Barite Deposits Research Articles

Минерально-сырьевые ресурсы Воркутинского района и перспективы их освоения

The analysis of the state and prospects for the development of the mineral resource base of the Vorkuta region of the Komi Republic, belonging to the Arctic zone, was carried out. It is shown that the coking coal deposits of the Pechora basin, the development of which is the basis for the existence of the city of Vorkuta, were and still are the most impor-tant ones. The reserves of coking coal are significant, however, the supply of them to operating mining enterprises is becoming more and more limited. To maintain and develop coal mining, it is necessary to build new mines. Along with the coal deposits, the Vorkuta region is of great interest in relation to other minerals. In the Kosyu-Rogovsk and Koro-taikha depressions, there are potential oil and gas-bearing structures, on the western slope of the Polar Urals – barite deposits, gold, chromium and copper occurrences, deserving further geological study and prospecting works. For a more complete disclosure and development of the mineral resource potential of the Vorkuta region, the extension of transport infrastructure is of great importance. The implementation of plans for the construction of railways, access to the Northern Sea Route, can contribute, in particular, to increasing the volume of coal production and wider supplies of coal using sea transport, and raising the investment attractiveness of the Arctic territories.

Evaluation of exploiting barite, the critical raw material in Slovakia, and benefits of its mining

Purpose. There are several deposits of critical raw materials in the Slovak Republic, but currently only one is mined. This is a barite deposit in Spiš, which shows an ever-lower volume of exploited raw material year-on-year. However, this area is rich in several confirmed barite veins, which represent potential strategic raw materials. The presented article analyzes in detail and describes the Jaklovce I. deposit, which is located in the Gelnica district in north-east of Slovakia. Despite the fact that Slovakia, as well as most EU countries, is dependent on imports of raw materials, the new deposits represent new potential. Determination of the economic value of these deposits creates a promising potential for the investor, but also, secondarily, a potential for the socio-economic development of regions, as well as for the state. Methods. Based on the evaluation of dynamic economic variables, the article predicts the benefits which mining in this deposit would bring, which are also supported by SWOT analysis of barite exploitation. Findings. According to the methods used during the financial evaluation of the single mined deposit of CRM in Slovakia, which was developed because of CRM criticality in EU, we showed, based on § 14 of the Mining Act no. 44/1988 Coll. the necessity of CRM mining from the view of regions, the state and investors. The present article summarizes impacts of exploiting the barite from Jaklovce I. deposit for the investor, as well as for the state, which is also underlined through SWOT analysis. Originality. This study attempts to point out that mining critical raw materials is economically suitable not only for the state, but also for investors. SWOT analysis also pinpoints most threats, opportunities and some forecasts which should be taken into account while designing the investment project. Practical implications.I nvestment project in mining area is one of the most critical and challenging decisions that experts have to make mainly based on geological, economical and geotechnical properties of the deposit, which are very specific. The same is true for the investment project which represents huge investments and rate of risk

Physicochemical Parameters of the Origin of Hydrothermal Mineral Deposits: Evidence from Fluid Inclusions. VI. Fluorite and Barite Deposits

Authors’ original continuously updated database, which currently comprises data from 22 300 publications on mineral-hosted fluid and melt inclusions, is used to generalize data on the physicochemical parameters of processes that produced fluorite and barite deposits. The paper presents data on the following parameters of the fluids: temperature, pressure, density, salinity, and gas composition. The average composition (Н2О, CO2, CH4, N2, H2S, and CnHm) of fluids at fluorite–barite deposits is calculated. The paper reports the average composition of major gas components (CO2, CH4, N2, and H2S) of natural fluids at these deposits on the basis of Raman spectroscopic analyses of individual inclusions. Average F, S, and Ba concentrations are calculated for silicate magmatic melts and natural mineral-forming fluids.

Geochemistry, Mineralogy and Petrogenesis of the Vein-Type Barites of Some Portions of the Benue Trough, Nigeria

Several barite deposits have been reported to occur in Nigeria within the Benue Trough, one of the West Central African Rift Systems (WCARS) considered variously as an aulacogen, strike-slip or pull-apart basin. In spite of these occurrences and the high local and international demand for barites, Nigerian barite is yet to find a place even in its local market probably due to the poor knowledge of the fundamental properties of the barites. To throw more light on this some deposits that are mined on artisanal basis in the Trough were studied alongside an overview of the evolution of the basin and the geochemistry and petrogenesis of the barite. Barites in the area of study occur as white, reddish-brown and clear varieties with specific gravity varying between 3.3966 and 4.3432 based on pycnometric and immersion methods. They occur as epigenetic veins of between about 0.1 m to more than 1.5 m, which encourages open cast mining. Chemical analysis show that the samples studied contain between 72.61 and 72.12% Ba corresponding to a calculated total BaO of 48.37 and 60.1%. The other relatively significant elements but of less value in the samples include Si, Fe, Sr, Ca, Al, Pb, Mg, Mn, P, and Ni. XRD results also show barite mineralogical association with wenkite and plumbian barite of insignificant quantity. The barites likely formed from intermingling of infiltrating solutions containing barium with soluble sulphates arising within the rocks passing through fractures created during the Late Cretaceous inversion in the basin. The inversion is suggested herein to have resulted from magmatic underplating and consequent peneplanation in the middle Benue Trough.

Formation and genesis of Paleozoic sediment-hosted barite deposits in Turkey

Most barite deposits in Turkey are sediment-hosted deposits which are located in different lithologies within passive margin sediments from the Paleozoic. The Şarkikaraağaç, Hüyük and Tordere deposits occur in the western part of the Tauride-Anatolide tectonic unit, whereas the Şekeroba and Önsen region deposits located in the eastern part of Turkey occur on both Arabian and Tauride-Anatolide microplates. While the former deposits occur as both concordant and discordant bodies within Early Paleozoic carbonates, the latter deposits are found as discordant, fracture filling and replacement-type ore bodies.O, D, S, Sr and Pb isotope studies were used to determine and correlate the formation conditions of these deposits. δ18OSMOW mean values of the Tordere barite deposit are slightly higher (mean 16.2‰) than the mean values for the Şekeroba (10.8‰) and Önsen (11.3‰) deposits. The δ18OSMOW (mean 15.83‰) and δDSMOW (mean −67‰) values obtained from fluid inclusions in quartz veins in the Şekeroba barite deposit correspond to metamorphic or deep circulation hydrothermal waters. Mean δ34 SCDT values from Şekeroba, Tordere and Önsen deposits are 31.7, 33.8 and 20.6‰, respectively, which are compatible with the early Paleozoic seawater, except for the Önsen deposit.87Sr/86Sr mean values for the barite deposits of Turkey are defined as follows (‰); Şekeroba: 0.713, Önsen: 0.711, and Tordere: 0.711, which are higher 87Sr/86Sr isotope ratios than Paleozoic seawater. The Pb isotope values in Şekeroba and Tordere deposits are similar and mean is 206Pb/204Pb = 18.28, 207Pb/204Pb = 15.67 and 208Pb/204Pb = 38.50. High radiogenic Sr and Pb isotope data from the deposits indicate that Ba was generated from thick Paleozoic clastics or the older crust beneath them.Sr, S, and O isotopes and the positive Gd anomaly in the barites are very similar to those of Paleozoic stratiform cold-seep barites. The primary stratiform-stratabound barite deposits, like Şarkikaraağaç-Hüyük deposit, could have formed either by cold seep or diagenetic processes at the sediment–seawater interface or within the sediment related to sulfate-methane boundary. Although there are similar Sr and Pb isotopic signatures between the western and eastern region deposits, the eastern region Şekeroba, Önsen and Tordere barite deposits show discordant ore geometry and highly radiogenic isotope values indicating that primary stratabound-stratiform barite was dissolved and remobilized along deep-seated fault zones during the Hercynian orogenesis and deposited in different Paleozoic lithologies related to cooling and/or increase in Eh.

Deposition of sulfate aerosols with positive Δ33S in the Neoarchean

Anomalous sulfur isotope compositions present in Archean rocks have been intensely scrutinized over the last 20 years because they record key aspects of Earth's atmospheric composition prior to the appearance of free molecular oxygen ca. 2.3 billion years ago. These isotopic compositions can be described as mass anomalous fractionations (MAF) and are produced in the atmosphere as UV light interacts with SO2 molecules. Most interpretations suggest that atmospheric processes generate a reduced S-phase with a positive (33S-enriched) MAF signature, as measured in pyrites, and an oxidized S-phase with a negative anomaly, as measured in bedded barite deposits. However, recent data for carbonate-associated sulfate (CAS) — a direct proxy for the isotopic composition of sulfur from seawater sulfate — in Neoarchean rocks showed no such negative values, but rather the opposite. To understand if the positive MAF anomalies we measured in Neoarchean CAS reflect secondary processes (diagenetic, metamorphic, handling) instead of original signals of Archean seawater sulfate, we collected additional sample suites with various degrees of preservation and metamorphic alteration across the Campbellrand-Malmani platform in South Africa. Results illustrate that within this comprehensive suite, less-altered samples all contain positive MAF values while secondary processes tend to either remove CAS from the sample and/or decrease the 33S-enrichment. This positive MAF signal in sulfate is therefore reasonably interpreted as a primary depositional origin, and implies that the assumption that sulfate always carries a negative MAF anomaly throughout the Archean rock record needs to be reconsidered. Our CAS observations suggest that future experiments and calculations should also consider atmospheric and/or sulfur cycling processes that can produce oxidized sulfur with a positive MAF signature.

In situ S-isotope compositions of sulfate and sulfide from the 3.2 Ga Moodies Group, South Africa: A record of oxidative sulfur cycling.

Sulfate minerals are rare in the Archean rock record and largely restricted to the occurrence of barite (BaSO4 ). The origin of this barite remains controversially debated. The mass-independent fractionation of sulfur isotopes in these and other Archean sedimentary rocks suggests that photolysis of volcanic aerosols in an oxygen-poor atmosphere played an important role in their formation. Here, we report on the multiple sulfur isotopic composition of sedimentary anhydrite in the ca. 3.22Ga Moodies Group of the Barberton Greenstone Belt, southern Africa. Anhydrite occurs, together with barite and pyrite, in regionally traceable beds that formed in fluvial settings. Variable abundances of barite versus anhydrite reflect changes in sulfate enrichment by evaporitic concentration across orders of magnitude in an arid, nearshore terrestrial environment, periodically replenished by influxes of seawater. The multiple S-isotope compositions of anhydrite and pyrite are consistent with microbial sulfate reduction. S-isotope signatures in barite suggest an additional oxidative sulfate source probably derived from continental weathering of sulfide possibly enhanced by microbial sulfur oxidation. Although depositional environments of Moodies sulfate minerals differ strongly from marine barite deposits, their sulfur isotopic composition is similar and most likely reflects a primary isotopic signature. The data indicate that a constant input of small portions of oxidized sulfur from the continents into the ocean may have contributed to the observed long-term increase in Δ33 Ssulfate values through the Paleoarchean.

New Discovery of Selenides in the Shiti Barite Deposit, Dabashan Region and its Geological Significances

New Discovery of Selenides in the Shiti Barite Deposit, Dabashan Region and its Geological Significances

Origin of barite deposits in dolomite-limestone units, Gazipasa, Eastern of Antalya: geology, geochemistry, statistics, sulfur isotope composition

The study is supported with the FYL-2016-1832 Project by Akdeniz University Scientific Research Projects.

Geology, mineralogy, and geochemistry of Mashkan barite deposit, north eastern Sabzevar, Khorasan Razavi province

Geology, mineralogy, and geochemistry of Mashkan barite deposit, north eastern Sabzevar, Khorasan Razavi province

Modelling of solid formation by heterogeneous reactions through a multicomponent transport model of diluted ionic species: Simulation of barite fouling in a geothermal heat exchanger

AbstractA general model is proposed in order to describe the growth of a deposit by heterogeneous reactions. The hydrodynamics in the fluid is described by a multicomponent transport model for ionic species diluted in a solvent and heat transfer is taken into account in both liquid and solid domains. The boundary condition at the interface where the reaction takes place is described thoroughly. It involves the reaction kinetics and gives access to the velocity of the interface, ie, the mass rate of the solid deposit. The model is then applied to the case of barite crystallization in a heat exchanger. The liquid phase is therefore composed of two ionic species Ba2+ and SO42− diluted in water. The solid phase is modelled as a homogeneous barite deposit. The fully dynamic CFD simulation of the model is made using Comsol Multiphysics, in a cylindrical pipe. The solid growth is analyzed over time and space in terms of the relevant variables of the model.

Comparison of Nigerian Barite Production with some Top Barite Producing Countries

Barite is a very important industrial minerals used as weighting material in the petroleum industry. The nature of barite ores, geology of barite ores based on location were discussed. This paper presents top barite producing countries in the world, their production and consumption of barite, as well as their reserve. Despite all the barite deposits in Nigeria, which is approximately 15 million tonnes, it still imports barite from other countries for use in the drilling of oil and gas in Nigeria. This of course brings about unnecessary expenses been incurred by the government of Nigeria. Some of the challenges faced with the mining and processing of the Nigerian Barite were discussed. Proposed solutions to the mentioned challenges were also stated. The main challenge of the Nigerian barite is not with the American Petroleum Institute (API) standard, but the policies which do not favour investors. Investment by private companies into the mineral sector of Nigeria will bring about a lot of revenue to the government, if the right things are set in place. Keywords— Barite, producing countries, low-grade

The Extent of Fault-Associated Modern Authigenic Barite Deposits Offshore Northern Baja California Revealed by High-Resolution Mapping

High resolution mapping with an autonomous underwater vehicle (AUV) of a section of the San Clemente fault, offshore Southern California, reveals the largest documented cold seep-associated barite deposits discovered to date. Although barite deposits along this fault, north of the mapped area, have been observed and sampled before in submersible dives, this study reveals massive newly found outcrops. The high-resolution surveys resolve their small scale morphology, their large geographical extent and the structural controls on their emplacement. Detailed bathymetry (1m x 1m x 0.25 m grid resolution) of a ~12 km2 area intersected by the fault exhibits quasi-circular mounds of 10-30 m planar dimensions rising up to 11 m above the surrounding seafloor on a 30-45 m high and at least 1,100 m long ridge, and along truncated outcropping strata, but not along the fault trace. Observations from a remotely operated vehicle (ROV) show that the mounds consist of steep sided dark-varnished blocks of barite. Active barite precipitation occurs as white friable spires emerging from the older deposits, or as white porous precipitates filling fissures. Upward thinning spires and microbial mats occurrences atop the spires are consistent with aggradational growth due to precipitation from upward flowing solutions. Live Lamellibrachia tubeworms are found in association with the fissure-filling barite precipitates. Mapping surveys were also conducted along a short section of the San Clemente fault south of the Navy Fan. In addition, a 9 km2 area along the San Diego Trough Fault south of the US-Mexico border was mapped and visited in an ROV dive. In the three mapped regions sub-bottom chirp profiles indicate that barite precipitation occurs where strata, truncated and uplifted by the fault, has thin or no sediment drape allowing for Ba-rich solutions flowing along bedding planes to mix with seawater sulfate at the seafloor interface. Despite the massive scale of the barite mounds, they are not resolvable in surface ship multibeam-generated bathymetry (25 m grid resolution). As only a few areas have been mapped at the high resolution employed in this study, the full extent of these deposits along the San Clemente Fault and other faults remains unknown.

Barium-isotopic constraints on the origin of post-Marinoan barites

Measurements of triple oxygen isotope ratios in barite horizons within post-Marinoan cap carbonates have provided some of the most compelling evidence that the Marinoan glaciation was a Snowball Earth event. However, the origin of these barite horizons remains unresolved. To constrain the Ba sources, and thus formation mechanisms of these horizons, we analyzed the Ba isotope composition of post-Marinoan barite deposits from Northwest Canada, Northern Norway, Brazil and South China. We augment these analyses with a Ba isotope survey of almost 100 modern and ancient additional barite measurements, including samples from pelagic (or ‘marine’), hydrothermal, terrestrial, Proterozoic stratiform and cold seep environments. Unlike modern cold seep or terrestrial barites, we find that globally-distributed post-Marinoan barites exhibit a relatively narrow isotopic range, suggesting a well-mixed, effectively limitless Ba source. Moreover, post-Marinoan deposits exhibit a similar mean Ba isotope composition to modern marine barites, which we interpret as evidence of a marine Ba source. Considered alongside existing geochemical, geological, and new Ba isotope survey data, we conclude that Ba in barite horizons was sourced from a well-mixed, Ba-replete but SO4-poor reservoir that accumulated during the Marinoan Snowball Earth interval. This deep Ba reservoir was then transported upward—either by ocean circulation or dolomitization of underlying cap carbonates—and was brought into contact with continental weathering-derived sulfate in a post-glacial meltwater surface layer. Thus, in addition to providing a plausible mechanism for generating globally-synchronous deposition of post-Marinoan barite horizons that reconciles all existing geochemical and geological data, our results demonstrate the utility of Ba isotopes to interrogate the origin of enigmatic barite deposits throughout the sedimentary record.

Exhalative deposits in eocene volcano-sedimentary rocks in the middle part of the Urumieh-Dokhtar magmatic belt: Detailed evidence from nabar deposit, west of Kashan, Urumieh – Dokhtar Magmatic Belt

Meso-Cenozoic magmatic belt of Urumieh–Dokhtar resulted from subduction of Neothetys oceanic crust beneath the Central Iran Block with Gondwanic signature is dominated by calc-alkaline to alkaline igneous rocks. The magmatic rocks has mainly occurred in submarine environments as volcanic-volcanoclastics with interlayers of sedimentary rocks in the Eocene, while it has occurred as intrusive and subvolcanics in the Neogene. In the Nabar area volcano-sedimentary rocks of Eocene have been covered unconformably by Oligo-Miocene sedimentary rocks (Qom Formation). The Eocene and Oligo-Miocene sequences are intruded by Middle-Upper Miocene intrusive and subvolcanic bodies. Igneous rocks of Eocene and Middle-Upper Miocene are of I-type and calc-alkaline belonging to arc and post-collisional setting of continental margin, respectively. The mineralization consists of pyrrhotite, pyrite, minor chalcopyrite and sphalerite, mainly hosted by Eocene volcanoclastics and particularly by the contact metamorphic halos of Qom formation. Irregular veinlets (stringer zone) in the lower part change to massive lenses upward which conformable with Eocene enclosing rocks, and have sharp contact with overlying Qom formation. Low grad ores with irregular shape (patches, veinlets, cavity and fracture filling) which are resulted from remobilization of previous mineralization, occurred within the contact metamorphic halos of Middle-Upper Miocene intrusions. According to geochemical analysis and mineralogical studies, iron, copper, gold, silver, arsenic, lead and zinc are enriched in the ore zone. Two types of fluid inclusion (L-V and L-VS) were distinguished in quartz veinlets. The homogenization temperature and salinity of fluid inclusions vary from 121 °C – 537 °C and 9–45 wt% NaCl equivalent, respectively. These data indicating the mixing of magmatic water with meteoric water in the later stage of mineralization. The δ34S values of pyrite and pyrrhotite which varies from 10.5 to 11.6 wt% compatible with massive sulfide and skarn type deposits. Field observations, mineralogical, geochemical, fluid inclusion and isotopic data suggest that, the Nabar deposit is probably a Kuroko type massive sulfide deposit which has been partly changed to skarn during penetration of Middle-Upper Miocene subvolcanic intrusions. The Kuroko type barite deposit of Dorreh and exhalative Mn deposit of Venarch and Shahrestanak were formed at the same time, within the Eocene volcanoclastic sequences.

Crustal fracturing, unconformities, and barite deposition, 3.26–3.23 Ga, Barberton Greenstone Belt, South Africa

Small sedimentary barite deposits are widespread in the 3.258–3.225 Ga Fig Tree Group, Barberton Greenstone Belt (BGB), South Africa. This report explores the stratigraphy of these units, the types of barite present, their depositional settings, and the controls on sedimentation in the Barite Valley area. Five morphological types of barite are recognized: masses of irregularly layered bladed barite termed barite plugs, mounded barite, barite splays, flat-layered bladed barite, and barite sand. In all areas studied, barite deposition was closely associated with active faults and fractures in the underlying rock sequences that are inferred to have been conduits by which barium-bearing fluids made their way to the surface. The barite deposits are also associated with unconformities below, within, and/or above the barite layers. Associated sedimentary rocks show evidence of deposition within intertidal, fan delta, and shallow water to subaerial settings. Previous sulfur isotopic studies have shown that the sulfate originated by photolysis in the atmosphere. We infer that the barite was deposited where barium-bearing, shallow subsurface waters vented to the land surface via mostly small, cool springs and interacted directly with sulfate-bearing meteoric waters, probably often rainwater, triggering barite precipitation. Plug barite marks spring vents, mounds developed in pools, and the outflow systems were characterized by layered bladed barite with increasing barite sand toward more distal settings. Associated thin jasper beds are thought to have formed by oxidation of sedimentary pyrite and siderite by meteoric waters carrying photolysis-produced oxidants, probably H2O2 and perhaps O2. The Barite Valley barite deposits do not appear to have developed in open marine or evaporitic settings and their geochemistry may carry little information on the composition of Archean sea water or nature of the underlying crust.

Evaluating of lithological and structural controls on the barite mineralization by using the remote sensing, Fry and fractal methods, Northwest Iran

The most part of barite deposits in the NW Iran have been epigenetically formed in the form of veins, fracture, and/or open-space fillings. For this reason, structural evaluation is the important factor for investigation of the barite mineralization in the host rocks. Fault and fracture are the predominant structures that can be distinguished in the studied area. Two approaches are proposed for analyzing the structures; the first one is visual investigation. This approach produces a fracture density map and a fracture rose diagram. The second one is used to quantify the fracture distribution by using the fractal dimension. The results indicated that the fracture distribution is not only the controlling factor of the barite mineralization, but also the presence of hydrothermal fluids and the lithology of the host rock that are other important factors in the productivity of the fractures as well. For this reason, despite the high fractal dimension (1.92) in the SE of the studied area, the barite indices have not been introduced up until now, whereas several barite indices in the NW of the study area with low value of fractal dimension (1.62) have been found. Fry analysis data can help us to identify the trend of mineralization in barite deposits. Fry analysis results revealed that E-W trending fractures are the most important structures for barite vein emplacement and subsidiary N-S striking fractures also host for the barite veins, but NE-SW trending fractures are almost barren. In this research, pyrite strain firings were used for temporal evolution of ore deposition. Wrapping of barite around the porphyroblasts reveals that coeval growth of fractures and mineralization with deformation of shear zone and exhumation of host rocks are done by a set of thrust faults in the study area.

Geological setting of the barite-fluorite deposit at Jeżów Sudecki (Kaczawa Mts.)

From 1969 to 1993, investigation for the Ba-F mineralization was executed within the metamorphic Kaczawa complex, north of the Intra-Sudetic Fault in the Jeżów Sudecki-Dziwiszów area (Kaczawa Mts., Western Sudetes). The article presents unpublished results of those prospecting works. A small deposit of Ba-F with Zn, Pb, Cu-sulphides, on the SE slope of the Szybowisko hill near Jelenia Góra, was documented in 1994. The economic mineralization is developed in the Jeżów Sudecki fault, steep fracture zone running parallel to the Intra-Sudetic Fault, and was identified at a distance of 600 m along the strike of the fault (in the W–E direction) and up to a depth of 500 m along the dip (towards the south). Two (locally three) bifurcating veins were found. The average content of the main components is: BaSO4 – 63.18%, CaF2 – 8.60%. The Ba-F mineralization is associated with the Jeżów Sudecki fault, synchronous with the formation of the Intra-Sudetic Fault zone. Both of these faults are Variscan and fall steeply southward. Younger, alpine (?) inverse and transverse normal faults were formed after the intrusion of a rhyolite dyke into the Kaczawa complex rocks and after the formation of the barite deposit. The Ba-F mineralization developed in a multi-stage process and shows a pulsatory nature. Five mineral parageneses were distinguished in the deposit. The age of the Ba-F mineralization has not been definitively established.

Geochemical studies, mineralization and mineral potential of Tafresh area, the Iran-Markazi

The study area is part of the Urumieh–Dokhtar volcanic arc that a large part of its surface is covered by extrusive Igneous rocks (tuff, intermediate lavas and ignimbrites sheets), plutonic igneous (diorite and granodiorite) and semi-deep stones (dyke and sill). Studied samples are situated in calc-alkaline domain of magmatic series diagrams. Harker diagrams show the fractional crystallization of Clinopyroxene, amphibole, plagioclase, alkali feldspars and opaque minerals (ilmenite Titano-magnetite, ilmenite and rutile). In spider diagrams, light rare earth elements (LREE) are enriched compared to heavy rare earth elements (HREE), and HFS elements (Ti, Nb) show negative anomaly and LFS elements (Cs, K, Pb) show positive anomaly, showing that it is a distinct characteristic of subduction zones. Skarns of the area mainly are of exoskarns and are rich in plagioclase, microcline, amphibole, biotite and epidote. Skarn is enriched of iron, copper, molybdenum, vanadium, lead, zinc and silver. Deposits of barite in the area show characteristics of volcanic-sedimentary barites and are associated to ore-bearing hydrothermal solutions. Using satellite images and processing information, four areas with high mineral potential are identified in the area.

The genesis of the Dahebian Zn-Pb deposit and associated barite mineralization: Implications for hydrothermal fluid venting events along the Nanhua Basin, South China

The Dahebian stratiform barite deposit, which is situated in the Nanhua Basin, is one of the world’s largest and most important barite deposits. This deposit was formed through sedimentary exhalative processes in the early Cambrian stage. Recently, beneath stratiform barite ore, stratabound Zn-Pb-(Fe-bearing) sulfide mineralization, which is hosted by the Doushantuo Formation, was discovered. Ores that represent Zn-Pb sulfide mineralization are mainly discordant but stratabound. The Doushantuo Formation consists of laminated interbedded layers of micritic dolomite and carbonaceous mudstone, associated with phosphorite and chert. The sulfide ores consist primarily of sphalerite, pyrite and galena. The associated gangue minerals are barite, quartz, minor calcite, as well as trace amounts of apatite and hyalophane. Hyalophane found in the stratiform barite ore is richer in barium but poorer in potassium than that associated with the sulfide ores. This outcome corresponds to ascending hydrothermal fluids that are richer in barium along with sulfide mineralization. Investigation of the ore fluid reveals relatively high temperature (142–368 °C) with scattered salinity (0.53–25.62 wt% NaCl eq.). This finding suggests that fluid cooling and/or mixing with seawater could be the primary mechanisms that prompted the ore formation. Sulfides selected from the zinc-lead sulfide ores and stratiform barite ore have similar sulfur isotopic compositions, with δ34S values ranging from 13.5‰ to 30.0‰; δ34S values of barite from these ores are analogous, with δ34S values ranging from 29.5‰ to 55.1‰. The sulfur isotopic fractionation between minerals (barite and sulfide) and the early Cambrian seawater is ΔBarite-Seawater = 7.8‰ and ΔSulfide-Seawater = −12.1‰, respectively, demonstrating that the sulfur in the Dahebian zinc-lead deposit and the stratiform barite deposit were derived from the early Cambrian stratified seawater column. Lead isotopic compositions of sulfide ores indicate that these ore metals are mainly sourced from rocks of the Doushantuo Formation and the underlying fold basement.Therefore, the Dahebian zinc-lead deposit and stratiform barite deposit probably arose from Selwyn-Type sedimentary exhalative hydrothermal fluids. Zn-Pb sulfides were mineralized in the feeder zone of these hydrothermal fluids, and the stratiform barite ore deposits represent the upper sedimentary-exhalative mineralization. This finding points to intensive Zn-Pb-Fe-Ba hydrothermal fluid venting into the Nanhua Basin and to relatively oxic deep ocean waters during the early Cambrian.