Barite Mineralization Research Articles

Open system sulphate reduction in a diagenetic environment – Isotopic analysis of barite (δ34S and δ18O) and pyrite (δ34S) from the Tom and Jason Late Devonian Zn–Pb–Ba deposits, Selwyn Basin, Canada

Highly positive δ34S values in sulphide minerals are a common feature of shale hosted massive sulphide deposits (SHMS). Often this is attributed to near quantitative consumption of seawater sulphate, and for Paleozoic strata of the Selwyn Basin (Canada), this is thought to occur during bacterial sulphate reduction (BSR) in a restricted, euxinic water column. In this study, we focus on drill-core samples of sulphide and barite mineralisation from two Late Devonian SHMS deposits (Tom and Jason, Macmillan Pass, Selwyn Basin), to evaluate this euxinic basin model. The paragenetic relationship between barite, pyrite and hydrothermal base metal sulphides has been determined using transmitted and reflected light microscopy, and backscatter electron imaging. This petrographic framework provides the context for in-situ isotopic microanalysis (secondary ion mass spectrometry; SIMS) of barite and pyrite. These data are supplemented by analyses of δ34S values for bulk rock pyrite (n=37) from drill-core samples of un-mineralised (barren), siliceous mudstone, to provide a means by which to evaluate the mass balance of sulphur in the host rock.Three generations of barite have been identified, all of which pre-date hydrothermal input. Isotopically, the three generations of barite have overlapping distributions of δ34S and δ18O values (+22.5‰ to +33.0‰ and +16.4‰ to +18.3‰, respectively) and are consistent with an origin from modified Late Devonian seawater. Radiolarian tests, enriched in barium, are abundant within the siliceous mudstones, providing evidence that primary barium enrichment was associated with biologic activity. We therefore propose that barite formed following remobilisation of productivity-derived barium within the sediment, and precipitated within diagenetic pore fluids close to the sediment water interface. Two generations of pyrite are texturally associated with barite: framboidal pyrite (py-I), which has negative δ34S values (−23‰ to −28‰; n=9), and euhedral pyrite (py-II), which has markedly more positive δ34S values (+8‰ to +26‰; n=86). We argue that stratiform pyrite and barite developed along diagenetic redox fronts, where the isotopic relationships (δ34Spyrite≈δ34Sbarite) are explained by anaerobic oxidation of methane coupled to sulphate reduction (AOM-SR). Furthermore, the relatively narrow distribution of δ34Sbarite values is consistent with an open system model of sulphate reduction, in which reduced sulphur generation occurred with a reduced isotopic fractionation (ε34S=<15‰) linked to higher rates of sulphate reduction and AOM-SR. Importantly, hydrothermal sulphides (pyrite, sphalerite and galena) all post-date this diagenetic barite-pyrite assemblage, and textural and mineralogical evidence indicates barite replacement to be an important process during hydrothermal mineralisation. Neither the textures nor the documented isotopic relationships can be produced by processes operating in a euxinic water column, which represents a major departure from the conventional model for SHMS formation at Macmillan Pass. We suggest that positive δ34S values in sulphides, a common feature of SHMS systems both in the Selwyn Basin and throughout the geologic record, could be linked to AOM-SR. At Macmillan Pass, positive δ34Spyrite values developed during open system diagenesis, which was critical for rapid sulphur cycling and the development of an effective metal trap.

مطالعات کانی سازی، ژئوشیمی، سیالات درگیر و ایزوتوپ پایدار گوگرد کانسار Cu-Zn-As باقرق با سنگ میزبان کربناته (شمال شرق انارک)

کانسار Cu-Zn-As باقرق در شمال شرق شهر انارک و در استان اصفهان قرار دارد. کانی‌سازی به‌صورت دیرزاد، ماهیت چینه‌کران و بافت و ساخت پرکننده فضای خالی در سنگ میزبان کربناتی رخداده است. کانی‌شناسی بخش درون‌زاد شامل کالکوسیت، کالکوپیریت، پیریت، اسفالریت، گالن، انارژیت، باریت و کلسیت و کانیهای بخش برون‌زاد شامل مالاکیت، آزوریت، کوولیت، کریزوکولا، کالکوسیت، سروزیت، اسمیت‌زونیت، مس طبیعی، هماتیت، گوتیت و لیمونیت می‌باشد. سنگ میزبان کربناتی در اطراف زون‌های کانه‌دار متحمل دگرسانیهای دولومیتی‌شدن و کلسیتی‌شدن شده است. مس به‌عنوان عنصر اصلی ذخیره (با میانگین 28/20 درصد وزنی) و پس از آن عناصر روی (با میانگین تقریبی 1 درصد وزنی) و آرسنیک (با میانگین تقریبی 1 درصد وزنی) می‌باشند. مطالعات سیالات‌درگیر روی کانی باریت نشان می‌دهد سیال کانه‌دار سولفیدی دارای محدوده دمای همگن شدن بین 259 تا 354 درجه سانتی‌گراد و میزان شوری بین 8 تا 13 درصد وزنی معادل NaCl می‌باشد. سیال کانه‌دار در مراحل پایانی کانی‌سازی با آبهای جوی دچار اختلاط شده و فاز تأخیری غیر سولفیدی کلسیتی با محدوده دمای نسبتا پایین ‌(78 تا 112 درجه سانتی‌گراد) و درجه شوری پایین (بین 3 تا 6 درصد وزنی معادل NaCl) را تشکیل داده است. محدوده مقادیر 34Sδ کانی‌ باریت کانسار باقرق بین 13+ تا 14+ در هزار بوده در حالی‌که محاسبه مقدار 34Sδ مربوط به سیال کانه‌دار پس از تصحیح دمایی بین 7- تا 8- در هزار به‌دست آمد. منشأ گوگرد باقرق با توجه به شباهت ایزوتوپ باریت با سولفات‌های دریایی کرتاسه، احتمالا از لایه‌های تبخیری این دوره زمانی تأمین شده است. این سولفا‌ت‌ها توسط فرآیند‌های ترموشیمیایی به‌صورت بخشی به گوگرد احیایی با مقدار ایزوتوپی سبک‌تر (حدود 21 در هزار) تبدیل و جهت ته‌نشست سولفیدها مورد استفاده قرار گرفته است. کانسار باقرق با توجه به خصوصیاتی همچون سنگ میزبان کربناته، غیاب فعالیت آذرین، بافت پرکننده فضای خالی، دگرسانی دولومیتی،کانی‌شناسی، ژئوشیمی ماده‌معدنی (وجود As و Sb بالا و عدم حضور Bi)، داده‌های دماسنجی و مقادیر ایزوتوپ گوگرد، شباهت زیادی با کانسارهای مس با سنگ میزبان کربناته در افریقا و به‌ویژه نوع سومب (Tsumeb) در نامیبیا نشان می‌دهد. کانسار باقرق احتمالا مرتبط با سیالات دگرگونی آزاد شده در حین فازهای کوه‌زایی مرتبط با بسته‌شدن اقیانوس نئوتتیس می‌باشد.

The chemical composition and industrial quality of Barite mineralization in Calabar flank, Oban Massif, Mamfe embayment and Obudu Plateau, southeastern Nigeria

Barite occurrences in the Calabar Flank, Oban massif, Mamfe Embayment and Obudu Plateau of Southeastern Nigeria have been sampled and analyzed for the purpose of assessing their chemical composition and industrial quality. Barite occurrences were observed mostly along faults and unconformities marking the boundaries between the Precambrian basement rocks of Oban and Obudu massifs and the Cretaceous sediments of the Calabar Flank and Mamfe embayment. Occurrences were also observed within the sediments. The chemical data show that BaSO 4 , SiO 2 and TiO 2 are the major chemical species of the barite. The Ba and SO 4 content vary between 53.62 – 56.10 wt% and 27.57 – 39.35 wt% respectively across the sampled areas. The specific gravity is 4.45 and this combined with high BaSO 4 (approximately 94 wt%) shows that the mineralization is of high industrial quality and compares favourably with the Azara barite deposits of the Benue Trough. The quality of the barite meets American Petroleum institute (API) requirements for use as drilling mud.

Diagnóstico hidrogeológico da região de Aramari e Ouriçangas-Bahia

Aspectos hidrogeológicos e hidroquímicos da água subterrânea nos municípios de Aramarí e Ouriçangas foram estudados, com o objetivo de avaliar o potencial de produção de água de poços tubulares da região, relacionando-os com as principais formações sedimentares presentes na área, além de obter informações sobre a sua tipologia e qualidade. Os dados hidrogeológicos possibilitaram definir a direção NE-SW do fluxo de água subterrânea. Foram estabelecidos os limiares estatísticos das vazões, determinando os melhores poços da área e sua ligação com as formações Barreiras, Marizal, São Sebastião, Candeias/Sergi e o Grupo Ilhas Indiviso. Em relação à qualidade, deu-se ênfase principalmente a presença de bário, componente do mineral barita, que ocorre como cimento em lentes de arenitos da Formação Marizal percolados pela água subterrânea na região, e que pode causar graves danos à saúde humana. Foi utilizado o diagrama triangular de Piper para estabelecer a classificação dessas águas, revelando-se essencialmente de natureza cloretada sódica em onze poços estudados. São em geral águas de boa qualidade, com exceção de algumas com alta salinidade e que têm influências da formação Candeias/Sergi. Nitrato, potássio, bário, chumbo e alumínio excederam o valor máximo aceitável para consumo humano em algumas amostras, sendo os dois primeiros oriundos provavelmente de contaminação antrópica enquanto o bário, chumbo e alumínio estariam associados a contaminação geogênica.

Pangea rifting and onward pre-Central Atlantic opening as the main ore-forming processes for the genesis of the Aouli REE-rich fluorite–barite vein system, Upper Moulouya District, Morocco

The Aouli fluorite–barite±sulphides vein system in the Upper Moulouya District of Central Morocco is hosted in a folded and low to medium grade sedimentary and volcanic rocks, unconformably overlaid by Permo-Triassic to Cretaceous red beds and limestones. Intrusion of the hydrothermally altered multiphase ca. ∼330–319Ma Aouli granite batholith has contact metamorphosed the host rocks to a metamorphic assemblage of cordierite, andalusite, chlorite, muscovite, and biotite±sillimanite±garnet.The mineralized structures that consist mostly of quartz, fluorite, and barite occur principally as ENE–WSW, WNW–ESE, and E–W-trending trans-tensional steeply dipping veins, veinlets and en echelon tension gash fillings. Irrespective of colour, location, paragenesis and textural position within the mineralized vein structure, the fluorite is characterized by high total REY contents ranging from 250 to 662ppm, distinctive positive Eu and Y anomalies, and middle rare-earth element enrichment.Fluid inclusion data indicate that the ore-forming fluids correspond to evolved NaCl–CaCl2+other cations sedimentary (94–174°C), saline (14–24wt% NaCl equiv.) brines. The strontium isotopic compositions of fluorite (87Sr/86Sr=0.710155–0.712293) and barite (0.710215–0.701401), along with the Liassic dolomitized limestones (0.707867–0.708140) are more radiogenic than the Cambro-Ordovician and Triassic–Early Jurassic seawater values, with the Aouli Late Variscan granite (0.70814±12) and the Triassic arkoses (0.709839–0.712313) displaying the highest 87Sr/86Sr ratios. Barite separates show uniform δ34S ratios of +11‰ to +13.4‰ consistent with Permian–Triassic seawater sulphate.The calculated REY fluid compositions along with fluid inclusion, strontium and sulphur isotope data point to the role of hot sedimentary brines with fluid–rock interaction at high fluid/rock ratios. The fluid system is likely related to the Pangea rifting and subsequent Central Atlantic opening during Permian–Triassic time. The fluorite–barite mineralization is likely due to mixing at the basement–cover interface of an ascending deep-seated fluid that equilibrated with Variscan crystalline basement rocks and cooler more dilute formation water.

Rare earth elements, S and Sr isotopes and origin of barite from Bahariya Oasis, Egypt: Implication for the origin of host iron ores

Based on their occurrences and relation to the host iron ores, barites are classified into: (1) fragmented barite occurs as pebble to sand-size white to yellowish white barite along the unconformity between the Bahariya Formation and iron ores, (2) interstitial barite is present as pockets and lenses of large and pure crystals inside the iron ores interstitial barite inside the iron ores, and (3) disseminated barite occurs at the top of the iron ores of relatively large crystals of barite embedded in hematite and goethite matrix. In the current study, these barites have been analyzed for their rare earth elements (REE) as well as strontium and sulfur isotopes to assess their source and origin as well as the origin of host iron ores.Barite samples from the three types are characterized by low ΣREE contents ranging between 12 and 21ppm. Disseminated barite shows relatively lower ΣREE contents (12ppm) compared to the fragmented (19ppm) and interstitial (21ppm) barites. This is probably due to the relatively higher Fe2O3 in the disseminated barite that might dilute its ΣREE content. Chondrite-normalized REE patterns for the three barite mineralizations exhibit enrichment of light rare earth elements (LREE) relative to heavy rare earth elements (HREE) as shown by the high (La/Yb)N ratios that range between 14 and 45 as well as pronounced negative Ce anomalies varying between 0.03 and 0.18. The 87Sr/86Sr ratios in the analyzed samples vary between 0.707422 and 0.712237. These 87Sr/86Sr values are higher than the 87Sr/86Sr ratios of the seawater at the time of barite formation (Middle Eocene with 87Sr/86Sr ratios of 0.70773 to 0.70778) suggesting a contribution of hydrothermal fluid of high Sr isotope ratios. The δ34S values in the analyzed barites range between 14.39‰ and 18.92‰. The lower δ34S ratios in the studied barites compared with those of the seawater at the time of barite formation (Middle Eocene with δ34S ratios of 20–22‰) is attributed to a possible contribution of hydrothermal fluid of low δ34S values that lowered the δ34S values in the studied barites.Rare earth elements distribution and patterns, as well as strontium and sulfur isotopes suggest a mixing of seawater and a hydrothermal fluid as possible sources for barite mineralizations in the Bahariya Oasis. The seawater source is suggested from the low Ce/La ratios, “V” shape of the rare earth patterns and pronounced negative Ce anomalies. On the other hand, the hydrothermal fluid contribution is evident from the low concentrations of rare earth and the deviation in both S and Sr isotopic compositions from those of the seawater during the time of barites formation (Middle Eocene). The relatively heterogeneous Sr and S isotope ratios among the studied barites suggest the Bahariya Formation and Basement Complex as possible sources of the hydrothermal fluids. The similarity in the REE as well as S and Sr isotopic compositions of the three types of barite suggest that they form simultaneously.As the geology and occurrence of the barites suggest a genetic relationship between these barites and the host iron ores, the mixed seawater and hydrothermal sources model of the barites is still applicable for the source of the host iron ores.

BIOGEOCHEMICAL CHARACTERISTICS OF EGGS OF BACKYARD POULTRY FROM BARITE MINERALIZATION, ANDHRA PRADESH, INDIA

In the present study an attempt has been made for biogeochemical studies involving elemental distribution and interactions in backyard poultry eggs from Vemula barite mineralized area to determine their indicator characteristics and of their possible application in applied environmental geoscience. The samples of backyard poultry eggs of hen were collected systematically. Their physical properties like moisture, organic matter and ash content are determined which shows wide variations. Trace element analysis of these samples was carried out for Ba, Sr, Cu, Pb, Zn, Mn, Ni, Co, Cr, Fe Mg, and Al. the parameter Coefficient of Apparent of Organic Binding (CAOB) is calculated for each element for the eggs. Wide variations are observed in the distribution of chemical elements in backyard poultry eggs. Ba occupies first position in the sequence in all parts of the raw eggs both on ash weight and dry weight bases. The enrichment of Ba concentration in backyard poultry eggs may be due to the presence of barite mineral. Therefore backyard poultry eggs may ideally be used as tools for their possible application in mineral exploration. This study has given greater scope in biogeochemical orientation surveys, and in environmental studies.

Origin of early Cambrian black-shale-hosted barite deposits in South China: Mineralogical and geochemical studies

The barite deposits hosted in early Cambrian black shales in South China are a classic example of sediment-hosted stratiform barite deposits, and their origin is controversial. In this paper, we address the origin of these deposits by a comprehensive integrated study of mineralogy and geochemistry, based on a case study of the Dahebian deposit in Tianzhu County, Guizhou Province, which contains the largest global reserve of barite. Particular attention was paid to a comparison between ore and non-ore horizons, as this has not been fully addressed previously. The results indicate that the ore horizon is dominated by barite with intergrown hyalophane, quartz and pyrite. The hyalophane is zoned, implying hydrothermal activity. In contrast, the non-ore horizons contain minor amounts of granular barite and are free of hyalophane, suggesting that these horizons experienced weaker hydrothermal activity. The contrasting trace and rare earth element compositions of the ore and non-ore samples indicate dilution of complex geochemistry with multiple ore-forming processes and materials during barite mineralization. The barite mineralization was rapid, as demonstrated by the relatively low terrigenous input in the ore samples compared with the non-ore samples. The ore samples have positive Eu anomalies (>3.0), indicative of hydrothermal activity during mineralization. Organic geochemical analyses provide evidence of the development of abundant organic matter and hydrothermal activity. The sulphur isotopic values (δ34S) of the ore samples show an enrichment relative to contemporaneous early Cambrian seawater and substantial variation (+36.7‰ to +43.8‰), indicative of sulphur derived from seawater that was affected by sulphate-reducing bacteria and hydrothermal activity in a restricted marine environment. To summarize, the barite deposit in the Dahebian site was most likely formed in a generally restricted and reducing marine basin environment with rapid sedimentation during a period of hydrothermal activity. These results have general implications for the future study of other black-shale-hosted deposits worldwide.

The Chaqupacha Mississippi Valley-type Pb–Zn deposit, central Tibet: Ore formation in a fold and thrust belt of the India–Asia continental collision zone

The newly discovered Chaqupacha Mississippi Valley-type (MVT) Pb–Zn deposit in central Tibet has been found to be helpful for understanding MVT ore formation relative to tectonic evolution of a foreland fold and thrust belt. The deposit lies in the Tuotuohe area of the western Fenghuo Shan-Nangqian fold and thrust belt of the India–Asia continental collision zone. It contains NNW-striking and folded Late Permian strata including an upper clastic unit and an underlying limestone unit. The strata overlie late Oligocene clastic rocks through a south-dipping reverse fault that is associated with regional northward thrusting during the Paleogene. The Late Permian and late Oligocene strata are unconformably overlain by flat-lying early Miocene marl and mudstone of the Wudaoliang Formation. Lead and zinc ores are mainly hosted by pre-ore dissolution and collapse breccias in the Late Permian limestone. The style of mineralization is epigenetic, as shown by replacement of the pre-ore dissolution breccia matrix and open-space-fill by galena, sphalerite, calcite, and minor barite and pyrite. δ34S values of the main sulfide galena range from −27.5‰ to +12.6‰. These features, together with the lack of magmatic activity during the mineralization, suggest that Chaqupacha is an MVT deposit. Subordinate mineralization is also present in the early Miocene Wudaoliang Formation marl and the paleokarst breccia which contains matrix compositionally equivalent to strata of the Wudaoliang Formation. The mineralization shares similar mineral associations and textures with the pre-ore dissolution breccia-hosted mineralization. Thus, the Pb and Zn mineralization in the entire deposit probably resulted from the same mineralizing event, which is younger than the youngest ore-hosting rocks (i.e., the early Miocene Wudaoliang Formation). Considering that thrusting in the Tuotuohe area had ceased prior to deposition of the Wudaoliang Formation host rocks, the mineralization at Chaqupacha post-dated the regional deformation. The Chaqupacha deposit thus provides a good example of MVT mineralization in a foreland fold and thrust belt that post-dates regional thrusting.

Preparation and Characterization of Barite/TiO2Composite Particles

To make full use of barite mineral and obtain a kind of composite particles material which has the property of both barite and TiO2, the composite particles material with TiO2coated on the surface of barite particle was prepared by the method of TiOSO4solution chemical hydrolysis and precipitation to form hydrolysis composite, removing the impurities of hydrolysis composite, drying, and calcination in this study. The results were evaluated by the covering power of composites. Composite structure and properties were characterized by means of XRD, SEM, FTIR, and XPS. The results showed that the surface of barite had been coated with rutile TiO2uniformly and compactly and the hiding power value and oil absorption value of the composite powder were 18.50 g/m2and 15.5 g/100 g, respectively, which had similar pigment performances to TiO2. The results also showed that it was mainly the strong chemical bond between barite and TiO2that combined them firmly in barite/TiO2composite particle (B/TCP).

Geology, geochemistry, sulfur isotope composition, and fluid inclusion data of Farsesh barite deposit, Lorestan Province, Iran

Farsesh barite in the central part of Iranian Sanandaj-Sirjan zone is a sample of epigenetic hydrothermal mineralization in dolomitized limestone, which provides appropriate chemicophysical conditions making the passage of mineral-bearing fluids possible. Barite veins may range from a few centimeters to 2 m in thickness that increases downward. The microthermometry measurements obtained from more than 30 fluid inclusions show relative homogenization temperatures ranging from 125 to 200 °C with an average of 110 °C for Farsesh barite deposits. The mean salinity measured proves 16 times as much as weight percentage of NaCl for barite. Coexistence of liquid- and vapor-rich fluid inclusions in barite minerals may provide an evidence of boiling in ore veins. Moreover, occurrence of bladed calcite, high-grade ore zones, and presence of hydrothermal breccia are all consistent with boiling. Thermometric studies indicate that homogenization temperatures (Th) for primary and pseudosecondary fluid inclusions in barite range from 125 to 200 °C with an average of 1,100 °C. The δ34S values of barite also lie between 8.88 and 16.6 %. The relatively narrow spread in δ34S values may suggest uniform environmental conditions throughout the mineralization field. Thus, δ34S values are lower than those of contemporaneous seawater, which indicates a contribution of magmatic sulfur to the ore-forming solution. Barite is marked by total amounts of rare Earth elements (REEs) (6.25–17.39 ppm). Moreover, chondrite-normalized REE patterns of barite indicate a fractionation of light REEs (i.e., LREEs) from La to Sm, similar to those for barite from different origins. The LaCN/LuCN ratios and chondrite-normalized REE patterns reveal that barite in Farsesh deposit is enriched in LREEs compared with heavy rare Earth elements (HREEs). Similarity between Ce/La ratios in barite samples and those found in deep-sea barite supports its marine origin. Lanthanum and Gd exhibit positive anomalies, which are common features of chemical marine sediments. Cerium shows a negative anomaly in most samples inherited from the negative Ce anomaly of hydrothermal fluid that is mixed with seawater at barite precipitation. The available data including tectonic setting, host rock characteristics, REE geochemistry, and sulfur isotopic compositions may support a hydrothermal submarine origin for Farsesh barite deposit.

Stable strontium isotope fractionation in synthetic barite

The mineral barite (BaSO4) accommodates strontium (Sr) in its crystal structure, providing an archive of Sr-isotopes (87Sr/86Sr and δ88/86Sr) in the highly stable sulfate mineral. We investigated mass dependent stable Sr-isotope fractionation (Δ88/86Sr=δ88/86Srsolid−δ88/86Srsolution) during inorganic precipitation of barite from a barium-rich solution by addition of sulfate under controlled conditions and compared this to equilibrium isotopic fractionation calculated using Density Functional Theory modeling. Sr-substituted barite is predicted to have lower 88Sr/86Sr than any other studied species, and at 25°C will be about 0.6–0.7‰ lower than the two modeled Sr(H2O)82+-bearing salts that could approximate aqueous Sr2+. This agrees in direction and order of magnitude with experimental results that estimate equilibrium Sr-isotope fractionation in barite to be 0.3‰ lower than aqueous Sr2+ at ∼20°C. The high ionic strength of some of the precipitating solutions (up to 1M) and potential differences in the average coordination number of aqueous Sr2+ add to uncertainty in a direct comparison of the calculated equilibrium isotopic fractionation values with the experimental results.Stable Sr-isotope fractionation varied along with the distribution coefficient of Sr [Kd(Sr)=[Sr/Ba]barite/[Sr/Ba]solution], which is a function of both temperature and barite saturation state. However the relationship between mass dependent isotopic fractionation and Kd(Sr) is different for conditions of changing temperature versus barite saturation state. With increasing temperature (from 5 to 40°C), the barite phase became isotopically lighter (Δ88/86Sr=−0.29‰ to −0.41‰). Conversely, with increasing saturation state (saturation index of barite=3.0–4.3) the barite phase became isotopically heavier (Δ88/86Sr=−0.25‰ to −0.10‰). These observations suggest chemical kinetic effects control isotopic fractionation rather than equilibrium temperature effects. The relationship with saturation state indicates the potential presence of a diffusive boundary layer. Barite crystal morphology appears to be affected by the diffusion rate of solute (sulfate) to the growing crystal surface relative to the overall growth rate of barite crystals during precipitation.

Study on a Lead-Zinc-Fluorite-Barite Symbiotic Ore

The ore using in this paper was obtained from Hunan Province, China, which contains fluorite (15.65%), barite (48.42%), quartz (30.56%), sphalerite (0.57%), galena (0.54%) and other minerals. After fluorite-barite mixed flotation, fluorite-barite separation flotation, and anti-flotation of lead and zinc minerals, the fluorite concentrate with 97.35% CaF2 and barite concentrate with 95.49% BaSO4 was gotten. The recovery of the fluorite concentrate was 81.85% and the recovery, specific gravity, whiteness of the barite concentrate was 95.00%, 4.34g/cm3, 90.65%, respectively. This symbiotic ore can be comprehensive utilized by this beneficiation procedure.

Petroleum Migration, Fluid Mixing, and Halokinesis as the Main Ore-Forming Processes at the Peridiapiric Jbel Tirremi Fluorite-Barite Hydrothermal Deposit, Northeastern Morocco

The Jbel Tirremi fluorite-barite sulfide deposit in northeastern Morocco is hosted in a Jurassic-aged structurally high carbonate platform known as the Jbel Tirremi dome. The host rocks consist of unmetamorphosed, flat-lying early Jurassic dolomitized limestones, locally intruded by Eocene lamprophyre dikes. The orebodies consist mostly of fluorite and barite, and occur as open-space fillings and partial to massive replacement of the enclosing medium- to coarse-grained dolomitized limestones. The ore mineralogy is dominated by fluorite of different colors and habits, barite, and, to a lesser extent, sulfides. Rare earth element compositions along with fluid inclusion, halogen and isotopic data suggest that the fluorite barite mineralization and the spatially associated Eocene alkaline magmatism are petrogenetically unrelated, pointing instead to the regional circulation of hydrothermal basinal brines mixed to various degrees with meteoric water in a dominantly closed rock-buffered system at progressively higher temperatures and fluid/rock ratios. In this respect, fluid inclusion microthermometric measurements show that the ore-bearing hydrothermal system developed in two separate stages of fluorite-barite mineralization, as also revealed by isotopic data. Both stages precipitated from saline fluids at shallow crustal levels (i.e., = 82 degrees C and possibly up to 218 degrees C, whereas in the second stage the mineralizing fluid had a similar temperature range, but lower salinities (similar to 20-10 wt % NaCl equiv). The recorded high salinities are interpreted to represent the involvement of a mixture of halite dissolution water and evaporated seawater component. Oxygen (delta O-18 = 21.7 to 29.6%0 V-SMOW) and carbon (delta C-13 = -7.9 to 0.2%0 V-PDB) isotope data along with strontium (Sr-87/Sr-86 = 0.70300-070789) and lead (Pb-206/Pb-204 = 17.961-20.96, Pb-207/Pb-204, 15.511-15.697, Pb-208/Pb-204 = 37.784-39.993) isotope ratios suggest the involvement of a mixture of oil-bearing fluids, basinal brines, and meteoric fluids that interacted extensively with the early Jurassic host carbonates, the underlying Triassic salt-bearing diapir, associated siliciclastic rocks, and the highly fractionated and greisenized Hercynian granitic crystalline basement, resulting in the release of fluoride, metals, and other constituents to form the Jbel Tirremi deposit. Petroleum-bearing fluid, released from overpressured portions of the Guercif Basin at lithostatic pressures, and bittern brines dominated the first stage of mineralization. Mixing of saline, oxidized, CaCl2- and sulfate-rich bittern brine with oil-bearing fluid resulted in fluorite precipitation of stage I. Conversely, during the second stage of mineralization, the hydrothermal system was open to the influx of oxidized meteoric water as a consequence of the upward migration of the Triassic salt-bearing diapir and associated pressure decrease. The shift from stage I to stage II is associated with the evolution of the system from lithostatic to mostly hydrostatic pressure conditions. Stage I mineralization is thought to have occurred during the Late Miocene in response to rapid sedimentation and high subsidence rates and subsequent hydrocarbon migration associated with the outward migration of the Rif thrust front. Conversely, stage II mineralization occurred coevally with the uplift phase during Tortonian time.

Correlation of the Particle Size Distribution Parameters with Sieving Rate Constant

Controlling the particle size distribution (PSD) of raw materials, intermediates, and end products is very critical to the success of the powder technology related processes. This study presents the evaluation of the sieving characteristics of some industrial minerals, namely, quartz, talc, and barite, and the establishment of possible correlations between the PSD and kinetics parameters. PSD of the −600 µm fractions of quartz, talc, and barite minerals were plotted in Schuhmann mathematical approach. The size modulus (ks) and distribution modulus (αs) were obtained for each mineral. Then, sieving kinetics study was carried out for each mineral to determine optimum sieving time and sieving rate constant (kk). Further, the size distribution parameters were correlated with the sieving rate constant values for those minerals. While distribution modulus (αs) increases, size modulus (ks), and average sieving rate constant values (kk) decrease. The correlations were found to be ks = −293.52αs + 730.87 and kk = −0.0041αs + 0.0454. The results showed that near-mesh particles play important role in the overall kinetic process.

Baseline Concentration and Sources of Trace Elements in Groundwater of Cross River State, Nigeria

Groundwater samples were collected from wells in Cross River State (Nigeria) and analysed for trace elements including Ba, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Sr and Zn. The primary aim of the study was to determine the baseline concentrations of these metals, while the secondary aim was to assess the present level of pollution, as a basis for future impact of human and industrial activities on the groundwater quality. Multivariate statistical methods were applied to determine the relationships between the different trace elements and also infer their different sources. The results showed that the contents of Ba, Fe, and Pb in groundwater from some locations were higher than the World Health Organisation, WHO maximum admissible concentration (MAC) of 700µg/l, 300µg/l and 100µg/l respectively. The contents of Cd, Co, Cu, Fe, Mn, Ni, Pb, Rb and Zn were lower than the concentrations in freshwater, while the contents of Ba, Cr, Li, Mo and Sr in some of the locations exceeded the values in typical freshwater. Correlation and cluster analyses indicated common sources for some elements, while factor analysis suggested dissolution of brine, dissolution of barite mineral, weathering of the bedrock and prevailing oxidation-reduction potential of the environment as the main factors responsible for the occurrence of these trace elements in groundwater. The present data therefore is expected to serve as a good guide for future groundwater management of the area.

Biotite and Apatite as Tools for Tracking Pathways of Oxidized Fluids in the Archean East Repulse Gold Deposit, Australia

Fluid pathways in hydrothermal ore deposits can potentially be traced through alteration zoning patterns and the chemistry of mineral phases (i.e., major, trace elements, and isotopic composition), which provide insight into the physico-chemical gradients within and adjacent to pathways. World-class Neoarchean gold deposits of the eastern Yilgarn can be zoned with respect to alteration assemblages, but in many cases fluid pathways are poorly understood, which makes it difficult to identify the nature and source of fluids. This study conducted detailed core logging, SEM mineral mapping of alteration assemblages, and microprobe analysis of biotite and apatite in order to identify chemical gradients across the East Repulse gold deposit of the St. Ives gold camp, eastern Yilgarn, Western Australia. Results show that the East Repulse deposit is vertically zoned with relatively oxidized sulfate-rich alteration in the footwall of the deposit (anhydrite, celestine and/or barite), sulfide-rich alteration in the core of the deposit (pyrite ± magnetite with minor barite and celestine), and relatively reduced sulfide-only assemblages (pyrite ± pyrrhotite with minor pentlandite, millerite, and cobaltite) in the hanging wall of the deposit. Gold was identified as inclusions in pyrite and associated biotite implying a link between biotite-pyrite alteration and gold mineralization. The abundance of F in biotite and apatite progressively decreases from the footwall of the deposit into the mineralized core. This trend of decreasing F in biotite and apatite with decreasing depth is consistent with an hypothesis that oxidized F- and K-bearing fluids were focused along subvertical pathways beneath the deposit, within or subjacent to granitoid dikes. The biotite-apatite geothermometer shows that these fluids were relatively hot (~480° ± 60°C) at the time of alteration. These relatively high temperature, oxidized, F- and K-bearing fluids may have been derived from a proximal magmatic source.

Mine water geochemistry and metal flux in a major historic Pb-Zn-F orefield, the Yorkshire Pennines, UK

Recent studies have shown up to 6 % of rivers in England and Wales to be impacted by discharges from abandoned metal mines. Despite the large extent of impacts, there are still many areas where mine water impact assessments are limited by data availability. This study provides an overview of water quality, trace element composition and flux arising from one such area; the Yorkshire Pennine Orefield in the UK. Mine drainage waters across the orefield are characterised by Ca-HCO3-SO4-type waters, with moderate mineralization (specific electrical conductance: 160-525 μS cm(-1)) and enrichment of dissolved Zn (≤2003 μg L(-1)), Ba (≤971 μg L(-1)), Pb (≤183 μg L(-1)) and Cd (≤12 μg L(-1)). The major ion composition of the waters reflects the Carboniferous gritstone and limestone-dominated country rock, the latter of which is heavily karstified in parts of the orefield, while sulphate and trace element enrichment is a product of the oxidation of galena, sphalerite and barite mineralization. Contaminant flux measurements at discharge sites highlight the disproportionate importance of large drainage levels across the region, which generally discharge into first-order headwater streams. Synoptic metal loading surveys undertaken in the Hebden Beck sub-catchment of the river Wharfe highlight the importance of major drainage levels to instream baseflow contamination, with diffuse sources from identifiable expanses of waste rock becoming increasingly prominent as river flows increase.

Barite Veins in the Benue Trough: Field Characteristics, the Quality Issue and Some Tectonic Implications

The Benue trough is Nigeria’s main, but not exclusive source of barite mineralisation. There are at least ten barite fields in the trough, each containing swarms of veins or concordant stratiform minerals flats of hydrothermal origin. There are only two vein trends in the trough: the NW-SE trend, which tends to be orthogonal to the axis of the trough; and the N-S to NNE-SSW trend, which is younger than the former. Both vein sets are formed from ac tension joints reflecting different post-sedimentary deformation phases in the trough. The NW-SE veins are also more frequent than the N-S veins, almost in the ration of 2:1. Although 86 veins have been studied, not one was found oriented parallel to the axis of the trough, a good indication of structural control on mineral vein orientations. The dips of the veins tend to be high (>80o), a condition that favours manual mining. Veins tend to display a simple block profile and their widths vary from a few centimetres to as much as 6m, though the most frequently occurring widths are between 50cm and 1m. The implication of this is that BaSO4 concentrations in hydrothermal fluids in the trough were probably low during the Cretaceous period. In many veins, there is barite quality contrast between the top part and the lower portions. Higher quality barite tends to come from the lower portions. Hence it is expected that much of the low quality stigma associated with Nigerian barite from the trough would be relieved when mining gets down to good depths. For this reason, mining in those veins of low quality barite should proceed by vertical stripping.

Barite in the ocean – occurrence, geochemistry and palaeoceanographic applications

AbstractThe mineral barite (BaSO4) can precipitate in a variety of oceanic settings: in the water column, on the sea floor and within marine sediments. The geological setting where barite forms ultimately determines the geochemistry of the precipitated mineral and its usefulness for various applications. Specifically, the isotopic and elemental composition of major and trace elements in barite carry information about the solution(s) from which it precipitated. Barite precipitated in the water column (marine or pelagic barite) can be used as a recorder of changes in sea water chemistry through time. Barite formed within sediments or at the sea floor from pore water fluids (diagenetic or cold seeps barite) can aid in understanding fluid flow and sedimentary redox processes, and barite formed in association with hydrothermal activity (hydrothermal barite) provides information about conditions of crust alteration around hydrothermal vents. The accumulation rate of marine barite in oxic‐pelagic sediments can also be used to reconstruct past changes in ocean productivity. Some key areas for future work on the occurrence and origin of barite include: fully characterizing the mechanisms of precipitation of marine barite in the water column; understanding the role and potential significance of bacteria in barite precipitation; quantifying parameters controlling barite preservation in sediments; determining the influence of diagenesis on barite geochemistry; and investigating the utility of additional trace components in barite.