Manganese Deposits Research Articles

Hepatic encephalopathy on magnetic resonance imaging and its uncertain differential diagnoses: a narrative review.

Hepatic encephalopathy (HE) is a severe neuropsychiatric abnormality in patients with either acute or chronic liver failure. Typical brain magnetic resonance imaging findings of HE are bilateral basal ganglia high signal intensities due to manganese deposition in chronic liver disease and hyperintensity in T2, fluid-attenuated inversion recovery, or diffusion-weighted imaging (DWI) with hemispheric white matter changes including the corticospinal tract. Low values on apparent diffusion coefficient mapping of the affected area on DWI, indicating cytotoxic edema, can be observed in acute HE. However, neuropsychological impairment in HE ranges from mild deficits in psychomotor abilities affecting quality of life to stupor or coma with higher grades of hepatic dysfunction. In particular, the long-lasting compensatory mechanisms for the altered metabolism in chronic liver disease make HE imaging results variable. Therefore, the clinical relevance of imaging findings is uncertain and differentiating HE from other metabolic diseases can be difficult. The recent introduction of concepts such as "acute-on-chronic liver failure (ACLF)," a new clinical entity, has led to a change in the clinical view of HE. Accordingly, there is a need to establish a corresponding concept in the field of neuroimaging diagnosis. Herein, we review HE from a historical and etiological perspective to increase understanding of brain imaging and help establish an imaging approach for advanced new concepts such as ACLF. The purpose of this manuscript is to provide an understanding of HE by reviewing neuroimaging findings based on pathological and clinical concepts of HE, thereby assisting in neuroimaging interpretation.

The Late Cretaceous Goft manganese deposit, southwest Sabzevar basin, Iran: geological, geochemical, and modelling evidence for a low-temperature exhalative origin into an oxic seafloor basin

The Late Cretaceous Goft manganese deposit, southwest Sabzevar basin, Iran: geological, geochemical, and modelling evidence for a low-temperature exhalative origin into an oxic seafloor basin

Petrogenesis and 40Ar/39Ar dating of hydrothermal romanechite from the sub-aerial fault-related Romanèche Mn deposit (France)

This study discusses the hydrothermal formation of romanechite (Ba0.7Mn4.5O10.1.1H2O) in the Romanèche Mn deposit and the significance of its age by combining ore petrogenesis and 40Ar/39Ar ages. Romanechite occurs as a minor phase in various manganese deposit types and remains poorly studied in comparison with other K-bearing Mn oxides (i.e., coronadite group) because of its scarcity, small grain size, intermixing and poor crystallinity. The fault-controlled Romanèche Mn deposit (Massif Central, Eastern France) investigated herein exhibits a well-crystallized and late stage massive romanechite ore occurring in a quartz-barite-fluorite gangue. Petrographical and geochemical data support manganese ore formation under sub-aerial conditions with temperatures close to fluorite precipitation (100–200 °C) and characterized by a Mn-Ba-W-As association. Five out of the eight studied samples have produced 40Ar/39Ar plateau ages ranging from 25.2 ± 0.3 to 18.2 ± 0.5 Ma. Despite a low K content (0.1–0.6 wt% K), the good crystallinity of romanechite due to its epithermal formation likely favours a better production and/or retention of the radiogenic argon than poorly crystallized phases of supergene origin. Therefore, the dataset identifies a period of at least c. 7.6 My of discontinuous hydrothermal activity, which is consistent with graben-related fault reactivation and likely volcanic activity in the Massif Central. Ultimately, this study confirms the feasibility of romanechite 40Ar/39Ar dating.

The paleoenvironmental implications of pre-Great Oxidation Event manganese deposition in the Mesoarchean Ijzermijn Iron Formation Bed, Mozaan Group, Pongola Supergroup, South Africa

The Ijzermijn Iron Formation Bed occurs in the Vlakhoek Member of the basal Sinqeni Formation of the Mesoarchean Mozaan Group of the Pongola Supergroup of southern Africa. It represents the oldest known supracratonic Superior-type iron formation that has significant manganese enrichments. Lithostratigraphic correlation between the Mozaan Group and the Witwatersrand Supergroup indicates that there was a larger Witwatersrand-Mozaan depositional basin on the Kaapvaal Craton during the Mesoarchean. Detailed stratigraphy, mineralogy, petrography, carbonate mineral chemistry, major and trace element geochemistry and carbonate oxygen and carbon isotopes are presented for two drill cores intersecting the Ijzermijn Iron Formation Bed. Drill core PMH 24, which represents a more coast-distal depositional setting, is characterized by manganese-rich siderite, higher Fe2O3 and lower MnO and Al2O3 contents, more prominent europium anomalies, lower GdSN/YbSN values and less depleted δ13CPDB values. Drill core DDN 1, which represents a more coast-proximal depositional setting, is characterized by iron-rich rhodochrosite, lower Fe2O3 and higher MnO and Al2O3 contents, less prominent europium anomalies, higher GdSN/YbSN values and more depleted δ13CPDB values. The presence of early diagenetic magnetite, hematite and 13C-depleted carbonates indicate the iron and manganese, which were sourced from hydrothermal plumes, were deposited by oxidation, with subsequent diagenetic reduction by organic carbon. The most efficient oxidative mechanism would have been biological oxidation. The increase in manganese contents towards the paleocoastline further supports manganese oxidation as it was redox buffered by Fe2+ in the water column and could only be deposited and preserved once Fe2+ had been removed through oxidation further away from the distal hydrothermal plume source. This is supported by previously published iron isotope data, where δ56/54Fe values are more depleted closer to the paleocoastline. Deposition of iron and manganese was restricted to below the photic zone. This implies that microaerophilic chemolithoautotrophs were responsible for iron and manganese oxidation. This requirement of free oxygen in the Ijzermijn Iron Formation Bed has been supported by earlier molybdenum isotope studies. The presented work therefore further supports the idea of pre-Great Oxidation Event marine oxygen oases that did not lead to any appreciable build-up of oxygen in the atmosphere.

Mohammadabad Manganese deposit, southwest Sabzevar basin, Iran: Evidence of sea-floor exhalation and geochemical studies in the late Cretaceous volcano-sedimentary sequence

The southwest Sabzevar basin in northeast Iran is one of the most important areas for volcanogenic stratiform manganese deposits. The Mohammadabad Mn deposit, found in this basin, is hosted by the upper late Cretaceous marly tuffs in a region that has an active history of tectonism. Their geology, mineralogy and geochemistry, including major, trace and rare earth elements (REE), are described in this work. The main ore minerals include pyrolusite, psilomelane, cryptomelane, with minor braunite and manganite. Four styles of manganese mineralization are recognized: (1) layered; (2) nodular; (3) disseminated; and (4) replacement to massive. Regardless of style, pyrolusite, psilomelane, and cryptomelane usually tend to parallel the stratification of sediments, while braunite veins occur in high angle fractures. The replacement of radiolarian and foraminiferal fossils by manganese minerals during diagenesis near the seawater-sediment interface suggests that mineralization occurred in oxygen-rich conditions under the influence of low-temperature hydrothermal fluids. The geochemistry of trace elements of manganese oxides and rare earth elements gives clear evidence of hydrothermal-exhalative origin for Mohammadabad deposit. In general, ore minerals have Co/Ni ratios above 0.12, and U/Th ratios vary from 0.13 to 11.29. The presence of negative Eu anomalies in manganese minerals shows that the ore-forming fluids were generally low-temperature and oxic during mineral formation. In-situ mineralogy studies based on SEM-EDS have distinguished syngeneic and diagenetic Mn systems during the formation of manganese mineralization. The Mohammadabad deposit is considered a typical case of volcanic hydrothermal exhalative-diagenetic Mn mineralization, in which minerals deposited when hydrothermal fluid was released from oxic to dysoxic water columns.

The seasonal assessment of heavy metals pollution in water, sediments, and fish of grey mullet, red seabream, and sardine from the Mediterranean coast, Damietta, North Egypt

The current study investigated the deposit of heavy metals, including copper (Cu), zinc (Zn), cadmium (Cd), manganese (Mn), lead (Pb), chromium (Cr), and iron (Fe) in grey mullet (Mugil cephalus), red seabream (Pagrus pagrus), and sardine (Sardinella aruita) over winter and spring seasons 2022 at the Damietta port, a marine port constructed in 1982 on the north coast of Egypt, and the surrounding region. Water, sediment, and fish samples were collected from four sites near Damietta port throughout the spring and winter of 2022 to evaluate the amount of heavy metal in water, sediment, muscles, and fish liver. Heavy metal concentrations significantly differed across organs; however, their levels in liver tissues exceeded those in muscle tissues. It was noted that M. cephalus had the highest concentrations of heavy metals compared with other fish species. Heavy metals accumulation in fish organs was in the following order: Fe > Zn > Mn > Pb >Cu > Ni > Cd > Cr. During winter season, metals levels in water samples were in the following sequence: Fe > Ni > Zn > Cd > Cr > Pb > Cu > Mn, meanwhile in spring season, the order was as follows: Ni > Pb > Fe > Cr > Zn > Cd > Cu > Mn. During the winter time, the order of metals levels in sediment samples was Zn > Fe > Mn > Cu > Pb > Ni > Cd > Cr, but in the springtime, it was Zn > Fe > Mn > Cu > Ni > Pb > Cd > Cr. Finally, the human risk assessment concluded that grey mullet, red seabream, and sardine in Damietta port and neighboring regions are safe for human feeding and that various wastes may be disposed of securely, avoiding the buildup of heavy metals.

KARAKTERISTIK DAN GANESA ENDAPAN POLIMETALIK DAERAH GUNUNG KASIH, PUGUNG, TANGGAMUS, PROVINSI LAMPUNG

Indonesia is a country that has economically valuable mineral deposits such as nickel, aluminum, cobalt and manganese. These economical metallic minerals have an important role in the sustainability of the battery industry's long-term plans required during the energy transition. Manganese (Mn) is the fourth most widely used metal in the world which can be used as an industrial alloy. This study aims to determine the type of manganese that can be found in the research area, determine the hostrock (carrying rock) of sediment, and determine the type of deposit in the study area. Research data collection was carried out at 13 different points centered on the Gunung Kasih area and its surroundings. The data taken in the form of rock samples. Processing of data using petrological analysis and taking microscopic photos in the laboratory. The results showed that there were three forms of manganese oxide minerals, namely acicular, botryoidal and dendritic. Manganese oxide minerals in this area were found filling the fractures in several types of rock, namely red clay, clay, andesite, and lapilli tuff. The type of manganese oxide deposits in the study area is included in the type of residual manganese deposits associated with hydrothermal deposits. Rocks carrying manganese oxide minerals can come from red claystones of the Menanga Formation or igneous rocks and pyroclastic rocks of the Hulusimpang Formation.

Fault control and timing of manganese deposits at Abu Ramad, South Egyptian margin of the Red Sea

ABSTRACT Over thirty manganese deposits have been discovered and mined along the southern Egyptian Red Sea coast (Abu Ramad area). The manganese deposits are hosted in Miocene-Pliocene syn-rift sediments of the downdip portion of the NW-oriented rift-border fault and are in a tectonically complex area. The NW-oriented rift-related extensional fault system is overprinting the old NE to ENE-oriented Onib-Sol Hammad suture. The latter was reactivated as sinistral faults during the Pliocene. The rift-related fault pattern, including the reactivated, inherited Precambrian faults and shear zones, plays a vital role in the distribution and genesis of manganese deposits. In this work, results from field investigation, geological mapping, and boreholes data were integrated to establish a geological model for the fault-controlled manganese deposits east Abu Ramad city. Manganese minerals occur as fault-hosted lenses and vein-like bodies (Type I) and cementing material in the Pliocene manganiferous sandstone (Type II). These two types are genetically related and mapped together at or near the intersection zones between NW-oriented normal faults and ENE-oriented transfer faults. The damage zone of the cross-trend at their intersections with the NW-oriented faults hosted the high-grade manganese deposits (Type 1), while the low-grade type II deposits were formed as the cement of the Pliocene sandstone. Pliocene reactivation of the ore-rich shear zones causes high permeability damage zones that act as a corridor through low-permeable Pliocene shale and brings the manganese-rich solution into localized fault-bounded basins. Additionally, the sinistral offset for the NW-oriented faults enhances the permeability at faults intersection zones, which act as a structural trap of the manganese deposits. This study recognizes multi-reactivated faults and fault intersection zones as crucial targets for manganese mineral exploration along the Red Sea margin.

Geology, mineralogy, geochemistry and deposit model of iron and manganese in Bouarfa mine, Eastern High Atlas, Morocco

The Bouarfa Iron and Manganese Deposits are contained in the Sinemurian carbonate formations in the eastern High Atlas. It is a large deposit which has allowed the exploitation of more than 1.5 million tons of manganese and which still contains millions of tons of reserves. The mapping carried out shows the extension of the mineralization with oxides and hydroxides of Mn and Fe. The definition of types of mineralization shows that they are essentially stratiform deposits with some bodies and veins in the fault zones. The result of the mineralogical identification and geochemical analyses shows that it is a sedimentary deposit resulting from at least two mineralizing events with a high Fe-Mn content during the installation of the Sinemurian shallow carbonate platform. This is an environment of rapid oxidation and relatively sufficient sulphide inputs under redox conditions.

Comparative Study of Formation Conditions of Fe-Mn Ore Microbialites Based on Mineral Assemblages: A Critical Self-Overview

The role of biogenicity in the mineral world is larger than many might assume. Biological processes and physical and chemical processes interact both at the Earth’s surface and far underground, leading to the formation of banded iron and manganese deposits, among others. Microbial mats can form giant sedimentary ore deposits, which include enrichment of further elements. This article reviews the ways in which microbially-mediated processes contribute to mineralization, the importance of mineralized microbial textural features, and the methods that must be used to obtain high-resolution datasets. If the chosen methodology and/or the size dimension of investigation is not appropriate, then it is not possible to recognize that a system is microbially mediated, and the conclusion will be incomplete. We call attention to variable authigenic mineralization as the result of complex mineralization of cells and extracellular polymeric substances in the starving basins, which form giant ore deposits together with ore-forming minerals. Microbial mats and other biosignatures can serve as indicators of environmental reconstruction in ore formations. We suggest tests and analyses that will allow the potential role of biomineralization to be properly investigated for a more comprehensive view of formation processes and their implications.

Field Observations and Geophysical Research Applied to the Detection of Manganese (Mn) Deposits in the Eastern Part of Oban Massif, South-Eastern Nigeria: An Integrated Approach

The growing need for an industrialized world, especially in Africa, cannot be feasible without adequate mineral resources. Thus, the search for more mineral deposits will continue to be necessary. An integrated approach involving geological mapping and a high-resolution geophysical (aeromagnetic) investigation was conducted to assess the manganese mineralization in parts of the Oban Massif, southeast Nigeria. The aeromagnetic data were processed using regional-residual anomaly separation techniques, first vertical derivative (1VD), analytical signals, source parameters imaging (SPI), and Euler deconvolution to better understand magnetic source distributions and their depths of occurrence. The geological investigation revealed a dominant variety of metamorphic rock types, including migmatitic (banded) gneisses hornblende granite gneisses, amphibolites, charnockites, and some quartzite ridges. Also present are some indications of pockets of dolerites. The study area also observed epithermal Mn+Fe+Qtz vein type mineralization associated with hydrothermal alteration zones whose orientation coincides with dominant structural orientation from aeromagnetic interpretation. Analysis of aeromagnetic data shows that the study area is dominated by ENE, NNE, and E-W structural directions (near-surface basement structures), with the ENE trends related to mineralization in the area. The manganese mineralization within Oban Massif is structurally controlled. The depths of the magnetic anomalies in the study area were estimated using SPI and Euler decomposition algorithms. SPI delineated the shallow, intermediate, and deep magnetic anomalies at 84–142 m, 152–200 m, and 215–656 m, respectively. Euler decomposition, however, revealed that shallow, intermediate, and deep depths occurrence of the magnetic anomalies are at 200–377 m, 393–472 m, and 499–793 m, respectively.

Mesoproterozoic surface oxygenation accompanied major sedimentary manganese deposition at 1.4 and 1.1Ga.

Manganese (Mn) oxidation in marine environments requires oxygen (O2 ) or other reactive oxygen species in the water column, and widespread Mn oxide deposition in ancient sedimentary rocks has long been used as a proxy for oxidation. The oxygenation of Earth's atmosphere and oceans across the Archean-Proterozoic boundary are associated with massive Mn deposits, whereas the interval from 1.8-1.0Ga is generally believed to be a time of low atmospheric oxygen with an apparent hiatus in sedimentary Mn deposition. Here, we report geochemical and mineralogical analyses from 1.1Ga manganiferous marine-shelf siltstones from the Bangemall Supergroup, Western Australia, which underlie recently discovered economically significant manganese deposits. Layers bearing Mn carbonate microspheres, comparable with major global Mn deposits, reveal that intense periods of sedimentary Mn deposition occurred in the late Mesoproterozoic. Iron geochemical data suggest anoxic-ferruginous seafloor conditions at the onset of Mn deposition, followed by oxic conditions in the water column as Mn deposition persisted and eventually ceased. These data imply there was spatially widespread surface oxygenation ~1.1Ga with sufficiently oxic conditions in shelf environments to oxidize marine Mn(II). Comparable large stratiform Mn carbonate deposits also occur in ~1.4Ga marine siltstones hosted in underlying sedimentary units. These deposits are greater or at least commensurate in scale (tonnage) to those that followed the major oxygenation transitions from the Neoproterozoic. Such a period of sedimentary manganogenesis is inconsistent with a model of persistently low O2 throughout the entirety of the Mesoproterozoic and provides robust evidence for dynamic redox changes in the mid to late Mesoproterozoic.

A new metallogenic model for the giant manganese deposits in northeastern Guizhou, China

The recently discovered multiple world-class Nanhuanian manganese (Mn) ore deposits at Datangpo of northeastern Guizhou province in southern China provides substantial amount of Mn that can be economically important for industrial usage. Studies that we previously conducted suggest that these Mn ore deposits are likely manifestations of the deposition of volatile-rich Mn-bearing ore-forming materials originating from deep reservoirs. However, ore-forming structures that transport ore-forming materials, if existed, have not yet been identified. Here, integrated with three-dimensional (3D) geological modeling, aeromagnetic △T data processing and Bouguer gravity anomaly analysis, we found that the intersections of the northwest (NW)-trending early rift basins and the near east–west (EW)-trending Nanhua rift basins overlap with the localities of the giant Mn ore deposits in northeastern Guizhou. In addition, a seismic reflection profiles passing through the Mn mining district reveals an upward-widen, funnel-shaped seismically abnormal structure with a dimension of about 3-km-wide and 45-km-deep. The seismically abnormal structure highly likely represents a deep-seated diapir channel beneath the mining district. Such a structure could contribute to the transportation of Mn-bearing materials that are responsible for the final deposition of Mn ore deposits. This study not only offers a visualization of a deep-seated channel that may be part of ore-guiding structures, but also sheds light on a new metallogenic model of Mn ore deposit.

PENYISIHAN KADAR BESI (Fe) DAN MANGAN (Mn) DALAM AIR SUMUR DENGAN MEDIA PASIR TERLAPIS MANGAN DIOKSIDA

Well water often contains considerable iron (Fe) and manganese (Mn). The iron and manganese content often transforms actually clear water into yellowish-brown. When iron and manganese content exceed quality standards, it can harm human health. To manage iron and manganese pollutants in well water, it would require research to reduce iron and manganese deposits in an easy and inexpensive way for people who still use water for domestic purposes, according to the Indonesia republic's health minister No. 492/ Menkes/IV/2010. Based on preliminary tests, the results of the initial iron component analysis of 1.06 mg/L and mangan 0.98 mg/ L. The variable in the study is a high proportion of the media filters of greensand on every reactor which is 30 cm, 50 cm and 70 centimeters with 5, 10, 15 and 20 minutes of operation. The reactor is four inches of PVC pipe and the reactor is 80 cm tall, 100 centimeters and 120 centimeters tall. The fe and mn levels that have experienced the filtration treatment of every reactor have generally decreased. The deposite-based percentage is 0.02 mg/L with a set of exclusion efficiency of 98.11% and between 0.048 mg/L and the results of 95.92%.

The suitability of physical and chemical properties of rocks for land reclamation in different subzones of the Ukrainian Steppe


 
 
 The study of the properties of disturbed soils and rocks makes it possible to establish the parameters of the natural fertility of the studied substrates, to detect limiting factors, and to determine a set of restoration measures. The tested overburden rocks with the largest stratigraphic share of the open-pit quarries of the Nikopol manganese and Kerch iron ore deposits were loamy-like loess (Quaternary) and grey-green clay (Neogene). There is a certain parametric relationship between texture, density, porosity, the structural and physical state of different models of artificial reclaimed profiles. The composition and properties of rocks of edaphic structures of technosoils differ according to zonal natural and climatic conditions of the subzones of the Ukrainian Steppe. Loess-like loam and grey-green clay of the Kerch iron ore deposit are distinguished by a higher bulk density, lower porosity, and wilting moisture compared to samples from the Nikopol manganese ore basin. The use of the rotor complex leads to mechanical destruction and an increase in the content of small particles of rocks. Self-compacting processes occur to a large extent in multilayer structures. This pattern is observed at the boundary of the backfill differentiated in texture layers of technosoils. This indicates the existence of a barrier that prevents the relationship of edaphic properties between substrata stratums. Optimal ratio of clay minerals provides a rather high capacity of grey-green clay for water absorption. The model of technosoil composed of grey-green clay differs in a larger number of water-resistant micro-aggregates. The best conditions for land reclamation are connected with including grey-green clay in two- and three-layer constructions of technosoils, providing a waterproofing effect.
 
 

Mineralogy and geochemistry of Kliripan manganese ore deposit, Hargorejo Village, Kokap District, Kulonprogo Regency

This study discusses the mineralogy and geochemistry of manganese deposits in the Kliripan area, where manganese had been mined since the Dutch occupancy until the 1970s. Although mining has been discontinued since then, the demand for manganese has increased in various industries, prompting exploration to continue to meet this demand. We performed petrographic, XRD, and XRF analysis of the ore and wall rock samples. Jasper and grainstone from the Sentolo Formation are the two lithologies where manganese mineralization occurs. Manganese-bearing minerals include pyrolusite, manganite, rhodochrosite, and lithiophorite, while the gangue minerals consist of quartz, calcite, hematite, and clay minerals. We interpret that Jasper is a product of alteration and has MnO content as high as 5.02 wt.%. Meanwhile, the economic grade manganese ore in grainstone has an MnO content up to 48.51 wt.%. The elements Ce, Zr, Co+Ni+Cu, are important discriminants to determine the type of manganese deposit. The results showed that the diagenetic process in reductive water formed the manganese ores. Oxidation of divalent manganese ion formed pyrolusite and manganite. Rhodochrosite crystallized when dilute manganese solution reacts with CO2 from limestone diagenesis. We concluded that the Kliripan manganese ore deposit has both hydrothermal and diagenetic deposits.

Specific Features of the Rare Earth Element Distribution in Rocks and Ores of the Porozhinsk Manganese Deposit (Yenisei Ridge, Krasnoyarsk Region)

Specific Features of the Rare Earth Element Distribution in Rocks and Ores of the Porozhinsk Manganese Deposit (Yenisei Ridge, Krasnoyarsk Region)

Mineralogy and Origin of the Manganese Deposit in the Sulaimani Province, Kurdistan Region of Iraq: Insight to Serpentinization-Induced Manganese Production Scenario

The Manganese deposits in Sulaimani metallogenic province mainly occur within the top Qulqula Radiolarite chert unit of the Penjween ophiolite complex as strata bound type deposits near Kani Saif village, 15 km south of the Penjween district within the Imbricated zone, Kurdistan Region of Iraq. A restricted occurrence of massive manganese boulders was identified, 1 km north to the Mawat District, associated with the Oligocene Merga Red beds Group. The Qulqula Radiolarite represents the Middle Jurassic-Early Cretaceous sedimentary cover of Neo-Tethys oceanic crust deposits throughout the early to mature stages of the Neo-Tethys ocean opening along the northern and eastern margins of the Afro-Arabian plate. The field and petrographical data indicated that the nature of manganese mineralization in the area is of various forms including veins, brecciated, micronodules, banded and massive types. Reflected light microscopy, high resolution scanning electron microscope and X-ray diffraction reveal that the mineral assemblages are dominated by barunite, rhodinite, hematite, quartz and carbonate for the massive metamorphosed type deposit in the Mawat area. Meanwhile, the mineralogy of the vein, micronodule and banded types are simple and dominated by pyrolusite, hollandite minerals close to Kain Saif village. Combinations of the modal manganese minerals, filed and textural observations, a paragenetic-time model suggests that the manganese deposit in the area formed via a sequence of multiple processes (1) serpentinization of the upper mantle at mid oceanic ridge during the Cretaceous period, (2) deposition from diluted hydrothermal fluids in the Neo-Tethys mature oceanic basin, (3) the diagenetic modification of the manganese bearing sediment and (4) metamorphism of sediment a combing Zagros orogeny in Paleogene. Overall data suggest that the manganese deposits in the Kurdistan region of Iraq are cogenetic and spatially related to those which occur along the entire margin of the Arabian plates from Oman to Turkey associated with the radiolarite facies.

Source Characteristics of the Carboniferous Ortokarnash Manganese Deposit in the Western Kunlun Mountains

The specific source of ancient sedimentary manganese (Mn) deposits is commonly complex. Here we use systematic major and trace element data with strontium (Sr) and neodymium (Nd) isotopic analyses of the Ortokarnash Mn(II) carbonate ores and associated carbonate rocks from the Upper Carboniferous Kalaatehe Formation (ca. 320 Ma) in order to constrain the Mn source. This formation consists of three members: the first member is a volcanic breccia limestone, the second member is a sandy limestone, and the third member is a black marlstone with the Mn(II) carbonate interlayers. Petrographic observations in combination with low Al2O3 (<3.0 wt%) and Hf (<0.40 ppm) contents and the lack of correlations between the Al2O3 and 87Sr/86Sr ratios as well as εNd(t) values demonstrate a negligible influence of terrigenous detrital contamination on both Sr and Nd isotopic compositions of the Mn(II) carbonate ores. The Sr isotopes of Mn(II) carbonate ores are most likely affected by post-depositional alteration, while Nd isotopes remain unaltered. The initial 87Sr/86Sr ratios in the associated carbonate rocks are likely the result of a mixture of the chemical components (i.e., seawater) and the Al-rich components (e.g., volcanoclastic material), while the detrital effects on Nd isotopes are negligible. In addition, both Sr and Nd isotopes in these non-mineralized wall rocks remained unchanged during post-depositional processes. The relatively low Th/Sc ratios and positive εNd(t) values suggest that the aluminosilicate fraction in the calcarenite and sandy limestone was mainly derived from the weathering of a depleted mafic source, representing the riverine input into the seawater. Given that the Mn(II) carbonate ores are characterized by negative εNd(t) values, these suggest that seafloor-vented hydrothermal fluids derived from interaction with the underlying old continental crust mainly contribute to the source of the Mn(II) carbonates.

Production of electrolytic manganese metal using a new hyperchaotic circuit system

A hyperchaotic circuit power supply system for electrodeposition of manganese was designed and employed. It was found that the anodic potential oscillation behavior was suppressed to a certain extent under the action of the hyperchaotic current. The average oscillation period was increased by 5.6 s and the average oscillation amplitude was decreased by 38 mV, which was beneficial to reduce the additional energy consumption in the electrolysis process. At the same time, the by-product MnO2 anode mud produced on the anode was significantly reduced compared with the direct current treatment, and the anode surface was relatively flat and compact, which improved the corrosion resistance of the anode. In addition, smooth and less dendrite manganese deposits were obtained at the cathode. Although the average current efficiency by using the hyperchaotic current was only 61.92% and required further exploration, it provided a promising power supply mode with different parameters to be used in the electrolysis process.