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Many buried karst areas in Iran, and in other parts of the world have not yet been mapped using detailed geological or geophysical studies to delineate susceptibility to sinkhole development. The purpose of this paper is to investigate the possibility of using the results of hydrogeochemical analysis with routine measurements of physicochemical parameters to evaluate and detect areas prone to sinkhole develop. Sixteen spatial maps were prepared using analyzed data from 77 water samples from monitoring water wells in the Kabudar Ahang, Razan, and Qahavand (KRQ) sub-catchments of the Hamadan province, western Iran. By use of geographic information system tools 16 thematic maps for physicochemical parameters (EC, pH., TDS, and groundwater temperature), major cations (Ca2+, Mg2+, Na+, and K+), anions (HCO−3, SO42−, NO3−, and Cl−), and calcite, dolomite, gypsum, and partial pressure of CO2 saturation indices (SIC, SID, SIG, and SIpCO2) were prepared. It was hypothesized that the anomalies of each parameter concentration could be consistent with sinkhole prone areas. To evaluate this assumption, the area under the Receiver Operating Characteristic (ROC) curve was calculated by 100 points as a true sinkhole pixel (50 positive true) and non-sinkhole point (50 true negative). The areas under curve of ROC for these thematic maps were calculated for the 16 variables. Results show that the dolomite and calcite saturation indices (0.49 and 0.43, respectively) are poor indicators, whereas HCO−3 and pCO2 saturation indexes (0.83 and 0.78, respectively) are good indicators of sinkhole susceptibility in the study area. The result confirmed application of hydrogeochemical anomaly analyses and the ROC validation method in covered karst can be a useful tool for prediction of sinkhole prone zones forming in region, where sparse data are available. [ABSTRACT FROM AUTHOR]

The restricted platform facies dolomites are widely distributed in the northern and northeastern Guizhou, China, and they are the main lithology of karst groundwater and a primary target for locating drinking water resources in the province of Guizhou. The geological history and deposition environment of the restricted platform dolomite facies vary significantly across the province, making it more difficult to evaluate the dissolution and water-bearing capacity of karstic dolomites. This paper explores a quantitative approach to assessing the solubility of four typical geological strata using analytical hierarchy process (AHP) modeling. Properties including CaO/MgO, clast content, porosity, permeability and fracture density are investigated and used as the major criteria in the AHP analysis to render the rankings for solubility among the studied formations. Hydrogeological characteristics are also discussed. Overall the presented results demonstrate the feasibility of AHP as a modeling tool to provide a quantitative approach when a wide range of properties need to be considered. The explored approach can have strong implications for the exploitation and utilization of karst groundwater in Guizhou, China. [ABSTRACT FROM AUTHOR]

The dolomite in the Yuntai Mountain, Shibing, Guizhou, China constitutes the gentle stratum, affected by several weathering processes. It is coupled with a vertical joint development, which makes it easy to form the collapse and stone peaks corroded by running water. The aim of this paper is to study the effects of weathering processes of dolomite outcropping in the Yuntai Mountain (Shibing, Guizhou, China). This work shows the dolomite's physical and mechanical characteristics, microscopic characteristics of rock and pore structure based on chemical and minero-petrographic analyses. The findings indicate that the dolomite in this region is gray, pure quality and hard-packed superfine grain to fine grain. Mass surface voids suggest that the dolomite's pass is small and has more pore throat. Its grain cementation is relatively poor. The degree of rock weathering is relatively high. The mechanical strength is lower than that of the surrounding limestone. This work shows how the macro-micro characteristics of the dolomite affect the formation of collapse and stone peaks. This work further focuses on the study of the cone-shaped peak cluster basement and the upper tower-shaped stone peaks, which are the most important features of this region. [ABSTRACT FROM AUTHOR]

This article focuses on the petrographic and microfacial characterization of the building stones of buildings, monuments, and quarries of the archeological site of Calakmul to document aspects of composition, lithologies, and stone exploitation. Microfacial analysis shows that the used building rocks are highly recrystallized biosparudites (grainstones to packstones) with the presence of reef and shallow waters fauna (boundstones). These rocks have an intermediate porosity (10–20% pore volume values). XRD analysis confirms that the mineral composition is mainly not only calcite, but also dolomite. Microfacies analysis demonstrates that the limestone of the stelae and the SubII c-1 main façade comes from the same quarry since both have the same textures and microfacial features. Their fine texture corroborates that these stones are suitable for carving and lime production. Microfacial analysis also showed that samples from St. XX Gran Acropolis and from Chan Chi'ich Group come from different quarries. These results help us to identify the origin of the rocks, their use in the buildings and monuments studied, and contribute to the knowledge of their lithological characteristics and their response to weathering in a tropical context. Such aspects are crucial to the decision making for future conservation processes. [ABSTRACT FROM AUTHOR]

Basic knowledge of the characteristics of copper-bearing rock such as dolomite is essential to locate those areas of the deposit which have different structural and textural properties. Those regions can be important in terms of the assessment of the possibilities of gas accumulating in them as well as in terms of gasogeodynamic hazard. To better understand those threats, it is necessary to locate, monitor and analyse those areas in detail. This article characterises the structural and textural parameters of dolomite from the Polkowice-Sieroszowice copper mine in Poland. The study involved five samples from various areas of the mine. A number of research methods were selected. Reflected and transmitted light microscopy (MS), computer microtomography (Micro-CT), gas adsorption porosimetry (LPNA), mercury porosimetry (MIP), helium and quasi-fluid pycnometry (Pycno. He, DryFlo). Each of the methods examined a different scope of the pore size, which enabled to achieve a full view of the porous nature of those rocks. We determined their porosity (open, closed, total), surface area as well as mean size and volume of the pores. Also, we studied the character and the pore size distribution from a few nm to a few mm. Comprehensive dolomite properties analyses showed that these rocks are characterised by high structural variability. They have mesopores and macropores but few micropores. The analyses presented in this paper are determined by a large petrographic diversity of the deposits containing dolomite. This article is an example of a comprehensive approach to the rock analysis in copper ore mines. [ABSTRACT FROM AUTHOR]

A thorough study of reservoirs is required for the planning of effective production strategy with careful analyses of the areas, in which the oil can be potentially unswept before any field abandonment. This study presents a modelling workflow to evaluate changes in water saturation due to a long oil production period to localize the remaining oil. The static model of water saturation at the beginning of oil production is compared with the water saturation model before the abandonment obtained using dynamic simulation. Structural, lithological and petrophysical factors controlling the fluid distribution are studied for two reservoirs: the Middle Gharif consisting of Upper Haushi Sand (UHS), Dolomite Drain (DD), and Sandstone Drain (SD) and the Lower Gharif consisting of Lower Haushi Sand (LHS). Following the transition from proximal to basinal settings across the marginal slope, the fractions of sand and shale in all reservoir units decrease while calcite and dolomite increase from the eastern and southeastern parts toward the western and northwestern parts of the field. Controlled by the geologic structure, petrophysical properties and OWCs, water saturation before abandonment varied significantly in various directions. The oil is fully extracted in UHS from the areas with the best porosity and permeability, while overall oil recovery from the reservoir is very low because of the poor rock properties. Oil recovery was high from the DD, but the oil remains in two domes due to the absence of producing wells. Oil is concentrated in the elevated part of the ridge in SD while water saturation reached more than 90% in other parts. Although the LHS with the best petrophysical properties was the most prolific, it experienced early water breakthrough with oil remaining in the ridge and two domes. [ABSTRACT FROM AUTHOR]

In this study, the chemical characteristics, isotopic compositions (δ18O, δ2H), geothermal properties, and suitability for irrigation of groundwater resources were explored in Çubuk-Melikşah (Ankara/Turkey). Water types present in the study area were mainly CaMgHCO3 and NaHCO3, with isotope compositions ranging from − 10.6 to − 9.06 for δ18O and from − 75.62 to − 61.93 for δ2H. The mineral saturation index showed that samples were saturated with respect to aragonite, calcite, and dolomite, while anhydrite and gypsum were undersaturated. Reservoir temperatures, computed from silica geothermometers were 60–75 °C for Melikşah thermal water. Based on the sodium adsorption ratio, residual sodium carbonate, soluble sodium percentage, permeability index, sodium percentage, boron and electrical conductivity values, waters examined in the study area were generally considered to be suitable for irrigation purposes. [ABSTRACT FROM AUTHOR]

Centurion is a fast developing area facing severe karstic sinkhole development. The area is predominantly underlain by fractured dolomite formations that include Oaktree, Monte Christo, Lyttelton, and Eccles of the Malmani Dolomite Group (~ 2600 and ~ 2500 Ma). Fractures of the underlying dolomite formations were investigated as one of the most influencing factors in karstic sinkhole formation using fieldwork mapping, petrology, and remote-sensing techniques (automated lineament extraction methods). Fieldwork results indicate that the study area has two prevalent fracture orientations trending N–S and ENE–WSW with average orientations of 178°/86° E and 073°/67° N. The fieldwork mapping results coincide with those acquired using remote-sensing techniques by automated extraction of lineaments from colour-shaded image and from four Sobel directional filtered images. Remote-sensing techniques indicate that there are extra two prevalent lineament directions; NE–SW and E–W in the study area and majority of the sinkholes develop in areas with high lineament density. Eccles, Monte Christo, and Oaktree dolomite formations exhibit a unidirectional fracture system while Lyttelton dolomite formation exhibit bidirectional fracture system. It is, therefore, concluded that (1) geological lineaments extracted using remote sensing and fractures present in the underlying dolomite formations play a significant role in controlling fluid circulation and thus influencing karstic processes such as dissolution, and therefore, (2) sinkhole development is primarily structurally controlled; however, it is exacerbated by anthropogenic activities due to the influence of water ingress. [ABSTRACT FROM AUTHOR]

Sorption experiments of the Cd, Zn, and Pb(II) ions from aqueous solutions on waste dolomite powder were investigated. Waste dolomite powder is inconvenient during storage due to fine particle size; therefore, its practical application is needed. The sorption experiments were conducted with variables: initial metal concentration (500, 1000, and 2000 mg/dm) in single- and multi-element solutions, adsorbent dose (0.5, 1, and 2 g), and contact time (45, 90, and 180 min). Results showed that dolomite powder removed all ions from experimental solutions. For multi-element solution, Pb(II) was adsorbed almost in 100% at the initial concentration equal to 2000 mg/dm. For Cd and Zn, sorption properties decreased with the increase in the initial metal concentration and the maximum values at the initial metal concentration of 500 mg/dm were 42 and 47%, respectively. The results suggest that waste dolomite powder can be considered for application as sorbent in wastewater purification. [ABSTRACT FROM AUTHOR]

Presence of fluoride in groundwater is a public health problem in the so-called endemic fluorosis belt of the central Iran, where the groundwater is the major source of drinking water in most urban and rural areas. Therefore, an attempt has been made to determine the hydrogeochemical factors controlling fluoride enrichment in the groundwater resources at this belt. Fluoride concentrations ranged from 0.20 to 1.99 mg/L (1.02 ± 0.47) in groundwater samples. The presence of different F-bearing minerals and also clay minerals in the soils and aquifer materials was confirmed using XRD analysis. To identify probable sources of dissolved F and investigate groundwater quality, multivariate statistical analyses were carried out. Geochemical modeling indicated that all samples were undersaturated with respect to fluorite, halite, gypsum and anhydrite and mostly oversaturated with respect to calcite and dolomite. Contrary to most high-fluoride regions in the World, the high F content was dominated by Na-Cl- and Ca-SO-type groundwater in the study area. Besides, fluoride showed negative relationship with pH and HCO in groundwater. In order to assess the bioavailability of fluoride in soils, a two-step chemical fractionation method was applied. The results showed that fluoride in soils mostly accompanied with the residual and water-soluble fractions and was poorly associated with soil's bonding sites. Calculated aqueous migration coefficient demonstrated that fluoride in the studied soils was mobile to easily leachable to the groundwater. Finally, the results demonstrated that combination of water-rock interaction and influence of clay minerals is geochemical mechanism responsible for controlling fluoride enrichment in groundwater. [ABSTRACT FROM AUTHOR]

Natural tracers can be used in arid regions to gain an understanding of streamflow generation and seasonal streamflow sources; their application can support water resources management, water quality studies, and assessments of the impacts of climate change. In this study, we identified hydrological processes in different seasons based on the chemical and isotopic compositions of the Urumqi River. Stable isotope (O and D) ratios and major ion concentrations were measured on a monthly basis at six sites along the Urumqi River from December 2011 to October 2012. Most waters (groundwater, precipitation, glacier, meltwater, and river water) of the Urumqi River basin are the Ca-HCO water type. In the slow flow period, the ionic composition of the river water reflects weathering and dissolution of dolomite and gypsum. Water-rock interactions control the hydrochemical processes during the slow flow period, while the hydrochemical characteristics of river water in the quick flow period are controlled by precipitation, glacier water, and groundwater. The seasonal variation in river δO and δD values at different sites was similar to that of water entering the headwaters of the Urumqi River basin. The isotopic composition of precipitation was evaluated to obtain information on the effects of subcloud evaporation and moisture recycling on the formation and isotopic composition of precipitation in arid climatic conditions. We identified five different periods in streamflow using water chemistry and isotopic composition. [ABSTRACT FROM AUTHOR]

Landslide databases are essential tools for risk assessment. In the Italian portion of the South-Eastern Alps these archives are managed by the Veneto Region and by the provinces of Bolzano and Trento, as part of the Italian Inventory of Landslides. About 750 rockfall events recorded in these archives were checked, put together and completed to create a new integrated database. Information on 24 new rockfalls were added from different research sources. Descriptive statistic shows that the most affected slopes with the highest frequency of rockfall are the southern ones. The distribution of rockfalls during the year presents three peaks in March, June and November. The most commonly affected lithologies are massive dolomites, effusive rocks and mica schists. Roads proved to be the most commonly involved feature. The hypsographic curves obtained from the DEMs of the provinces of Belluno, Bolzano and Trento have shown that the different areas potentially affected by periglacial processes experience rockfalls during summer and autumn, thus representing a risk to tourists and hikers. This study is the first attempt to collate and extend the available information in the various rockfall databases in the Eastern Italian Alps, with the aim at creating uniform data collection for the whole Alpine range. [ABSTRACT FROM AUTHOR]

Approximately all types of surface and underground karst elements are represented in the Urals. Rock formations are elongated in the longitudinal direction, which allows for a comparative analysis of the processes in karst landscapes in different latitudinal geographic areas. During the long geological history of the Urals, karst development occurred in conditions of extensive occurrence of soluble rocks in the territory and in the geological section in cratons, folded zones and depressions. The most intense karstification occurs in Paleozoic sediments. Sulfate rocks (gypsum and anhydrite) located on the eastern margins of the East European Craton and adjacent parts of the Ural Foredeep are the most karstified. These deposits are also intercalated with thin layers of limestone and dolomite of the Irenskaya Suite, and to a lesser extent—limestones and dolomites of the Filippovsky Unit of the Kungurian Stage and limestones of the Artinskian Stage of Lower Permian. Salt-bearing and sulfate deposits are mainly found in the Ural Foredeep. Karst development in the Devonian, Carboniferous, and Permian carbonate strata with a total thickness of more than 2000 m is typical for the folded zone of the West Ural and Central Ural uplifts. The western slope of the South Urals is the most intensely karstified. Hypogenic karst cavities occur from the Polar to the Southern Urals on the western and eastern slopes. The article presents the most interesting examples of hypogenic speleogenesis in the Ural. [ABSTRACT FROM AUTHOR]

Groundwater in the Driftless Area of northwestern Illinois is a very hard Ca–Mg-bicarbonate-type water that reflects the dolomite aquifer material in this karst region. Groundwater in shallow aquifers has a short residence time and is susceptible to surface-borne contaminants. Deeper aquifers have distinct chemistry indicating longer flowpaths, most clearly indicated by low tritium values and elevated potassium and fluoride concentrations. Thirty water samples were collected from springs from across Jo Daviess County in northwestern Illinois between 2015 and 2016. The groundwater samples collected from what were initially identified as springs were found to be of two types: (1) natural springs that are stratigraphically controlled and discharging from crevices and bedding planes, especially where the underlying Galena Dolomite or overlying Silurian dolomite aquifer intersects the Maquoketa Shale; and (2) abandoned flowing-artesian wells, often with no identifiable well casing at the surface, that had been mistaken for springs. Background concentrations of eight water-quality parameters were calculated to determine pre-settlement and present-day background thresholds. The background concentrations, overall chemical compositions, tritium concentrations, and F/Cl and K/Cl ratios were used to characterize and group groundwater within the study area. The results of this investigation combined with recent work by the authors [Panno et al. (IL State Geological Survey Circular 586, 2017)] were used to determine the geologic, hydrogeologic, and geochemical controls on springs in this part of the Driftless Area. The results of this investigation revealed the susceptibility of the Galena Dolomite and Silurian dolomite aquifers to surface-borne contaminants. In addition, this work has developed a means, using ion ratios and spring location relative to bedrock geology to identify discharge from abandoned wells. [ABSTRACT FROM AUTHOR]

The Central West Bank aquifer (CWB) is one of the most important resources of fresh groundwater of Palestine. The geology of the area consists mainly of karstic and permeable limestones and dolomites interbedded with argillaceous beds of late Albian-Turonian age. Exploitation of the CWB aquifer, combined with lack of information required to understand the groundwater pattern, represents a challenge for reservoir management. The present work reports hydrogeochemistry, microbiology and environmental isotope data from spring water samples, which were utilized to understand recharge mechanisms, geochemical evolution and renewability of groundwater in CWB aquifer. Besides the major chemical compositions, ionic ratios were used to delineate mineral-solution reactions and weathering processes. Interpretation of chemical data suggests that the chemical evolution of groundwater is primarily controlled by (1) water-rock interactions, involving dissolution of carbonate minerals (calcite and dolomite), and (2) cation exchange processes. The measured equation of the local meteoric water line is δD = 5.8 δ18O + 9.9. Stable isotopes show that precipitation is the source of recharge to the groundwater system. The evaporation line has a linear increasing trend from south to north direction in the study area. All analyzed spring waters are suitable for irrigation, but not for drinking purposes. The results from this study can serve as a basis for decision-makers and stakeholders, with the intention to increase the understanding of sustainable management of the CWBs. [ABSTRACT FROM AUTHOR]

The chemical and mineral composition and formation conditions of dense grey-yellow colour crusts on the surface of monuments and bowls of decorative fountains in Peterhof (Russia) were studied using a wide range of methods (XRD, SEM, EMPA, Raman spectroscopy). The crusts consisted of calcium carbonates (monohydrocalcite, aragonite, calcite), magnesium carbonates (lansfordite, nesquehonite), and Sr-, Pb-rich carbonates (aragonite-cerussite-strontianite solid solution; up to 29 wt% PbO and 43 wt% SrO). Carbonates formed on all types of materials (gold, polyester resin, marble, granite) and do not interact with it. The cause of the formation of carbonate crusts on decorative fountains is the high content of carbonate ions in water. The variety of mineral phases is associated with fluctuations in the pH and Mg/Ca ratio. Recommendations are given on conservation measures that inhibit the formation of carbonate layers that threaten the preservation of the cultural heritage of this UNESCO World Heritage Site. [ABSTRACT FROM AUTHOR]