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The ash generated by Circulating Fluidized Bed (CFB) boilers is featured by its looseness and porosity, low content of glassy substances, and high contents of calcium (Ca) and sulfur (S), thus resulting in a low comprehensive utilization rate. Currently, the predominant treatment approach for CFB ash and slag is stacking, which may give rise to issues like environmental pollution. In this paper, CFB ash (with a CaO content of 7.64% and an SO3 content of 1.77%) was used as the main raw material. The high-temperature melting characteristics, viscosity–temperature characteristics, and initial crystallization temperature of samples with different acidity coefficients were investigated. The final drawing temperature range of the samples was determined, and mechanical property tests were conducted on the prepared inorganic fibers. The results show that the addition of dolomite powder has a significant reducing effect on the complete liquid phase temperature. The final drawing temperatures of the samples with different acidity coefficients range as follows: 1270–1318 °C; 1272–1351 °C; 1250–1372 °C; 1280–1380 °C; 1300–1382 °C; and 1310–1384 °C. The drawing temperature of this system is slightly lower than that of basalt fibers. Based on the test results of the mechanical properties of inorganic fibers, the Young's modulus of the inorganic fibers prepared through the experiment lies between 55 GPa and 74 GPa, which basically meets the performance requirements of inorganic fibers. Consequently, the method of preparing inorganic fibers by using CFB ash and dolomite powder is entirely feasible. [ABSTRACT FROM AUTHOR]

Reactive transport modeling (RTM) is an emerging method used to address geological issues in diagenesis research. However, the extrapolation of RTM results to practical reservoir prediction is not sufficiently understood. This paper presents a case study of the Eocene Qaidam Basin that combines RTM results with petrological and mineralogical evidence. The results show that the Eocene Xiaganchaigou Formation is characterized by mixed siliciclastic-carbonate-evaporite sedimentation in a semiclosed saline lacustrine environment. Periodic evaporation and salinization processes during the syngeneticpenecontemporaneous stage gave rise to the replacive genesis of dolomites and the cyclic enrichment of dolomite in the middle-upper parts of the meter-scale depositional sequences. The successive change in mineral paragenesis from terrigenous clastics to carbonates to evaporites was reconstructed using RTM simulations. Parametric uncertainty analyses further suggest that the evaporation intensity (brine salinity) and particle size of sediments (reactive surface area) were important rate-determining factors in the dolomitization, as shown by the relatively higher reaction rates under conditions of higher brine salinity and fine-grained sediments. Combining the simulation results with measured mineralogical and reservoir physical property data indicates that the preservation of original intergranular pores and the generation of porosity via replacive dolomitization were the major formation mechanisms of the distinctive lacustrine dolomite reservoirs (widespread submicron intercrystalline micropores) in the Eocene Qaidam Basin. The results confirm that RTM can be effectively used in geological studies, can provide a better general understanding of the dolomitizing fluid-rock interactions, and can shed light on the spatiotemporal evolution of mineralogy and porosity during dolomitization and the formation of lacustrine dolomite reservoirs. [ABSTRACT FROM AUTHOR]

This paper investigates the origin of ultra-deep dolostone and the factors influencing large-scale dolostone reservoirs, focusing on the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan Basin. The study involves petrology, microscale X-ray diffraction, trace element analysis, and C-O-Sr-Mg isotope experiments to provide a detailed analysis. The research findings indicate that the Dengying and Longwangmiao formations comprise six types of matrix dolostone and four types of cement. The Dengying Formation, which developed under a sedimentary background of a restricted platform, contains special microbial and microcrystalline dolostones. The dolomite grains are small (<30 µm) and have a low order degree (Min=0.55), with large unit cell parameters and an extremely high Na content (Max=788 ppm). The 87Sr/86Sr value of the dolostone is consistent with contemporaneous seawater, while the δ13C and δ18O values are lower than those of the contemporaneous seawater. The δ26Mg value is small (Min=−2.31‰). Powder crystal, fine-crystalline, and calcite dolostones with coarser and more ordered crystals exhibit similar δ13C and 87Sr/86Sr values to microbial and microcrystalline dolostone. During the sedimentary period of the Dengying Formation, ancient marine conditions were favorable for microbial survival. Microorganisms induced the direct precipitation of primary dolomite in seawater, forming microbial and microcrystalline dolostones during the seawater diagenesis period. During the subsequent diagenesis period, dolostones underwent the effects of dissolution-recrystallization, structures, and hydrothermal fluids. This resulted in the formation of dolostone with coarser crystals, a higher degree of order, and various types of cement. The Longwangmiao Formation was developed in an inter-platform beach characterized by special particle dolostone. The particle dolostone has a large grain size (>30 µm), high order degree (Min=0.7), small unit cell parameters, high Na content (Max=432 ppm), and low Fe and Mn content. The δ26Mg and δ13C values are consistent with the contemporaneous seawater, while the δ18O and 87Sr/86Sr values are higher than those of the contemporaneous seawater. There is mutual coupling between multiple-period varying δ26Mg values and sedimentary cycles. The dolostone in the Longwangmiao Formation resulted from the metasomatism of limestone by evaporated seawater. The thickness and scale of the dolostone in the Longwangmiao Formation are controlled by the periodic changes in sea level. The period of dolostone development from the Sinian to the Cambrian coincides with the transition from Rodinia's breakup to Gondwana's convergence. These events have resulted in vastly different marine properties, microbial activities, and sedimentary climate backgrounds between the Sinian and the Cambrian. These differences may be the fundamental factors leading to the distinct origins of dolostone formed in the two periods. The distribution of sedimentary facies and deep tectonic activities in the Sichuan Basin from the Sinian to the Cambrian is influenced by the breakup and convergence of the supercontinent. This process plays a key role in determining the distribution, pore formation, preservation, and adjustment mechanisms of ultra-deep dolostone reservoirs. To effectively analyze the genesis and reservoir mechanisms of ultra-deep dolostone in other regions or layers, especially during the specific period of supercontinent breakup and convergence, it is crucial to consider the comprehensive characteristics of seawater properties, microbial activities, sedimentary environment, and fault systems driven by tectonic activities. This can help predict the distribution of high-quality and large-scale ultra-deep dolostone reservoirs. [ABSTRACT FROM AUTHOR]

Petrography, fluid-inclusion microthermometry, stable isotope analyses, and radiometric (206Pb/238U) dating of Upper Triassic dolostones, saddle dolomite, and quartz and calcite cements were used to constrain the timing and conditions of dolomitization and cementation in the context of the tectonic evolution of a basin in the northern United Arab Emirates. Dolomitization (ca. 152.4 Ma) and precipitation of saddle dolomite (ca. 146.8 Ma), calcite (ca. 144.6 Ma), and quartz cements are attributed to focused synrifting flow of hot basinal brines into grain-supported limestones in which permeability was enhanced by incursion of meteoric waters beneath a disconformity surface. Another calcite cement generation (ca. 99.7 Ma) was formed by flow of hot brines during tectonic compression related to the obduction of Oman ophiolites in the Late Cretaceous. Thus, this paper provides new insights into (1) stratigraphic controls on and timing of hydrothermal (hot basinal brines) dolomitization, (2) the origin of closely associated intraformational limestones and dolostones, and (3) linkages between diagenesis and thermochemical modifications of basinal brines during tectonic evolution of sedimentary basins. [ABSTRACT FROM AUTHOR]

Natural aggregates from sedimentary rock, like limestone and dolomite, are of a great use in various practical applications. To evaluate their quality, among others, the test of methylene blue adsorption (MB value) using a filter paper is recommended. However, one can consider it as a rough test. In this paper we wished to evaluate its quality by comparison with a more precise spectrophotometric method, i.e., to perform adsorption isotherms of methylene blue from aqueous solutions, as well as determine other parameters characterizing the aggregates. For this purpose, methylene blue adsorption on samples of limestone and dolomite natural aggregates having various grain sizes were studied to assess quality (fine particles content) of the manufactured aggregates. To determine the amount of adsorbed dye two methods were used: the methylene blue stain test and the dye adsorption from its solutions at various concentrations under static conditions. From the linear form of Langmuir adsorption isotherms of methylene blue, the monolayer capacity was determined, and then the specific surface areas of all fractions of aggregates. The structural (N2 adsorption/desorption), textural (SEM/EDS) and crystallographic structure of the aggregates were studied. It was determined that the MB values for 0–2 and MBF for 0–0.125 mm aggregates fractions fulfill the criteria set out in the specifications required for pavement construction. A very good repeatability of the adsorbed amount of methylene blue on the dolomite and limestone aggregates were obtained by these two different methods. These results confirm the reliability of the method blue test used typically in industrial conditions. The measured specific surface areas of limestone and dolomite using N2 adsorption (SBET) are smaller than SMB determined by methylene blue adsorption from aqueous solutions. This is because in aggregates, apart from calcite and dolomite, there is a small admixture of quartz and clay minerals. During N2 adsorption in dry condition, the external surface of the grains is determined, while in the aqueous solution of methylene blue, both the external and inner surfaces of clay minerals are determined. [ABSTRACT FROM AUTHOR]

Old paper samples are bleached using pulsed laser radiation with a wavelength of 532 nm. The ablation products of five paper samples that differ by composition and production dates are studied using Raman microspectroscopy. Cellulose, protein, calcite, titanium dioxide (anatase, rutile, and brookite), quartz, lazurite, bonattite, and dolomite are identified as ablation products. [ABSTRACT FROM AUTHOR]

Efficient separation of Carlin-type gold deposits is a challenge for the utilization of gold ores. The majority of gold in Carlin-type gold ores occurs as invisible gold within pyrite, resuiting in the poor crysta1lization of pyrite. The previous investigation has shown that oxidation caused the homogenization effect, thereby resuiting in adhesion, thus, deteriorafing the separation resuits of Carhn-type gold deposits. Based on the understanding of interacfions mechanssm between pyrite and dolomite,a technical prototype of "strengthening dsspersion" to opttmize the separation index of Carlintype gold deposits was preliminari1y proposed and highly selective reagents sodium amino phosphate was se!ected to realize the apphcation of the technical prototype, good separation indccators have been obtained in the laboratory. In this paper,the turbidity test was used to verify the effects of se!ected reagents on strengthening dispersion, meanwhlle, the artificial mixed ore and the real ores of high-and low-grade Carlin-type gold deposit were used to demonstrate the effect of reagent on mineral separation. The resuits showed that; sodium aminophosphate can achieve the expected goal of increasing the Fe and Au recovery in the concentrate, and decreasing the MgO floating ratio, whUe,increasing the Au enrichment ratio to about 3. 5. The above resuits show that sodium amino phosphate can improve the separation effidency between pyrite and dolomite by strengthening the dsspersion of oxidized pyrite and dolomite particles,so as to optimiie the flotation index of Carlintype gold mine. The prototype technology provides a reference for the development of effic!ent separation between pyrite and dolomite minera!s,and has the potential for popuiarizafion and apphcation. [ABSTRACT FROM AUTHOR]

The Cambrian pre-salt dolomite sequence in the Tarim Basin is a target zone of great strategic significance for hydrocarbon exploration in the basin. Using the results of the interpretation of 3D seismic data from Lunnan and 2D seismic data covering the whole basin, and based on a synthesis of outcrop data, drilling data, well logs, core data, and thin-section data, and the findings from previous studies, this paper studies the characteristics of the facies of the Middle–Lower Cambrian in the platform area in the Tarim Basin, the formation and evolution of platform margins, and the sedimentary characteristics, lithofacies, and paleogeographic characteristics of the Middle–Lower Cambrian series. Based on the types of lithofacies and the seismic facies analysis, the sedimentary facies of the Middle–Lower Cambrian strata can be classified into the five types. From bottom to top, the Middle–Lower Cambrian have experienced several development stages, including the deposition of continental shelf sediments of the Yuertusi Formation, gently sloping non-rimmed platform margin sediments of the Xiaoerbulake Formation, weakly rimmed platform margin sediments of the Wusongger and Shayilike formations, and strongly rimmed platform margin sediments of the Awatage Formation. In each stage, the platform margin shifted further east relative to its location in the previous stage. Based on these results and previous studies, the lithofacies and paleogeography maps of the Middle–Lower Cambrian in the Tarim Basin are modified, and the implications for hydrocarbon exploration in this area are discussed. [ABSTRACT FROM AUTHOR]

B In this issue... b Papers in this thematic issue focus on Zechstein petroleum system elements in the North Sea and adjacent areas. The following three papers report on Z2 (Hauptdolomit) Zechstein carbonate platforms in and around the Mid North Sea High (MNSH), a Variscan uplift offshore eastern England, and its extension to the SE in Dutch waters known as the Elbow Spit High. However a separate Zechstein reservoir unit at the Jarvis structure consists of Z2 and Z3 dolomites which contain oil whose origin has not been studied before in detail. [Extracted from the article]

This paper provides an updated understanding of the reservoir stratigraphy, sedimentology, palaeogeography and diagenesis of the Upper Permian Hauptdolomit Formation of the Zechstein Supergroup ("Hauptdolomit") in a study area on the southern margin of the Mid North Sea High. The paper is based on the examination and description of core and cuttings data from 25 wells which were integrated with observations based on existing and new 3D seismic. Based on thin‐section petrography of cuttings and core from the wells studied, it is evident that Hauptdolomit microfacies are distributed in a relatively predictable way, and well‐defined platform interior, platform margin, slope and basin settings can be distinguished. Platform margins are typically characterised by the development of ooid shoals and, to a lesser‐extent, by microbial build‐ups. High‐energy back‐shoal settings are characterised by a more complex combination of peloid grainstones, thrombolitic and microbial build‐ups, and fine crystalline dolomites. Lower energy lagoons which developed further behind the platform margin are characterised by a variety of microfacies types; fine crystalline dolomites are common in this setting as well as peloidal facies and local microbial build‐ups. Intertidal and supratidal settings are typified by increased proportions of anhydrite and the development of laminated microbial bindstones (stromatolites). Platform margins are in general relatively steep and pass into slope and basinal settings. Only a few wells have penetrated Hauptdolomit successions deposited in a slope setting, and these successions are characterised by a range of resedimented shallow‐water facies together with low‐energy laminated dolomicrites and fine crystalline dolomites. Slope zones in the study area are interpreted from seismic data to be typically 1‐1.5 km in width. Basinal Hauptdolomit deposits have been strongly affected by post‐depositional diagenesis and are dedolomitised to variable degrees. The original depositional facies are rarely preserved. Diagenetic studies show that dolomitisation has affected almost the entire Hauptdolomit Formation throughout the study area in both basinal and platform settings. The dolomite is considered to result from seepage‐reflux processes and is an early diagenetic phase. Mouldic porosity is present in many facies types as a result of dissolution, especially in ooid grainstones, thrombolitic build‐ups and peloidal facies. The dissolution cannot be associated with any one diagenetic phase but was most likely a result of the dolomitisation process itself. Stable isotope analyses indicate that all dolomites were precipitated from Permian marine‐derived pore fluids. Fluid inclusion analyses of dolomite cements indicate that cementation continued into the burial realm. Anhydrite cementation occurs in two phases: early anhydrite precipitation was associated with dolomitisation, and can be distinguished from a later, pore‐filling cement which is highly detrimental to reservoir quality. The Hauptdolomit succession in basinal wells (and in some slope wells) in the study area has undergone significant dedolomitisation. Dedolomitisation was a shallow burial process which affected precursor dolomites, whereby excess calcium from the transition of gypsum to anhydrite during burial combined with CO2 and organic acids derived from basinal sediments. The process was triggered by excess calcium reacting with excess carbonate ions from dissolution. 3D seismic volumes supplemented by numerous 2D lines were available in the study area and allowed an interpretation to be made of Hauptdolomit gross depositional settings; platform margins and base‐of‐slope polygons were mapped, with the greatest confidence in areas of 3D seismic. The basin, slope and platform settings were distinguished using seismic data integrated with the results of micro‐facies analysis and incorporating seismic‐to‐well ties. The data shows that large parts of the study area are characterised by the presence of polyhalites within the overlying (Z2) Stassfurt Halite Formation, which may create particular seismic geometries at the Hauptdolomit slope. These are interpreted to be intra‐Stassfurt Halite features, providing an alternative model to the thickened, prograded Hauptdolomit which has been suggested in previous publications. Because few wells drilled in the study area had the Hauptdolomit as the primary target, cores were limited but significant data was obtained from cuttings analyses. More than 400 thin sections were evaluated, allowing depositional models based on microfacies observations to be developed, verifying the seismic‐scale observations. [ABSTRACT FROM AUTHOR]

Medium-coarse-crystalline dolomite is a major variant of dolomite, and its structural heterogeneity inside and outside the crystals makes it an ideal vehicle for studies of dolomite genesis, fluid evolution and elemental migration. In this paper, the medium-coarse crystalline dolomite from the fifth section of the Majiagou Formation of the Lower Ordos Basin was systematically studied by petrographic, cathodoluminescence and related geochemical methods. The rock is developed in the context of mud powder crystal dolomite and granular dolomite, possessing significant ring band structure, fluorite and quartz intergrowth. Compared with other dolomites, it is characterized by Fe and Mn enrichment and low Na and Sr contents, as well as a negative δEu anomaly and a strong negative δ18 O offset. Combined with the evolutionary history of diagenesis, it is believed that the medium-coarse-crystal dolomite is the end product of a series of diagenetic effects such as early dolomitization-atmospheric freshwater leaching-secondary burial recrystallization-deep burial dissolution. Electron microprobe analysis reveals the structural and compositional heterogeneity inside and outside the crystals. The formation of mediumcoarse- crystalline dolomite is associated with an increase in Fe-Mn content, a rise in the Mn/Sr ratio, a decrease in Sr, and a first rise and then a fall in Na concentration. This study provides a valuable reference for further research on the genesis of the medium-coarse crystalline dolomite. [ABSTRACT FROM AUTHOR]

Siliceous minerals of the Dengying Formation in the Gaoshiti–Moxi area in the central Sichuan Basin exhibit four types of quartz crystals (cryptocrystalline quartz, chalcedony, microcrystalline quartz, and megacrystalline quartz) and three structural types: cryptocrystalline, microcrystalline, and mosaic (laminated mosaic, window-hole interrupted mosaic, and arc-laminated mosaic). Siliceous minerals have a great influence on the storage performance of the reservoirs in the Dengying Formation. According to the petrophysical parameters of the Dengying Formation and porosity intersection diagrams, the siliceous dolomite and the reservoirs have low impedance characteristics, which makes it difficult to distinguish between them and leads to difficulties in the characterization and prediction of the reservoirs. The transverse wave velocity is favorable for reservoir characterization. Currently, the main method used to estimate the transverse wave velocity is petrophysical modeling, which establishes a relationship between the elastic and physical parameters of the reservoir. In this paper, the siliceous minerals in the dolomite in the study area are regarded as solid inclusions, and the calculation method of the rock matrix modulus is improved by using solid replacement. Then, an improved petrophysical model is constructed by combining the KT (Kuster–Toksöz) model, the DEM (Discrete Element Method) model, the Gassmann equation, and the Wood equation. The transverse wave velocity is estimated using the improved model under the constraint of the longitudinal wave velocity. The shapes of the transverse wave velocity curves obtained by the improved model and the deviations from the measured velocities are significantly better than those of the Xu–Payne model and other models. The results show that the improved model can effectively estimate the transverse wave velocity of the reservoir in this area, which provides a basis for future reservoir predictions in this area. [ABSTRACT FROM AUTHOR]

Ultra-High Molecular Weight Polyethylene (UHMWPE) polymers have been used in biomedical applications due to its biocompatibility, durability, toughness and high wear resistance. To enhance the mechanical properties, various types of minerals are commonly utilized as fillers in UHMWPE. One of the minerals is dolomite, which has been recognized as a valuable mineral with versatile applications, particularly in the field of biomedical applications. This paper presents the tensile properties of UHMWPE composites that filled with dolomite and treated-dolomite at various filler loading (i.e., 1-5 wt.%). Nitric acid and diammonium phosphate were used to treat the dolomite. From the results, the peaks of the FTIR spectrum displays carbonate (CO3-2), phosphate (PO4-3) and hydroxyl (OH-) groups in the ct-dolomite powder sample while the XRD pattern reveals that using dolomite treated with 1M nitric acid resulted in the presence of calcium hydroxide phosphate (Ca10(PO4)5(OH)) and MgO. For tensile strength, UHMWPE/ct-dolomite composites show better tensile strength than the pure UHMWPE composites. Treated improve the dolomite filler and resulted in significantly better matrix-filler interfacial interactions and improve the properties. [ABSTRACT FROM AUTHOR]

This paper looks at the changes in urban air quality and the effect on building materials, particularly concerning their deterioration arising from pollution due to vehicles. The paper aims to review basic information on the likely effect of ozone on calcareous building materials (limestone, marble, dolomite, and calcareous cemented sandstone). Controlling factors in the reaction and oxidation of sulphite to sulphate is the type and porosity of the stone. The level of humidity, is effected by the nature of the oxidants and to a lesser extent the presence of other extraneous reactants, e.g. metal oxides, chlorine and ammonia salts. [ABSTRACT FROM AUTHOR]

This paper provides preliminary data about the influence of gray and yellow lichens on the monuments in the Stobi archeological site. The origin of the minerals which adhere to the rhizine/hyphae was also determined. According to the SEM results, small grains of minerals are found in lichens which originated from parent rocks or weathering. In the lichens on marble the presence of the following minerals was determined: calcite, dolomite, Fe carbonate, Ca silicate, Ca, Fe, Al silicate and Fe, Al silicate. Carbonate minerals come from marble while silicates are the result of weathering. In lichens on sandstone the following minerals were determined: K, Al silicate, Ca carbonate quartz, Fe, Mg silicate, Fe-oxide, zircon, and Na, Ca, Al silicate. Carbonate minerals are the result of weathering while other determined minerals originate from sandstone. Clay minerals are the result of the decomposition of feldspars. [ABSTRACT FROM AUTHOR]

In the field of mineral processing, the successful flotation of target minerals requires sufficient liberation through grinding. The aim of this paper is to compare and evaluate the performance of ball versus short cylindrical media for comminution of dolomite by point and line contact, respectively. The results of the grinding experiments indicate that short cylinders generate more angular particles with intermediate sizes and exhibit a higher grinding efficiency compared to balls. The Population Balance Model demonstrates the distribution of broken fragment sizes during the breaking stage for each size range. The results of the DEM (discrete element method) grinding simulation are consistent with the experimental findings in terms of the distribution of particle sizes, the shape of the particles, and the distribution of broken fragment sizes. Furthermore, short cylinders selectively produce more active {104} crystal surface of dolomite, which possess a higher adsorption capacity with collectors and are preferentially floated as the concentrate. In reverse flotation for removal of dolomite, tests confirm that the products obtained from grinding with short cylinders exhibit a higher flotation recovery of dolomite compared to those obtained from ball grinding. This study provides a reference scheme for optimizing the grinding and flotation processes of valuable minerals. [ABSTRACT FROM AUTHOR]

Smithsonite, dolomite, and calcite are carbonate minerals. The crystal structures and spatial distribution characteristics of their common surface metal sites are similar, leading to difficulty in the flotation separation of smithsonite from these carbonate gangues. In this paper, the floatability of smithsonite, dolomite, and calcite in sodium oleate, salicylhydroxamic acid, and their combined-collector system were systematically studied through single-mineral flotation tests, respectively. The results showed that it was difficult to obtain a noticeable recovery difference between smithsonite–calcite and smithsonite–dolomite in a single-collector system of sodium oleate and salicylhydroxamic acid, both at the same time. In the combined-collector system of salicylhydroxamic acid and sodium oleate with total dosage of 6 × 10−4 mol/L, molar ratio of 3:1, and pH of 8.0, the recovery difference of smithsonite–calcite and smithsonite–dolomite could reach the highest values of 38.46% and 37.98%, respectively, while obtaining the highest smithsonite recovery of 88.19%. The adsorption mechanism of the combined collectors was investigated via Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, a collector adsorption test, and zeta potential measurements, respectively. [ABSTRACT FROM AUTHOR]

AG-MP-1M anion exchange resin is commonly used to separate and purify Cd from geological and environmental samples. However, a second column using anion exchange, TRU Spec, or BPHA extraction resins is also required to further purify Cd from the residual Sn for high-precision Cd isotope ratio measurements. In this study, a new and efficient single-stage separation method using AG-MP-1M (100–200 mesh) anion exchange resin was developed to separate Cd from geological and environmental samples for high-precision Cd isotope ratio measurements. Most of the Sn (>99%) is effectively stripped from the resin using a 2 M HCl + 4 M HF mixed eluent, unlike commonly used separation protocols with AG-MP-1M anion exchange resin, which only removes ∼65% of the Sn using HCl eluent. Furthermore, potential residual Sn is retained on the resin by elution of 0.04 M HCl + 2 M HF and 0.005 M HCl + 2 M HF, which allows quantitative collection of the Cd fraction (∼99.5%) without Sn tailing. The single-stage purification procedure takes advantage of the different affinities of Sn on AG-MP-1M anion exchange resin at different HCl and HF concentrations in mixed HCl + HF solutions, which allows direct and effective separation of Cd from Sn and other complex sample matrices. We used this procedure and the double-spike MC-ICP-MS method to determine the δ114/110CdNIST SRM 3108 values for Mn nodule, igneous rock, shale, soil, and sediment reference materials, and obtained results that agree within analytical uncertainty with the values reported in previous studies. In addition, the δ114/110CdNIST SRM 3108 values of soil (GSS-1a), sediment (GSD-4a), and dolomite (GSR-12) standard reference materials are reported for the first time in this paper. The described purification procedure allows efficient and rapid Cd isotopic analysis in different types of geological and environmental samples. [ABSTRACT FROM AUTHOR]

This work describes a procedure for building a high-quality 3D model of a rocky pinnacle in the Dolomites, Italy, using Structure from Motion (SfM) techniques. The pinnacle, known as "Campanile di Val Montanaia", is challenging to survey due to its high elevation and sub-vertical cliffs. The construction of the 3D model is the first step in a multi-disciplinary approach to characterize the rock mass and understand its behavior and evolution. This paper discusses the surveying operations, which involved climbing the pinnacle to collect Ground Control Points (GCPs) and using a UAV to capture aerial imagery. The photographs were processed using SfM software to generate point clouds, mesh, and texture, which were then used for rock mass discontinuity mapping. The study compares models of different qualities and point densities to determine the optimal trade-off between processing time and accuracy in terms of discontinuity mapping. The results show that higher quality models allow for more detailed mapping of discontinuities, with some drawbacks due to noise in the case of the densest solution (e.g., increase in frequency of outliers across the point cloud). These pros and cons are also discussed in relation to the computational cost necessary to build the models. The study also examines the limitations and challenges of performing discontinuity mapping in the different models, including subjectivity in interpretation. A further element of interest is the publication of a high-quality 3D georeferenced model of the "Campanile di Val Montanaia" to be used for several potential further applications, such as stability analyses and numerical modeling. [ABSTRACT FROM AUTHOR]

Lower Cretaceous carbonates of the Fahliyan Formation form prolific reservoir rocks at oilfields in the Dezful Embayment, central Zagros fold‐thrust belt, SW Iran. The carbonates have undergone significant diagenetic alteration in phases which can in general be linked to the pre‐, syn‐ and post‐tectonic evolution of the fold‐thrust belt. This paper investigates the impact of diagenetic processes on the reservoir quality of the carbonates using integrated petrographic, geochemical and sedimentological analyses of subsurface and outcrop samples of the formation. Diagenetic alterations include: (i) pre‐tectonic eogenesis in the marine and shallow‐burial realm, which resulted in micritization of allochems and cementation by equant and isopachous calcite rims and framboidal pyrite together with limited dolomitization and dissolution of metastable bioclasts. The isotopic compositions of micrite and early calcite cement depart from postulated values of Lower Cretaceous marine carbonates, signifying early stabilization of precursor metastable carbonate minerals and the possible effects of the incursion of meteoric waters and/or increasing burial temperatures; (ii) mesogenesis during the subsequent syn‐tectonic phase, which included Late Cretaceous ophiolite obduction at the northern margin of the Arabian Plate and the later Zagros orogeny in the Miocene‐Pliocene. Diagenetic modifications included the emplacement of hydrocarbons, the development of stylolites and fractures, and the precipitation of saddle dolomite, replacive rhombic dolomite, discrete pyrite, microcrystalline quartz, kaolin and anhydrite. The average stable isotope compositions of saddle dolomite (δ18O: ‐6.9 ‰ ±.9 and δ13C 0.5 ‰ ± 1.6, respectively) also reflects the influence of high temprature basinal fluids; and (iii) "late" (telogenetic, post‐tectonic) uplift‐related modification starting in the Pliocene, when the incursion of meteoric waters resulted in the formation of vugs, the calcitization of dolomite, and cementation by fracture‐filling blocky calcite. The negative δ18O and δ13C stable isotope values (average: ‐5.5 ‰ ± 1.5; and ‐3.6 ‰ ± 5.9, respectively) of late blocky calcite cement suggest the incursion of meteoric water into the system. This study demonstrates that diagenetic processes in carbonates in the Fahliyan Formation, which exerted a significant control on the distribution of secondary porosity, can be related to the tectonic evolution of the central Zagros fold‐thrust belt. Thus, constraining the diagenetic history of carbonate successions within the context of their wider tectonic evolution is important for the prediction of the spatial and temporal distribution of reservoir quality. [ABSTRACT FROM AUTHOR]

This document is an editorial for a special issue of the journal Minerals, focusing on the heterogeneities of carbonate reservoirs. The editorial emphasizes the importance of understanding these heterogeneities for optimizing exploration and production strategies, as they influence fluid flow behavior and the recoverable reserves within the reservoir. The editorial also highlights the need for further research to explore the implications of heterogeneities at a broader scale and recommends the use of advanced technologies and multidisciplinary approaches. The document provides a summary of five papers included in the special issue, which cover topics such as the genetic mechanism of dolomite reservoirs, diagenetic alterations in the Chiltan Formation, the formation mechanism of dolomite-mottled limestone reservoirs, characteristics of crystalline dolomites in the Sanshanzi Formation, and facies variations in the Sarvak Formation. The research presented in this special issue contributes to our understanding of ancient carbonate platforms and dolomite reservoirs and provides a framework for future studies in oil and gas exploration. [Extracted from the article]

Rock and gas outbursts occur most frequently in coal mining. Gas-induced geodynamic events in dolomite are a new and unexplored phenomenon. In the last time, two outbursts of gas and dolomite have occurred in the Legnica-Głogów Copper Region in southwestern Poland, which is one of the world's largest copper ore mining regions. Gas-induced geodynamic events are dependent on the co-occurrence of two factors: rock porosity, and the presence of gas under significant pressure in the pores and crevices of the rock. This paper presents a condensed energy balance for the phenomenon of outbursts of dolomites and gases. The quantity of energy depends on the type of transformation taking place during decompression. The work produced enables first the disintegration of the rock, and then its transportation along the mine working space. This paper has focused on the estimation of the energy required to disintegrate the rock. It has been estimated that 0.38 MJ is needed for the size reduction of 1 m3 of ejected mass. Highlights: In the case of a dolomite outburst, the energy is accumulated primarily in the form of compressed gas present in the porous structure of the rock and causes the rock to disintegrate and its transport along the mine working space. Gas decompression during a gas-induced geodynamic phenomena can be between isothermal and adiabatic. Existing disintegration theories: Rittinger's, Kick's and Bond's are based consists chiefly of crushing, compression or abrasion, caused by the action of external factors. Author's theory of disintegration of research on tensile stress and is based on Brazilian tests. The disintegration of 1 m3 of rock requires the production of energy of approximately 0.38 MJ. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel collector DDALA is developed based on dodecylamine (DDA) structure. • The reagent system composed of DDALA and xanthan gum has better flotation selectivity for apatite/quartz. • DDALA/oleic acid combined collector exhibits different competitive adsorption configurations on apatite and dolomite surfaces. • DDALA/oleic acid molecular aggregates on apatite surface dictate its weakened capturing ability. This paper introduces a novel amphoteric collector, N -dodecyl-β-alanine (DDALA), derived from the molecular structure of dodecylamine, with the incorporation of a propionic acid group. In the study, flotation experiments are undertaken to examine the selectivity of DDALA in apatite flotation. Results demonstrate that DDALA, in combination with xanthan gum (XG) depressant and oleic acid collector successfully accomplishes the reverse flotation separation of apatite from quartz and dolomite. In addition, the synergistic application of zeta potential experiments, X-ray photoelectron spectroscopic tests, and first-principles calculations has been employed to delve into the action mechanisms of DDALA collector and XG depressant. By combining the results with existing research, the paper proposes that the selective adsorption of XG between apatite and quartz surfaces facilitates the selective separation of these two minerals by DDALA collector. Moreover, the intermediate collecting ability of DDALA/oleic acid combined collector for dolomite results from the competitive adsorption of DDALA neutral molecules and oleic acid anions on dolomite surface. Furthermore, the formation of hydrophilic molecular aggregates between DDALA neutral molecules and oleic acid anions on apatite surface diminishes the collecting ability of DDALA/oleic acid combined collector for apatite compared to the individual use of each collector. [ABSTRACT FROM AUTHOR]

The Guizhou Province is located in karst mountainous area, so it is very important for the future layout and planning of the city to study the underground geological structure of the city based on seismic detection technology. In this paper, taking the underground active fault detection in the Liupanshui City, Guizhou Province, China as an example, a set of appropriate evaluation techniques for the accurate spatial location, structural characteristics and latest activities of the fault suit for mountainous area are proposed. Through pre-stack noise suppression, amplitude fidelity and consistency processing, and multiple iterative analysis of velocity residual statics, the resolution of the geological structure of the underground rock has been significantly improved. Based on the detailed interpretation of the shallow seismic data and the regional geological analysis, it is concluded that the main fault strike of the Weining – Shuicheng section of the Weining - Shuicheng fault is NW, mainly normal fault, the dip direction is mainly southwest, partly northeast and the dip angle is 60-70°. The strata of the two fault plates are strongly compressed and broken, and the limestone and dolomite are generally recrystallized, and calcite veins and masses can be seen. [ABSTRACT FROM AUTHOR]

Sandy dolomite, being a soluble rock, is prone to dissolution and erosion caused by groundwater, leading to the formation of underground caves and fractures. This may result in geological disasters such as ground subsidence and collapse. In this paper, the changes and mechanical properties of black sandy dolomite after hydrochemistry are studied. A semi-immersion test with different concentrations of iron sulfate solution was carried out to simulate the water-rock interaction in different water environments. After that, scanning electron microscope (SEM) results could reflect the dissolution and pore development of rock by the effect of water-rock interaction from the microscopic. Water-rock interaction enlarges cracks in rocks and dissolves pyrite, carbonate minerals, and other components, reducing the cementation between particles. The change in the mechanical properties of black sandy dolomite under water-rock chemical interaction was revealed by uniaxial compression test. The mechanical properties of the samples exhibit varying degrees of deterioration, with strain increased ranging from 4.96 to 29.58%. The brittleness index modified (BIM) values for each sample ranged from 5.20 to 6.20%, all of which are larger than 4.70% in the natural state. [ABSTRACT FROM AUTHOR]

Pore fluids control the diagenetic processes and storage spaces of deep clastic rock reservoirs and have become a major area of interest within the fields of sedimentology and petroleum geology. This paper aims to relate the diagenetic processes of the Oligocene Zhuhai sandstones in the Baiyun Sag to pore fluids varying with burial depth. The types and distribution patterns of authigenic minerals are investigated through analysis of petrographic, mineralogical, and geochemical features to illustrate the origin and flow patterns of pore fluids and their influences on reservoir diagenesis. Strong cementation of eogenetic carbonate cement near the sandstone–mudstone interface was a consequence of material migration from adjacent mudstones on a large scale. The pore fluids were mainly affected by microbial methanogenesis and carbonate mineral dissolution in adjacent mudstones during eogenesis. The pore fluids were diffusively transported in a relatively open geochemical system within a local range. Support for this model is provided by the heavier stable isotopic values present in eogenetic calcite and dolomite. Feldspar dissolution during early mesogenesis was spatially accompanied by the precipitation of authigenic quartz and ferroan carbonate cement. Pore fluids in this period were rich in organic acids and CO2, and their migration mechanism was diffusive transport. The obviously lighter carbon and oxygen isotopic compositions of the ferroan calcite support this inference. During late mesogenesis, the input of deep hydrothermal fluid might have been partly responsible for the precipitation of ankerite, barite and authigenic albite. Oil charging may have inhibited carbonate cementation and compaction, accordingly preserving porosity, and together with authigenic kaolinite, might have promoted the transition of the reservoir from water wet to oil wet to the benefit of oil entrapment. The findings reported here shed new light on the evaluation and prediction of sandstone reservoirs that have experienced multiple periods of fluid flow. [ABSTRACT FROM AUTHOR]

This paper addresses the issue of environmental noise from mining operations, focusing on the specific case of a quarry located in the municipality of Trebejov, Slovakia. The study aims to demonstrate an effective approach to reducing noise pollution through the implementation of mobile noise barriers. The research was motivated by the negative impact of noise from the processing line on the wellbeing of the population residing in the vicinity of the facility. The study involved conducting extensive noise measurements at various locations surrounding the quarry. The collected data were analyzed to assess the existing noise levels and identify the areas of highest noise exposure. Based on the findings, the implementation of mobile noise barriers was proposed as a solution. The results of the study demonstrated that the mobile noise barriers successfully reduced the noise levels below the legal limits, significantly improving the well-being of the population living near the quarry. The case study opens up the possibility of using mobile noise barriers in other areas and operations with high noise exposure. [ABSTRACT FROM AUTHOR]

With the great breakthrough in natural gas exploration of Paleozoic Taiyuan formation in Longdong exploratory area in the southwestern part of Ordos Basin, it is urgent to solve the petrological nomenclature of sedimentary bauxite, so as to further study the pore formation mechanism, distribution law, and controlling factors of bauxite reservoirs. In this paper, X-ray diffraction, polarizing microscope, scanning electron microscope, and other methods are used to analyze the mineral composition and structure of bauxite rocks in the study area and give appropriate names. The results show that the sedimentary sequence of bauxite in the study area can be divided into five sections: A, B, C, D, and E. The main mineral components are diaspore (C section content can be more than 90%), illite, kaolinite, and chlorite; accessory mineral include anatase and pyrite; trace components include quartz, feldspar, rutile, hematite, and rock salt; and some of the pores are filled with calcite, siderite, and (iron) dolomite. The rock structure is mainly bedding and massive structure, and some of them have geopetal structure. The texture mainly consists of granular texture, grain (powder crystal) texture, gel texture, and algal bonding texture. Considering the special lithology of section A~C and the lack of existing nomenclature method, based on mineral composition and sedimentary fabric, a triangulation classification nomenclature method is established, which adopts structure+texture as secondary name and the main mineral components diaspore-mud-pyrite of the three end-member mineral components as primary name. It can not only highlight the mineral assemblage characteristics of sedimentary sequence of bauxite but also reflect the lithologic characteristics of reservoir development section and the influencing factors of reservoir formation, effectively reflecting the petrological characteristics of bauxite reservoir. Among them, the diaspore rocks with granular, bean-oolitic, and grain texture are the main lithologies forming the natural gas reservoir space of Taiyuan formation in Longdong area. The naming method is feasible and reliable for sedimentary bauxite rocks, which lays a good foundation for the study of natural gas reservoir, pore formation mechanism, and distribution law in Longdong area, southwest of the basin. [ABSTRACT FROM AUTHOR]

The removal of hazardous heavy metals that have been released into the environment due to industrial activities has become an important issue in recent years. The presented study concerned the removal of copper(II) ions from aqueous solutions using dolomites. Dolomite is a very attractive adsorbent due to its wide availability, low cost, good adsorption, and environmental compatibility. The paper describes the properties of D-I and D-II dolomites from two different open-cast mines in Poland. The properties of natural adsorbents were determined based on point of zero charges (PZC), elemental analysis of the adsorbent composition, FT-IR, XRD, and SEM spectra analysis. Depending on the initial concentration of the solution used, the adsorption efficiency of copper(II) ions was 58–80% for D-I and 80–97% for D-II. The adsorption mechanism in the case of D-II dolomite was mainly based on ion exchange, while chemisorption dominated the D-I dolomite surface. Considering the possibility of the regeneration and reuse of the adsorbent, dolomite D-II is a better material (the desorption efficiency of copper(II) ions was 58–80%). The adsorption behavior of dolomites has been described using six adsorption isotherms. The best fit was obtained for the Redlich–Peterson, Jovanović, and Langmuir isotherms, indicating that monolayer adsorption occurred. The maximum adsorption capacity for copper(II) was 378 mg/g of D-I and 308 mg/g of D-II. [ABSTRACT FROM AUTHOR]

This paper presents the results of detailed geological investigations of the Middle Triassic dolomite deposit of Nikolin Potok, which is located west of Bugojno. Based on the established borders of surface distribution and research results, geological reserves of about 4.6 million m³ have been determined in the wider area of the deposit. The dolomite reserves that have been established so far in this area are at a low level of geological exploration. For this reason, the level of research should be significantly increased, because the calculated and confirmed reserves are very modest compared to the potential possibilities. The paper contains a description of the geological characteristics of the area and the qualitativequantitative characteristics of dolomite. The results of the conducted research point that the general geological and technical-exploitation factors are favorable and indicate profitable exploitation of the deposit in the coming period as well. Taking into account the significant raw material potential, and the possibility of expanding the existing raw material base, this area has a special significance for the perspective development of dolomite exploitation and its use in the production of technical-building stone. [ABSTRACT FROM AUTHOR]

In the paper “Formation mechanism of deep Cambrian dolomite reservoirs in the Tarim basin, northwestern China” ( Zhu et al., 2015 ), we concluded that hydrothermal alteration further enhanced porosity in the deep Cambrian dolomite reservoirs in the Tarim Basin, NW China. Professor Ehrenberg and Bjørlykke made comments that the hydrothermal dolomitization and increase in porosity were not well supported and casted doubt on the exploration potential. We insist the influence of hydrothermal alteration on and large exploration potential in the deep Cambrian dolomite reservoirs due to the unique geological conditions and the recent exploration results. [ABSTRACT FROM AUTHOR]

In the first part of this paper the occurrence of dolomite in B&H karst, as well as active and potential dolomite deposits for dimension stone with different trade names ("Rujan", "San", "Gradac") are presented, with the available results of their testing. The final section of the paper gives a brief historical overview of the applications of dolomite as dimension stone in Herzegovina, which is attested by many tombstones, but also some religious and residential buildings. However, with its beauty of textures and colors and quality in workmanship, in the last several decades it has been widely used in the interior and exterior cladding of numerous buildings in Herzegovina, as well as in several regional architectural projects along the Adriatic coast, in the Republic of Croatia and Republic of Montenegro. The final section of the paper provides relevant conclusions related to the application of dolomite as dimension stone. [ABSTRACT FROM AUTHOR]

Although archaeological excavations have recovered a large number of vessels used to hold perfumes or ointments in ancient Rome, little is known about the chemical composition or origin of the substances they contained. Most available information pertains to ointment and/or cosmetic bases rather than to essences. The discovery in 2019 of an ointment jar (unguentarium) made of rock crystal (quartz) that was sealed with a stopper and contained a solid mass in a Roman tomb in Carmona (Seville, Spain) was a rather unusual finding. This paper reports the results of an archaeometric study of the unguentarium stopper and its contents. Based on them, and on comparisons with commercially available patchouli and nard oil standards, the perfume held in the unguentarium was probably patchouli. To our knowledge, this may be the first time a perfume from Roman times has been identified, which is a major advance in this field. The unguentarium stopper consisted of dolomite, a material also unknown in this type of use, and bitumen was used to seal the unguentarium with the stopper. [ABSTRACT FROM AUTHOR]

The tight carbonate reservoir was controlled by various geological factors, and such factors played different roles in buried depths and formations. Therefore, studies related to the factors controlling carbonate reservoir distribution are of great significance for the prediction and evaluation of high-quality dolostone reservoirs. In this paper, we focus on the controlling factor of the submember Ma55 dolostone reservoir in the western Ordos Basin. The main rock types, reservoir pores, physical properties, and pore structure characteristics of the reservoir were analyzed by thin section identification, physical property analysis, and mercury injection, respectively. Then, the main controlling factors of reservoir development were comprehensively analyzed from the perspectives of palaeostructure, lithofacies palaeogeography, diagenesis, and diagenetic facies. The results show that two kinds of dolostone reservoirs in the submember Ma55 developed in the western Ordos Basin, including intercrystalline pore-type and dissolution pore-type. The former reservoir is primarily characterized by powder-fine dolostone with residual structure, dolomite intercrystalline pore, and micropore with porosity ranging from 2% to 11%. There are three types of pore structures developed in it, such as macropore-medium throat-single peak (MAMS), macropore-fine throat-single peak (MAFS), and medium pore-fine throat-single peak (MEFS). The latter reservoir is mainly featured by powdery crystalline dolostone with gypsum and halite dissolution, moldic pore, and dissolved pore between breccias with a porosity greater than 5%. It consists of two types of pore structures, such as macropore-fine throat-single peak (MAFS) and medium pore-coarse throat-multipeak (MECM). The intercrystalline pore-type dolostone reservoir is mainly controlled by the lithofacies palaeogeographic environment and diagenesis. In specific, the shoal microfacies at the edge of the platform and the active reflux seepage dolomitization are the basic sedimentary environment conditions for reservoir formation and the key to reservoir formation, respectively. The dissolution pore-type dolostone reservoir is primarily influenced by both paleostructure and diagenesis. The relatively high part of the paleostructure provides favorable conditions for the formation of evaporate minerals, and early freshwater dissolution is the key to reservoir formation. This research will provide a theoretical basis for forecasting the favorable distribution areas of different types of dolostone reservoirs. [ABSTRACT FROM AUTHOR]

This paper evaluates the physicochemical and mechanical characteristics of the Limestone of the Kohat Formation. The Eocene Kohat limestone is generally exposed in the Kohat, Hangu, and Bannu districts. Kohat Formation limestone is well exposed throughout the Northern Kohat fold and thrust belt at Togh Bala village. It is cream to grey, hard, compact, well-bedded and fossiliferous. Kohat Formation has been identified into two lithofacies which are from base to top calcareous shale lithofacies with large benthic foraminifera and limestone lithofacies. The faunal assemblage indicates that the Kohat Formation was deposited in an inner to middle shelf environment. The petrographic analyses of samples of the Kohat Formation depict that it principally consists of calcite (60-90%) with a small to trace assemblage of dolomite (0- 3%), ungraded quartz (0-1.5%), opaque minerals (0-1.2%) and fossils (8-40%). Aggregate physical properties like water absorption (0.88%), specific gravity (2.69), soundness (2.55%), Los Angeles abrasion value (23.06%), aggregate crushing value (11.56%), aggregate impact value (12.68%), flaky index (9.90%), elongation index (12.76%) and coating and stripping values (96.27%) conform to available standards. Our results indicate that Kohat Limestone is safe in terms of Alkali Carbonate Reactivity (ACR) and AlkaliSilica Reactivity (ASR). The facies, thin section study, geochemical, and geotechnical understanding of Kohat Formation indicate that these aggregate deposits are potential aggregate sources for ballast (railway), road, building material, concrete, mortar and other mega projects for connecting Asia and Europe. [ABSTRACT FROM AUTHOR]

The formation timing of stylolites, which is of great importance for analyzing the controls of stylolites, has nearly never been examined. In this paper, based on the data of cores, imaging logging, conventional logging, and mercury injection, the characteristics of stylolites formed in different stages of tectonic movement were investigated, and the controlling factors of oil-stained stylolites, formed in the second period of tectonic movement, were analyzed in particular. Furthermore, the influence of different controlling factors on the development of stylolites was compared, by using grey correlation analysis. The results show that there are three periods of stylolites in the study area, and all three periods developed both low-angle stylolites and high-angle stylolites. The prominent characteristics of both the low-angle and high-angle stylolites of the second period, are being oil-stained. The higher the structural location, the greater the buried depth, the lower the dolomite content, the higher the calcite content, the higher the clay content, the smaller the rock density, the greater the porosity, the smaller the rock grain size, the easier it is to develop both the low-angle stylolites and the high-angle stylolites. The influence of different controlling factors on the development of low-angle stylolites is given by depth, porosity, curvature, rock density, rock grain size, clay content, dolomite content, and calcite content, in this order. The importance of the influences on the development of high-angle stylolites proceeds as follows: curvature, calcite content, depth, rock particle size, clay content, rock density, dolomite content, and porosity. Tectonism is the most important influencing factor on the development of stylolites. [ABSTRACT FROM AUTHOR]

Worldwide, the known recoverable heavy oil and bitumen reserves make up more than 64% of the total reserves, of which more than 60% are trapped in carbonates. Air injection has immense potential for hydrocarbon recovery from various reservoirs. While most of the successful air-based techniques are performed within carbonate reservoirs containing light oil, theoretically, in situ combustion (ISC) has also shown great potential for recovering heavy oil and bitumen. Carbonates are complex in terms of geology and are often associated with fractures and vugs that affect the fluid flow, pressure propagation and progression of the ISC reactions. This paper describes the first experiment in which the triple-porosity concept was applied to simulate heterogeneity through artificially induced vugs, core matrix and fractures. This approach was used to study the feasibility of the ISC recovery technique for heavy oil (14° API) within a dolomite reservoir using a combustion tube (CT) in an experiment performed at 1740 psig. The combustion front advanced through 78% of the core length prior to the termination of air injection, producing 80% of the initial oil. To differentiate between the various sources of the CO2 gas (a product of carbonate decomposition vs. the combustion reaction) the atomic ratios of (CO2 + CO)/CO = 6 and (CO2 + CO)/N2 = 0.21 were applied. Additionally, partial upgrading of the produced heavy oil was observed. [ABSTRACT FROM AUTHOR]

The porosity and permeability of the rock surrounding lead–zinc deposits are key factors for controlling the migration and precipitation of ore-forming hydrothermal fluid. In this paper, the Huize super-large lead–zinc deposit was taken as the case study, and variations in the porosity and permeability of the wall rocks and their relationship with the orebody were analyzed by using CT scanning technology. The experimental results showed that the average pore radius of dolomite with a decreasing distance to the orebody ranged from 1.60 to 1.65 μm, increasing to 1.77~2.05 μm. The CT porosity increased from 2.76%–2.81% to 3.35%–3.99%. The average pore throat length decreased from 29.57–39.95 μm to 13.57–16.83 μm. In the research, it was found that the hydrothermal fluids rich in chemical elements changed the properties of the surrounding rocks. Temperature rise will lead to dolomitization of limestone and recrystallization of dolomite. This process led to an increase in the porosity of the wall rocks. During the formation of the orebody, the metal minerals in the hydrothermal fluid entered the pores of the rock. As a result, the pore radius and pore volume of the wall rocks were reduced, along with the pore throat radius and pore throat length. Therefore, the wall rock pores near the orebody were isolated from each other, and the permeability of the surrounding rock decreased. The variation characteristics for the porosity and permeability of the dolomite at various distances from the mine can be used to discover orebodies. [ABSTRACT FROM AUTHOR]

The use of the calcareous soil as a backfill material in ocean constructions faces pervasive challenges due to the significant rate of particle fracture. To meet the requirements of marine ecological protection, a bio-cementing technique, microbially induced carbonate precipitation (MICP), has emerged as a green method for improving the soil properties of calcareous sands. This paper presents a detailed study on the effect of MICP on the fracture behaviours of calcareous particles and its treating mechanism at microscopic scale level. First, individual calcareous and dolomite particles were treated by MICP for different numbers of rounds. The increase ratio of the particle mass and the filling degree of the intra-particle pores were then measured to evaluate the treatment effect of MICP on individual sand particles. Combining with scanning electron microscopy measurements of the evolution of the particle morphology and internal microstructures of the calcareous particles, the intra-particle pore filling effect as well as the surface coating effect induced by MICP treatment were directly observed. Finally, a series of single-particle crushing tests indicated that the intra-particle pore filling effect of MICP rather than the surface coating effect played the dominant role in improving the fracture pattern and fracture strength of calcareous sand particles. [ABSTRACT FROM AUTHOR]

In order to reduce the environmental impact caused by the migration of heavy metals in electrolytic manganese residue to water, this paper added calcined dolomite sand to electrolytic manganese residue to solidified Mn2+, and analyzed the microstructure and microstructure of dolomite sand before and after calcination by XRD, BET and SEM methods. The stabilization effect of calcined dolomite sand on Mn2+ in electrolytic manganese residue at different dosage was analyzed and evaluated. The results show that with the calcination temperature increasing from 600 °C to 800 °C, the dolomite sand gradually decompositions to form alkaline oxides such as CaO and MgO. The specific surface area, pore volume and pore size of calcined dolomite sand increase continuously, which are 1.16 ~ 3.96 times, 1.7 ~ 4.18 times and 1.99 ~ 16.12 times of uncalcined dolomite sand, respectively. When 10% calcined dolomite sand at 800 °C is added to electrolytic manganese residue, the stabilization efficiency of Mn2+ is 99. 95%, and when 30% calcined dolomite sand at 700 °C is added, the stabilization efficiency of Mn2+ is 99.85%, and the concentration of Mn2+ is as low as 1.66 mg/L. The stabilization effect of calcined dolomite sand on Mn2+ in electrolytic manganese residue is mainly that Mn2+ is solidified in the form of MnO2 and MnOOH. The calcined dolomite sand at 700 * 800 °C can be used as an effective stabilizer to solidified Mn2+ in electrolytic manganese residue. [ABSTRACT FROM AUTHOR]

The carbonate-evaporite sequence of the Arab Formation constitutes the important reservoir unit in the Persian Gulf and adjacent area. The paper aims to present detail facies characteristics, depositional environment and sequence stratigraphic analysis of the Arab Formation in an oil field in the Persian Gulf. A total of 12 microfacies (MF) and 3 dolomitic (diagenetic) facies (DF) were identified, and are interpreted as a homoclinal carbonate ramp platform. The Arab Formation is divided into four third order sequences corresponding to main reservoir intervals (Arab-A, B, C, D). The results highly correlate with the sequences of local and regional studies in the Arabian Plate. It is probably due to the cake layer nature of the Arab Formation and high impact of the world eustatic sea-level fluctuations (global curves) on the facies stacking pattern. [ABSTRACT FROM AUTHOR]

The deep-burial Ordovician carbonate reservoirs in the Yangshuiwu area (Jizhong Depression) have shown significant hydrocarbon potential since 2016. In this paper, based on the systematic investigation of characteristics and diagenesis of the reservoirs using cores, thin sections, logging, drilling, and geochemical analysis, their controlling factors and formation mechanism were discussed. The three high-quality reservoir belts (RBs) developed in the Ordovician strata are named RB1 (karst reservoirs), RB2 and RB3 (dolostone reservoirs) from top to bottom, each with its own set of pores, vugs, caves, and fractures. The results show that dolostones have relatively higher porosity and permeability than limestones and breccias. Unfilled and partly filled fractures, in particular, multiply enhance reservoir permeability. Additionally, the diagenetic paragenesis developed in marine, meteoric, and burial environments leads to the porosity evolution of Ordovician carbonates, mainly including compaction, calcite cementation, dolomitization, dissolution, and fracturing. Notably, sedimentation and dolomitization controlled by sea-level fluctuations are critical for the reservoirs formation. The tidal-flat sequence of each cycle of sea-level fluctuations influences their distribution. Subaerial meteoric water dissolution triggered by the Late Ordovician uplift plays an important role in the RB1, but has a negligible effect on the RB2 and RB3. Most importantly, the conductive high-angle fractures induced by the activities of the Yangshuiwu and Hexiwu faults from the Eocene to Pliocene can enhance all RBs potential, contributing to the ultimate reservoir quality. Therefore, a four-stage theoretical development model of the Ordovician reservoirs was established in combination with the tectonic background. [ABSTRACT FROM AUTHOR]

Investigations of an Lower Carnian Wettersteinkalk ammonoid fauna found in the Hochobir massif (Carinthia/ Austria) gave rise to problems in the taxonomic relationship within the Triassic ammonoid Family Pinacoceratidae. The morphological parameters of the ammonoid genus Pompeckjites are rather unclear. Morphological variation of at least two ammonoid species as Pompeckjites layeri Hauer on one end, Placites urlichsi Bizzarini on the other end have to be take into account. Numerous field surveys, studies and excavations on upper Wettersteinkalk sites within the Karavank Mountains and Hallstatt-facies sites in the Northern Calcareous Alps were implemented and compared with the reference sites in the Dolomites. As a consequence of our investigations, the Hochobir Wettersteinkalk ammonite assemblage is thought to be equivalent in time to the ammonoid fauna of the Upper San Cassian Formation. The frequent occurrence of the Julian (Lower Carnian) ammonoid Placites urlichsi Bizzarini may be a powerful tool in field investigations for a refined correlation of the upper Wettersteinkalk reef limestone to the coeval basinal facies of the Upper San Cassian Formation (Lower Carnian/upper Trachyceras aonoides Zone). As a result of this study Placites urlichsi was included in the genus Pompeckjites. This paper could be an attempt to recognize the differences in juvenile forms of Pompeckjites layeri and Placites urlichsi and other similar disciform ammonoid genera like Carnites floridus and Sageceras sp. based on suture lines, polished transversal-sections and morphological features. [ABSTRACT FROM AUTHOR]

The use of geothermal energy, which comes from both deep geothermal systems and the shallow underground, has been developing rapidly in the last few decades. The purpose of the paper is to present the results of measurements of the thermal properties of all rock samples and sediments that were available from boreholes, two tunnels and numerous surface locations in Slovenia in the period from 1982 to the end of 2022. In relation to the shallow geothermal potential, a special effort is needed to characterize the thermal properties of the rocks and sediments and to implement thermal energy transfer technology. In this sense, knowledge of the thermal conductivity of rocks and sediments is required to assess the possibility of low-enthalpy heat exchange in a given local area. The largest number of measurements was taken to determine thermal conductivity. Determinations of thermal diffusivity were carried out on a much smaller number of rock and sediment samples, as well as determinations of radiogenic heat production in rocks. The results of thermal conductivity measurements on 430 samples from 119 wells, 20 samples from two tunnels and 156 samples from surface locations are shown. The highest thermal conductivities are shown by samples of dolomite, quartz conglomerate and conglomerate, phyllonite, quartz phyllite and gneiss, while the lowest are measured in sediments such as clay, lignite with clay, peat and dry sand. The determined radioactive heat generation is the lowest for milonitized dolomite and highest for dark grey sandstone with shale clasts. Our results are comparable to those already published worldwide, and they could be the basis for the possible future Slovenian standard for the thermal properties of measured rocks and sediments. [ABSTRACT FROM AUTHOR]