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Carbonates and Evaporites (08912556) 40(2)
The continental closed basin playas often serve as the discharge point of regional water flow systems and the evolution of brines and salts in these areas is a response to fluctuations in recharge or evaporation. This research discusses the geochemistry, brine type, and evaporite minerals of the Jandaq and Khur sabkhas located in the Great Kavir, Iran. The sabkhas consist of four main sub-environments: sand flats, mud flats, saline mud flats, and salt pans. Samples of brine, primary and secondary salt were collected and analyzed for their pH, major cations and anions, mineralogy. Brines of the sabkhas are moderately acidic and the low pH of the brines is likely due to the oxidation of Fe sulfides present in the green marl deposits. The quantities of Na+, Cl- and SO42- are lower in the brines than in the salts, while the amounts of Mg2+, Ca2+, K+ and Sr2+ are higher in the brines. The average contents of major cations in the primary salts are higher than those in the secondary dendritic salts, and the primary salts of the Jandaq sabkha have higher contents than those of the Khur sabkha. Halite is the primary mineral formed under natural conditions, and tachyhydrite may form during the final stages of concentration. The ionic strength and sum of Na+, K+, Ca2+, Mg2+, and Cl- quantities increase with evaporation, while pH decreases from the precipitation stage to desiccation stage. Carbonates in the pH range of the brines mostly exist as HCO3-. SO42- occurs in the secondary dendritic salts, primary salts, and brines, respectively, in order of abundance. The brine of the salt pan is of Na-(Mg)-Cl type. The brines are supersaturated with respect to calcite, aragonite, dolomite, and halite, indicating precipitation of these minerals. However, the brines are undersaturated with respect to barite, gypsum, sylvite, and celestite. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Salehi, M.A. ,
Bahrami, A. ,
Moharrami, S. ,
Vaziri moghaddam, H. ,
Pakzad, H.R. ,
Shakeri, B. Journal of African Earth Sciences (1464343X) 171
The predominantly warm greenhouse climate and high global sea level during the Middle–Late Devonian resulted in fully marine conditions along the northern Gondwana margin, including the Iranian Plate. Over three-hundred meter-thick fossiliferous Middle-to Late Devonian carbonate deposits of the Bahram Formation in the Anarak region (western Central Iran) are composed of dark grey limestone, dolostone, and interbedded shale. Seventeen microfacies have been distinguished, which correspond to four depositional sub-environments, i.e., tidal flat, lagoon, shoal, and open marine. The Middle–Late Devonian carbonate deposits were deposited on a homoclinal carbonate ramp. Seven third-order depositional sequences are identified, apparently controlled by relative sea level change. Carbon and oxygen stable isotopes, and major and trace elements of micritic carbonate samples document details about the geochemical, palaeoenvironmental, and diagenetic processes; they also indicate that the carbonates underwent meteoric diagenesis within a semi-closed diagenetic system. The low concentrations of trace elements indicative of euxinic conditions, including Mo, Cr, V, and As, suggest well-oxygenated depositional environment. Carbon isotope values show a meaningful relationship to major sequence-stratigraphic key surfaces, with more negative values occurring at the sequence boundaries and positive values corresponding to maximum flooding surfaces. © 2020 Elsevier Ltd
Salehi, M.A. ,
Sebdani, Z.M. ,
Pakzad, H.R. ,
Bahrami, A. ,
Fürsich, F.T. ,
Heubeck, C. Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen (00777749) 288(1)pp. 49-77
The “Jurassic Gap” between Upper Triassic and Lower Cretaceous siliciclastic strata at the southwestern margin of the Central East Iranian Microcontinent (CEIM) represents the Cimmerian orogenic events. However, the provenance of siliciclastic rocks above and below this prominent unconformity is poorly known, negatively affecting our ability to reconstruct paleogeography and orogenic dynamics. Here, we analyze the provenance of the uppermost Triassic Qadir Member of the Nayband Formation and the red beds of the Lower Cretaceous siliciclastic succession in central Iran, based on conglomerate clast composition, sandstone modal analysis and sandstone geochemistry. Based on the notable compositional variation, we assign the Qadir Member to a transitional continental-tectonic setting and the red beds of the Lower Cretaceous siliciclastic rocks to a recycled-orogen setting. Geochemical analyses shows that the parent rocks of the Qadir Member were intermediate igneous, felsic and metamorphic rocks; and were sedimentary quartz, felsic igneous and metamorphic rocks for the Lower Cretaceous red beds. The modal analysis also indicates semi-humid weathering conditions in the Late Triassic but more humid conditions during the Lower Cretaceous which the strata were largely influenced by the deposition of recycled Jurassic sediments. We infer the Sanandaj–Sirjan Zone (SSZ) to the south to be the main provenance region for both stratal packages. © 2018 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.
Zare, M.R. ,
Kamali, M. ,
Fallahi kapourchali, M. ,
Bagheri, H. ,
Khoram bagheri, M. ,
Abedini, A. ,
Pakzad, H.R. Environmental Science and Pollution Research (09441344) 23(4)pp. 3285-3299
Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of 235U, 226Ra, 232Th, 40K, and 137Cs in sediment samples ranged between 1.05 ± 0.51–5.81 ± 0.61, 18.06 ± 0.63–33.36 ±.0.34, 17.57 ± 0.38–45.84 ± 6.23, 371.88 ± 6.36–652.28 ± 11.60, and 0.43 ± 0.06–63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36–5.97, 22.71–38.37, 29.27–42.89, 472.66–533, and 1.05–9.60 Bq/kg for 235U, 226Ra, 232Th, 40K, and 137Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland. © 2015, Springer-Verlag Berlin Heidelberg.
Carbonates and Evaporites (08912556) 30(2)pp. 135-143
The Gavkhuni playa lake consists of sand, mud, and salt flats. The salt pan covers extensive part of the playa. Its color is usually clear and white, but black, pink and green colors also occur. The black color of halite has been caused by impurities of detrital sediments. The sand detrital sediments have been derived from the aeolian sands located in the west of the playa lake. The pink to light red color of the halite is due to the existence of iron oxides or/and microbial effects. There are potentials for natural concentrations of heavy metals in the evaporite sediments of this lake especially due to the occurrence of sedimentary Pb/Zn ore deposits in its drainage basin. To study the concentration of the heavy metals in the salt pan, 18 samples were taken from the salt pan and analyzed. The results show that average concentrations (ppm) of the heavy metals in the salt pan are Ni (56.46), Sr (26.46), Pb (11.42), Ag (10.70), Mn (6.15), Co (2.86), Cd (1.98), Zn (1.48) and Cu (1.14) in their order abundances. The amounts of Zn, Mn, Sr, Cu, Cd and Pb are relatively high in samples containing calcium minerals. The concentrations of Mn and Cu in the pink and green salts are relatively higher than the white ones, because these metals tend to be adsorbed by organic matter. Manganese oxides are important factors influencing the Ni concentration in the sediments. The Mn and Sr concentrations increase in the samples containing iron silicate minerals and carbonate grains. The Co and Ni concentrations are high in the samples containing Fe/Mg-bearing clastic grains. The Ag concentration is high in the samples containing sulfide minerals. Strong adsorption of Mn2+, Co2+ and Zn2+ to clay minerals and precipitation of Cu as Cu°, Cu2S, CuS and Pb as PbCO3 and PbS in the mud sediments can be the reasons for the lower concentrations of these elements in the pure salt sediments than the mud deposits. Enrichment factor indicates that Ag is moderately enriched and other elements are weakly enriched in the evaporite deposits. © 2014, Springer-Verlag Berlin Heidelberg.
Quaternary International (10406182) 345pp. 138-147
In order to study natural concentration of heavy metal in sand sediments of the Oman Sea and its relationship with composition and provenance of the deposits, the concentrations of Cd, Co, Cu, Sr, Pb, Cr, Zn, Ni, Mn and Fe were determined. Relationships between the heavy metal concentration with composition of the sediments and rocks existing in the rivers drainage basins of the area were studied. The results indicate that the Zn and Cu concentrations are closely related to biotite and muscovite contents of the sediments. The amounts of Sr, Cd and Pb change similarly to the variation of calcium carbonate content in the sand sediments. The Fe and Mn concentrations show correlations with the total amount of heavy minerals. The distribution pattern of Cr resembles the pyroxene content. The Co and Ni concentrations fluctuate similarly to the variation of the amphiboles and the intrusive igneous fragments, respectively. © 2014 Elsevier Ltd and INQUA.
Environmental Earth Sciences (18666299) 71(11)pp. 4683-4692
The sedimentary basin of Gavkhuni playa lake includes two sedimentary environments of delta and playa lake. These environments consist of mud, sand and salt flats. There are potentials for concentration of heavy metals in the fine-grained sediments (silt and clay) of the playa due to existence of Pb/Zn ore deposits, industrial and agricultural regions in the water catchment of Zayandehrud River terminating to this area. In order to study the concentration of heavy metals and the controlling factors on their distribution in the fine-grained sediments, 13 samples were taken from the muddy facies and concentration of the heavy metals were determined. The results showed that the heavy metal concentrations range in the sediments (in ppm) are Mn (395.5-1,040), Sr (100.4-725.76), Pb (14.66-91.06), Zn (23.59-80.9), Ni (37-73.66), Cu (13.83-29.83), Co (5.73-13.78), Ag (3.03-4.76) and Cd (2.3-5.5) in their order of abundances. The concentration of Ag is noticeable in the sediments relative to the average concentration of this element in mud sediments. The amounts of Pb and Zn are relatively high in all the samples in comparison with the other elements. The concentration of Ni is relatively high in the oxidized samples. The distribution of Pb is directly related to organic matter content of the sediments. The concentrations of Zn, Sr, Cu, Co and Cd in the samples of the playa are lower than those in the delta. The amount of illite is another factor influencing Zn and Pb concentrations. Sr is more concentrated in the sediments with the high content of calcium carbonate. The distribution pattern of Cu, Co, Pb and Mn resembles to that of the clay content of the sediments. The clay content shows positive correlations with Co, Cu and Mn concentrations and negative correlation with Ag. The Sr and Ag concentrations are positively correlated with the amount of CaCO3. The amounts of Co, Cu, Ni and Mn show negative correlations with the calcium carbonate content. Pb and Co are noticeably correlated with Mn. © 2013 Springer-Verlag Berlin Heidelberg.
Carbonates and Evaporites (08912556) 22(1)pp. 1-5
Common features on the sand flat are gypsiferous marl mounds, gypsum interlayers, thin efflorescent salt crust, puffy surface and tufa. The first four features suggest periodic flooding and desiccation. Bi-carbonate-rich springs probably built small tufa mounds. Hard porous surface pitted by small holes with a few centimeters wide and deep is remarkable morphology on the mud flat/saline mud flat. This results from flooding, desiccation and evaporation of capillary brines and rapid and differential rising of the sedimentary surface. Polygonal halite crusts, halite pressure ridges and efflorescent cauliflowers (popcorn) are common features on the salt pan. They suggest volume reduction caused by either thermal contraction or desiccation and pumping of subsurface brine and subsequent evaporation along the cracks between the polygons.
Carbonates and Evaporites (08912556) 22(2)pp. 93-100
The Gavkhoni playa lake is surrounded by alluvial fan deposits to the north, south and east and the Varzaneh aeolian sand field to the west. Four major sub-environments including: sand flat/saline sand flat, sand beach, mud flat/saline mud flat and salt pan and seven major facies can be recognized in this playa lake. Sand flat results from transportation of sand by wind from the adjacent sand dunes. The mud flat reflects rapid deposition on a lower flood plain during wet, shortly after sheet floods. The saline mud flat and salt pan is as a result of three stages: flooding, evaporation and desiccation. After flooding, when the shallow ephemeral lake becomes concentrated by evaporation, saline mud flat is formed and finally the formation of salt pan starts. Regarding the sub-environments it is supposed that climatic changes played an important role in sedimentation. During periods of increased run off, sedimentation of alluvial/fluvial occurred and water table was raised at the playa lake. During periods of reduced run-off and falling water table, the saline mud flat and salt pan were formed and wind erosion of alluvial deposits resulted in formation of sand dune and sand flat.
American Journal of Applied Sciences (discontinued) (15469239) 4(8)pp. 547-553
The main mineralogical/lithological composition of the Varzaneh aeolian sands is sedimentary and igneous lithics. The minor one is metamorphic lithics and mineral grains (such as quartz, feldspar and heavy mineral grains) respectively. The origin of the sedimentary lithics (mainly carbonates) mostly is from sedimentary rocks exposed in the west and the southwest of the study area. These rocks belong to Cretaceous and Jurassic outcrops. The origin of the igneous lithic grains chiefly belongs to Tertiary highlands, located to the north and the northeast of the study area. The main origin of the metamorphic lithic grains is from the mountain ranges located in the north-western and the western part of the drainage basin of the Zayandeh river. Texture of the aeolian sand grains is similar to the Zayandeh river sediments. Concentration of the aeolian sands at the west of the Zayandeh river delta, variation of their mineralogical/lithological composition from north to south, and textural characterizations of sand grains indicate that the water laid sediments of the Zayandeh river, widespread to the north of the aeolian sands, are the main supply of the aeolian sands and sediments deposited by the two ephemeral streams in the south and the southwest of the sand dunes are minor one. © 2007 Science Publications.
Carbonates and Evaporites (08912556) 19(1)pp. 67-74
The Gavkhoni Playa Lake is located to the southeast of Esfahan, Iran. It is surrounded by the Varzaneh aeolian sand field to the west and alluvial/fluvial sediments to all other directions. It is typical of the few permanent lakes within closed drainage basins in Iran. The properties of intermittent fine-grained and coarse-grained siliciclastic and finally fine-grained evaporite sediments suggest that the basin was influenced repeatedly by wet and dry periods. During periods of flooding, it had been a shallow permanent lake. With increasing aridity, the middle of the lake became increasingly restricted and shallower which resulted in the formation of a salt pan, contributing to the nature of the lake brine. Due to the enclosed nature of the lake system, the water chemistry of Gavkhoni Playa Lake is dominated by sodium and chloride ions but shows wide variations in composition and concentration through time and location. The percentage of Na+(1,012 to 10,3040 ppm), Cl(4,118 to 19,9365 ppm), Mg2+ (360 to 25,691 ppm), and K+(78 to 3,570 ppm) is highest toward the south and at a minimum in the north. Calcium content, ranging from 160 to 3,480 ppm, appears highest in the north. The percentage of strontium (5 to 292 ppm) with the highest value to the north, is extremely low in comparison to other elements. Sulfate is another abundant anion in the brines with the highest content of 22,051 ppm. Bicarbonate is a minor anion ranging from 73 to 450 ppm with the highest values to the north and west. The concentration of sulfate and bicarbonate does not change regularly in the brines from north to south, nor does it vary seasonally. The chemical analysis of the brine shows that it becomes progressively depleted in carbonate and sulfates from the margins to the center of the lake. It ultimately became a Na+, (Mg2+), Cl-brine type in the northern section and a Na+, Mg2+, Cl-brine type in the central part of the lake. After complete desiccation, the mineral assemblage exhibited halite, camallite, bischofite, and tachyhydrite in abundance.
