Marble Formation Research Articles

The occurrence and enrichment of cobalt in skarn Pb-Zn deposits: A case study of the Niukutou Co-rich deposit, East Kunlun metallogenic belt, western China

The East Kunlun orogenic belt is one of the most important Co-rich polymetallic metallogenic belts in China. Niukutou, a typical Pb-Zn-(Fe) skarn deposit, is situated within the marble formations of the Ordovician-Silurian Qimantagh Group in this belt. Six distinct stages of mineralization have been identified: (1) prograde skarn stage, (2) hydrous mineral-oxide stage, (3) pyrrhotite stage, (4) chalcopyrite stage, (5) sphalerite-galena stage, and (6) carbonate stage. Co enrichment predominantly manifests at chalcopyrite stage, with two distinct Co minerals identified: glaucodot and cobaltite. Co is also present as isomorphous substitution in sulfides (mostly arsenopyrite) and as inclusions in chalcopyrite. Variations in As and S contents in arsenopyrite suggest a steady decrease in ore-forming fluid temperature from the pyrrhotite stage to sphalerite-galena stage. Variations in the Co, Ni, Se, As, Sb, Cu, Sn, Ag, and Zn contents in pyrite indicate fluctuations in temperature, oxygen fugacity, and fluid composition during ore formation. Sulfur isotope compositions (δ34S) through the pyrrhotite stage to the sphalerite-galena stages show a limited range from +3.4 to +7.0 ‰, suggesting a predominantly magmatic source. Whereas, the δ34S of pyrite and marcasite in carbonate stage exhibit significant variations from −22.5 to +22.7 ‰. We propose that this significant variation may be caused by mixing of sulfur from the surrounding rocks and the large fluctuations in oxygen fugacity due to the influx of meteoric water at the carbonate stage. Overall, Co in Pb-Zn skarn system may occur either as independent minerals or as lattice substitution in sulfides such as arsenopyrite. The deposition of Co-bearing minerals is related to decreases in temperature and fO2 during the chalcopyrite stage.

Impact of coating particles on liquid marble lifetime: reactor engineering approach to evaporation.

Liquid marbles are soft matter objects characterised by a liquid droplet enclosed within a hydrophobic particle coating, preventing wetting. This distinctive structure serves as active sites for solid-liquid-gas reactions. However, the impact the chosen coating material has on liquid marble stability, particularly regarding the number of coating layers and material wetting, remains uncertain. There is a need for a modelling approach to predict the overall lifetime considering these coating characteristics. This study reveals that for PTFE liquid marbles evaporating at ambient temperature, smaller coating particles (250 nm) extend their lifetime by forming a multilayered coating. Conversely, using larger particle sizes (200 μm) results in the formation of monolayer liquid marbles with shorter lifetimes than their equivalent naked droplets. Additionally, a higher number of particle layers and a larger contact angle generally enhance the liquid marble's lifetime. For multilayered liquid marbles comprised of smaller particles (250 nm), the particle contact angle is found to have a more significant impact than the number of layers on lifetime extension, whereas the opposite holds true for larger particle sizes (20 μm). A modelling approach using the reactor engineering method for liquid marble evaporation demonstrates excellent agreement with experimental results, yielding an R2 of 0.996. The implementation of this specific model, capable of assessing lifetime across various physical modifications, will enhance our understanding of liquid marble properties before their application in biomedical, microreactor, and green technologies.

Impact of high conductivity on particle transport to liquid droplets for liquid marble formation

Observing the interplay between material conductivity, cohesion and density for electrostatic liquid marble formation using metal-shell polymer particles.

Exploring hindered decarbonation in contact metamorphism: A glimpse into marble aureoles in Southern Tibet

Fluid-driven contact metamorphism in the Gangdese Arc, resulting from Late Cretaceous intrusions, led to a diverse range of aureoles in carbonate sequences in southern Tibet. These include extensive carbon loss in calc-silicate rocks with minor calcite remnants and minimal carbon loss in predominantly pure marble formations. Many studies connecting contact metamorphism and decarbonation flux focus on metacarbonate aureoles comprising calc-silicate assemblages, while marble formations represent a less prominent endmember. To investigate the factors determining decarbonation extent, we analyzed the thermobarometric, geochemical, and isotopic signatures of two representative marble aureoles in southern Tibet. Our findings suggest that isobarically exsolved magmatic fluid from a neighboring ∼64 Ma granodiorite pluton led to limited fluid-rock interaction in the marble aureole. Based on the petrologic observations, we present a conceptual model to elucidate this process. The heating and fluid infiltration were brief, likely due to short-lived intrusion events. Consequently, a thin ductile layer was formed adjacent to the pluton, while the majority of the country rock remained brittle. The lithostatic fluid in the ductile layer likely escaped through structurally weak zones, creating veins along the boundary between the pluton and marble. The fluids traversed the brittle-ductile transition experienced a sudden pressure drop from lithostatic in the ductile rock to hydrostatic in the brittle regime. The boiling fluid escaped by brecciating the brittle country rock and resulted in brecciation and stockwork of veins. In both cases, most fluid escaped through pathways, preventing infiltration into the country rock and decarbonation reactions. In contrast, a longer-lived heat source would have produced more extensive ductile country rocks, allowing for widespread fluid infiltration and calc-silicate formation. Thus, the thermal history of the intrusion and the rheology of the country rock significantly influence the extent of decarbonation in contact aureoles.

Thermal influence of sills on the chemostratigraphy and mineralogy of carbonate rocks from the Irati formation, Paraná basin

Carbonate rocks and shales are prominent lithologies in atypical petroleum systems. In these settings, the thermal effects of sills play a crucial role leading to mineralogical and geochemical alteration in the host rocks and in the maturation process of the associated organic matter. While extensive research has been conducted on shales within atypical systems, the understanding of the petrophysical and geochemical properties of carbonate rocks remains uncertain in numerous basins. In this study, we selected the Irati Formation (Paraná Basin) to investigate the thermal effects caused by diabase sills on the chemostratigraphic and lithologic features of carbonate rocks. We conducted mineralogical analyses, examined oxygen and carbon stable isotopes, and analyzed inorganic geochemical data from two distinct sections of the formation: one with diabase sills intruding the sequence and the other without identified intrusions in the area. Widespread recrystallization of minerals is observed throughout the studied rock wall, resulting in the formation of marbles and calc-silicate rocks, where dolomite is mainly replaced by calcite. The carbonate bank, located 5–7 m below the sill, is marked by brucite and chrysotile, while the rocks up to 1 m below and above the intrusion show the presence of tremolite, diopside, and antigorite. Substantial variations in elemental data are observed, including a significant increase in SiO2 and K2O below the sill, as well as elevated MgO levels within the carbonate bank. Additionally, stable isotopic signatures of oxygen and carbon display a negative shift influenced by decarbonation and intense fluid flow controlling the reactions. The contact aureole resulting from the intrusion is identified at least 7 m above and below the sill based on mineralogical and inorganic geochemical data.

Geochemistry of thermal springs and associated gases along the Strymon River Valley (Bulgaria and Greece)

This paper presents and discusses the water and gas geochemistry of a large number of thermal springs occurring along the N-S trending Strymon Valley, from its source, near Sofia (Bulgaria), to the Aegean Sea (Greece). In Bulgaria springs have markedly alkaline pH, relatively low Total Dissolved Solids and prevalent Na-HCO3 to Na-Cl(SO4) in composition while the associated gas phase is mostly N2-dominated. When moving to the Greek sector, the thermal springs, Ca(Mg)-HCO3 to Na-HCO3, become less alkaline and more saline whereas the associated gas phase is CO2-dominated. The abrupt geochemical change in the Greek sector is caused by a variation in the thickness and nature of the sediments filling the Strymon Valley, the latter being characterized by a relevant amount of Neogene marine material. Such changes occur south of an important E-W lineament named Middle Mesta, south of which marble formations extensively crop out and are likely occurring below the sedimentary succession. The presence of these carbonate sequences embedded in the Neogene sediments is explaining the CO2-rich gases associated to the Greek springs. Water isotopes indicate a meteoric origin for the studied waters. From a geothermometric point of view, solute (previous studies) and gas (this work) geothermometers suggest that no high enthalpy systems occur in the Bulgaria and northern sector of Greece with estimated temperatures <120 °C. Consequently, these thermal springs can be regarded as tectonically-derived along the many fault systems that border the Strymon Valley. The convective circuits are thus originated from rainfall in the crystalline massifs that border the valley, i.e. the Serbo-Macedonian to the west and the Rhodope to the east.

Petrography and Geochemistry of Gahirat Marble in Relation to Geotechnical Investigation: Implications for Dimension Stone, Chitral, Northwest Pakistan

The modernization of human civilization has led to the prospect of better and more durable building materials. Marble, found in various colors and textures, has been used as a building stone for centuries, either as cut stone or polished stone. The present study evaluated the petrological, geochemical, and geotechnical characterizations of the Gahirat Marble formation as a building stone. It is exposed over an area of 160 square kilometers in southwestern Chitral. The Gahirat Marble formation has been divided into two parts, i.e., the eastern and western parts. The eastern part is a coarse crystalline rock that exhibits a granulose structure and was subjected to amphibolite facies metamorphism, whereas its western part is a coarse-to-medium crystalline rock that displays a differential granulose structure and was subjected to green schist facies metamorphism. Petrographically, it is composed mainly of calcite (&gt;92%) with minute quartz, chlorite, muscovite, biotite, garnet, and opaque minerals. The X-ray fluorescence (XRF) technique was used to analyze the chemical composition of the Gahirat Marble showing that it is a pure calciocarbonate marble (CaO: 53.16–55.02 wt.%). The specific gravity measured varies from 2.46–2.71 gm/cm3, water absorption is &lt;0.2%, sulfate soundness is &lt;0.65, and due to its unconfined compressive strength, it is classified as strong rock, thus conforming to ASTM C503 specifications. The results acquired from the investigated samples suggest they are suitable as dimension stones. Until now, it has been limitedly mined and marketed but can be further exploited for export trade, based upon its petrographic, geotechnical, and geochemical characterization.

Droplet-Impact Driven Formation of Ultralow Volume Liquid Marbles with Enhanced Mechanical Stability and Sensing Ability.

Liquid marbles (LMs), droplets encapsulated with micro/nanoparticles, have attracted significant attention owing to their potential applications in various fields, ranging from microbioreactors to sensors. The volume of the LMs is a key parameter determining their mechanical stability and gas sensing ability. It is ideal to work with small volumes because of their better mechanical stability and gas sensing power compared to the larger LMs. Though many methods exist for producing LMs in the volume range above 2 μL, no reliable method exists to prepare fully coated submicroliter LMs with tunable volume. The situation becomes even more difficult when one attempts to produce tiny Janus Liquid Marbles (JLMs). This paper presents a simple, single-step, and efficient strategy for obtaining both the pristine LMs and JLMs in the volume range 200 nL to 18 μL. The core idea relies on the impact of a liquid drop on a particle bed at a Weber number of ∼55 to produce two daughter droplets and to convert these droplets into LMs/JLMs. The whole process takes only a few tens of milliseconds (∼50 ms). We have rendered the experimental schemes so that both the JLMs and pristine LMs can be produced in a single step, with control over their volume. The mechanical stability analysis of the prepared marbles indicates that 200 nL is 5 times more stable than 10 μL of LMs. The 0.72 μL LMs prepared with a 0.5 v/v % phenolphthalein indicator solution showed 3 times faster response time to ammonia gas sensing than 10 μL of LMs. The results presented in this work open up a new route for the rapid and reliable production of both multilayered LMs and JLMs with tunable volume in a wide range (200 nL to 18 μL).

New allotherian specimens from the Middle Jurassic Woodeaton Quarry (Oxfordshire) and implications for haramiyidan diversity and phylogeny

We report new allotherian tooth specimens from the Middle Jurassic White Limestone Formation at Woodeaton Quarry (Oxfordshire), United Kingdom. Two teeth are assigned to Kermackodon (=Eleutherodon) oxfordensis, a taxon whose original generic name (Eleutherodon) was preoccupied and is here assigned to Kermackodon to form a new binomial combination for the species name. Butlerodon quadratus gen. et sp. nov. (family Kermackodontidae), based on 13 cheek teeth and incisors, shows dental features intermediate between K. oxfordensis and the Late Triassic “haramiyidans” (Haramiyavia and Thomasia). Woodeatonia parva gen. et sp. nov. (family indeterminate), based on three teeth, is characterized by its small size. A second upper molar from a multituberculate is identified as Hahnotherium cf. H. antiquum, which possesses characters typical for multituberculates but distinctive from “haramiyidans”. The allotherian teeth from the Forest Marble Formation, previously assigned to the haramiyidans “Eleutherodon”, “Millsodon” and “Kirtlingtonia”, and the multituberculate Kermackodon, are reinterpreted as teeth from different upper or lower dental loci of the same haramiyidan species K. oxfordensis, which result in significant taxonomical modification of these allotherians (“haramiyidans” and multituberculates). Given that Kermackodon has been regarded as a transitional form between multituberculates and “haramiyidans”, these taxonomical modifications would affect interpretation of early evolution of allotherians. In a comparison of molars in known “haramiyidans”, we delve into their occlusal patterns and cusp homologies that have been controversial but pivotal for understanding evolution of allotherians. We further conduct the first phylogenetic analysis of haramiyidan species. The European Late Triassic species form the stem-ward taxa of “haramiyidans” and the Jurassic species from the United Kingdom are grouped with arboroharamiyids from the Yanliao Biota, China, and nested in “haramiyidans”. http://zoobank.org/urn:lsid:zoobank.org:pub:38F1FB5A-17A2-498F-B1FD-38D975548201 http://zoobank.org/urn:lsid:zoobank.org:act:FF5ADA10-C044-4541-ADA6-54448F17C673 http://zoobank.org/urn:lsid:zoobank.org:act:6E59071A-56DF-43D2-A140-2860465BFECA http://zoobank.org/urn:lsid:zoobank.org:act:CA2EE3CF-951C-450A-879D-2AE438F6BB2A http://zoobank.org/urn:lsid:zoobank.org:act:6B26D9C3-9FC3-4517-A1EF-51822067F970

Hierarchical liquid marbles formed using floating hydrophobic powder and levitating water droplets

HypothesisLiquid marbles i.e. droplets coated by hydrophobic particles may be formed not only on the solid substrates but also on the floating layers of hydrophobic powders such as fluorinated fumed silica or polytetrafluoroethylene. ExperimentsFormation and growth of liquid marbles on fluorinated fumed silica or polytetrafluoroethylene powder floating on a heated water-vapor interface is reported. Marbles emerge from condensation of water droplets levitating above the powder layer. FindingsThe kinetics of the growth of droplets is reported. Growth of droplets results from three main mechanisms: water condensation, absorption of small droplets and merging of droplets with neighboring ones. Growing droplets are coated with the hydrophobic powder, eventually giving rise to the formation of stable liquid marbles. Formation of hierarchical liquid marbles is reported. Growth of liquid marbles emerging from water condensation follows the linear temporal dependence. A phenomenological model of the liquid marble growth is suggested.

Levitating clusters of fluorinated fumed silica nanoparticles enable manufacture of liquid marbles: Co-occurrence of interfacial, thermal and electrostatic events

We report non-contact coating of water droplets with levitating clusters of fumed silica nanoparticles placed on a heated substrate. The coating process results in the formation of liquid marbles. We relate the observed phenomenon to the electrostatic attraction between a water droplet and levitating clusters of fumed silica nanoparticles. A water droplet dispensed from a polymer (polypropylene) micropipette almost always have an intrinsic positive electrical charge which promotes electrostatic attraction of the levitating fumed silica powder to the droplet. The role of the natural convection of air is discussed. The clusters of fluorinated fumed silica nanoparticles gain their surface charge under contact with humid air. A qualitative phenomenological theory of the effect is suggested. Formation of composite marbles, built of water droplets coated with a silicone oil layer containing the clusters of fumed silica nanoparticles, is also demonstrated.

Deformed liquid marble formation: Experiments and computational modeling

We consider the formation of liquid marbles via impact onto powder beds. Experimentally we analyze how much powder the surface of the drop is able to harvest and discover how this determines the threshold for marble formation. This motivates the development of the first mathematical model for this process and simulations based on this model qualitatively recover many features of the experiments, while also highlighting avenues for future research.

Stimulus Responsive Remotely Rupturable Adhesive Marbles Realized through a Hybrid Nanoparticle Concept.

Adhesive marbles, an innovative concept derived from liquid marble technology that is "remotely breakable on demand" by external stimuli, offer diverse application prospects. Therefore, a chemically linked superomniphobic hybrid perfluorinated carbon black-silica nanoparticle (PCBSN) was realized by functionalizing surface groups and used for encapsulating adhesives. PCBSN successfully encapsulated liquids and adhesives to form water (WM, contact angle 158°), epoxy (EM, contact angle 145°), and silicone (SM, contact angle 135°) marbles, regardless of the surface tension and polarity. Studies on the interface characteristics revealed that the work performed for marble formation maintained an inverse relationship with the surface energy of particles and the surface tension of encapsulated liquids. The marble formation energy was determined to be higher for EM (1.071 × 10-17 J) and lower for SM (0.946 × 10-17 J). Upon exposure to laser, marbles showed a rapid photothermal response, and the heat transferability on the surface of marbles followed the order SM > EM > WM. The marbles were remotely rupturable by regulating the applied laser power, with breaking time being tunable from <10 to 500 s. The photothermal efficiency (%) of marbles can be graded as good and falls in the range of 88.6 × 10-3 (EM) and 162.9 × 10-3 (SM) at 1.5 W laser power. The marbles possessed high mechanical integrity and repeated cyclability before breaking on the rolling impact test. These adhesive marbles formed from PCBSNs may represent attractive candidates for such applications as "bonding from a distance" through remote means.

Capillarity: revisiting the fundamentals of liquid marbles

Liquid marble, an emerging platform for digital microfluidics, has shown its potential in biomedical applications, cosmetics, and chemical industries. Recently, the manipulation and fundamental aspects of liquid marbles have been reported and attracted attention from the microfluidics community. Insights into their physical and chemical properties allow liquid marbles to be utilised in practical applications. This review summarises and revisits the effect of capillarity on the formation of liquid marbles and how it affects the effective surface tension as well as their robustness. The paper also systematically discusses the applied aspect of capillarity of the carrier liquid for transporting floating liquid marbles.

Monolayer Nanoparticle‐Covered Liquid Marble Production with Low Surface Tension Liquids

AbstractAs an emerging droplet system, monolayer nanoparticle‐covered (mNPc) liquid marbles have shown fascinating properties and application values. Their formation process has been clear, but liquid availability for production has yet to be clarified. This study addresses this issue from the angle of surface tension, revealing critical surface tension and contact angle values for mNPc liquid marble production with both rolling and compression methods. Water‐ethanol and water‐surfactant systems are employed as testing liquids. With irreversible pinning as criterion, critical surface tension values that allow mNPc liquid marble formation are obtained with the two kinds of liquids, forming ranges from 38.6 to 31.8 mN m−1, and from 36.7 to 27.6 mN m−1, for the rolling and compression methods, respectively. Correspondingly, contact angles in the ranges from 132° to 126° and from 116–124° are regarded as the lower limits for mNPc liquid marble production with the rolling and compression methods, respectively. In addition, rupture and deformation behaviors under low surface tension are systematically investigated and a depinning approach that facilitates marble formation is proposed. This study could provide important guidance for various applications that require low surface tension liquids to produce mNPc liquid marbles.

Core-Shell Beads as Microreactors for Phylogrouping of E. coli Strains.

Multiplex polymerase chain reaction (PCR) is an effective tool for simultaneous detection of target genes. Nevertheless, their use has been restricted due to the intrinsic interference between primer pairs. Performing several single PCRs in an array format instead of a multiplex PCR is a simple way to overcome this obstacle. However, there are still major technical challenges in designing a new generation of single PCR microreactors with a small sample volume, rapid thermal cycling, and no evaporation during amplification. We report a simple and robust core-shell bead array for a series of single amplifications. Four core-shell beads with a polymer coating and PCR mixture were synthesized using liquid marble formation and subsequent photo polymerization. Each bead can detect one target gene. We constructed a customised system for thermal cycling of these core-shell beads. Phylogrouping of the E. coli strains was carried out based on the fluorescent signal of the core-shell beads. This platform can be a promising alternative for multiplex nucleic acid analyses due to its simplicity and high throughput. The platform reported here also reduces the cycling time and avoids evaporation as well as contamination of the sample during the amplification process.

Electrostatic Transfer of Conductive Particles for the Formation of Liquid Marbles–Charge Transfer Behavior

The electrostatic method for liquid marble formation has shown great promise in allowing contactless particle delivery to pendent liquid droplets. However, size has been shown to be a significant l...

Particle Monolayer-Stabilized Light-Sensitive Liquid Marbles from Polypyrrole-Coated Microparticles

Liquid marbles are water droplets coated with solid particles that prevent coalescence and allow storage, transport, and handling of liquids in the form of a powder. Here, we report on the formation of liquid marbles that are stabilized entirely by a single monolayer of solid particles and thus minimize the amount of required solid material. As stabilizing particles, we synthesize relatively-monodisperse, 80 m-sized polystyrene (PS) particles coated with heptadecafluorooctanesulfonic acid-doped polypyrrole (PPy-C8F) shell (PS/PPy-C8F particles) by aqueous chemical oxidative seeded polymerization of pyrrole using FeCl3 as an oxidant and heptadecafluorooctanesulfonic acid as a hydrophobic dopant. We characterize the physicochemical properties of the particles as a function of the PPy-C8F loading. Laser diffraction particle size analyses of dilute aqueous suspensions indicate that the polymer particles disperse stably in water medium before and after coating with the PPy-C8F shell. X-ray photoelectron spectroscopy studies indicate the formation of a PPy-C8F shell around the PS seed particles, which was further supported by a deflated morphologies observed by scanning electron microscopy after extraction of the PS component from the PS/PPy-C8F particles. We investigate the capabilities of the dried PS/PPy-C8F particles to act as a liquid marble stabilizer. Stereo- and laser microscope observations, as well as gravimetric studies, confirm that the PS/PPy-C8F particles adsorb to the water droplet surface in the form of a particle monolayer with the characteristic hexagonal close-packed structure expected for spherical (colloidal) particles. Mechanical integrity of the liquid marble increases with an increase of PPy-C8F loading of the PS/PPy-C8F particles. The water contact angle of the PS/PPy-C8F particles at air-water interface increases from 82±12º to 102±17º with an increase of PPy-C8F loading. This increase in water contact angle directly correlates with the shape of the LM, with higher contact angles giving more spherical LMs. Furthermore, the broadband light absorption properties of the PPy coating was used to control evaporation rate of the enclosed water phase on demand by irradiation with a near infrared laser. The evaporation rate could be finely controlled by the thickness of the PPy-C8F shell of the particles stabilizing the liquid marbles.

Formation of liquid marbles &amp; aggregates: rolling and electrostatic formation using conductive hexagonal plates

A conductive coating is added to PET plates using a novel synthetic method and liquid marble manufactured using electrostatics forces.

Predictive Framework for the Spreading of Liquid Drops and the Formation of Liquid Marbles on Hydrophobic Particle Bed.

In this work, we have developed a model to describe the behavior of liquid drops upon impaction on hydrophobic particle bed and verified it experimentally. Poly(tetrafluoroethylene) (PTFE) particles were used to coat drops of water, aqueous solutions of glycerol (20, 40, and 60% v/v), and ethanol (5 and 12% v/v). The experiments were conducted for Weber number ( We) ranging from 8 to 130 and Reynolds number ( Re) ranging from 370 to 4460. The bed porosity was varied from 0.8 to 0.6. The experimental values of βmax (ratio of the diameter at the maximum spreading condition to the initial drop diameter) were estimated from the time-lapsed images captured using a high-speed camera. The theoretical βmax was estimated by making energy balances on the liquid drop. The proposed model accounts for the energy losses due to viscous dissipation and crater formation along with a change in kinetic energy and surface energy. A good agreement was obtained between the experimental βmax and the estimated theoretical βmax. The proposed model yielded a least % absolute average relative deviation (% AARD) of 5.5 ± 4.3 compared to other models available in the literature. Further, it was found that the liquid drops impacting on particle bed are completely coated with PTFE particles with βmax values greater than 2.