Sedimentology
Afshin Karimkhani-Bahador; Sadat Feiznia; Mohsen Aleali; Mehran Arian
Abstract
To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy ...
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To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy of waves and sea currents, as well as how the slope of the seabed changes, play a role in the production and diversity of the sedimentary facies. 9 sedimentary facies are the most abundant in the surface deposits of this area and on average, in the sediments of the continental shelf, there are 1% by weight of coarse-grained particles, 25% by weight of medium-grained particles and 74% by weight of fine-grained particles. The composition of sedimentary facies in this area is controlled by indicators such as the size of sedimentary particles, the amount of sedimentary load carried to the environment, the energy of waves and sea currents, and how the slope of the seabed changes. In the marine environment of the study area, sub-sedimentary environments, Backshore, Foreshore, Shoreface, Offshore transition zone and offshore can be identified. The two facies of slightly gravelly Mud and Mud are more abundant than other facies.
M Nemati; J Hollingsworth; M.R Ghassemi
Abstract
Our research focuses on the seismotectonics of the north of Eastern Alborz and southeast of the Caspian Sea. Eastern part of the Caspian fault, and seismological active plain situated in north of the area have been studied. The seismological data of microearthquakes (ML>4.5) recorded by the local ...
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Our research focuses on the seismotectonics of the north of Eastern Alborz and southeast of the Caspian Sea. Eastern part of the Caspian fault, and seismological active plain situated in north of the area have been studied. The seismological data of microearthquakes (ML>4.5) recorded by the local network of the Geological Survey of Iran (installed during 2009 and 2010) and regional seismicity located by seismological networks of the Geophysics Institute of University of Tehran and International Institute of Earthquake Engineering and Seismology of Iran were used. Also geomorphological evidences in the area and dynamic parameters of the 1985 Gorgan earthquake, MS=6.0, are included for getting a better justification. Although deep thrust mechanisms of the 1999, 2004 and 2005 earthquakes indicate N-S compressional regime at depth and normal component of shallow earthquakes (ML>4.5) shows extensional regime at near surface in southeast of the Caspian Sea. The morphological evidences confirm this normal kinematics. In addition, the dynamical parameters of the 1985 Gorgan earthquake and its focal mechanism introduce the Caspian fault as the source of this thrust earthquake. All evidences confirm probable underthrusting of southeast of the CaspianBasin beneath the Eastern Alborz.
Y Vasigh; A Darvishzadeh; M Vosoughi Abedini; M.H Emami
Abstract
Heiran area is located in northwest of Ardabil and southwest of Caspian Sea. Field evidences indicate submarine volcanic activities in this area. The rocks in this area are of basaltic composition. The outcrops of pillow lavas, prisms, dykes and lava flows in different points are evidences showing the ...
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Heiran area is located in northwest of Ardabil and southwest of Caspian Sea. Field evidences indicate submarine volcanic activities in this area. The rocks in this area are of basaltic composition. The outcrops of pillow lavas, prisms, dykes and lava flows in different points are evidences showing the existence of oceanic crust in this area. Studies on other locations of southern margin of Caspian Sea as well as structural and petrological similarities between Heiran and these areas may confirm the fact that Heiran area is part of geo-suture of Caspian Sea southern margin. The submarine lavas in this area attributed to late Cretaceous-Eocene. With regard to petrographical characteristic, these rocks range from andesitic basalt to olivine basalt, and belong to alkaline series. The tectonomagmatic environment of these lavas is related to back arc basin. These magma originated from sub continental lithospheric mantle and formed in a supra subduction environment. During late Cretaceous-middle Paleogene, the closure of Sevan-Akera-Qaradagh led to the formation of marginal basin in the form of a back arc basin in the margin of Caspian Sea. The submarine lavas of Heiran likely originated from the volcanic activities in this marginal basin.
A. Uromeihy; A. Karim-khani
Abstract
Erosion and sedimentation are among the natural processes continuously changing the land surface. This deformation may affect the development activities of the coastal areas such as Bandar Anzali region. In order to evaluate the potential of erosion in the region, various methods ...
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Erosion and sedimentation are among the natural processes continuously changing the land surface. This deformation may affect the development activities of the coastal areas such as Bandar Anzali region. In order to evaluate the potential of erosion in the region, various methods of zonation mapping were reviewed. The region was divided into a number of grid lines and the weight of each grid was measured. The computer program Arc-GIS was used to calculate the weighing factors of each cell and finally to draw the zonation map. In this regard, five factors including lithology, slope angle, fault types, drainage pattern, and land-use (vegetation) were considered as major affecting factors on the erosion phenomena. The results showed that the effect of lithology and land-use are higher as accompanied by the effect of fault type and slope angle, and the effect of drainage pattern is most noticeable in mountainous areas. The geochemical characteristics of the sediments in Anzali wetland indicate that the percentage of SiO2, Al2O3, and CaO2 is higher than that of other elements such as FeO, MgO and MnO. These sediments represent the lithological setting of the provenance region of the originated sediments.
B. Vahdati Daneshmand; M.R. Ghassemi; M. Ghorashi; N. Haghipour
Abstract
According to historical maps of Iran, changing the course of Sepidrud from Dastak to Kiyashahr has occurred in a very recent time. Although migration of meandering streams over the delta plain is a natural phenomenon and oscillations of Caspian Sea might have affected the course ...
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According to historical maps of Iran, changing the course of Sepidrud from Dastak to Kiyashahr has occurred in a very recent time. Although migration of meandering streams over the delta plain is a natural phenomenon and oscillations of Caspian Sea might have affected the course of SepidrudRiver, the deflection of Sepidrud between Astaneh and Koochesfahan is probably related to activity of concealed structures wit
hin the delta deposits. This research uses calculation of morphotectonic indexes to study effects of active range boundary within range faults in study area on drainage pattern and river streams.
