Iranian Journal of Geology
Year:2008 | Volume:2 | Issue:6|Papers Count:7

Coastal zone of Khuzestan Province, which has an area of 1359832 hectare, is covered by various coastal (i.e. estuary, lagoon, delta) and continental (i.e. river and alluvial fan) environments. In this research, TM (1988) and ETM+ (2000) satellite images were used for recognition and differentiation of coastal environments. This study is based on combination of visual and digital image analysis in a GIS environment. The best images were formed by combination of 432 bands of TMand 431 bands of ETM+ sattelites. Polygon maps showed that most part (>70%) of region is covered by delta, lagoon and tidal flat environments.

Katalehkhor cave, in SW of Zanjan Province/Iran, has been studied. It is the longest cave in Iran. The cave is located within the Central Iranian Zone. It is developed mainly within the Qom limestone (Oligomiocene) of Saghez-lou Mountain. Katalehkhor is a multistage cave with three levels ranging from 1670 to 1742 m above mean sea level. Calcite speleothems (stalactite, stalagmite, column, flowstone and helictite) occur locally in zones of water percolation from overlying formations. According to previous studies, Katalehkhor cave is an anastomosis maze cave. The evidences demonstrate the floodwater origin of Katalehkhor cave. Cave levels have been developed due to fluctuation of the water table.

The vulnerability of ground water pollution in Varamin plain, located in the southeast of Tehran, has been evaluated using DRASTIC method in GIS environment. The DRASTIC parameters have been calibrated with respect to migration of nitrate ion in the aquifer. The weights of depth to groundwater, soil, unsaturated zone, and hydraulic conductivity have been modified accordance to observed data of nitrate concentrations. This study produced a pollution potential map for the area and classified 9% as having very low pollution potential, 38% as having low pollution potential, 26% as having moderate to low pollution potential, 17% as having moderate to high pollution potential, 8% as having high pollution potential, 1.94% as having very high pollution potential, and 0.06% as having complete vulnerability. The northeast and southwest areas of Varamin plain have more pollution potential rather than middle parts of the plain. The unsaturated adsorption coefficients have been modeled as surface 2D parameter in GIS environment for evaluation of vulnerability of aquifer with respect to adsorb able contaminants. Assessment of adsorption in the unsaturated zone shows that the west and south of Varamin plain have very high pollution potential and the northwest areas of the plain have lowest vulnerability indices. The central parts of the plain have moderate to high adsorption indices and therefore have lower risk of ground water pollution. In general, the results of DRASTIC have relative correlation with the results of the model of unsaturated zone evaluation, in Varamin plain.

Chenaran watershed is located in the northern Khorasan Province, at northern slopes of Aladagh range and is one of the Atrak river subbasins. Several large scale landslides occur in this basin which led to a lots of damages. In order to recognize the mass movements, all aspects of the factors and processes which continually affect on slopes and led to instability, of slope should be identified. In this research the geology, hydrology, topography and landcover-landuse factors were studied.At the first step, the weight of quantitative & qualitative effective variables in basin mass movements was determined, by using “Landslide Index Method” (LIM) model. Then by obtaining of “Logistic regression” model of mass movements in basin, final map for prediction of mass movements probability with 2 classes was prepared. According to the vulnerability about landslide hazard, subbasins were ordered by calculation of weighted accumulation per hectar. Thus, the “Shurijeh Formation” (Ksh) consists of clastic rocks (siltstone and marl) and evaporites, which are impermiable, with assistance of slope, altitude, ground waters, landuse and Chenaran river under cutting, are the most important factors for mass movements in chenaran watershed.

Flat lying Pliocene-Quaternary detritic sediments with various thickness and color were cut by normal faults in restricted area in the Zanjan depression, 45 km northwest of Zanjan city. Along the road cuts, including the Zanjan-Tabriz free-way, young flat-lying Pliocene-Quaternary sediments were cut and displaced by abundant normal faults that exposed locally in 90 square kilometers. These normal faults are approximately E-W in strike and have pure dip-slip movements. Horst and graben structures are abundant in the study area due to conjugate faulting. Along the fault zones, structures like: change of dip due to layers lithology and reology, fibers growth of gypsum, striations and grooves on the fault planes are developed. Striations on the fault planes are parallel to the main dip of the fault planes implying displacement due to gravity. Development of normal faults in restricted area in Zanjan depression produced as a local pull-apart basin along the major Tabriz basement fault.

For lithofacies analysis and recognization of architecture elements of silisiclastic sediments of Dahu Formation (Late Camberian), two stratigraphy sections at Dahuieh (type section) and Gazuieh have been measured and the thickness are 240 and 227 meters, respectively. This study led to identification of 9 lithofacies and 5 architecture elements. Lithofacies classified into three categories including coarse grain (Gcm), medium grain (Sp, St, Sh, Sl, Sr, Sm), and fine grain (Fl, Fm). The interpreted architecture elements are CH, LA, FF, CS, CR. Based on lithofacies and architecture elements, it is interpreted that these silisiclastic sediments may have been deposited in sand-bed meandering river. Sequence stratigraphy analysis show that the Dahu Formation formed during the sea level fall in the Early Camberian time. Many fining upward cycles, that have been formed the highstand system tract (HST), deposited during laterally migration of channel and subsidence of basin. We hope that this information can be used to basin analysis and paleogeographical reconstruction of the Early Camberian time in local and regional scales.

Hamedan-Bahar plain is influenced by contamination agents such as Hamedan and Bahar sewage treatment, Hamedan industrial shambles, henneries and heavy agricultural activity. To provide the useful data for simulation of contamination transport in the study area, 23 wells were sampled during two periods. Ground water flow and nitrate transport were simulated using MODFLOW and MT3D codes. This study indicates that Yeknabad area have a Maximum nitrate concentration that rises due to agricultural fertilizer and strengthening by fine grain sediment (silt and clay). Nitrate transport from surface to groundwater is increased by low thickness of alluvium in Hamedan industrial shamble and southern study areas. High thickness of alluvial sdiments and sanitary area in Hamedan drinking water wells, decrease the groundwater contamination. Also the quality of groundwater in Bahar third dam and Ghorogh Bahar areas, in despite of contaminant agent, improve.