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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]

Crushed dolomite stone can be used as a part of concrete for hot weather. Fine dolomite as a filler is not commonly included in Portland cement. In this paper, the properties of a blended binder based on Portland cement and dolomite filler are presented. Dolomite filler was obtained from dust grains by mechanical activation in a laboratory ball mill to increase the specific surface area and its chemical activity. It is shown that the impact of mechanical activation allows to obtain dolomite filler with a median particle size of 1.4 μm and a specific surface area of 639.9 m2/kg. The content of dolomite filler in Portland cement was 10, 30 and 50%. The main properties of blended cements, i.e., the standard consistency, setting time, compressive strength, average density, and drying shrinkage, were determined on pastes. The mineralogical composition of the hydrated pastes was determined by XRD at 28 days. The presence of dolomite filler at levels higher than 10% decreases the compressive strength of blended cements. The dolomite filler decreases the water demand, shortens the setting time, and mitigates the development of drying shrinkage in the blended binder. To prevent concrete cracking, the application of dolomite filler in blended cement is relevant in hot weather due to its reduced drying shrinkage. [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]

During weathering and pedogenesis of carbonate rock with poor-uranium (U) and thorium (Th), U and Th present the characteristics of strong leaching (especially U) and significant residual enrichment, the cause of which is still unclear. In this paper, a weathering profile developed by dolomite in karst area of Guizhou province in southwest China was selected, which showed zonation characteristics of bedrock (Y), powdery rock (Yf), and soil layer (T1 to T12) from the bottom to up. Through the determination of the occurrence speciation of U and Th in Y and weathering profile, combined with mineralogical, geochemical characteristics, and element mass balance calculation, the constraints of U and Th speciation on the geochemical behavior of U and Th during the weathering of carbonate rock were revealed. The results proved that U and Th in Y preferentially existed in acid insoluble phase, for example, the contents of U and Th in Y were 0.90 mg·kg−1 and 0.28 mg·kg−1, respectively, while those in acid insoluble matter were 2.34 mg·kg−1 and 2.57 mg·kg−1, respectively, but because the mass percentage of acid insoluble matter was extremely low (0.95%), the mass percentages of U and Th in the acid soluble phase in the whole rock were absolutely superior (96% of U and 86% Th). The U and Th in the acid soluble phase of Y were mainly adsorbed on the crystal surface of carbonate minerals or existed in the cement, and the U and Th in the carbonate lattice only accounted for a small proportion. From Y to Yf with the initial dissolution, U and Th released from the surface of carbonate minerals and cements were in carbonate-rich alkaline environment, and these portions of U and Th were leached out, resulting in strong loss of U and Th in the Yf (the loss rates are 83% of U and 65% of Th, respectively). From the Yf to the overlying soil layer T1, the carbonate components were completely dissolved, and the U and Th released from the carbonate lattice showed different behaviors, where U was completely leached and Th tended to stay in the weathered residue. Thus, in the soil layer T1 formed by Y or Yf , the residual U was the inheritance of the U in the acid insoluble phase of Y; For Th, it not only inherited the Th of acid insoluble phase of Y, but also superimposed the Th from carbonate lattice in Y. On the other hand, during the evolution process from Y to Yf and to soil layer T1, with the dissolution of carbonate, the acid insoluble phase also showed a significant tendency of chemical weathering. However, the U and Th in the Y acid insoluble phase were not leached with the decomposition of the acid insoluble phase but were redistributed among the residual phases. For the geochemical behaviors of U and Th in the evolution of soil profile (T1~T12), they were subjected to the occurrence speciation of U and Th in T1 and the change of U and Th occurrence speciation with the upward direction of soil profile. The U and Th released from the carrier minerals were mainly redistributed among the residual solid phases, which weakened the intensity of their further loss. This study deepens the understanding of the geochemical behavior of radionuclides in karst environment and provides reference for the treatment of radioactive pollution in karst areas. [ABSTRACT FROM AUTHOR]

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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 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]

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]

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]

Copyright of Tesla Revista Científica is the property of Puerto Madero Editorial Academica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

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 concern of this study is to continue the investigation of convergence properties of Urysohn type generalized sampling operators, which are defined by the author in [Dolomites Res. Notes Approx. 2021, 14 (2), 58–67]. In details, the paper centers around to investigation of the asymptotic properties together with some Voronovskaya-type theorems for the linear and nonlinear counterpart of Urysohn type generalized sampling operators. [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 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 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]

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Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Quaternary sediment in the Labrador Sea was derived from many proglacial sources in Greenland and eastern Canada. Understanding the spatial and temporal changes in sediment provenance provides information on ice extent and sediment dispersal patterns. Variations in mineral composition of sediment from late Quaternary cores has been determined by a whole pattern of quantitative X-ray diffraction procedure. Mineral facies were extracted statistically by a supervised analysis of 90 samples from bedrock and ice-rafted clasts, which were then used to predict the most probable mineral facies in 1443 marine sediment samples. We used a non-parametric Classification Decision Tree (CDT) to validate that decision. Only 26% of the samples were misclassified in the CDT. The six facies identified consisted of four facies reflecting differences in the composition of Canadian and Greenland Precambrian igneous and metamorphic bedrock, a set of samples dominated by high weight percentages of calcite and dolomite (detrital carbonate (DC) and Hudson Strait Heinrich (HS-H) events), and a "shale" facies. We isolated 284 sediments from the HS-H DC facies and determined that they could be divided into four categories based on differences in their mineral proportions. These categories vary geographically, based on non-carbonate sediment supply during these events from Greenland, the Canadian Shield, the Appalachians, and the outer continental shelf. In the Holocene of the Labrador Sea, dolomite is derived from Baffin Bay and abundance of calcite is influenced by both biogenic productivity and dissolution. [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]

Sintered ceramics, represented by ceramic tiles or clinker bricks, are widely used in the building materials industry due to their technological properties and visual qualities. The topic of color changing of ceramic materials from cream‐firing clays with the use of mineral additives has not been addressed to date. The aim of the paper was to investigate the effect of granulation of dolomite additives to ceramic masses based on cream‐firing Borkowice clay on the color and properties of fired ceramic materials. The paper proposes that grain size of mineral additive affects the color of sintered ceramics. In order to confirm this hypothesis, a number of experiments were performed, consisting of determination of the color and technological properties of ceramic materials. The conducted tests showed that the color and technological properties of sintered ceramics are influenced by the grain size of the additives used. [ABSTRACT FROM AUTHOR]

A very rich gastropod fauna from the upper Anisian (Nevadites secedensis Zone) platform carbonates of the Dolomites, represented by more than 200 species, was collected over recent decades. Its study contributes to a better understanding of the dynamics of the recovery after the end-Permian mass extinction. This paper deals with the Pleurotomariida. A total of 35 species, 22 genera and 9 families have been identified. Of these, 12 species and 7 genera are new, namely Rufilla wilckensi sp. nov., Rufilla giacomellii sp. nov., Viezzenella ruvida gen. et sp. nov., Temnotropis maestroettorei sp. nov., Cancellotomaria boninsegnai sp. nov., Stuorella crenulata sp. nov., Codinella? fontanai sp. nov., Fiacconella pericincta gen. et sp. nov., Fiemmespira gen. nov., Texturaspira gen. nov., Nodocingulum ogilvieae sp. nov., Dimorphotomaria fassaensis gen. et sp. nov., Moenaspira crassa gen. et sp. nov. and Predazzella elongata gen. et sp. nov. Comparison with the gastropod fauna of the St Cassian Formation indicates that, from the late Anisian to the Carnian, in the Dolomites the richness of the Pleurotomariida increased by 54% at species level, 26% at genus level and 22% at family level. A comprehensive palaeobiogeographical analysis highlights a very high degree of endemism: 90% of the species are exclusive to single palaeogeographical units. This suggests that species diversification at a strict local scale was a major feature of the Middle Triassic phase of recovery of the Pleurotomariida. Seemingly, the non-planktotrophic development of this group combined with a patchy resurgence of the carbonate platforms played an important role in hampering dispersal. [ABSTRACT FROM AUTHOR]

Apatite and dolomite present challenges in their separation due to their similar surface chemistry. To achieve flotation separation of apatite and dolomite, depressants are required, but conventional depressants have several drawbacks. Hence, the development of effective and environmentally friendly depressants is of great importance. This study aimed to investigate the depressive effect of gallic acid (GA) on the flotation separation of apatite from dolomite using sodium oleate (NaOL) as the collector. The floatability of apatite and dolomite was examined through micro-flotation. The findings revealed that, with 1.0 × 10−4 mol L−1 NaOL, the recovery rates of apatite and dolomite were 86.29% and 77.42%, respectively. After introducing 2.0 × 10−4 mol L−1 GA, the recovery of apatite remained at 83.42%, while that of dolomite drastically decreased to only 14.33%. The selective depression mechanism of GA in the flotation separation of apatite from dolomite was investigated using various techniques, including zeta potential, contact angle, UV-vis, FTIR, XPS, ToF-SIMS, and AFM analyses. The results demonstrated that GA increased the hydrophilicity of the dolomite surface and impeded the adsorption of NaOL on that surface without affecting the apatite. GA was found to bind to Ca and Mg sites on the dolomite surface through –OH and –COOH groups. The adsorption of GA on the dolomite surface was substantial, with the adsorption height primarily concentrated in the range of 10–30 nm. GA exhibited selective depression on dolomite, thus, enabling successful flotation separation of apatite from dolomite. [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]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we present mineralogical, whole-rock geochemical, Sr and Pb isotopic, and zircon trace elemental and U–Pb geochronological data for the newly-discovered Pengco listvenite in central Tibet, in an attempt to probe the petrogenesis of listvenite and the tectonic environment. The listvenite is composed of magnesite, quartz and minor dolomite and Cr-spinel. Chemistry of abundant protogenetic Cr-spinel in the Pengco listvenite as well as the whole-rock Cr and Ni concentrations and low rare-earth element contents indicates the harzburgite protolith. Addition of Ca and K and redistribution of Si at sample scale suggest that the formation of Pengco listvenite was not an isochemical process. Serpentinization could partly accounts for the enrichments in some fluid mobile elements before listvenitization. The εHf(t) values of xenocrystic zircons in the Pengco listvenite are dominantly negative, suggesting a continental crustal source. The zircon age spectra and high whole-rock initial 87Sr/86Sr values (0.7094–0.7107, and one up to 0.7193) and high 207Pb/204Pb (15.750–15.759), 208Pb/204Pb (39.145–39.215) and 206Pb/204Pb (18.542–18.567) of the Pengco listvenite are similar to those of the Qiangtang continental sediments/upper crust, indicating the terrigenous source of reactant fluids and fluid-assisted solid-state transfer during the formation of listvenite. The Pengco listvenite is likely formed in the forearc extensional environment of the Bangong Meso-Tethyan ocean during the Late Jurassic. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geologija (0016-7789) is the property of Geological Survey of Slovenia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)