Coarse-grained Limestone Research Articles

Mechanical properties of wetting contacts between coarse-grained limestone

Mechanical properties of wetting contacts between coarse-grained limestone

Apparent calcium retention and digestibility coefficients of limestone with different particle sizes in laying hens

Apparent calcium (Ca) retention and digestibility coefficients are affected by limestone particle size in the diet of laying hens. This study aimed to determine the apparent retention and digestibility coefficients of Ca in limestone of different particle sizes in laying hens. The study comprised 288 Lohmann Brown laying hens (50 weeks of age; 1,964 ± 98 g) distributed in a completely randomized experimental design with a 3 × 2 factorial arrangement [three Ca concentrations (10, 20, and 30 g kg–1) × two limestone particle sizes (480 and 1,978 µm)] with eight repetitions per treatment and six birds per experimental unit. The experiment included five days for adaptation and five days for total excreta collection. All birds were slaughtered at the end of the ten days to collect the ileal contents. The total or ileal Ca content was plotted against the Ca of diets concentration using linear regression analysis. The regression line slope represented the apparent retention (CaR) and digestibility coefficients of Ca (CaD) in limestone. There was interaction between Ca concentration in the diet and limestone granulometry on CaD (p = 0.001) and CaR (p < 0.001). The CaD and CaR of fine- and coarse-grained limestone increased linearly with increasing Ca concentrations in the diet. The apparent digestibility coefficients estimated for laying hens fed with fine-grained and coarse-grained limestone were 0.72 and 0.35, respectively. The apparent retention coefficients estimated for laying hens fed fine-grained and coarse-grained limestone were 0.96 and 0.47, respectively.

A glimpse of the lost Upper Triassic to Middle Jurassic architecture of the Dinaric Carbonate Platform margin and slope

In the southernmost outcrops of the Slovenian Basin the Middle Jurassic coarse-grained limestone breccia (mega)beds are interstratified within a succession that is otherwise dominated by hemipelagites and distal turbidites. In this paper, these beds are described as the Ponikve Breccia Member of the Tolmin Formation. We provide descriptions of the studied sections with detailed geological maps and analysis of the breccia lithoclasts. From the latter, a non-outcropping margin of the Dinaric Carbonate Platform is reconstructed. In the Late Triassic the platform margin was characterized by a Dachstein-type marginal reef. After the end-Triassic extinction event, the platform architecture remained, but the reefs were replaced by sand shoals characterized by ooids. In the late Early Jurassic and/or early Middle Jurassic a slope area might have been dissected by normal faults and a step-like paleotopography was formed. In the Bajocian, during a period of major regional geodynamic perturbations, extensional or transtensional tectonic activity intensified and triggered the large-scale collapses of the Dinaric Carbonate Platform margin producing the limestone breccias described herein. This may in turn have caused a backstepping of the platform margin, as is evident from the occurrence of Late Jurassic marginal reefs that are installed directly above the Upper Triassic and Lower Jurassic inner platform successions.

Properties of cement composites based on limestone depending on their granulometric composition

Introduction. The use of limestone in cement compositions as an additional cementing agent solves both environmental and economic problems, namely, reduction of construction costs. In this regard, the study of the properties of the granulometric composition and volumetric content of cement composites, containing limestone, becomes increasingly important. The mission of this research is to optimize the properties of composite materials containing Portland cement and limestone by changing the granulometric composition of flour limestone.&#x0D; Materials and methods. Limestone, having three different Blaine milling fineness values of 250, 300 and 450 m2/kg, was used; its content reached 10, 15, 25 and 35 %. Cement and sand mortars were applied for testing purposes. The influence of the granulometric composition of limestone on the workability and compressive strength of composite cement was determined.&#x0D; Results. The effect of limestone on the limit shear stress becomes more pronounced when the amount of limestone increases to 25 and 35 %. This is most noticeable for limestone with a high content of fine fractions of 5–20 µm. The use of finely milled limestone increases the initial strength of the composite material. By adding 10 and 15 % of such limestone we can increase the strength by 16–20 %, and supplementary 25–35 % of limestone increases strength by 5–8 %. Strength enhancement is due to the reactivity of limestone and formation of calcium hydrocarbon aluminate 3CaO∙Al2O3∙СаСО3∙12H2O, which promotes formation of the crystal framework of the cement matrix. Additional formation of crystalline hydrates in the initial coagulation structure deteriorates the mortar workability, but increases its strength.&#x0D; Conclusions. The use of coarse-grained limestone significantly improves mortar workability, while the use of fine-grained limestone increases its content without reducing its strength. The granulometric composition of ground limestone shall be as close as possible to the granulometric composition of cement for the properties of composite materials containing Portland cement and limestone to be optimized.

Submarine hydrothermal contribution for the extreme element accumulation during the early Cambrian, South China

Throughout the geological history of the Earth, submarine hydrothermal activity has played an important role in seawater chemistry, biological evolution and enrichment of metals in the Earth crust. However, the prospect of hydrothermal activity for extreme element accumulation during the early Cambrian, a key geological period, in South China has not been well-constrained. This study reports geochemical (e.g. REE and Sr isotope) investigations of a coarse-grained limestone layer and associated calcite veins in Zunyi and Nayong areas, Guizhou Province, to constrain the hydrothermal activity and evaluate the significance of hydrothermal contribution to extreme element accumulation during the early Cambrian, South China. Our results reveal positive Eu anomalies and higher initial 87Sr/86Sr ratios (0.7083–0.7150) for carbonate samples than those of early Cambrian seawater, indicating the presence of hydrothermal processes. Combined with constraints from the spatial relationships and coincidence with adjacent mineralization, these hydrothermal processes provide the most probable contribution for polymetallic Ni–Mo–PGE mineralization. Furthermore, there are abundant hydrothermal dolomite and barite-calcite veins in the dolostone of the Dengying Formation, indicating the occurrence of a variety of hydrothermal fluids. Overall, multi-stage hydrothermal pulses with different fluid compositions spanned the Ediacaran–Cambrian transition in South China. In particular, these hydrothermal fluids with positive Eu anomalies and enriched radiogenic Sr, originating from Proterozoic mafic/ultramafic rocks, may have flowed through the underlying Precambrian silicate clastic rocks (e.g., Xiajiang, Banxi and Lengjiaxi Groups) and may have been crucial for the marine environment, biological diversity and extreme element accumulation during the early Cambrian, South China.

Nanoscale Morphology of Brine/Oil/Mineral Contacts in Connected Pores of Carbonate Reservoirs: Insights on Wettability From Cryo-BIB-SEM

Summary We used broad-ion-beam slope cutting in combination with scanning electron microscopy undertaken under cryogenic conditions (Cryo-BIB-SEM) to study mineral/oil/brine contacts in reservoir carbonates. This direct-imaging method allows pore-scale investigation of in-situ fluids and their distributions down to the nanometer scale. In this study, we compare two types of carbonate reservoirs: a fine-grained Lixhe limestone (Belgium) and a coarse-grained limestone from the Maastricht area (The Netherlands). In both rock types, we first quantify the porosity with BIB-SEM and derive the spatially resolved pore connectivity of the rock from BIB-SEM on Wood's Metal (WM) injected subsamples. In the second step, subsamples were saturated with the oil analog n-hexadecane, and then flooded with NaCl brine and MgSO4 brine, respectively, to study the effect of the brine chemistry on the microscopic fluid distribution. Cryo-BIB-SEM in combination with high-resolution energy-dispersive-spectroscopy (EDS) imaging and automated image analysis on the saturated samples allowed for a quantification of the oil-droplet size, the lengths of carbonate/oil interfaces, and the 2D contact angle of carbonate with brine and oil. Our results show that these features (e.g., interface length, contact angles, effect of asperities) are present on the scale of a few tens of nanometers to a few micrometers, which is in agreement with numerous theoretical and experimental studies. Lixhe limestone showed relatively less carbonate/oil contacts despite a larger oil fraction in the MgSO4-brine-flooded sample compared with the sample flooded with NaCl brine, indicating a more-hydrophilic nature of the carbonate surface in this experiment. This feasibility study showed that the technique permits the testing of predictions on the morphology and dynamics of contact lines in relation to the mineral properties, which is not possible with other imaging methods, such as X-ray microcomputed tomography (µ-CT), because of limits in resolution.

Small-scale cyclic deposition in the Frasnian (Upper Devonian) of the Holy Cross Mountains, Poland

Abstract In sections exposing Frasnian limestones at five outcrops in the Holy Cross Mountains, five lithofacies (L1 to L5) that represent upper slope to basinal environments are identified. These lithofacies are characterised by dark-coloured micritic limestones-marly shale couplets with many light-coloured intercalations of fine- to coarse-grained limestones (= event beds). This lithofacies pattern characterises mostly low-energy domains punctuated by storm episodes. In addition, these upper-slope to basinal lithofacies are arranged into small-scale, coarsening-upward beds and cycles. The cycles are locally composed of fining/thinning-upward beds. The small-scale cycles have a calculated duration of 19 to 42 kyr. The differential thickness of beds and cycles within and between sections was probably caused by differential subsidence and local tectonics. Possible evidence of tectonic activity is also related to a difference in number of cycles recorded in the time-equivalent sections. The recognised cyclicity shows sea-level fluctuations and a few deepening episodes. Some of them are correlated with the Timan global eustatic events. However, local tectonics and episodic subsidence may have played a significant role in recording brief deepening pulses. Thus, low-amplitude sea-level changes were major factors in platform generation and evolution in the Frasnian of the Holy Cross Mountains modified by local, block-related subsidence.

Limestone weathering rates accelerated by micron-scale grain detachment

The weathering of carbonate rocks plays a critical role in the evolution of landscapes, the erosion of buildings and monuments, and the global-scale shifting of carbon from the atmosphere to the ocean. Chemical dissolution is often assumed to govern the rates of weathering of carbonate rocks, although some studies have suggested that mechanical erosion could also play an important role. Quantifying the rates of the different processes has proved challenging, in part due to the high degree of variability encountered across different scales in both field and laboratory conditions. To constrain the rates and mechanisms controlling long-term limestone weathering, we analyze a lidar scan of the Western Wall, a Roman-period edifice located in Jerusalem. We find that extreme erosion rates in fine-grained micritic limestone blocks are as much as two orders of magnitude higher than the average rates estimated for coarse-grained limestone blocks at the same site. Atomic force microscope imaging of dissolving micritic limestone suggests that these elevated reaction rates are likely to be the result of rapid dissolution along micron-scale grain boundaries, followed by mechanical detachment of tiny particles from the surface. Our analysis indicates that such grain detachment could be the dominant erosional mode for fine-grained carbonate rocks in many regions on Earth.

On the use of different metrics for assessing complex pattern reproductions

Nowadays, there is an increasing interest in multi-point models and their applications in Earth sciences. However, users not only ask for multi-point methods able to capture the uncertainties of complex structures and to reproduce the properties of a training image, but also they need quantitative tools for assessing whether a set of realizations have the properties required. Moreover, it is crucial to study the sensitivity of the realizations to the size of the data template and to analyze how fast realization-based statistics converge on average toward training-based statistics. In this paper, some similarity measures and convergence indexes, based on some physically measurable quantities and cumulants of high-order, are presented. In the case study, multi-point simulations of the spatial distribution of coarse-grained limestone and calcareous rock, generated by using three templates of different sizes, are compared and convergence toward training-based statistics is analyzed by taking into account increasing numbers of realizations.

Nannostratigraphy, nannofossil events, and paleoclimate fluctuations in the lower boundary of Kalat formation in East Kopet Dagh (NE Iran)

The biostratigraphy and the response of calcareous nannofossils to the End Cretaceous warming are investigated in the lower boundary of Kalat formation through the record of species richness, diversity, distribution patterns, and statistical treatments. The Kalat formation comprised of coarse-grained detritus limestone with subordinate sandstone intercalations. In the studied sections, the number of ten samples were taken and prepared with smear slide. In Dobaradar, section 22 species; in Kalat, section 25 species; and in Chahchaheh, section 32 species have been determined. Based on nannoplanktons and as a result of biostratigraphic studies, the nannofossil standard zones (CC25–CC26) were identified in all of sections. According to these zones in all of sections, the age of the studied thickness is Late Maastrichtian–Late Late Maastrichtian. In these sections, the presence of Micula murus at the end of Neyzar formation and the presence of this species at the lower part of Kalat formation indicate that the investigated boundary is Late Maastrichtian in age. The paleoecological results point to warm climate. The presence of warm water indicators (M. murus and Micula prinsii) and the absence of cool water indicators (Ahmuellerella octoradiata, Kamptnerius magnificus, and Nephrolithus frequens) suggest warm surface water conditions in these areas. In the lower boundary of Kalat formation, base on Lithraphidites spp. and Watznaueria barnesae, lowered fertility condition with low productivity at the end of the Maastrichtian were suggested, and the studied area was deposited in shallow marine environment in relatively low latitude.

Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)

Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)The Kostomłoty-Mogiłki succession is situated in the Kostomłoty transitional zone between the shallow-water Kielce stromatoporoid-coral platform and the deeper Łysogóry basin. In the Kostomłoty-Mogiłki quarry, the upper part of the Szydłówek Beds and Kostomłoty Beds are exposed. The Middle-Upper Frasnian Kostomłoty Beds are composed of shales, micritic and nodular limestones with abundant intercalations of detrital limestones. The dark shales and the micritic and nodular limestones record background sedimentation. The interbedded laminated and detrital limestones reflect high-energy deposition (= event beds). These event beds comprise laminated calcisiltites, fine-grained calcarenites, coarse-grained grain-supported calcirudites fabrics, and matrix-supported calcirudites. The material of these event beds was supplied by both erosion of the carbonate-platform margin and cannibalistic erosion of penecontemporaneous detrital limestones building the slope of this platform. Storms and the tectonic activity were likely the main causes of erosion. Combined and gravity flows were the transporting mechanisms involved in the reworking and redeposition.

Use of Pressure Fluctuations to Determine Online the Regime of Gas−Solids Suspensions from Incipient Fluidization to Transport

A novel quantity, based on the concept of symmetry of the sampled pressure fluctuating signal, is developed and incorporated into our extended fluctuation model of fluidized gas−solid suspensions. The new measure of the signal symmetry makes it possible to define the transition from the final bubbling regime to the onset of turbulence in the bed. Experimental measurements were performed in a transparent glass, 6-m-tall column with an inner diameter (i.d.) of 0.08 m. Three different kinds of solids were employed in the experiments: ceramsite (particle size 1.0−1.25 mm; group D particles; spoutable particles), glass beads (particle size 0.8−1.00 mm; group D particles), and high-calcium, coarse-grained limestone (particle size 0.50−0.65 mm; group B powder; sandlike particles). It was discovered that also the different bubbling regimes and the starting point of dilute (entrainment) regimes can be identified with the aid of the proposed method. The development of the diluted beds is considerably influenced by the architecture and configuration of the top of the fluidization column.

Transitional reef-to-basin facies of Lower Frasnian limestones determined by microfacies analysis (Wietrznia, Holy Cross Mts, Poland)

Wietrznia section is situated between the shallow-water carbonate platform in the Kielce region and the Łysogory basin. The transitional facies of the Wietrznia Frasnian includes two overlapping types of deposits: (1) thin-bedded dark-coloured limestone-marl alternations similar to the basin facies and (2) coarse-grained detrital limestones. Three lithotypes of limestones were identified: laminated or graded micritic, nodular, and detrital. The petrographic study makes it possible for the recognition of six major microfacies (MF 1 to MF 6). These lithotypes were formed by redeposition in a low- to high-energy environment. Their source material was the stromatoporoid-coral Dyminy reef in the central part of the Kielce region. Storms are considered to be the main agent, which causes in erosion and transport; micritic limestones and distal tempestites occur together, whereas detrital limestones are associated with proximal tempestites. Most probably, part of the detrital beds was formed as a result of grain-flow initiated under storm conditions.

Ultrasonic Pulse Wave Velocity Test for Monitoring Changes in Hot-Mix Asphalt Mixture Integrity from Exposure to Moisture

The ultrasonic pulse wave velocity test is evaluated as a possible tool for monitoring changes in the integrity of mixtures due to moisture conditioning. Two sets of mixtures were prepared. The first group involved fine-grained (above the restricted zone) and coarse-grained (below the restricted zone) limestone mixtures commonly used by the Florida Department of Transportation (FDOT) that were produced with multiple void structure and permeability configurations by varying the gradations and proportions for a common set of aggregates and asphalt cement. The second set of mixtures consisted of three granite-based mixtures commonly used by FDOT. The results presented show that the small strain modulus obtained with the ultrasonic pulse wave velocity test appears to be sensitive to changes in mixture integrity due to moisture, and therefore it may be a possible tool for the characterization of damage in both laboratory and field specimens. Additional work remains to be performed to better define the meaning of the values obtained. However, the current results indicate that the ultrasonic pulse wave velocity test may be used as an indicator of damage in specimens as well as a quick monitoring device for detecting changes in the integrity of mixtures due to exposure to moisture.

Durva mészkő viselkedése légköri szennyeződés hatására

Durva mészkő viselkedése légköri szennyeződés hatására

Sulphur Deposition and Damage on Limestone and Sandstone iN Stockholm City Buildings

390 Stockholm city buildings with sculptural decorations, or facades, of limestone or quartzitic sandstone have been investigated. The observed damage has been expressed by digital codes. The chemical analysis was mainly undertaken with SEM/EDS. The study has verified that quartzitic sandstone is more resistant towards weathering than limestone. Coarse-grained limestone with pores and cracks are most weathering-prone. Climatic conditions and air pollution are the major causes of the degradation. The data have been evaluated by means of statistical multivariate analysis. There are significant relationships between car traffic and damage, and between car traffic and soiling, also between observed damage and present degree of sulphation at limestone surfaces. The most common damage is pitting and soiling.

Sedimentology of the lowest Windsor carbonate rocks; base metal hosts in the Maritimes Basin of Eastern Canada

The Mississippian (Visean) Macumber and Gays River Formations of the Windsor Group in Nova Scotia are host to Pb-Zn-Ba (Cu-Ag) deposits. Transport and deposition of base metals were possible because of an efficient porosity-permeability system developed in both units. Depositional facies is a key parameter controlling the potential openness of carbonate units.The Macumber facies were deposited after the collapse of the Acadian orogen and ensuing tectonically driven sea-level rise. The Macumber Formation is divided into two regional lithosomes: a lower thin unit (<2 m) of fine- and coarse-grained limestones deposited below the fairweather wave base positioned on an outer shelf with local chemosynthetic mounds, and an upper thicker unit (avg 10 m) of planar-bedded micritic limestones, most likely representing upper slope microbial mats interbedded with deep marine sulfates. The permeability system was created by various brecciation events affecting the upper part of the formation.The Gays River Formation, deposited upslope of the Macumber facies, is dominated by various organic mounds with intervening facies. The boundstone facies are indicative of below fairweather wave base deposition, roughly at the limit of the photic zone. Primary growth porosity of the mounds provided the plumbing system later used by mineralizing fluids. These mounds also record the effects of a sea-level rise culminating in regional deposition of deep marine sulfates.Outside the eastern margin of the Laurentia craton, a similar Visean-aged mixed limestone sulfate succession is known from the Franco-Belgian basin in Baltica. Distribution of shelf and slope facies within the Visean mid-European ocean separating Laurentia, Baltica, and Gondwana suggests that restricted oceanic circulation in a rapidly closing sea was instrumental in the local occurrence of a salinity-stratified water mass and, hence, responsible for the presence of below wave base marine limestone and sulfate facies on the Laurentia and Baltica continental margins.

Critical re-evaluation of differential stress estimates from calcite twins in coarse-grained limestone

Comparison of two techniques to estimate differential stress magnitude based on calcite twinning reveals significantly different calculated values of differential stress for limestone experimentally and naturally deformed at low temperature. This inequality may be due to fundamental differences between the rock type (marble versus limestone) and deformation temperatures (above and below 200°C) for samples used in technique calibration versus samples used in testing and application. A technique that was empirically derived from marble experimentally deformed at 200–800°C yields values of differential stress that are factors of 2 to 9 times larger than maximum differential stress measured during experimental deformation of limestone at low temperature (<200°C). Differential stress estimates from naturally deformed rocks differ by factors of 4 to 20, depending on the stress estimation technique used. Calcite tends to develop thin twins when deformed at temperatures below 200°C, and thick twins when deformed at temperatures above 200°C. Because of the temperature dependence of calcite-twin morphology, and possible effects of strain, grain size, and porosity, twin-based differential stress estimates should be used cautiously and particular attention given to deformation temperature.

Relative timing of calcite twinning strain and fold-thrust belt development; Hudson Valley fold-thrust belt, New York, U.S.A.

Coarse-grained limestone samples were collected across the Hudson Valley Fold-Thrust Belt with the aim of determining the temporal and spatial relationship between calcite twinning strain and fold-thrust belt development. The majority of the samples have well defined oblate strain ellipsoids with the maximum shortening axes (e 3) perpendicular to bedding strike, and e 3 magnitudes that range from ∼ 1.5% to 6.5%. Whereas twinning magnitude does not vary systematically through the fold-thrust belt, twinning fabrics fall into two populations based on the presence of outcrop-scale deformational features. Calcite twinning strain preserved in samples from limestone layers absent of any small-scale penetrative deformation, such as cleavage and/or microfaults, are defined as component A strains. Component A strains generally have maximum shortening axes (e 3) inclined consistently less than, but in the same E-W direction as, bedding dip. The second population of calcite twinning strain, population B, occurs in limestones pervasively cut by cleavage and/or microfaults. Component B strains has maximum shortening axes (e 3) that are horizontal irrespective of bedding dip. Strain population A initiated as a pre-folding, layer-parallel shortening strain that was subsequently modified to its present orientation by active grain-scale rotation during flexural folding. Strain population B reflects post-folding superimposed homogeneous strain, and is restricted to limestone samples with relatively high clay content.

High Resolution Sequence Stratigraphy in the Upper Jurassic Carbonate Platform of the Paris Basin: Reservoir Geometries in Lagoonal, Protected Marine and Ooids Shoals Environments: ABSTRACT

Reservoir geometry reconstruction within carbonate platforms has been carried out in the Upper Jurassic of the Paris Basin based on high-resolution sequence stratigraphy correlations (cores and well-logs). 18 cored wells over 25 kM{sup 2} have been correlated (Saint-Clair-sur-Epte field, Gaz de France). During lower and middle Oxfordian the Paris Basin is a carbonate platform prograding southward. This progradational trend can be subdivided into three upper order sequences (parasequences sets, mean duration: one m.y.). The lower parasequence-set is a stacking of shallowing-upward parasequences made up of tidal ooids bars surrounded laterally and backward by more protected environments (large variety of coated grains). The middle parasequence-set is recorded in lagoonal environments with numerous channels and lobes of storm washover-fans. Metric-thick sequences have been correlated over the field. They are ernersive upward (subtidal lagoonal deposits cut by storm-induced channels and lobes, covered by small karsts). The upper parasequence-set is made-up of protected-marine deposits grading into lagoonal sediments. The metric thick shallowing-upward sequences are composed by sheet-shaped, strongly bioturbated, medium to coarse-grained bioclastic limestones. Correlation levels are the deepest facies (strongly monospecifically bioturbated wackstones). Shape and size of reservoirs will be quantified.