Response to the comments made by Möller, P., E. Rosenthal, E. and Siebert, C. to the paper “The Sdom evaporite formation in Israel and its relationship with the Messinian Salinity Crisis” by J. Charrach Abstract I thank the discussors for their critique of the above paper. In geology there are rarely any absolute models but working hypotheses, which will be modified with new data. The paper under discussion, Charrach (Carbonates Evaporites 33:727–766, 2018a), presents a very new large data set, which is multi-disciplinary and integrated the most recent research. The critique by Möller et al. (Carbonates Evaporites https://doi.org/10.1007/s13146-019-00486-3, 2019) and their paper of 2018 (Int J Earth Sci 107:2409–2431, 2018),  presents a computer simulation, which must be validated with field evidence and recent research in the area, and not based on assumptions, which have turned into facts over time. The discussors may be unfamiliar with the geological research that has been published over the last 20 years in the areas under consideration. Furthermore, the research on marine–non-marine evaporite formations is hardly considered in their discussion, yet much has been published.

Comments on “The Sdom evaporite formation in Israel and its relationship with the Messinian Salinity Crisis” by J. Charrach Abstract According to J. Charrach, the Sdom formation is a major non-marine evaporite sequence deposited during the climax of the Mediterranean Salinity Crisis (MSC). Hydrochemical studies, however, reveal that the evaporites of the Sdom and Zemah stratigraphic columns dominantly originate from evaporated Tethys seawater mixed with some local drainage water. The formation of evaporites in the northern and southern Inland Sea lasted about 2 Ma, a period that could only be pre-Messinian, i.e., most probably Tortonian.

Introductory editorial Abstract In order to understand the genesis of a carbonate (karst) aquifer from its initial stage to a fully developed karst system number of different methods have been developed over the last 50 years. Nevertheless, with the continued progress of new technologies developing, the groundwater genesis of the karst aquifer becoming more and more precisely defined. Still, more investigation, specific forums and scientific discussion as well as publications are necessary to improve the knowledge of groundwater genesis within carbonate aquifers, as a main step of karst groundwater protection and utilization. With increasing demands on water resources protection, water supply, urbanisation, construction of large dams, reservoirs, tunnels, railways, roads, mines, tailings and waste disposal structures also increase necessity for close co-operation of a wide spectrum of scientist in precise defining and modeling of groundwater genesis. Groundwater from carbonate aquifer as a rule have good physic-chemical characteristics, and inside of the carbonate rocks can accumulate a large quantities of groundwater, which are ideal for watersupply. On the other hand, they are characterized with high vulnerability to pollution, due to weak autopurification properties of the medium, and big variation in discharging. In order of properly using of karst natural resources, the good knowledge of the hydrogeological system genesis is necessary, meaning primarily on carbonate or evaporitic formation with well-developed dissolution porosity. In a case of defining of groundwater genesis of carbonat aquifer as well as protection, a large number of methodological approaches can be applied in order to define the recharge zone and connection between the underground and surface waters, the mean residence time, as well as groundwater interaction with the hostrock, which have influence on chemical composition and temperature regime of discharged water. This special thematic edition partly includes extended versions of the selected papers that will have been presented at the International Symposium KARST 2018, which deals with the above presented and discussed topics precisely through the works of a large number of world-renowned authors. A number of papers will be presented by invitation, and will directly refer to specific areas of karst exploration: hydrogeology, geomorphology, engineering geology, speleology, all relating to the sustainable use of karst waters as an essential natural resource. The papers will cover a wide range of recent scientific research that was carried out in karst terrains all over the world (China, USA, Canada, Russia, Iran, Peru, Turkey, Malaysia and many European countries).

Microfacies and depositional environments of the Qom Formation in Barzok area, SW Kashan, Iran Abstract Qom Formation (Oligo-Miocene marine deposits of Middle Iran) in the southwestern Kashan was studied to determine its microfacies and depositional environments. Outcrops of the Qom Formation in the study area with 410 m, consist mainly of limestone, sandy limestone, shale and marl. Study section is unconformably underlain by the Eocene volcanic rocks and overlain by alluvium. Biogenic components of the Qom Formation comprise mainly of larger benthic foraminifera, coralline red algae and corals. Based on the presence of Nummulites spp. (Nummulites fichteli, Nummulites vascus, Nummulites cf. vascus, Nummulites sp.) throughout the study section, the Qom Formation is considered to be Rupelian in age. Microfacies analysis and field investigations on the study section led to recognition of six carbonate microfacies and two marl and shale facies. Two major depositional environments were identified in the study area including lagoon and open marine. Based on the recognized microfacies and field investigations, deposition of the Qom Formation in Barzok area took place on a carbonate ramp; besides, most of the carbonate parts of the study section are deposited in the open-marine settings. The high abundance of larger benthic foraminifera, coralline red algae and corals indicates that deposition took place in the tropical warm waters.

Delineation of groundwater potential zones using remote sensing (RS), geographical information system (GIS) and analytic hierarchy process (AHP) techniques: a case study in the Leylia–Keynow watershed, southwest of Iran Abstract In this research, a standard methodology has been applied to delineate groundwater resource potential zonation based on integrated remote sensing (RS), geographic information system (GIS), and analytical hierarchy process (AHP) techniques in Leylia–Keynow watershed, southwest of Iran. A total of five sets of criteria/factors (including lineament density, rainfall, lithology, slope, and drainage density) believed to be influencing groundwater storage potential in the area were selected. Each criterion/factor was assigned appropriate weight based on Saaty’s 9-point scale and the weights were normalized through the analytic hierarchy process (AHP). The process was integrated in the GIS environment to produce the groundwater potential prediction map for the area. The fi9-p groundwater prospect map obtained was classified as excellent potential, very good potential, good potential, moderate potential, and poor potential zone. The obtained results indicated that only 21% (122 km2) of the study area exhibit poor groundwater potential, whereas most of the regions (326 km2) in the research showed good to excellent groundwater potential. Also, about 24% (141 km2) was classified as having moderate groundwater potential. The good to excellent potential zones are characterized by the higher lineament density, higher rainfall, and lithology type such as limestone, whereas the poor to moderate groundwater potential zones are characterized by the lesser lineament density, lower rainfall, lithology type of shale and marl as well as shale and limestone. Based on the obtained evidences, the tectonic structures had an important role in fracturing and crushing of limestone units in the area and so are vital for karst and ground water sources development. The demarcation of groundwater potential zones in the Leylia–Keynow watershed will be helpful for future planning, development and management of the groundwater resources.

Formation of $${\text {CaCO}}_3$$CaCO3 varieties from a carbonated aqueous solution Abstract Experimental studies have been conducted to clarify the paragenetic conditions of \({\text {CaCO}}_3\) varieties, calcite and aragonite formed from the same wall rock. In addition, the solubility dependence of calcite, aragonite, and limestone formed from limestone cave in \({\text {CO}}_2\)-saturated solutions was compared with the previous studies. First, the calcite and aragonite were powdered to below 200 meshes. In addition, the powders were, respectively, added into the \({\text {CO}}_2\)-saturated distilled water at 8, 13, 18, and \(22 \,^\circ {\text {C}}\) and were kept constant for 15 days. The amount of dissolved \({\text {CaCO}}_3\) was then measured. The solubility of aragonite was higher than that of calcite, and the solubility decreased exponentially with increasing temperature. Simultaneous production and growth of calcite and aragonite proceeded only when the saturation of aragonite was reached in aqueous carbonate solution. Conversely, when the dissolved amount of \({\text {CaCO}}_3\) has not been reached, calcite is only formed and grown. In these solutions, aragonite crystals dissolve and calcite crystals grow. The degree of saturation of aragonite can be reached by rapid evaporation of solvent, \({\text {CO}}_2\) gas degassing, and the presence of Mg. However, paragenesis of calcite and aragonite in natural caves can be explained by rapid evaporation of the solvent. A rapid evaporation of the solvent may occur at a place, where a small amount of karst solution flows and a large amount of air flows. In such places, paragenesis of calcite and aragonite is possible.

Khuzestan plain continental sabkhas, southwest Iran Abstract Khuzestan Plain is part of the Zagros basin that is located in the southwest of Iran. So far, no comprehensive study has been carried out on these sabkha in Khuzestan plain. This research is the first study on these environments in Khuzestan plain. In this study, continental sabkha of Khuzestan have been divided into four groups: playa, sabkha of dried floodplains, sabkha of dried lagoons, sabkha of ephemeral saline lake (pans). A playa, called Maleh, four sabkha of dried floodplains, with the names of east Zohreh, east Jarrahi, west Jarrahi–east Karoon and west Karoon, two sabkha of dried lagoons, called Hor Al-Azim and Shadegan as well as five sabkha of ephemeral saline lakes were identified in this plain. A total of 87 specimens were collected from the continental sabkha sediments of Khuzestan which classified according Shepard (J Sediment Petrol 24:151–158, 1954). Silt and then clayey silt and sandy silt are the most abundant sediments of continental sabkha of Khuzestan.

Origin of crystal dolomite and its reservoir formation mechanism in the Xixiangchi Formation, Upper Cambrian in Southeastern Sichuan basin Abstract This paper takes the thick and widely distributed crystal dolomite of Xixiangchi Formation, Upper Cambrian in Southeastern Sichuan basin as an example, the reservoir characteristics and main controlling factors of crystal dolomite have been analyzed systematically, and the genesis and reservoir formation mechanism of crystal dolomite have been discussed. It shows that the main reservoir rocks of crystal dolomite include powder crystalline dolomite and finely crystalline dolomites, and the intercrystal pores and dissolved intercrystal pores are the main reservoir spaces, with few dissolved vugs and fractures developed in the reservoir. The pore structure analysis shows that the throats of crystal dolomite reservoir are mainly lamellar, reflecting a good configuration between pores and throats, medium- low porosity and low permeability, representing typical porous-type reservoir. Dolomitization analysis indicates that the dolomitization occurred in the penecontemporaneous or early diagenetic stage. The degree of dolomitization decreased gradually from the top to the bottom in each sedimentary cycle, and distribution of dolomite in the study area shows that the content of dolomites decreases from the west to the east, which reflects the degree of dolomitization weakening eastward. Combined with the geochemical research of crystal dolomite, the C and O isotope data reflect the same characteristics of seawater during the late Cambrian. It indicates that the dolomitization might be related to the seepage-reflux of seawater in the early time. Recrystallization played an important role in the genesis of the crystal dolomite, because most of crystal dolomites remain residual granular texture. The intercrystal pores formed by seepage–reflux dolomitization acted as superior seepage channels for the reservoir transformation, and the recrystallization adjusted the previous pores and made them better, while the karstification was the key to the dissolved pore formation.

Difference in the relationship between soil CO 2 concentration and the karst-related carbon cycle under different land use types in southwest China Abstract As an important driving force for karstification, soil CO2 has a close relation with karst-related carbon cycle. However, their relationship may be disturbed when H2SO4 and HNO3 participate in karstification. Here, soil CO2 and spring water samples were collected from two catchments to examine the dynamics of carbon under different land use types. The net CO2 consumption at the Baishuwan spring catchment (BSW; range 1.7–2.69 mmol/L, average of 2.21 mmol/L) was higher than it was at the Hougou spring catchment (HG; range − 0.63 to 0.02 mmol/L, average of − 0.24 mmol/L). Due to the participation of H2SO4 and HNO3, CO2 was released from bedrock and reduced net CO2 consumption when this portion of CO2 escaped from the water. With regard to soil CO2 concentration, a bidirectional gradient of CO2 concentration occurred at BSW, while alternating bidirectional and unidirectional gradients occurred at HG. However, the δ13C of soil CO2 could not confirm whether the vertical changes in soil CO2 concentration as well as net CO2 consumption were related to the CO2 released from bedrock to soil. With regard to seasonal changes, net CO2 consumption was consistent with soil CO2 concentration at BSW, while the reverse relationship was found at HG. These observations indicated that soil CO2 concentration was not the dominant factor controlling net CO2 consumption at HG, which was affected by H2SO4 and HNO3, and more CO2 escaped from the water due to the reduced water–rock reaction time in the rainy season.

Some carbonate rocks utilized as a building material rocks, Egypt Abstract Studies of the geochemical, mineralogical, petrographical characteristics and the physicochemical properties were carried out on some carbonate rocks, so as to throw light on the possibility of utilizing them as a building stones. The dolomitic and dolostone rocks of Gebel Ataqa and Giran El-Ful quarries have been acquiring potential application in building and industry. Petrographically, the dolomite rocks of the Gebel Ataqa quarries are characterized by dolo-biomicrosparite and dolomitic limestone microfacies for Hassan Alaam quarry and dolosparite microfacies for Arab Contractors quarry, while those of Giran El-Ful (Abu Roash area) are mainly dolo-biomicite microfacies and dolostones. They are deposited in mixing zone environment. Mineralogically, XRD patterns indicate the dolomites of the Ataqa and Giran El-Ful quarries are non-stoichiometric. XRD with DTA revealed that the rocks of the three quarries are consisting mainly of dolomite (Ataqa quarries), calcite and ankarite (Abo Roash quarry), as the main constituents, besides quartz and halite as minor constituents. Geochemically, the normative dolomite contents in the studied rocks with an average ~ 90, ~ 35, and ~ 31% for Arab Contractors, Hassan Alaam and Giran El-Ful quarries; respectively. Thus, the dolomitization was more effective in the Cretaceous carbonates at Arab Contractors quarry than those in the Middle Eocene in Hassan Alaam and Giran El-Ful quarries. Arab Contractors have very high Mg content followed by Hassan Alaam, though impoverished in Na2O, K2O, Al2O3, Fe2O3, SO3, SiO2, TiO2, and Cl. Giran El-Ful quarry has very high Fe2O3 and MgO contents; on the other hand, poor in Na2O, K2O, Al2O3, SO3, SiO2, TiO2, and Cl. Sr contents indicate that the dolomite crystals were deposited in mixing zone environments. The total radioactivity measurements are ranging from 2 to 8 ppm for U and from 3 to 9 ppm for Th. The radioactivity measurements are approximately against to the background level of carbonates, and they are in the permissible limits for carbonates used in cement industries and as building stones. The dolomitic and dolostone rocks of the three quarries are proved chemically suitable for the industries relevant to crushed aggregates and lime production. Physically–mechanically examination revealed that the youngest carbonate deposits in the Middle Eocene (Hassan Alaam quarry) rocks have relatively low porosity, water absorption, and crushability, and highest compressive strength compared with those carbonate rocks of the two other quarries of Upper Cretaceous (Arab Contractors and Giran El-Ful). The petrographical, geochemical, and physical–mechanical observations recommended that the carbonates rocks of Hassan Alaam and Arab Contractors quarries in Gebel Ataqa area clearly can be used in the production of crushed aggregates to utilize in the concrete works. On the other hand, Giran El-Ful quarry can be used only in the mechanical sawing and in the production of limestone blocks.