundaries of the substrata were specified using the horizontal component of the electric field of the magnetic wave Manuscript profile

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