Sedimentology
Sara Ebrahimi Meymand; Hamed Zand-Moghadam; Mohammad Khanehbad; Asadollah Mahboubi Mahboubi; Gholamreza Hosseinyar
Abstract
Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this ...
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Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this study in order to achieve the formation of nebkha in the Shahdad plain, sedimentological parameters and the effect of vegetation on nebkha geomorphology have been investigated. Due to the expansion of the study area and the different geomorphology of the nebkha, 30 nebkha were sampled along with sediments between them. the analysis of these sediments shows that nebkha sediments are often fine sand sizes that are well-sorted and rounded. However, sediments between nebkha often have a range between gravel (pebble) and fine silt which are subdivided into either surface and sub-surface sediments (depth greater than 2 centimeters). Surface sediments are often coarse grains (granule to coarse sand) and have relatively well roundness and sorting. Field investigations and analyses have shown that genus and plant species are important in the geomorphology of nebkhas in the Shahdad plain but the effect of vegetation on the sedimentary parameters is insignificant. This is due to the fact that the three types of vegetation identified (Tamarix stricta, Seditzia rosmarinus, Prosopis farcta), the highest levels of nebkha is for Tamarix stricta but the sedimentary parameters with different vegetation are not significantly different.
Exploration and Mining
V. Joudaki; F. Koohiyan-Afzal; A. Aalianvari; R. Ajalloeian; A. Sohrabi-Bidar
Abstract
Part 4 of Ghomroud tunnel is located in the Sanandaj-Sirjan geological zone. In this area, due to the existence of numerous faults, crushed zones and significant development of major and minor catchments, the tunnel has been encountered with the risk of groundwater influx. On the other hand, due to some ...
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Part 4 of Ghomroud tunnel is located in the Sanandaj-Sirjan geological zone. In this area, due to the existence of numerous faults, crushed zones and significant development of major and minor catchments, the tunnel has been encountered with the risk of groundwater influx. On the other hand, due to some limitations such as thick(up to 600 meters in some localities)overburden over the tunnel and the lack of exploratory drilling down to the tunnel level, it has been difficult to forecast and estimate the groundwater flow in the tunnel route. Due to the existence of numerous faults in part 4 of the Ghomroud tunnel ,encountering of the drilling machine (Double Shield TBM) with high-pressure water could cause influx of large amounts of water into the tunnel and collapse of rock masses in the crushed zones. It hence could cause deviation of the machine and drilling stop. In this article, the lack of data from boreholes led us to try investigating the development of groundwater flow in the tunnel based on geomorphological evidence. Analytical modeling and geomorphological field survey in the area show a relative consistency between geomorphology and volume of water flowing in the tunnel excavation. Therefore, according to measurements conducted on the water entering the tunnel, about 80 liters per second of water flowed into the tunnel, which is in agreement with geomorphological studies. Results show that the study of morphology and surface features could provide useful information in order to identify more precisely the hydrogeologic conditions of the area.
A Ghazi; N Hafezi Moghadas; H Sadeghi; M Ghafoori; G Lashkaripour
Abstract
In this study, engineering geomorphology of MashhadCity is evaluated. For this purpose, aerial photos of the city, 180 drinking water wells and 1500 scattered geotechnical boreholes have been studied. Based on this information, the city divided into 6 geomorphologic units including rock outcrop, pediment, ...
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In this study, engineering geomorphology of MashhadCity is evaluated. For this purpose, aerial photos of the city, 180 drinking water wells and 1500 scattered geotechnical boreholes have been studied. Based on this information, the city divided into 6 geomorphologic units including rock outcrop, pediment, Golestan fan, Torough fan, southern fans and flat plain. Then, engineering geology properties of these units were investigated based on the geotechnical data sets. The geotechnical properties were evaluated just for the upper 10m of deposits. The results show predominant soil in the pediment and southern fans units is gravel, sandy and gravely soils are predominant in the Golestan fan unit, whereas clay and sand are predominant soils in the Torough fan and flat plain. In this study, earth evaluation was carried out based on the standard penetration test that shows the pediment unit has more resistance than other units. The clay minerals were determined based on the activity chart. Smectite and kaolinite are predominant clay minerals in the pediment and flat plain units, respectively.
B Azadbakht; M Zareinejad
Abstract
Water causes erosion of different forms in nature and creates diverse landforms on the earth’s surface depending on the manner it appears in nature. Although water is itself a former factor, it flows under the morphological effect of earth’s surface (Ramasht, 2005). The difference of earth’s ...
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Water causes erosion of different forms in nature and creates diverse landforms on the earth’s surface depending on the manner it appears in nature. Although water is itself a former factor, it flows under the morphological effect of earth’s surface (Ramasht, 2005). The difference of earth’s surface topography and its consequent of water movement on it, cause the formation of sub-basins. In order to recognition of morphology and morphometry of Damavand cone, the region drainage basins must be distinguished. Therefore, in this study 5 drainage basins were identified based on the main criteria including topographic contours with 10 m intervals, drainage system (main and subsidiary rivers, main and subsidiary streams), DEM map of the region, slope map, aspect map and satellite images. Area, perimeter, height classification for classifying the morphological landforms in different levels, hypsometric, drainage density, etc. were then calculated by using the ArcGIS software. The Damavand cone, with a height more than 5,000 m above the sea level, has a very hard-pass slopes. Our purpose in this paper is to identify the effect of drainage basins conditions on the erosion and formation of geomorphological landforms by using of SPOT and ASTER satellite images as well as data analysis o in GIS environment.
SH. Gholipouri; P. Ghazanfari; M. Almasian; N. Jalali
Abstract
Vardeh drainage basin is located at north of Karaj and belongs to Central Alborz structural zone and its climate is semi-humid. The area of Vardeh basin is 68,97km2. Formations in this basin mainly include shale, tuffaceous shale, tuffaceous sandstone and limestone. The age of Kahar Formation is Precambrian, ...
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Vardeh drainage basin is located at north of Karaj and belongs to Central Alborz structural zone and its climate is semi-humid. The area of Vardeh basin is 68,97km2. Formations in this basin mainly include shale, tuffaceous shale, tuffaceous sandstone and limestone. The age of Kahar Formation is Precambrian, the oldest formation and quaternary alluvial deposits are the youngest deposits at this basin. The aim of this study is Investigation of susceptibility of formations to erosion with qualitative methods, assessment of physiographic and geomorphology and quantitative ways, MPSIAC model and sedimentary yield. In this research, library studies, field surveys, interpreting Arial photos were carried out. The collected data taken into account from geometry factors, in V1 sub – basin minimum slope and altitude and in v7-2 maximum slope and altitude. Vardeh basin is divided into mountain (M,m), hills(h), and alluvial deposit (Qal,Qt). Mio fancies forms the most area of the basin. In MPSIAC model the effect of nine and EPM model the effect of 4 important factors on soil erosion and sediment yield were evaluated. Numerical values were assigned to them in terms of intensity and weakness of each factor. Using the sum of those values different factors, the amount of sediment yield in basin was calculated as Qs= 0.253e0.036R and finally the map for each of the 9 factors were prepared in Arc GIS environment. According to identifying sub- basins with high sediment yield, V2 and V3 sub- basins deposit and this basin shall be among first priority for soil protection planning.
B. Azadbakht; M. Zareinejad
Abstract
Takht-e-Solayman zone is highly rich from the viewpoint of diverse morphological units. This morphological diversity is mostly caused by climatic factors and lithological characteristics, erosion, weathering processes and tectonic movements. Geomorphologic characteristics of Takht-e-Solayman zone are ...
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Takht-e-Solayman zone is highly rich from the viewpoint of diverse morphological units. This morphological diversity is mostly caused by climatic factors and lithological characteristics, erosion, weathering processes and tectonic movements. Geomorphologic characteristics of Takht-e-Solayman zone are influenced by internal and external morphodynamic factors. As a geomorphologic-environmental achievement, this research has been dealt with the investigation of external factors. The available morphologic indications in the study area are divided into 3 general groups including morphodynamic, morphotectonic and morphogentic units and then presented in the form of a geomorphologic map. For this purpose, several new information layers of the zone are prepared in GIS environment using basic maps and field investigations and finally the landforms evaluated using ASTER and ETM+ satellite images.
K. Nejad. Afzali; F. Bayatani; E. Moghimi
Abstract
Coastal region are influenced by land and sea. Geomorphologic coast features are related to sea level change, regional river regime, erosion processes, sedimentation, climate change, geological outcrops and weathering and tectonics. Tom bolo, lagoon and barrier are geomorphologic coast features that ...
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Coastal region are influenced by land and sea. Geomorphologic coast features are related to sea level change, regional river regime, erosion processes, sedimentation, climate change, geological outcrops and weathering and tectonics. Tom bolo, lagoon and barrier are geomorphologic coast features that can be seen in Bir coast of Iran. Therefore, recognizing the producing mechanism and their changes, leads supervisors to have better management, and do their best for civil and improving planning in coast area. In this research in addition to field studies and sampling, aerial photos 1/40000(1993), topographic maps 1/20000, high resolution images (ETM and IRS) 1998, 2005, 2008 were used. It is concluded that the area is tectonically active, sedimentation; erosion processes, river regime and sea level change are caused to the Tom bolo, Lagoon and Barrier in Bir coast. Surveying the forms, sediment shows an obvious computation between marine currents as constructive process of Tom bolo, lagoon and barrier, and rivers as destructive process in Bir coast.
A. Lashkari; M. R. Ghassemi; M. Qorashi
Abstract
The Caspian (Khazar) fault is the boundary between the Caspian plain and AlborzMountain. As a major tectonic feature, this fault may be considered as the northern mountain front fault of the AlborzRange. Subsidence of the Caspian Sea in north, uplift of the Alborz Mountain, and its over thrusting on ...
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The Caspian (Khazar) fault is the boundary between the Caspian plain and AlborzMountain. As a major tectonic feature, this fault may be considered as the northern mountain front fault of the AlborzRange. Subsidence of the Caspian Sea in north, uplift of the Alborz Mountain, and its over thrusting on southern part of South Caspian basin has occurred along the Caspian fault. In this paper, a segment at the fault which is located between longitudes 52° 30׳ and 53° 00׳ - in the northern part of geological map of Qaemshahr - is considered as a segment that does not outcrop. This paper introduces the general structural and morphotectonic characteristics of this zone and describes the characteristics of the active anticlines (growing folds) and morphotectonic effects in this zone such as effects on rivers.
