Formation Of Manganese Research Articles

Highly siderophile element and Re-Os isotope systematics of a Neoproterozoic Iron Formation and its temporal relation to glaciation events

The Urucum iron- and manganese formation (IF-MnF) in the Santa Cruz Formation, Brazil, was deposited in a glacially influenced, late Neoproterozoic depositional environment. It has proven to be a reliable and robust archive for the late Neoproterozoic, allowing unique insights into the composition of seawater during an interval that is characterized by dramatic changes in the Earth’s litho-, hydros-, atmo-, and biosphere, including several episodes of low-latitude glaciations. Here we present highly siderophile element data of the Urucum IF-MnF to evaluate elemental sources that affected the Neoproterozoic seawater from which the Urucum IF-MnF precipitated. High uncertainties associated with current dating attempts of this formation overlapped with the Marinoan glaciation (∼650–635 Ma) as well as the Gaskiers glaciation event (∼580 Ma). A Re-Os regression line defined by iron-, manganese-, and chert-rich samples of the Urucum formation is interpreted as an isochron, yielding a refined age estimate of 577 ± 38 Ma and an initial 187Os/188Os ratio of 0.122 ± 0.003. The proposed depositional age overlaps with previous published age data of the Urucum IF-MnF, but relates the Urucum IF-MnF to the Ediacaran Gaskiers glaciation and overlaps with the age of the Shuram CIE (∼567 Ma). An initial 187Os/188Os ratio of 0.122 ± 0.003 is interpreted to represent pristine Neoproterozoic seawater and supports strong hydrothermal input, probably related to rifting, that promoted ferruginous conditions in the Urucum seawater.In an alternative scenario, Re-Os isotope data for the Urucum IF-MnF could also be interpreted in a multi-component mixing scenario, defined by hydrothermally influenced water masses that sourced most metals within the Urucum basin and a crustal component that entered the Urucum seawater either as detrital admixture or via riverine loads. Although none of the scenarios can be ruled out, we consider the isochron scenario as more plausible.

Artificial Manganese Metalloenzymes with Laccase-like Activity: Design, Synthesis, and Characterization.

Laccase is an oxidase of great industrial interest due to its ability to catalyze oxidation processes of phenols and persistent organic pollutants. However, it is susceptible to denaturation at high temperatures, sensitive to pH, and unstable in the presence of high concentrations of solvents, which is a issue for industrial use. To solve this problem, this work develops the synthesis in an aqueous medium of a new Mn metalloenzyme with laccase oxidase mimetic catalytic activity. Geobacillus thermocatenulatus lipase (GTL) was used as a scaffold enzyme, mixed with a manganese salt at 50 °C in an aqueous medium. This leads to the in situ formation of manganese(IV) oxide nanowires that interact with the enzyme, yielding a GTL-Mn bionanohybrid. On the other hand, its oxidative activity was evaluated using the ABTS assay, obtaining a catalytic efficiency 300 times higher than that of Trametes versicolor laccase. This new Mn metalloenzyme was 2 times more stable at 40 °C, 3 times more stable in the presence of 10% acetonitrile, and 10 times more stable in 20% acetonitrile than Novozym 51003 laccase. Furthermore, the site-selective immobilized GTL-Mn showed a much higher stability than the soluble form. The oxidase-like activity of this Mn metalloenzyme was successfully demonstrated against other substrates, such as l-DOPA or phloridzin, in oligomerization reactions.

Anodic dissolution and passivation of manganese monosilicide in fluoride-containing sulfuric acid solutions

The purpose of this study was to investigate the anode resistance of manganese monosilicide MnSi in fluoride-containing sulfuric acid solutions and the concentration effect of sodium fluoride on the anodic dissolution and passivation of the silicide. The study was carried out on a single-crystal MnSi sample in 0.5 M H2SO4 + (0.0025−0.05) M NaF solutions. The study presents micrographs and elemental composition of the electrode surface after anodic polarization from E corrosion to E = 3.2 V in 0.5 M H2SO4 and 0.5 M H2SO4 + 0.05 M NaF solutions. A stronger etching of the electrode surface was observed in the presence of fluoride ions; elemental analysis showed an increase in the oxygen content in certain areas of the silicide surface associated with the formation of manganese and silicon oxides and their partial removal at high polarization values. The kinetic regularities of the MnSi-electrode anodic dissolution were studied by the methods of polarization, capacitance, and impedance measurements. It was established that the addition of fluoride ions leads to weaker barrier properties of the silicon dioxide surface film, which determines the high silicide resistance in a fluoride-free medium. The order of the reaction was calculated for the MnSi anodic dissolution for NaF depending on the potential. In the region of low anodic potentials (from Ecor to E ≈ –0.2 V), the reaction order ranged from 1.8 to 1.1, which was due to the high influence of silicon in the composition of the silicide and its oxidation products. With an increase in the polarization value (up to E = 0.9 V), the reaction order decreased to 0.5. An increase in the contribution of manganese ionization and oxidation reactions to the kinetics of the anodic dissolution of the silicide was observed. The silicide passivation in a fluoride-containing electrolytewas characterized by higher values of the dissolution current density (10–4−10–3 A/cm2) as compared to a fluoride-free electrolyte (10–6 A/cm2), the reaction order in region of the passive state was ~1.0. Passivation was due to the formation of MnO2 and SiO2 oxides on the surface. In the transpassivation region (E ≥ 2.0 V), there was a weak dependence of the current density on the concentration of fluoride ions. Oxygen release was observed on the surface of the electrode, and the formation of MnO4 – ions was recorded in the near-electrode layer. The article discusses mechanisms and kinetic regularities of anodic processes on an MnSi-electrode in sulfuric acid solution in the presence of fluoride ions

Reductive Retrocyclization of a Mangana(II)cyclopentasilane to Form Manganese(0) Bis(η2-disilene) Complexes.

Ligand-exchange reactions on a mangana(II)cyclopentasilane complex that contains two THF ligands with aryl isocyanides led to the formation of manganese(0) bis(η2-disilene) complexes via a retrocyclization. In stark contrast, ligand-exchange reactions with CNtBu, an N-heterocyclic carbene, or pyridine-based ligands furnished manganese(II) complexes wherein the manganacyclopentasilane framework remained intact. The thermolysis of the obtained bis(η2-disilene) complex in the presence of mesityl isocyanide led to the formation of a cyclotetrasilane via the formal dimerization of the two η2-disilene moieties. The insertion of a mesityl isocyanide into the Mn-Siβ bond results in the formation of a manganese(II) complex supported by a [SiCSi]-type tridentate ligand scaffold.

Reductive Retrocyclization of a Mangana(II)cyclopentasilane to Form Manganese(0) Bis(η2‐disilene) Complexes

AbstractLigand‐exchange reactions on a mangana(II)cyclopentasilane complex that contains two THF ligands with aryl isocyanides led to the formation of manganese(0) bis(η2‐disilene) complexes via a retrocyclization. In stark contrast, ligand‐exchange reactions with CNtBu, an N‐heterocyclic carbene, or pyridine‐based ligands furnished manganese(II) complexes wherein the manganacyclopentasilane framework remained intact. The thermolysis of the obtained bis(η2‐disilene) complex in the presence of mesityl isocyanide led to the formation of a cyclotetrasilane via the formal dimerization of the two η2‐disilene moieties. The insertion of a mesityl isocyanide into the Mn−Siβ bond results in the formation of a manganese(II) complex supported by a [SiCSi]‐type tridentate ligand scaffold.

Deep eutectic solvent mediated synthesis of Mn-based hybrid electrocatalyst for oxygen evolution reaction: Insights into the effect of anion on the evolution of structure-activity

In this work, sulfur-doped manganese (S-Mn/CP) pre-catalysts supported by carbon paper (CP) were prepared from choline chloride/ethylene glycol-based deep eutectic solvent containing different manganese salts via electrodeposition method. The effect of anions, including NO3–, Cl-, SO42-, CH3COO–, and crystal water (H2O), on the evolution of the structure and OER activity of as-prepared Mn-based pre-catalysts was analyzed. It turns out that the NO3– and H2O can be reduced during the electroreduction of Mn(II) species and induce the formation of manganese oxide/hydroxide. Thiourea (TU), used as a sulfur source, decomposes at the cathode and releases S2-. The TU and H2O replace the Cl- in the [Mn(Cl)6]4- to form [Mn(Cl)6-x(H2O)x]x-4 and [Mn(Cl)6-x-y(TU)y(H2O)x]x+y-4 complexes, promoting the electroreduction of Mn(II) species. The OER intrinsic catalytic activity of the amorphous Mn3O4 pre-catalyst is 16.3 times lower than that of the metallic Mn0 pre-catalyst in a 1.0 M KOH solution. After annealing in an argon atmosphere, the surface of metallic Mn0 is in-situ converted into Mn3O4 and exhibits superior activity (0.0395 A g−1 cm-2ECSA) than the ordinary Mn3O4 electrode (0.0088 A g−1 cm-2ECSA). This study brings insights into the effect of anion on the evolution of structure-activity of Mn-based pre-catalysts during the electrodeposition and OER catalytic process.

Phase diagrams of oxide system FeO–MnO–MgO–SiO2. Report 1. Binary oxide systems MnO–SiO2 and MgO–SiO2

Manganese and silicon are present in almost any steel, and magnesium can enter the metal from the lining and magnesian slags or be introduced in the form of an alloy, so knowledge of the thermodynamics and phase equilibria of liquid and solid silicate solutions allows to predict the appearance of non-metallic inclusions in steel. The FeO–MnO–MgO–SiO2 system includes six double and four triple phase diagrams of oxide systems. The binary phase diagrams of FeO–MnO, FeO–MgO, FeO–SiO2, and MnO–MgO oxide systems were previously studied. In this work, the phase diagrams of the MnO–SiO2 and MgO–SiO2 systems were considered, the liquidus lines and thermodynamic data on the melting of manganese and magnesium silicates – the enthalpies and entropies of melting of ortho- and metasilicates of manganese (Mn2SiO4 and MnSiO3) and magnesium (Mg2SiO4 and MgSiO3) were calculated. The theory of subregular ionic solutions, which takes into account the dependence of the coordination number on the melt composition, is used to calculate the activities of the components of the oxide melt and accurately describes the diagrams with two immiscible liquids and is consistent with the experimental data presented in the literature. The obtained data on the energy parameters of the theory of subregular ionic solutions for the systems MnO–SiO2 and MgO–SiO2, as well as the thermodynamic data on the formation of manganese and magnesium silicates, make it possible to proceed to the study of ternary oxide systems belonging to the FeO–MgO–MnO–SiO2 system.

Phase diagrams of oxide system FeO–MnO–MgO–SiO2. Report 1. Binary oxide systems MnO–SiO2 and MgO–SiO2

Manganese and silicon are present in almost any steel, and magnesium can enter the metal from the lining and magnesian slags or be introduced in the form of an alloy, so knowledge of the thermodynamics and phase equilibria of liquid and solid silicate solutions allows to predict the appearance of non-metallic inclusions in steel. The FeO–MnO–MgO–SiO2 system includes six double and four triple phase diagrams of oxide systems. The binary phase diagrams of FeO–MnO, FeO–MgO, FeO–SiO2, and MnO–MgO oxide systems were previously studied. In this work, the phase diagrams of the MnO–SiO2 and MgO–SiO2 systems were considered, the liquidus lines and thermodynamic data on the melting of manganese and magnesium silicates – the enthalpies and entropies of melting of ortho- and metasilicates of manganese (Mn2SiO4 and MnSiO3) and magnesium (Mg2SiO4 and MgSiO3) were calculated. The theory of subregular ionic solutions, which takes into account the dependence of the coordination number on the melt composition, is used to calculate the activities of the components of the oxide melt and accurately describes the diagrams with two immiscible liquids and is consistent with the experimental data presented in the literature. The obtained data on the energy parameters of the theory of subregular ionic solutions for the systems MnO–SiO2 and MgO–SiO2, as well as the thermodynamic data on the formation of manganese and magnesium silicates, make it possible to proceed to the study of ternary oxide systems belonging to the FeO–MgO–MnO–SiO2 system.

The Formation and Transformation of Manganese Oxide Minerals on the Surface of Kaolinite

AbstractThe formation of manganese (Mn) oxides is influenced by environmental conditions and, in some red soils, Mn oxides occur as coatings on the surface of kaolinite particles in the form of colloidal films or fine particles. The present study aimed to explore the types of formation mechanisms of Mn oxide minerals on the surface of kaolinite. Mn oxide minerals synthesized by reducing the Mn in KMnO4 with a divalent Mn salt (MnSO4) were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of various initial molar ratios of Mn2+/Mn7+ (R = 1:0.67, 1:1, 1:2, and 1:4), cationic species (Na+ or Mg2+), synthesis temperatures (30, 60, and 110°C), and amount of added kaolinite (0.25, 0.5, 1.0, 2.0, and 5.0 g) on the formation of Mn oxides were studied. The results showed that Mn oxide mineral types were affected by the initial R value and the background cation. With decreases in the initial R value, the synthesized minerals transformed from cryptomelane to birnessite. The relative mass ratios of kaolinite to Mn oxide were calculated as 1:0.92, 1:0.63, 1:1.15, and 1:1.63. The sodium cation (Na+) had a greater role than Mg2+ in promoting the dissolution–recrystallization of birnessite to cryptomelane. The synthesis temperature had no effect on mineral types, but Mn content increased as temperature increased. When the amount of added kaolinite was increased from 0.25 to 5.0 g, Mn oxide minerals formed gradually and transformed from birnessite to cryptomelane. This work revealed a possible formation process and reaction mechanism on the surface of kaolinite particles in some red soils.

Formation of inorganic liquid gallium particle-manganese oxide composites.

Gallium (Ga) is a low melting point post-transition metal that, under mild mechanical agitation, can form micron and submicron-sized particles with combined fluid-like and metallic properties. In this work, an inorganic network of Ga liquid metal particles was synthesised via spontaneous formation of manganese (Mn) oxide species on their liquid metallic surfaces forming an all-inorganic composite. The micron-sized Ga particles formed by sonication were connected together by Mn oxide nanostructures spontaneously established from the reduction of a Mn salt in aqueous solution slightly above the melting point of Ga. The formed Mn oxide nanostructures were found to coalesce from the surface of the Ga particles into a continuous inorganic network. The morphology of the composites could be altered by varying the Mn salt concentration and by performing post-treatment annealing. The composites presented a shell of various Mn oxide nanostructures including wrinkled sheets, rods and nanoneedles, around spherical liquid Ga particles, and a liquid metal core. The photoelectric and optical properties of the composites were thoroughly characterised, which revealed decreasing bandgaps and valence band edge characteristics as a function of increased Mn oxide coverage. The photoluminescence properties of the composites could be also engineered by increasing the Mn oxide coverage. The all-inorganic liquid Ga composite could be formed via a straightforward reduction reaction of a Mn-rich salt at the surface of liquid Ga particles with tunable surface properties for future optoelectronic applications.

Thermal Migration Promotes the Formation of Manganese and Nitrogen Doped Polyhedral Surface for Boosted Oxygen Reduction Electrocatalysis.

Increasing the oxygen reduction reaction (ORR) catalytic activity of carbon-based electrocatalysts with robust stability is of great significance for their application. Herein, a feasible thermal migration strategy was proposed to construct manganese- and nitrogen-doped carbonaceous polyhedron frameworks coupled with manganese monoxide microrods (MnO-NC). Mn species were migrated to the surface of polyhedron frameworks, the shape of which was maintained at the high-temperature treatment. The Mn thermal migration not only created highly dispersed Mn-Nx active sites but also promoted graphitization, which benefited ORR electrocatalysis. Moreover, the MnO microrod-supported polyhedron frameworks provide beneficial mass transfer channels for electrocatalysis. Therefore, MnO-NC exhibited impressive ORR catalytic activity and stability in both alkaline and neutral electrolytes compared to commercial Pt/C catalysts. A magnesium-air battery (MAB) driven by MnO-NC delivered a high open circuit voltage and peak power density comparable to that driven by Pt/C. Notably, MnO-NC-driven MAB possessed a longer discharge time than the Pt/C-driven one, indicative of the superior catalytic performance of Mn-NC. This work provides a simple but effective strategy to construct carbonaceous framework electrocatalysts for boosted ORR, promoting the widespread application of metal-air batteries and fuel cells.

Ultrasonic treatment enhances the formation of oxygen vacancies and trivalent manganese on α-MnO2 surfaces: Mechanism and application

Catalytic activity is the main obstacle limiting the application of peroxymonosulfate (PMS) activation on transition metal oxide catalysts in organic pollutant removal. Herein, ultrasonic treatment was applied to α-MnO2 to fabricate a new u-α-MnO2 catalyst for PMS activation. Dimethyl phthalate (DMP, 10 mg/L) was almost completely degraded within 90 min, and the pseudofirst-order rate constant for DMP degradation in the u-α-MnO2/PMS system was ∼7 times that in the initial α-MnO2/PMS system. The ultrasonic treatment altered the crystalline and pore structures of α-MnO2 and produced defects on the u-α-MnO2 catalyst. According to the XPS, TG, and EPR results, higher contents of trivalent Mn and oxygen vacancies (OVs) were produced on the catalyst surfaces. The OVs induced the decomposition of PMS to produce 1O2, which was identified as the main reactive oxygen species (ROS) responsible for DMP degradation. The u-α-MnO2 catalyst presented great reusability, especially by ultrasonic regeneration of OVs toward the used catalyst. This study provides new insights into regulating OVs generation and strengthening catalyst activity in the PMS activation process for its application in water purification.

Linking the formation of varves in a eutrophic temperate lake to meteorological conditions and water column dynamics

Despite varved sediments being widely used for paleolimnological studies, little information is available about how climate and meteorological signals are recorded in varves at sub-seasonal to annual scale. We investigate links between meteorological and limnological conditions and their influence on biochemical varve formation and preservation of sub-seasonal climate signals in the sediments. Our study site is postglacial Lake Żabińskie located in NE Poland, in which thick and complex varved sediments have been studied for the last decade. These sediments provide an excellent material for studying the influence of short-term weather conditions on geological records. For this, we use an almost decade-long (2012–2019) series of observational data (meteorological conditions, physicochemical water parameters, and modern sedimentation observations) to understand varve formation processes. Then we compare these results with a high-resolution biogeochemical proxy dataset based on μXRF and hyperspectral imaging (HSI) measurements of a varved sediment core spanning the same period. Here we show direct links between the meteorological and limnological conditions and varve formation processes. This is particularly the case for air temperature which governs calcite laminae formation and primary production. We further show that calcite grain size is influenced by lake mixing intensity resulting from the wind activity, and that holomixis events lead to the formation of distinct manganese (Mn) peaks in the typically anoxic sediments. Our findings show that high-resolution non-destructive spectroscopy methods applied to complex biochemical varves, in combination with long observational limnological datasets, provide useful information for tracking meteorological and limnological processes in the past.

Solution Equilibria Formation of Manganese(II) Complexes with Ethylenediamine, 1,3-Propanediamine and 1,4-ButanediaMine in Methanol

Manganese is an abundant element that plays critical roles and is at the reaction center of several enzymes. In order to promote an understanding of the behavior of manganese(II) ion with several aliphatic ligands, in this work, the stability and spectral behavior of the complexes with manganese(II) and ethylenediamine, 1,3-propanediamine or 1,4-butanediamine were explored. A spectrophotometric study of its speciation in methanol was performed at 293 K. The formation constants obtained for these systems were: manganese(II)-ethylenediamine log β110 = 3.98 and log β120 = 7.51; for the manganese(II)-1,3-propanediamine log β110 = 5.08 and log β120 = 8.66; and for manganese(II)-1,4-butanediamine log β110 = 4.36 and log β120 = 8.46. These results were obtained by fitting the experimental spectrophotometric data using the HypSpec software. The complexes reported in this study show a spectral pattern that could be related to a chelate effect in which the molar absorbance is not directly related to the increase in the carbon chain of the ligands.

Hydrogeochemical characteristics, sources and human health risk assessment of heavy metal dispersion in the mine pit water–surface water–groundwater system in the largest manganese mine in Ghana

This study was conducted to appraise the hydrogeochemical characteristics and sources of heavy metals and the probable human health risks associated with the consumption of water contaminated with heavy metals in the mine pit water–surface water–groundwater system in the Nsuta manganese mining area in western Ghana. Therefore, a total of 29 samples were collected for hydrochemical analysis and the hydrochemical data was interpreted using multivariate statistical analysis. The results indicate that the pH of water in the mine pit water–surface water–groundwater system is slightly acidic to alkaline in nature. The groundwater evolved from Ca-Mg-SO4, Ca-Mg-HCO3-SO4, Ca-Mg-Na-Cl to Ca-Na-Cl-HCO3 water type with other mixed types, reflecting intense water–rock interaction and dissolution of rocks belonging to the Banded Manganese Formation and the Birimian metasediments in the area. The water is supersaturated with respect to goethite and hematite, pointing to precipitation and dissolution of these minerals. The Water Hazard Index values range from 0.20 to 30.5, implying minimal to extreme toxicity of the water. The mine pit water shows very high Fe, Mn, Ni, As and Sb concentrations, which resulted in hydromorphic dispersion of the heavy metals to the surface water and groundwater. The computed Hazard Index values show higher values (>1) in the surface water and mine pit water, and the carcinogenic risk is low in the groundwater, high in the surface water and extremely high in the mine pit water. Therefore, appropriate control and remedial measures should be urgently put in place to safeguard the health of the people.

Study of Manganese Recovery in the CaO-SiO<sub>2</sub>-MgO-Al<sub>2</sub>O<sub>3</sub>-MnO-Fe<sub>2</sub>O<sub>3</sub> System by Thermodynamic Simulation

The results of thermodynamic simulation of the manganese recovery in the CaO-SiO2-MgO-Al2O3-MnO-Fe2O3 system by carbon are presented. Parameters of the initial system are temperature range 1400-at a step of , a total pressure of 0.1 MPa, and N2. The composition of the oxide system is corresponded by the manganese ore (wt %) 1.1 MnO2, 44.3 MnO, 28.4 CaO, 9.3 SiO2, 5.4 MgO, 0.3 Al2O3, 11.2 Fe2O3 and silicomanganese slag. It contains (wt %) 16.3 MnO, 18.4 CaO, 52 SiO2, 7.8 MgO, 5.26 Al2O3, and 0.24 FeO. The amount of silicomanganese slag in the system was 0, 5, 12, and 25%. Carbon is used as a reducing agent. Its consumption is increased by 5% from the stoichiometry for the recovery of Fe and Mn and by 8% of the metal mass for the formation of iron, manganese, and silicon carbides. The simulation is carried out using HSC Chemistry 6.12 () software package. The thermodynamic characteristics of the Fe3C, Fe2O3, FeO, MnO2, Mn, Mn3C, Mn5C2, Mn7C3, Mn23C6, and SiC compounds existing in the database are refined. It was determined that an increase in the melt temperature from 1400 to increases the degree of manganese recovery (ηMn) for all compositions of the systems. An increase of the silicomanganese slag content in the mixture from 0 to 25% decreases ηMn from 89.3 to 85% at and from 95.8 to 91.5% at . The chemical composition of the high-carbon ferromanganese alloy is (wt %): 71.9-72.8 Mn, 16.6-17.9 Fe, 0.015-1.64 Si, and 9-. The simulation results can be used to develop a technology for producing a high-carbon ferromanganese when silicomanganese slag is involved in metallurgical processing.

Rechargeable zinc-ion batteries with manganese dioxide cathode: How critical is choice of manganese dioxide polymorphs in aqueous solutions?

In this work, different MnO2 polymorphs are applied as cathodes in zinc-ion batteries (ZIBs). All the polymorphs result in similar electrochemical behavior in weak acidic (1 М) ZnSO4 aqueous solutions at comparable specific capacity (200–225 mAh g−1), similar charge–discharge curves, and temporal stability owing to an irreversible modification of the pristine positive electrode during battery charge and discharge. This irreversibility stems from the dissolution and re-deposition of MnO2 and the formation of new manganese and zinc compounds (basic salt deposits such as ZnMn2O4, Mn2O3, and MnOOH). The additional (new) MnO2 phase is formed via two routes: disproportionation of Mn+3 ions formed during the discharge process and anodic oxidation of Mn2+ ions in a solution. According to X-ray diffraction and Raman spectroscopy analyses, the re-deposited MnO2 is in an amorphous state. The amorphous MnO2 covers the surface of the initial crystalline particles and affects the electrochemical behavior of the ZIBs. The strong pH dependence of the electrochemical response of the MnO2 electrodes is related to the H+ concentration effect on ionic equilibria in this system, such as the formation of basic zinc and manganese salts and hydroxides as well as the disproportionation of Mn+3 and anodic oxidation of Mn+2.

Technological importance of asteroid mining

With the ever-growing demands of the population and the ever-growing world of consumption and technology, the resources of the planet Earth are limited. According to Cohen (2007), some of the Earth's major resources, such as metals and minerals needed to develop the technology and food industries, may be depleted within the next 40-50 years, based on known terrestrial reserves and increased consumption. For industrial and technological development of humanity, new discoveries are needed in future realization as well as future discoveries. Asteroids are celestial bodies of scientific importance to reveal the formation, chemical composition and evolution of the Solar System. As the name implies, "Near Earth Asteroids", metal have been found to be potentially close to possible because they are sufficiently close and can be found in precious metals and minerals. The reservoirs of important substances such as water, metals and semiconductors can be found in these celestial bodies. Although the Asteroids and the Earth are composed of the same elements, the Earth's relatively stronger gravity has attracted all the heavy elements to its core over time. An asteroid rain deprived of such valuable elements results in the formation of gold, cobalt, iron, manganese, molybdenum, nickel, osmium, palladium, platinum, rhenium, radium, ruthenium and tungsten elements (from the core to the surface). Today, these metals are extracted from the Earth's crust and are required for economic and technological advancements. Therefore, the geological history of the Earth can be a very good step for the future of asteroid mining.

Formation and magnetic properties of low-temperature phase manganese bismuth prepared by low-temperature liquid phase sintering in vacuum

Low-temperature phase manganese bismuth (LTP-MnBi) was synthesized by low-temperature liquid phase sintering in ultrahigh vacuum at 275, 325 and 375 °C. The magnetic and structural properties of the sintered MnBi powders with two sets of different particle size ranges (<20 μm and 20–53 μm) were studied. It was found that the smaller particles exhibit twice the coercivity (Hc), with approximately 15% lower saturation magnetization, compared to the larger ones. Powder LTP-MnBi with a maximum Hc of 4.98 kOe could be produced at sintering temperature of 325 °C. The elemental depth profile in the MnBi layers at the inside-surface of the cracks in Mn powder particles were measured by using scanning electron microscopy combined with energy dispersive X-ray spectroscopy. MnBi is seeded at cracks through which liquid Bi flows during sintering and grows via diffusion. Variation of the liquid Bi flow rate in cracks results in a distribution of effective diffusion lengths. The diffusion coefficient was estimated from the maximum diffusion length to be 3.47 × 10-14, 7.68 × 10-14 and 15.30 × 10-14 cm2/s at 275, 325 and 375 °C, respectively. The coefficient follows a well-known Arrhenius equation with the pre-exponential factor of 5.33 × 10-10 cm2/s and activation energy of 0.45 eV.

The Bastar Craton of Central India: Tectonostratigraphic evolution and implications in global correlations

The Bastar Craton occupies a key position in the Peninsular India, being located between three cratonic nuclei of India, the Dharwar Craton in the southwest, the Singhbhum Craton in the northeast, and the Bundelkhand Craton in the northwest. The southeastern and the northern margins of the craton are bordered by the Proterozoic orogenic belts constituting the Eastern Ghats Mobile Belt and the Central Indian Tectonic Zone (the Satpura Mobile Belt), respectively. Analysis of the tectonostratigraphic evolution of the craton indicates the formation of the craton during Paleoarchean Era (~3582 Ma). The Archean evolution of the craton is marked by the development of granite-greenstone belts containing chemogenic sediments (Banded Iron Formations) and gold mineralisation . High-grade gneisses and granulites were developed during three orogenic episodes in the terrane (~2700 Ma Bailadila orogeny , ~2900 Ma Bengpal orogeny and ~3400 Ma Sukma orogeny). The Paleoproterozoic evolution of the craton is gleaned from the record of siliciclastic, volcaniclastics and chemogenic precipitates (carbonates, Banded Manganese Formation, and Banded Iron Formation) on the northern margin of the craton, which were deposited during the Great Oxidation Event (GOE; 2500–2300 Ma) and Paleoproterozoic glaciation (2400–2300 Ma) as well as immediately after the GOE (2050–1850 Ma). Effects of orogenic activities in the adjacent mobile belts are marked by the metamorphic and magmatic activities affecting the rocks at the margin of the craton. The Satpura orogenic event on the northern margin of the craton led to the amalgamation of the Bastar Craton with the Bundelkhand Craton at ~2250 and ~2100 Ma, forming the major part of the Peninsular India. Orogenic collapse (extension) developed basins transverse to the orogenic trend, where clastic, volcaniclastic and chemogenic sediments (Khairagarh and Chilpi Groups) were deposited. The southeastern margin of the craton has records of migmatisation and granite emplacement during the Eastern Ghats orogeny at ~1700 Ma. A number of sedimentary basins , aligned along a line parallel to the Eastern Ghats Mobile Belt, were developed during the orogenic collapse of the Eastern Ghats. Later orogenic activities along the Eastern Ghats were responsible for the development of depositional hiatus/unconformity within these sedimentary basins of the craton. Mafic dykes of different generations (2400 Ma, 2100 Ma and 1890 Ma) cutting across the Archean basement complex provide suitable markers for paleomagnetic reconstructions of the craton. The Archean and early Paleoproterozoic rock assemblages and mineralisation patterns in the craton show a broad similarity with the Western Australian Craton, indicating near-neighbourhood positions of the two ancient cratonic blocks. Paleomagnetic studies have shown the separation of these two blocks at ~2000 Ma, with the development of a paleo-ocean which closed subsequently during the amalgamation of the Bastar Craton with the East Antarctic Shield to form the Eastern Ghats Mobile Belt in three phases at ~1700–1600 Ma, ~1050–950 Ma and ~500 Ma, with extensional phase between 1450 and 1100 Ma. The Bastar Craton preserves important clues regarding the evolution of the ocean and atmospheric conditions in the early Earth. • The Bastar and Yilgarn Cratons were juxtaposed at ~2400 Ma. • Bundelkhand-Pilbara Cratons collided with Bastar-Yilgarn Cratons at ~2000 Ma. • Satpura-Singhbhum-Capricorn Orogen developed at ~2000 Ma. • No collision/accretion took place along the CITZ after ~1800 Ma. • New tectonic model for 1950–1000 Ma is proposed for Bastar-Yilgarn Cratons.