Mineral Carrier Research Articles

Synthesis and properties of morphologically interesting particles of zincite and periclase

Various particles based on zincite and periclase were prepared by thermal methods. In dependence on starting compounds, particles varying in shape and size were obtained. Synthesized particles were identified and determined by X-ray diffraction and Scanning Electron Microscope (SEM). Morphologically interesting particles of ZnO, MgO and ZnO, MgO layers on selected mineral carriers were applied to organic coatings for determination of its anticorrosive properties.

Sedimentology, clay mineralogy and grain-size as indicators of 65 ka of climate change from El’gygytgyn Crater Lake, Northeastern Siberia

El’gygytgyn Crater Lake, NE Siberia was investigated for sedimentological proxies for regional climate change with a focus on the past 65 ka. Sedimentological parameters assessed relative to magnetic susceptibility include stratigraphy, grain size, clay mineralogy and crystallinity. Earlier work suggests that intervals of high susceptibility in these sediments are coincident with warmer (interglacial-like) conditions and well-mixed oxygenated bottom waters. In contrast, low susceptibility intervals correlate with cold (glacial-like) conditions when perennial ice-cover resulted in anoxia and the dissolution of magnetic carrier minerals.

Fluid flow in the Duperow and Winnepegosis Formations, Williston Basin, Canada: Evidence from preliminary magnetic measurements

The Devonian Winnepegosis and Duperow Formations were examined in well 4-27-11-22W1, located in at the eastern edge of the Williston Basin in Manitoba. The variation in characteristic remanent magnetization (ChRM) direction and magnetic mineral carrier is obvious: the older Winnepegosis Formation has a primary or early post-depositional magnetization held in magnetite or pyrrhotite ( n = 15; D = 324.1°, I = − 27.3°, α 95 = 10.4°, k = 15.7), whereas the younger Duperow Formation magnetizations are carried by hematite and could be as late as Early Jurassic. The variability may be attributable to the intervening Prairie Evaporite acting as an aquitard to fluid migration.

Zinc sorption by some Torrifluvents soil of Sub-Saharian region South of Libya

Zinc sorption by four Torrifluvents soils from Sub-Saharian region, south of Libya was evaluated by equlibirating soil samples with concentrations of Zn covers a range of 0 to 320 ug/ml. Effect of zinc carrier were also examined by using two carriers i.e. sulphate and EDTA. Results obtained show that all soils have high affinity for Zn sorption. Sorption isotherm of L (high affinity) type was noticed with zinc sulpate wheras S (low affinity) type was noticed with EDTA. Curviline relation between sorped zinc and zinc concentration in solution was proved by excellent fit of sorption to Frundlich equation. High mean values for sorption coefficient were noticed with sulphate (2.658) compared to EDTA carriers (0.350), While low mean value for regression coefficient (1/n) for mineral carrier (0.354) was found compared to organic carrier (1.376). Sorption coefficient were significantly correlated with clay, silt, carbonate and organic matter contents in case of sulphate carrier only. While negatively correlated with carbonate and organic matter contents when EDTA was used.

Identification of Casein Phosphopeptides Released after Simulated Digestion of Milk-Based Infant Formulas

Adapted, follow-up, probiotic follow-up, toddler, and probiotic toddler infant formulas were subjected to an in vitro enzymatic procedure simulating physiological digestion. The formation and identification of casein phosphopeptides (CPPs) in the milk-based infant formulas were studied using reversed phase high-performance liquid chromatography coupled on line to an ion trap mass spectrometer. Most CPPs formed contained the cluster sequence SpSpSpEE, a mineral binding site. Phosphopeptide alpha(s2)-CN(1-19)4P was present in all formulas analyzed. Probiotic formulas released CPPs not detected in nonprobiotic formulas and probably formed by bifidobacteria action. These observations suggest that physiological digestion of these products promotes the formation of bioactive peptides with mineral carrier properties in the gastrointestinal tract, which resist further proteolysis.

Mineralogy and geochemistry of a Late Permian coal in the Dafang Coalfield, Guizhou, China: influence from siliceous and iron-rich calcic hydrothermal fluids

This paper describes the influence of siliceous and iron-rich calcic low-temperature hydrothermal fluids (LTHF) on the mineralogy and geochemistry of the Late Permian No. 11 Coal (anthracitic, R r=2.85%) in the Dafang Coalfield in northwestern Guizhou Province, China. The No. 11 Coal has high contents of vein ankerite (10.2 vol.%) and vein quartz (11.4 vol.%), with formation temperatures of 85 and 180 °C, respectively, indicating that vein ankerite and vein quartz were derived from low-temperature calcic and siliceous hydrothermal fluids in two epigenetic episodes. The vein quartz appears to have formed earlier than vein ankerite did, and at least three distinct stages of ankerite formation with different Ca/Sr and Fe/Mn ratios were observed. The two types of mineral veins are sources of different suites of major and trace metals. Scanning electron microscope and sequential extraction studies show that, in addition to Fe, Mg, and Ca, vein ankerite is the dominant source of Mn, Cu, Ni, Pb, and Zn in the coal, and the contents of these five elements are as high as 0.09% and 74.0, 33.6, 185, and 289 μg/g, respectively. In contrast, vein quartz is the main carrier mineral for platinum-group elements (PGEs) Pd, Pt, and Ir in the coal, and the contents of Pd, Pt, and Ir are 1.57, 0.15, and 0.007 μg/g, respectively. Sequential extraction showed a high PGE content in the silicate fraction, up to 10.4 μg/g Pd, 1.23 μg/g Pt, and 0.05 μg/g Ir, respectively. It is concluded that the formation of ankerite and quartz and the anomalous enrichment of trace elements in the No. 11 Coal in the Dafang Coalfield, Guizhou, result from the influx of calcic and siliceous low-temperature hydrothermal fluids.

Microencapsulated Short-Chain Fatty Acids in Feed Modify Colonization and Invasion Early After Infection with Salmonella Enteritidis in Young Chickens

Short-chain fatty acids (SCFA) are widely used as feed additives in poultry for the control of pathogenic bacteria, such as Salmonella enteritidis. Recently, a new range of products was developed in which SCFA are encapsulated in mineral carriers, resulting in a slow release during the transport of these carriers through the intestinal tract. To test the efficacy of this type of products against early colonization after Salmonella infection in poultry, a challenge experiment with S. enteritidis was performed. Five groups of 20 chickens were given feed with no supplement or feed supplemented with acetic acid (0.24%), formic acid (0.22%), or propionic acid (0.27%) as film-coated microbeads or butyric acid (0.15%) as spray-cooled microcapsules. The 5 groups were challenged with 5 x 10(3) cfu S. enteritidis at d 5 and 6 posthatch, and samples of ceca, liver, and spleen were taken at d 8 and analyzed for the number of colony-forming units of Salmonella per gram of tissue. Feed supplementation with acetic acid, and to a lesser extent formic acid, resulted in an increase of colonization of ceca and internal organs. Birds receiving propionic acid-coated microbeads as feed supplement were colonized with Salmonella to the same extent as controls. Butyric acid-impregnated microbeads in the feed, however, resulted in a significant decrease of colonization by S. enteritidis in the ceca but not in liver and spleen.

Results of rock magnetic investigations and relative paleointensity determinations on lacustrine sediments from Birkat Ram, Golan Heights (Israel)

Detailed rock magnetic investigations, including the analysis of the laboratory installed magnetizations, the measurement of hysteresis parameters, and the high temperature‐dependency of the saturation magnetization, were carried out on sediments from Birkat Ram, Golan Heights, Israel. The 550 cm long composite profile, composed of three single cores, is supposed to span the Late Holocene, i.e., the last 4400 years, at least. Titanomagnetites in the pseudo single‐domain range were identified as the main magnetic carrier minerals in the homogenous sediments. The variations in concentration and grain size of the magnetic fraction are only partly reflected in the sediment lithology. The relative paleointensity was estimated by normalizing the intensity of the natural remanent magnetization (NRM) after demagnetization at 20 mT (JNRM(20 mT)) by different concentration parameters. The median destructive field of the NRM (MDFNRM) is coherent with the relative paleointensity estimates, indicating that a sedimentary effect has not sufficiently been removed by the normalization process. The morphologies of these estimates, however, correspond to the archeomagnetic records from Bulgaria and Greece. Therefore a second normalization, based on the linear relationship between the paleointensity estimates and the MDFNRM, was applied, resulting in an improvement of the records.

Magnetic model of the central uplift of the Vredefort impact structure, South Africa

The Vredefort structure is the largest known impact structure on earth, with an original diameter estimated at—at least—250 km. The central uplift of this structure is about 80 km wide and contains a 40- to 50-km wide core of crystalline basement surrounded by a so-called collar of supracrustal sequences. Previous investigations of the structure of this large impact crater, based on integrated geophysical modeling, have shown that the central rise structure is an upper crustal feature with a presently recognized uplift of some 12 km, decreasing to about 4 km at the depth of the Moho. This study concentrates on the structure of the central uplift region (the Vredefort Dome), using aeromagnetic data along a SSW–NNE profile across its center. Available rock magnetic data were used to constrain the magnetic modeling. On the basis of this modeling, it is concluded that a 60- to 70-km wide region in the center of the structure experienced a magnetic overprint in connection with the impact event. This overprint is related to the occurrence of high-coercive magnetite and its subsequent thermal magnetization. Three sources for this thermal event are envisaged—the potential occurrence of a now eroded impact melt complex, the impact-related rise of hot crustal material of the crystalline core, and the thermal energy deposited by the shock wave. Thermal demagnetization of rocks from the crystalline core has shown that magnetite, most likely formed by shock dissociation of Mg–Fe silicates, is the dominant carrier mineral of the remanent magnetization. The thermal overprint has also included those parts of the upturned metasedimentary collar rocks, which contained suitable magnetic carrier minerals. Its present manifestation is the generally negative magnetic anomaly centered on, and encircling, the central uplift of the impact structure. Within the crystalline core, the magnetic models indicate structures of outward collapse along low-angle thrust surfaces. The impact event has, thus, caused an increased magnetic complexity both by drastic changes of the magnetic properties and by the structural perturbation of the upper crystalline crust.

Sheet silicates as effective carriers of heavy metals in the ophiolitic mine area of Vigonzano (northern Italy)

AbstractIn order to assess the role played by sheet silicates in controlling base metal distribution, the mineralogy of the <2 µm fraction of waste material, surface soils, and stream sediments was investigated in the surroundings of a pyrite-chalcopyrite mine area in northern Italy. The results indicate that smectite is very abundant in the <2 µm fraction of the tailings, and it exerts an effective control on the concentrations of Zn, Ni (and Cu). Normal soils and sediments are characterized by interstratified illite-smectite and by lower base metal concentrations. Away from the mine area, smectite decreases in the stream sediments, and chlorite becomes more important in controlling base metal distribution.Ni, Cr, Cu and Co increase with chlorite and talc, but are depleted in the <2 µm fraction compared to coarser fractions in the stream sediments, because the sand–silt fraction of sediments concentrates ophiolitic fragments, variably enriched in ores. A mechanical dispersion of chlorite is probably the controlling factor. Zinc displays a systematic enrichment in the clay fraction of waste material and in the stream sediments but the main mineral carrier is not identified.

A Study of Occurrences of Ag in Pb‐Zn‐Cu Ore Deposits in China

Abstract A systematic study of occurrences of silver in 156 Pb‐Zn‐Cu ore deposits indicates that silver mainly occurs in nonferrous metal ore deposits in forms of association and paragenesis. It occurs mainly as independent minerals in nature and occasionally as ion adsorption, isomorphous or amorphous silver minerals. Nearly 190 silver minerals have been discovered in China. Their shapes, constituents, textures, grain sizes, embedded types, distribution patterns, mineral assemblages and metallogenic series suggest that these characteristics are closely related to geneses of deposits and dependent of ore‐forming conditions. Pb, Zn and Cu sulphides are the main carrier minerals of silver. The partition of silver in ore is constrained by the mineralization intensity, grain size and embedded form of silver minerals and mineral assemblages.

Potassium, stardust, and the last supernova

No isotopic anomalies have yet been reported for K, but the relevant published literature is sparse and error limits for the scarce (0.01% abundance) isotope 40K are relatively large, 0.5 to 1%. We have developed thermal ionization mass spectrometric procedures by which error limits on 40K are an order of magnitude lower and applied them to analysis of a series of sequential dissolution fractions of the carbonaceous chondrites Orgueil (CI) and Murchison (CM), a sampling procedure known to reveal pervasive isotopic anomalies in Cr. Most of the fractions analyzed have 40K abundances that are normal (i.e., consistent with terrestrial composition) within analytical error limits. Whole–rock 40K abundances of Orgueil and Murchison are normal within about 1 permil or less. However, some dissolution fractions do exhibit evident isotopic anomalies, excesses of 40K up to about 35 ϵ. For K, as for Cr, the most plausible interpretation is that the anomalies reflect the presence of presolar grains that have not been thoroughly mixed with other solar system materials. In detail, the K anomalies do not correlate with the Cr anomalies, and thus probably represent different mineral carriers. Neither carrier phase is yet identified, but they differ from known and well-studied forms of presolar grains in that they are not acid-resistant. The isotopes of K are likely co-synthesized with some short-lived radionuclides, notably 26Al, the presence of which in the early solar system demands a “late” nucleosynthetic injection into the interstellar molecular cloud from which the solar system formed, no more than about 1 Ma before its collapse. It has been suggested that the distribution of 26Al (and other short-lived radionuclides) in early solar system materials was radically heterogeneous, perhaps because of the late injection. Because of its relatively short half-life (1.25 Ga), not in the “extinct radionuclides” range but still short compared to the age of the galaxy, 40K provides a usefully sensitive measure of the distribution of late nucleosynthetic additions to the solar system or its antecedent cloud. As a specific quantitative illustration, if a model 25-solar-mass supernova is invoked to account for observed levels of 26Al it will also provide about 1% of nebular 39K and about 3% of nebular 40K; the difference in the proportions of the K isotopes simply reflects the circumstance that by the time of solar system formation most of the 40K ever added to the sun’s precursor materials over the history of the galaxy had already decayed. There would be a 24‰ 40K anomaly between materials that did or did not incorporate such a contribution. The absence of so large a difference between the earth and the carbonaceous chondrites implies that they incorporate nearly the same amounts of any freshly synthesized K component of this magnitude. Unless some efficient mechanism for nebular scale chemical separation is postulated, the same should be true for co-synthesized nuclides such as 26Al.

Bioactive peptides in dairy products: synthesis and interaction with proteolytic enzymes

Food proteins are sources of peptides with various biological activities, such as opioids, mineral carriers, antihypertensives, immuno-stimulants, antithrombotics and antigastrics. These bioactive peptides are generated in vivo, in vitro and during food processing. Bioactive peptides are largely found in milk, fermented milks and cheeses. Proteolytic enzymes naturally occurring in milk, and enzymes from lactic acid bacteria or from exogenous sources contribute to the generation of bioactive peptides. Dairy processing conditions such as cheese ripening are also relevant. Once produced, bioactive peptides play a significant role in cheesemaking by selectively inhibiting proteolytic enzymes of lactic acid bacteria and subsequently affecting cheese quality. Sensitivity to inhibition is highly specific: enzymes of the same biochemical class and strains of the same species differ. Bioactive peptides also inhibit dairy spoilage enzymes.

Influence of physico-chemical properties of porous microcarriers on the adhesion of an anaerobic consortium

The ability for biomass colonization of four porous mineral microcarriers (sepiolite, clay, pozzolana and foam glass-Poraver), was studied and related to their surface properties. The surface hydrophobicity of the mineral carriers was a more important factor influencing colonization by the anaerobic consortium than was surface charge. It was possible to correlate linearly the degree of hydrophobicity with the biomass retention capacity. Although the thermodynamic theory did not explain adhesion, an increase in cell attachment was directly related to the decrease of the positive values of the free energy of adhesion. Surface roughness, porosity and the amount of surface Mg2+, were also determinant factors in bacterial immobilization. However a great biomass accumulation can originate a decrease in biological activity due to mass transfer limitations. Journal of Industrial Microbiology & Biotechnology (2000) 24, 181–186.

Geomagnetic events and relative palaeointensity variations during the past 300 ka as recorded in Kolbeinsey Ridge sediments, Iceland Sea: indication for a strongly variable geomagnetic field

Magnetostratigraphic analyses of five sediment cores recovered from the Kolbeinsey Ridge area revealed consistent records of several geomagnetic events linked with low relative palaeointensities within the past 300 ka. Interpretation of various rock magnetic parameters clearly rule out the possibility that the recorded non-normal polarity directions are linked to a deviating magnetomineralogical fraction or a distorted magnetic fabric. Therefore, these directions are interpreted as true recordings of geomagnetic field variations. Hysteresis parameters and thermomagnetic measurements revealed pure pseudo single-domain (PSD) magnetite with Curie temperatures of 580 °C as the dominant remanence carrier mineral. Due to the homogeneity of the rock magnetic parameters, the sediments are also suitable for relative palaeointensity determinations. Oxygen-isotope stratigraphies for two of the cores provided a time frame to estimate the age ranges for the recorded geomagnetic field variations. The obtained record of ten events of up to 12 ka duration during the past 300 ka and the related record of relative palaeointensity indicate a fairly dynamic character of the Earth's magnetic field, which is in clear contrast to published polarity time scales.

Geochemical studies on Dachang antimony ore deposit in Qinglong, Guizhou Province

The Dachang antimony deposit in Qinglong, Guizhou Province, is strictly controlled by the “Dachang Layer” which is a complex altered rock occurring at unconformity between the Permian Emeishan basalt and the Maokou limestone. Based on the studies of the hanging- and foot-wall rocks, the trace elements and REE contents of the rocks and ores and heavy placer minerals in the basalt, this paper is focused on the relations between these data and the “Dachang Layer” and its hanging- and foot-wall rocks. The author pointed out that the “Dachang Layer” and basalt are the source-beds of antimony; ilmenite and magnetite are the major mineral carriers of antimony. In the processes of halmyrosis and burial metamorphism of the “Dachang Layer” and basalt, antimony was mobilized along with the mobilization of iron and was preliminarily concentrated in the “Dachang Layer”.

Crude oil as carrier of gold: petrological and geochemical evidence from Lannigou gold deposit in southwestern Guizhou, China

Organic matter is related closely to mineralization of Lannigou gold deposit in southwestern Guizhou, China. Regionally, the distribution of organic carbon agrees well with that of faults within which gold deposits are hosted. Studies on organic petrology show that pyrobitumen, which is related most closely to mineralization, adheres to quartz vein or fills quartz veinlet. Proton-induced X-ray emission (PIXE) analysis shows an evident abundance of Au in pyrobitumen. Pyrobitumen paragenetically associates with pyrite and arsenopyrite which are the main carrier minerals of Au. The thermal simulation experiment indicates that about 99% of Au will be concentrated in oil phase in the coexisting system of oil and brine and rock. The role of crude oil in ore-forming process is: as carrier of Au, crude oil moves upwards, and undergoes thermal decomposition and thermochemical reduction when it encounters the oxidizing fluid within the Trassic turbidity; Au is thus released from crude oil, reduced and precipitated.

Indirect monitoring of heavy metals in volcanic gases by synchrotron X-ray microprobe (µ-SRXRF) qualitative analysis of sublimates

The results of a photon microprobe study carried out on incrustations and sublimates collected at active fumaroles of the Fogo Island volcano (Cape Verde Archipelago) following the eruption of April 1995 are reported. The mineral phases studied were previously identified by X-ray powder diffraction: sulfur, sodium and potassium chlorides, calcium sulfates with variable degrees of hydration and alums (hydrated Na/K Al-sulfates). Amongst the minor and trace elements detected, P, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Hg, Tl, Pb and Bi, the last four heavy metals may create an environmental concern due to their high toxicity. Thallium is reported for the first time as a chemical component of well identified minerals in volcanic fumarole sublimates, a result made possible by the unique characteristics of synchrotron radiation used in the photon microprobe. Chemical data are discussed taking into account the crystal structure of the carrier mineral phases. Comments are presented on possible geological implications of this micro-chemical study.

Interfacial interactions between nitrifying bacteria and mineral carriers in aqueous media determined by contact angle measurements and thin layer wicking

Contact angle measurements enable the determination of the surface free energy on flat and smooth solid surfaces. The thin layer wicking technique permits this determination for powdered materials. Both techniques were assayed on limestone and basalt which were the materials used as supports for bacterial adhesion. The resulting surface free energy components were compared. The free energy of interaction between nitrifying bacteria and support materials in aqueous medium (Δ G 132) was calculated and correlated with bacterial adhesion observed in a previous study. Although the values of the polar and apolar components were not exactly the same, both techniques lead to the same conclusions in terms of the ability for bacterial adhesion.

Electron microscopic and rock magnetic study of remagnetized Leadville carbonates, central Colorado

Thermal demagnetization of limestone and dolomite samples from the Lower Carboniferous Leadville Formation of central Colorado reveals four magnetization components, of which three (A, B, and C) are ancient. The syn-folding A component is found both in limestone and dolomite below about 350°C and yields a paleopole at 71.6°N, 203.3°E, near the Late Cretaceous to early Tertiary segment of the North American APWP. The B component is found only in the limestone and has a pole position at 68.5°N, 138.1°E in situ, and 51.6°N, 136.9°E after tilt correction. The in-situ pole and partially tilt-corrected poles (up to about 30% unfolding) resemble Middle–Late Jurassic paleopoles of cratonic North America. The C component is found only in the dolomite with paleopoles at 45.7°N, 110.0°E (in situ) and at 50.7°N, 112.8°E (after tilt correction). These poles fall near the Permian segment of the apparent polar wander path. The corresponding ages of these three magnetizations therefore are all younger than Early Carboniferous, indicating that they are all secondary magnetizations. A rock magnetic and electron microscope study was successful in linking these multiple remagnetizations to identifiable magnetic mineral carriers, which helps to infer the authigenesis in the carbonates. Unblocking temperatures of the natural remanent magnetizations (NRM) and three-component isothermal remanent magnetizations (3D-IRM) indicate that pyrrhotite and magnetite are the major magnetic carriers of the NRM. Electron microscopy of magnetic extracts revealed magnetite spherules and fine-grained magnetite growing on quartz, albite, and chlorite, whereas electron microscopy of thin sections revealed goethite, hematite, pyrite and pyrrhotite in addition to magnetite. Demagnetization characteristics of NRM and rock magnetic experiments are inconsistent with hematite or goethite carrying a detectable ancient remanent magnetization, and the magnetite spherules are unlikely to carry any magnetization other than the recent magnetic overprint. Pyrrhotite is a likely chemical remanence carrier of the Late Cretaceous–early Tertiary A magnetization in both dolomite and limestone samples. Non-spheroidal iron oxides are observed in scanning and transmission electron microscopy in three forms: (1) as grains on the boundary of residual dolomite and dedolomite, inferred to be magnetite and carrying the B magnetization; formation of this magnetite appears to be related to Jurassic dedolomitization; (2) as fine-grained iron oxide inclusions within calcite, dolomite, or bitumen veins; or (3) as fine-grained magnetite growing on secondary minerals such as quartz, albite, and chlorite. The inclusions in dolomite have been shown by selected-area electron diffraction (SAED) to be magnetite and are inferred to carry the C magnetization acquired during late Paleozoic dolomitization; the iron oxide inclusions in calcite and bitumen resemble those in the dolomite and may also be magnetite, but they could not be analyzed by SAED. The fine-grained magnetite growing on secondary minerals, surprisingly, contains small amounts of titanium and manganese; this observation has to our knowledge not been reported before for authigenic magnetite. The ulvöspinel content ( x) in these titanomagnetites (Fe 3− x Ti x O 4) ranges from 0 to 0.15. This study shows that electron microscope observations can successfully identify some of the magnetic carriers in multiply remagnetized carbonates, even if they are submicrometer in size.