جستجوی مقالات مرتبط با کلیدواژه « Khorasan Razavi » در نشریات گروه « زمین شناسی »

Estimating recharge is important in groundwater studies, especially in budget calculation to properly manage groundwater withdrawals. In this research, recharge value into the alluvial aquifer of Sarakhs, which is the only source of water for drinking, agricultural and industrial uses in Sarakhs Plain (NE Iran and adjacent to Iran-Turkmenistan border), was estimated using MODFLOW model in FREEWAT Software. After preparing the conceptual model of the aquifer and transforming it into a numerical model, the model was calibrated in unsteady states during a two-year period (water-year 2015-2016 and 2016-2017) and verified. The sensitivity process confirmed validity of the numerical model in estimation of the aquifer recharge. Accordingly, the annual surface recharge was estimated at 80 million cubic meters (Mcm), occurring from rainfall (32 Mcm/year) and irrigation return flows (48 Mcm/year). In this regard, rainfall recharge coefficient was estimated about 20% of the annual rainfall and irrigation return flow coefficient was calculated about 15% of the annual discharge rates of the discharging wells. Simulated temporal variations of the groundwater recharge indicates occurrence of the rainfall recharge during January to June and irrigation return flows from November to April each year. The estimated recharge coefficients can be used in budget studies to properly manage the Sarakhs aquifer, as well as the same aquifers in Iran.

Mashkan barite prospect area is located in the northeastern Sabzevar, Khorasan Razavi Province. Geology of the area includes sedimentary rocks of conglomerate, sandstone, limestone with interbeds of shale and shale with interbeds of sandstone and Eocene volcanic units of andesite and trachyandesite. Barite with open space filling, massive, radial, and planar textures occurs as vein-type with mostly northwest-southeast trend. Mineralogy of deposit includes barite, quartz, and calcite and secondary minerals are malachite, azurite, goethite and hematite. The vein mineralization was formed in two stages, including: 1. main stage (barite+quartz) and 2. late stage (calcite). Fluid inclusions in the quartz and barite samples are anhedral to subhedral forms (conical and rod) with a size of about 4 to 12 microns. Maximum  geochemical anomalies in veins are 394 ppm Zn, 52 ppm Sb, and 90 Pb ppm. Based on fluid inclusion studies of quartz and barite samples of the main stage, minimum formation temperature of mineralization is about 181 to 370ºC and with salinity of 6.5 to 13.6 NaCl wt. % equivalent. Based on evidence such as structural control (fault) of mineralization, geology, mineralogy, geochemistry, and fluid inclusion, veins are hydrothermal type. Temperature decreasing and mixing with high salinity fluid during the evolution of hydrothermal fluids are effective during the formation of vein.

Kardeh catchment is a part of the Kopet-Dagh zone and contains a variety of lithological composition. Mozduran and Shurijeh formations, Neogene and recent deposits form most of the outcrops in this area (Nabavieh, 1998). In this study, considering the importance of Kardeh catchment area as sources of water for the underground and surface water resources for drinking in the west of Mashhad, we have analyzed water samples from each sub-catchment and conducted chemical analysis of rocks. The impact of harmful elements in the river water, resulted from lithological erosion, in this basin are discussed. In addition, the water quality of the river in terms of agricultural use, drinking, and industry usage is also investigated (Li & Zhang, 2008; Han et al, 2010).

In this study, 17 water samples and 9 rock samples were collected for analysis. For this reason, temperature, pH, electrical conductivity (EC), total dissolved solids (TDS), concentration and absorption of some ions have been measured. Based on the results, in order to determine water quality for drinking, agriculture and industrial usage, we have made comparisons with the World Health Organization drinking water standards and data from the Standards and Industrial Research Institute of Iran (Schuler, Wilcox and Piper diagrams). Rock samples have been analyzed by ICP method. Two polished thin sections were studied to determine the composition of mineral components, using the Scanning Electron Microscope (SEM) equipped with EDS.

Based on the analysis carried out in the Kardeh catchment, the maximum TDS is 863.35 mg/l in the Al area, and the minimum is 571.95 mg/l in Karim-Abad. The maximum electrical conductivity (EC) is 557 microzimens/sec in the Al area, and the minimum EC is 369 microzimens/sec in Karim-Abad. The highest temperature of 24.6°C is related to the lake, and the minimum temperature measured is 10.3°C in the Mareshk area. The results indicate that among cations, magnesium and potassium have the lowest concentration, whereas sodium and calcium have the highest. Among anions, bicarbonate has the maximum concentration, and sulfate the minimum. Petrographic studies indicate that carbonate and sandstone are the main types of rocks in the study area. Carbonate facies are mainly dolomite, whereas sandstone facies are sublitharenite and feldspathic litharenite with silica, carbonate and iron oxide cements. Based on ICP analysis, aluminum, calcium, iron, potassium, magnesium, and sodium are the main elements in the rock samples. Mozduran (carbonate strata) and Shurijeh (siliciclastic strata) formations and also evaporative units are the probable sources of water-soluble ions (Kazemi et al., 1395). Based on the results of the analysis of water samples, the water is not suitable for industrial usage due to corrosion and precipitation of chemicals. Also, according to the Schuler diagram, some water samples are not suitable for drinking. On the other hand, according to the Piper diagram (Piper, 1944), the major water samples have good quality and contain sulfate, chloride, and calcium as main ions. Thus, according to the Wilcox diagram (Wilcox 1995), the major water samples are in class C2S1. So, based on the presence of slight salt in the water, therefore it is suitable for agricultural use.

The main ions in the Kardeh water samples are sodium, calcium, magnesium, iron, sulfate, and carbonate. Based on the analytical results, for drinking all samples are moderate to good, and are classified in class C2S1 of the Wilcox diagram. Although these samples are acceptable for agriculture, they are unacceptable for industrial usage. Finally, based on the Piper diagram, the quality of water samples are in sulfate and chloride groups. In the Kardeh catchment, the probable source of ions in water samples could be carbonate and siliciclastic rocks as well as Neogene and recent deposits.

The study area is located in the Southeast of Fariman and it is considered as a part of the central Iranian zone. According to field and petrographic studies the composition of volcanic rocks a range from basalt andesite-basalt andesite، trachyandesite to dacite with Paleocene-Eocene age. The dominant textures of the volcanic rocks are microlitic porphyric and glomeroporphyric and the major minerals are plagioclase، olivine، pyroxene، hornblende، alkali feldspar and quartz. Biotite، apatite، sphene and magnetite are as minor minerals. Microscopic studies reveal the presence of disequilibrium textures in plagioclases (eg. zoning and corrosion). The occurrence of xenolites indicates magma contamination. Based on geochemistry of major and minor elements، the studied rocks belong to calc-alkaline series with moderate to high potassium type and meta-aluminous nature. The geochemical behavior of major and trace elements reveals the normal trend of differentiation in the magma. According to geochemical data، garnet-lerzolite may be the principal source rock for the studied volcanic rocks which experienced 1 to 10% partial melting in a depth of around 90 to 100 km. Based on petrographic studies، some evidences of magmatic contamination can be distinguished which can be also supported by Nb and Ti negative anomalies and Pb positive anomaly on spider diagrams and Ce/Pb and Nb/U ratios. Enrichment in LILE and depletion of HFSE in the studied rocks as well as various petrologic diagrams point to magmatism in arc of an active continental margin.