Marble Formation Research Articles

Palaeontology, stratigraphy and sedimentology of Woodeaton Quarry (Oxfordshire) and a new microvertebrate site from the White Limestone Formation (Bathonian, Jurassic)

Woodeaton Quarry in Oxfordshire has previously yielded a number of large sauropod vertebrae and other (unpublished) dinosaur remains from a horizon in the Rutland Formation. No review of the wider terrestrial fauna from Woodeaton has been published to date. Here we present an overview of new material recovered from a microvertebrate site at the top of the White Limestone Formation (Middle Jurassic, Bathonian, Great Oolite Group, Retrocostatum Zone) and review the stratigraphy to provide a comprehensive local stratigraphic framework and place the quarry in the correct regional context. The terrestrial fauna is similar to that found from other UK Bathonian microvertebrate sites and includes probable dromaeosaurid theropods, ornithischians, tritylodontids and mammaliaforms such as amphitheriids, docodonts, ‘eutriconodonts’, ‘haramyids’ and multituberculates. Placement of the White Limestone Formation boundaries are clarified with respect to the Rutland and Forest Marble Formations. This indicates that the microvertebrate bed from Woodeaton is slightly older than that of the well-known mammal bed from nearby Kirtlington Quarry.

Influence of particle size on extraction from a charged bed - toward liquid marble formation.

The interactions between particles and the role of their physical properties are not well understood for the electrostatic formation of liquid marbles. Here we focus initially on the impact of increasing particle diameter (notionally 20 to 140 μm) on the ease of particle extraction from an advancing bed of charged particles beneath an earthed, suspended water droplet. A larger particle diameter increased the ease of extraction, due to decreased interparticle cohesion, with increased potential applied to the particle bed. Whilst particle extraction is a crucial step in liquid marble formation, transport to the droplet and subsequent coating and stabilisation of the liquid is also significant. Further investigation highlighted that the smaller particle diameters afforded increased liquid stabilisation due to increased coverage and smaller interstitial spaces between particles on the liquid surface. Optimal conditions for controllable liquid marble formation using electrostatics was postulated as a trade-off between drop-bed separation distance, applied potential and kinetics of coating when studying impact of particle size. Furthermore, preliminary modelling, utilising weakest-link statistics and fracture mechanics, of the experimental data was undertaken to focus on development of the relationship between particle properties and extractability in the presence of electrostatics. This model represents a step towards predicting the suitability of particles for use in the electrostatic formation of liquid marbles prior to undertaking experimental work.

Multidisciplinary approach in the study of marble quarries in the Apuan Alps

The Apuan Alps (Northern Tuscany, Italy) represent the world’s most important marble mining area, with historical significance and particular geomechanical rocks properties. A detailed knowledge of existing marble rock volumes is required in proper planning and management of mining activities. The aim of this study is the3D reconstruction of marble formation, taking into consideration the polyphasic deformation history of the Apuan Alps. This goal is pursued through a multidisciplinary approach: geological mapping is integrated with the most modern photogrammetric, GIS (Geographic Information System) and 3D modeling technologies. The project is carried out in different work-stages: i) aerial photo-interpretation; ii) geological field-survey; iii) revision and integration with new data of the existent geological maps; iv) creation of three-dimensional model of marble ore. The photo-interpretation phase is carried out in 3D by means of ESRI™ ArcGIS Pro 1.4 suite with the support of DTMs (Digital Terrain Models) and orthophotos at high spatial resolution (up to 5 cm ground pixel); then, through detailed geological mapping, critical data collected in the previous phase is verified. The integrationof previous activities leads to the updating and correction of the currently available geological maps and leads to the production of serial geological cross-sections necessary for the creation of 3D models related to both surface and underground geology. Models have been built within Rhinoceros 5.0®code. Final aim of present work is the calculation of marble formation volumes in some defined areas, with a view to proper manage the resource, as well as to plan the mining activities.

Petrofabric of forsterite marbles and related rocks from a low-pressure metamorphic terrain (Almadén de la Plata massif, Ossa-Morena Zone, SW Spain) and its kinematic interpretation

A fabric study of forsterite marble and calc-silicate rock paragenetic minerals is presented for samples collected in the Almadén de la Plata massif of SW Spain, that experienced Variscan low-pressure metamorphism related to the tectonic evolution of the suture between the Ossa-Morena and South-Portuguese zones of the Iberian Massif. Two tectonically stacked metamorphic units contain marble, metacarbonate and variably impure dolomitic rocks that record contrasting thermal conditions of the upper greenschist (structuraly upper unit) and the upper amphibolite/granulite facies (structuraly lower unit). Different reactional paths lead to formation of forsterite marbles in both units. Dolomite and calcite petrofabrics disclose their contrasting rheological behaviour during syn-metamorphic ductile deformation under temperatures between 500 and 700 °C. Dolomite formed (harder) porphyroclast systems and boudinaged bands, whereas weaker calcite underwent dynamic recrystallization. In both cases deformation was facilitated by activation of various intracrystalline slip systems, complemented by other deformation mechanisms. The fabrics of other paragenetic metamorphic minerals also denote crystal plasticity and exhibit close geometrical relationships with respect to the macroscopic foliation and mineral/stretching lineation, including a systematic asymmetry suggestive of non-coaxial deformation components. Foliations and lineations are interpreted as solid-state flow planes and directions bearing a kinematic significance. In particular, regional sinistral shear at mid-deep crustal realms coeval with low-pressure metamorphism explains the imbrication of metamorphic units and their exhumation, concomitant with the overall wrench tectonic framework ruling the tectonic evolution of the Ossa-Morena/South-Portuguese suture between the late Devonian (∼360 Ma) and the latest Carboniferous (∼300 Ma).

Liquid Marbles as an Easy-to-Handle Compartment for Cell-Free Synthesis and In Situ Immobilization of Recombinant Proteins.

Liquid marble (LM), a self-standing micro-scale aqueous droplet, emerges as a micro-bioreactor in biological applications. Herein, the potential of LM as media for cell-free synthesis and simultaneous immobilization of recombinant proteins is explored. Initially, formation of hydrogel marble (HM) by using an enzymatic disulfide-based hydrogelation technique is confirmed by incorporating three components, horseradish peroxidase (HRP), a tetra-thiolated poly(ethylene glycol) derivative, and glycyl-L-tyrosine, in LM. The compatibility of the enzymatic hydrogelation with cell-free protein synthesis in LM is then validated. Although the hydrogelation reduces the level of protein synthesis in LM when compared with that in a test tube, the biosynthesis of enhanced green fluorescent protein (EGFP) is achieved. Interestingly, EGFP synthesized in LM is entrapped in the HM, and the introduction of a cysteine residue to EGFP by genetic engineering further increases the amount of protein immobilization in the hydrogel matrices. These results suggest that the cell-free synthesis and HRP-catalyzed hydrogelation can be conducted in parallel in LM, and the eventual entrapment of the key components in HM is possible. Facile recovery of macromolecular products immobilized in HM by degrading the hydrogel network under reducing conditions should lead to the design of an easy-to-handle system to screen protein functions.

Liquid marble formation and solvent vapor treatment of the biodegradable polymers polylactic acid and polycaprolactone

Liquid Marbles were produced by rolling aqueous droplets on a powder bed of biodegradable polymers, namely polylactic acid (PLA), polycaprolactone (PCL) and blends of these. Solvent vapor treatment was subsequently applied with dichloromethane (DCM). This treatment aligned the polymer chains in order to form a smooth polymeric shell with enhanced mechanical and barrier properties. Whilst a wide range of potential applications for Liquid Marbles exists, the aim here is to encapsulate a solution containing a fertilizer, i.e. urea to produce a controlled release fertilizer. The influences of droplet volume, polymer particle size and solvent vapor treatment time on the liquid marble properties were investigated. Crystallinity and thermal properties were analyzed by differential scanning calorimetry (DSC), surface characteristics and shell thickness by scanning electron microscopy (SEM), mechanical strength and elasticity by compression tests and evaporation rates by thermogravimetric analysis (TGA).

GEOPHYSICAL RESEARCH FOR GEOLOGICAL STRUCTURE DETERMINATION IN THE REGION OF SOUTH MESOGHEIA (ATTICA)

During the last years the broader area of Koropi (Mesogheia-Greece), has faced rapidly increasing problems concerning irrigation and watering of the town, due to the brackish water in the water supply boreholes. Our main target is to determinate the subsurface geological structure of the study area, located NE of the Koropi city, where alterations of schists and carbonates, from three different post-alpine units, mainly appear and relate it with the groundwater flow paths. The dominant geological outcrops of the area are the Athenian Schist (Laurion-Attica Unit), the dolomitic marbles (Vari-Kirou Pira Unit) and the Lower Marble (Hymittos Unit). A geophysical research was carried out in the area mainly based on the geoelectrical methodology, including by executing fifteen Vertical Electrical Soundings and one Electrical Resistivity Tomography. The interpretation results of the geophysical data have been evaluated and combined with “in-situ” resistivity measurements and calibrated with cores coming from drilled boreholes revealing the area. Through this combining process important elements of the local geological subsurface structure have been determined, as the formation of the dolomitic marbles (massive or karstified) was found tilting southwards beneath the Athenian Schist. From a hydrogeological point of view, this alone adds a significant parameter to the subsurface geological structure which is highly related to the groundwater flow that is responsible for many problems and could be used for solving many others.

Metamorphic temperature investigation of coexisting calcite and dolomite marble––examples from Nikani Ghar marble and Nowshera Formation, Peshawar Basin, Pakistan

Using marble samples from the Nikani Ghar marble and Nowshera Formation from Northern Pakistan the determination of the temperature of metamorphism was undertaken with the help of calcite-dolomite solvus geothermometer. Two types of marbles, that is, calcite-dolomite marble and quartz-bearing calcite-dolomite marble were selected. Petrographic and scanning electron microscope analysis of dolomite samples indicated different grain sizes. X-ray diffraction technique indicated the calcites MgCO3 content up to 7.93 mol.%. Nikani Ghar marble samples have shown lower contents of MgCO3 as compared to samples from Nowshera Formation. The calcite-dolomite-quartz marble has also showed relatively lower MgCO3 content and hence rather low temperature (~500 °C). The temperature reached during peak metamorphism of the investigated marble occurrence, based on calcitedolomite solvus was 628 °C. Metamorphic temperatures derived from the present study were shown as a linear graph and values were in good agreement with the published literature.

Electrostatic formation of liquid marbles - Influence of drop and particle size

We report the first study of the influence of drop and particle size on the electrostatic manufacture and subsequent stability of liquid marbles. It is clear from this study that the ‘rules’ for electrostatic formation of liquid marbles are quite different for those for conventional direct-contact manufacture. Formation of liquid marbles was observed when an earthed water drop of volume 3–7μL was brought into proximity with a bed of highly-charged polystyrene particles of diameter 22–153μm. Under appropriate conditions the particles jumped to and coated the drop, producing a particle-liquid aggregate that dropped to the bed surface in the form of either a stable liquid marble or a particle-stabilised sessile drop. The subsequent evolution of the physical dimensions of the metastable aggregate was measured as the liquid drained into the bed, and its stability assessed. Formation of stable liquid marbles appeared to occur more easily for smaller drops and larger particles, and some of these considerably exceeded the conventionally-understood limit for the ratio of particle to drop size of stable liquid marbles.

Heterogeneous growth of calcite at aragonite {001}- and vaterite {001}-melt interfaces: A molecular dynamics simulation study

Crystal growth at the interface between a calcium carbonate (CaCO3) crystal and its melt at a high temperature of 1500K is investigated by means of a molecular dynamics simulation. The simulation is performed for the interfaces of a calcite {104} plane, aragonite {001}, {100}, and {010} planes, and vaterite {001}, {110}, and {100} planes. The growth from a pure melt and that from a melt containing Mg2+ are examined. Calcite growth occurs on the calcite {104} plane, aragonite growth occurs on the aragonite {100}, and {010} planes, and vaterite growth occurs on the vaterite {110} and {100} planes. However, the heterogeneous growth of calcite occurs on the {001} plane of aragonite and vaterite, irrespective of the presence of Mg2+. The results advance our understanding of geological processes that occur at high temperature, such as the formation of CaCO3 crystals from carbonatite magma and the formation of marble. Moreover, the results provide useful information for the control of CaCO3 crystal formation in material design.

Superhydrophobic Particles Derived from Nature-Inspired Polyphenol Chemistry for Liquid Marble Formation and Oil Spills Treatment

Nature has given us great inspirations to fabricate high-performance materials with extremely exquisite structures. Presently, particles with a superhydrophobic surface are prepared through nature-inspired polyphenol chemistry. Briefly, adhering of a typical polyphenol (tannic acid, widely existed in tea, red wine, chocolate, etc.) is first conducted on titania particles to form a multifunctional coating, which is further in charge of reducing Ag+ into Ag nanoparticles/nanoclusters (NPs/NCs) and responsible for grafting 1H,1H,2H,2H-perfluorodecanethiol, thus forming a lotus-leaf-mimic surface structure. The chemical/topological structure and superhydrophobic property of the as-engineered surface are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), water contact angle measurements, and so on. On the basis of the hierarchical, superhydrophobic surface, the particles exhibit a fascinating capability to form liquid marble and sh...

Spreading, encapsulation and transition to arrested shapes during drop impact onto hydrophobic powders

We present findings from an experimental study of the impact of liquid droplets onto powder surfaces, where the particulates are hydrophobic. We vary both the size of the drop and impact speed coupled with the size range of the powder in order to assess the critical conditions for the formation of liquid marbles, where the drop becomes completely encapsulated by the powder, and arrested shapes where the drop cannot regain its spherical shape.By using different hydrophobization agents we find that a lower particle mobility may aid in promoting liquid marble formation at lower impact kinetic energies. From observations of the arrested shape formations, we propose that simple surface tensions may be inadequate to describe deformation dynamics in liquid marbles.

Superhydrophobic magnetic poly(DOPAm-co-PFOEA)/Fe3O4/cellulose microspheres for stable liquid marbles.

Novel magnetic superhydrophobic cellulose-based microspheres were fabricated using poly(DOPAm-co-PFOEA), which provide remarkable stability to liquid marbles with various liquids for liquid droplet transportation and manipulation.

Geology and metallogeny of Jordanian uranium deposits

Uranium mineralisation has been known within the Hashemite Kingdom of Jordan for a long time and in 2014 maiden mineral resources were estimated for the Central Jordan Uranium Project (CJUP) following the reporting principles of the JORC Code (). Based on this estimate the CJUP contains 269 mt of mineralisation at an average grade of 135 ppm U3O8 (36·4 kt of contains U3O8) within an Inferred Resource. The objective of this paper is to describe the geology and the metallogeny of uranium mineralisation in Jordan, providing new insights into this mineralisation that remains largely unknown outside of the country. Most of Jordan's territory is covered by platform sedimentary rocks that generally formed during the Cretaceous and Paleogene. The majority of uranium mineralisation is confined to Upper Cretaceous sediments, in particular the Al Hisa Phosphorite (AHP) and the Muwaqqar Chalk Marl (MCM) formations. The MCM formation hosts surficial type-mineralisation that is mainly concentrated in a narrow, approximately 4·5 m thick layer that is distributed close to the topographic surface and is independent of phosphorite beds. This mineralisation, termed ‘surficial’, is the economically most important type of uranium in Jordan and currently represents the main exploration target in this area. The main uranium minerals within the surficial layer are uranium vanadates, colloquially referred as carnotite group minerals. The average uranium grade rapidly decreases below a depth of 4–5 m, although mineralisation continues to depths of 30–40 m. Beneath the surficial layer, uranium mineralisation is distributed as lenses that are generally small and discontinuous. This mineralisation, termed ‘Deep’, has many common features with the surficial mineralisation, including similar mineralogy and chemical composition and may represent a transition between surficial and phosphorite-hosted types. The metallogeny of surficial uranium mineralisation is well studied, although several important questions remains unanswered. In particular, close spatial relationships between pyrometamorphic marbles and the uranium mineralisation can be observed on regional geological maps and in the field. Two different models have been proposed to explain the formation of the pyrometamorphic marbles in central Jordan, namely the burning of bituminous marls and an alternative model involving the combustion of deep reservoirs of hydrocarbon gases relating to mud volcanoes. Tectonic faults have also possibly played a role in the distribution of uranium mineralisation in central Jordan. This is in particular relevant for the Khan Azabib area where higher grade mineralisation and their associated gamma anomalies are broadly coincident with regional faults. These faults may have acted as permeable zones, facilitating migration of the hyperalkaline solutions that leached uranium from the host rocks. Eventually, the liberated uranium was redistributed by supergene processes towards the surface, where uranium minerals precipitated along the contact between saprolite and fresh to weakly weathered rocks. In summary, the uranium deposits of Central Jordan resulted from the interplay of sedimentary, tectonic, and metamorphic events, with the final impact made by climatic factors and chemical weathering processes. The AHP formation hosts phosphorite-hosted type mineralisation that formed as a result of the synsedimentary concentration of uranium in apatite and is abundant in the Hasa–Qatrana area of central Jordan. The surficial parts of the phosphorite-hosted uranium mineralisation have also been partially modified by weathering, which has released uranium from apatite and redistributed and precipitated it as ‘carnotite’. This type of mineralisation is present at the Sahb El Abyad prospect located in the south-eastern part of Jordan. Uranium mineralisation also occurs in hydrothermal veins that cross-cut Cambrian rocks exposed along the plate margin in the Dead Sea rift valley. This mineralisation type is different to the mineralisation within the central Jordanian deposits and it is rare in Jordan, so far being found only in the Dana area.

Dynamics of a Liquid Droplet on a Granular Bed of Microstructured Particles: From Lens Formation to Marble Effect

We explore the dynamics and morphologies of a droplet permeation on a loosely bound granular bed composed of microporous or micropatterned particles. Naturally abundant particles such as Cycas revoluta (sago), Papaver somniferum (poppy), and Sinapis alba (mustard) have been employed to prepare homogeneous and heterogeneous porous-granular beds. The experiments uncovered that a highly porous bed of mustard particles could stabilize a static water lens by pinning the three-phase contact line of the droplet on the micropatterned particle surface. Interestingly, a water-lens could transform into a “liquid marble” when the bed was composed of smaller poppy particles with a micropatterned surface. Simulations uncovered that an upward convective current due to the deformation and recoil of the droplet together with the vertical component of the capillary force near the pinned contact line helped the poppy particles to climb on the water-lens to form the liquid marbles. A bed of microporous sago particles were also found to show a phenomenon similar to the marble effect in which the particles remained partially or fully embedded inside the drop-surface. Simulations uncovered that an air current issuing out of the porous bed due to droplet permeation enforced microporous particles dislodging from the bed. Heterogeneous porous-granular beds composed of poppy-crushed sago particles showed the two different types of marble effects occurring simultaneously from different sides of the same droplet. The study on the kinetics of the drop permeation showed that the rate of permeation was much slower when the drop passed through the bed–air interface than when the droplet was already inside the bed. Addition of surfactant to the water droplet resulted in a faster permeation rate, which also ensured a smaller lifetime for the lens and marble formation. In comparison, an increase in viscosity could kinetically stabilize the lens and delay the formation of the marble. Concisely, the study uncovered a multitude of interesting dynamics of droplets over granular beds composed of particles with microporous and micropatterned surfaces.

Spontaneous self-coating of a water drop by flaky copper powders: critical role of the particle shape.

The self-coating process of solid particles over a liquid drop is important for the formation of a liquid marble. Generally, some external forces such as rolling or flipping are used to cover a drop by small particles. In this work, it is observed that flaky copper powders can spontaneously spread over the planar water surface and form a dense flat cluster with a fractal dimension of 2. Moreover, flaky copper powders can cover the water pendant and sessile drops spontaneously and rapidly. This powder-coated drop can roll on an inclined plane at a relatively high speed. However, spontaneous self-coating disappears for spheroidal copper powders. To explain our observations, the shape factors of particles are introduced into the spreading coefficient S for powders on the liquid surface. The flaky powders have the lowest shape factors and therefore spontaneous self-coating formation, with S > 0.

Liquid marbles supported by monodisperse poly(methylsilsesquioxane) particles.

The preparation of model, well-controlled colloidal assemblies has been a central approach to understanding and optimizing the characteristics and functionality of complex colloidal dispersion systems. This approach, which has created a significant literature and rather deep understanding for emulsions and foams, has yet to be established for the liquid marble (water-in-air) motif. In this article we report the preparation of well-controlled liquid marbles using monodisperse micron-size particles of poly(methylsilsesquioxane) (PMSQ). The low cohesive nature of the stabilizing particles, their narrow size distribution, and their hydrophobicity permit the formation of liquid marbles containing a particulate monolayer with a hexagonally close-packed (HCP) structure. The "cleaning process" by rolling of liquid marbles under a flow of air on a hydrophobic substrate was useful to obtain the monolayer structure. Moreover, the monolayer structure was only obtained from liquids with high surface energy, whereas the others were not useful even though multilayered structure was formed from liquids that have intermediate surface energy.

Liquid marble granulation using super-hydrophobic powders

This work analyses the forces involved in liquid marble formation, primarily the surface energy of the powder on the liquid surface and the powder gravitational force, which we have shown to oppose liquid marble formation. In order to investigate these phenomena, hydrophobic powders possessing both high density and high contact angle need to be employed. For this purpose, superhydrophobic (SH) particles based on a copper substrate were prepared by a silver deposition technique of particle sizes 9, 20, 320 and 400μm having a contact angle with water approaching 160°. Liquid marbles formed using the SH copper substrate were compared with polymer powder (e.g., PMMA) based liquid marbles. Initially, the effective surface tension of the liquid marbles was determined using the maximal height methodology, which indicated that effective surface tension was a function of powder particle size. It is probable that the phenomena of heavy particles give rise to lower effective surface tension, is caused by the weight of the particles reducing the puddle height. Moreover, it was found that in cases with large dense SH powder particles, liquid marble formation was not possible, as the additional weight of the larger particles, lowered the “puddle” to an extent that marble became unstable and collapsed. Therefore, an analysis of the energies associated with the powder particles was undertaken to quantify the physical characteristics of powders that form liquid marbles under: (i) static and (ii) dynamic conditions. In addition, we have correlated this data using a regime map analysis in which we have plotted a surface energy versus a gravitational energy to provide operating regions within the regime map of potential liquid marble formation.

Complexity from Simplicity: Unique Polymer Capsules, Rods, Monoliths, and Liquid Marbles Prepared via HIPE in Microfluidics

Existing methods for preparing complex particles, i.e., hollow porous, depend on either multiple steps or a complex reactor design. Here, a straightforward method to prepare unique polymer particles with complex shapes via the use of simple equipment and readily available chemicals is reported. Beads, capsules, and rods with uniform size and interconnected pores are obtained through the formation of high internal phase emulsion (HIPE) droplets in a microfluidic channel. The method is applicable to a broad range of (meth)acralates. Controlling physical properties, such as viscosity and emulsion stability, is key to control the shape of the resulting particles. Post‐modification of the particles via click chemistry, their application in liquid marble formation, and their use as droplet reactors are also demonstrated.

Supergluing MOF liquid marbles

Growth of NH(2)-MIL-53(Al) on alumina microparticles followed by post-synthetic modification with perfluorooctyl or caproic groups produces highly hydrophobic microparticles which are utilized for the formation of liquid marbles. Interfacial polymerization of ethyl-2-cyanoacrylate on the surface of the liquid marbles produces stable liquid capsules.