Document Type : Research Paper
Authors
1 Ph.D. Candidate, Geomorphology, University of Tehran, Iran
2 Professor, Islamic Azad University, Science and Research Branch, Tehran, Iran
3 Professor, Faculty of Physical Geography, University of Tehran, Tehran, Iran
Abstract
To evaluate the hydrogeochemical characteristics of karst water resources of Oshtorankooh, chemistry details of springs has been considered as the most important evacuator of karst resources. This research has been performed to study hydrogeochemical nature of karst springs and their origin with an emphasis on the type of formation. Accordingly, five samples of the water of permanent springs of this region in the water scarcity time period have been collected and analyzed. To precisely characterize the hydrochemistry of the region, Piper as well as Stiff graphs were employed. The former graph confirmed that the dominant type of the water the region is Calcite-Bi carbonate based. This water possesses a temporal hardness wherein according to the Stiff graph the dominant cautions and anions are bicarbonate and calcium, respectively. The water of the springsPanbekar S1 and Gahar lake S3 are saturated of calcite mineral, and the positive saturation index implies a diffusive flow. The respective flow reflects less development of fractures in the catchment of the springs. The saturation index of dolomite in the springs of Absefid S2, Tamdarbasoo S4 and Mehrghayoonja S5 is negative implying the saturation conditions and reflecting the higher density of surface and sub-surface fractures as well as the type of conduit-diffusion flow along the flow path of these springs. The results of hydrogeochemical analysis also XRF of Karst springs of the field demonstrated that super saturation phenomenon mainly occurs in water scarcity period. Moreover, the chemical nature of the underground waters present in the carbonated stones (rocks) is strongly dependent on the dissolution of calcite also dolomite. The higher water temperature of the Panbekar spring is affected by saturation index of dolomite in Dalan formation. The results of factor analysis also verified that the most important factor could be dissolution of carbonate then magnesium and electrical conductivity. The water of this spring is classified in the group of relatively hard and hard waters.
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