From Alpine-type sulfides to nonsulfides in the Gorno Zn project (Bergamo, Italy)

Recent exploration of the Gorno Zn-Pb-Ag deposit in northern Italy identified 3.3 Mt of sulfides at 4.9% Zn, 1.3% Pb, and 27.2 g/t Ag (indicated+inferred resources), and a further mineralized nucleus of mixed sulfides-nonsulfides in the Val Vedra area, currently under evaluation. The ores are hosted in Triassic limestone and shale. Sulfides (sphalerite, Ag-bearing galena, minor pyrite, and chalcopyrite) paragenetically follow Mn-Fe-bearing saddle dolomite and sparry calcite. The mineral association, and the carbon and oxygen isotope ratios of the sparry calcite (avg. δ13C = 1.0 ± 0.6‰ V-PDB; avg. δ18O = 19.63 ± 1.25‰ V-SMOW), are in agreement with precipitation from hydrothermal fluids in a deep burial setting. Sulfide emplacement occurred before the Alpine orogeny, likely during the Early-Middle Jurassic, in analogy to other Alpine-type deposits. The nonsulfide ore formed at the expense of sulfides, and mainly consists of smithsonite, hydrozincite, hemimorphite, and cerussite. The C-O-isotope values of the early generations of Zn-carbonates are characterized by δ18O between 24.1 and 26.8‰ V-SMOW and δ13C ratios between − 3.1 and 1.7‰ V-PDB. The later generations have lower δ18O (21.9 to 23.9‰) and lower δ13C (− 6.2 to − 3.9‰). These compositions, as those measured on cerussite (δ13C = −6.3 and − 7.7‰; δ18O = 14.0 and 15.3‰), agree with the formation of the nonsulfides in a supergene environment, under climatic conditions warmer than today. The δ18O decrease from early to late generations suggests progressive involvement of meteoric water sourced from higher altitudes. These characteristics indicate that the nonsulfides formed during the exhumation of the Gorno area from Miocene to Pliocene

Geochemical characterization of bauxite deposits from the Abruzzi Mining district (Italy)

The Abruzzi bauxite district includes the deposits located on the Campo Felice plateau and those of the Monti d'Ocre, which had been mined in the first part of the 20th century. Bauxite is of the karst type, with textures ranging between oolitic and oolitic-conglomeratic, the latter suggesting a partial reworking of evolved lateritic soils. The high contents of Al2O3 and Fe2O3 (average values 53.76 and 21.76 wt %, respectively) are associated with the presence of boehmite, hematite, and minor goethite. SiO2 and TiO2 have average values of 7.79 and 2.75 wt %, corresponding to the presence of kaolinite, anatase and rutile. Among the minor so-called "bauxitophile" elements V, Co, Ni, Cr and Zr, the most enriched is Cr, with an average value of 0.07 wt %. Nickel has an average value of 210.83 ppm. Vanadium shows an average value of 266.57 ppm, whereas the average Co concentration is 35.89 ppm. The total rare earth elements (REE) concentration in the sampled bauxite sites is variable between ca. 700 and 550 ppm. Among REEs, the most abundant element is Ce, with Ce anomalies commonly associated with authigenic REE-fluoro-carbonates, probably produced after the REEs remobilization from primary detrital minerals and their precipitation in neo-formed phases during the bauxitization process. Scandium and Ga occur in small amounts (57 and 60 ppm, respectively), but geochemical proxies of their remobilization and uptake in neo-formed minerals (Feand Al-(hydr) oxides, respectively) have been observed. The mean Eu/Eu* and Al2O3/TiO2 ratios and the Ni-Cr contents of the Abruzzi bauxites suggest that the parent rock of these deposits was a material of acid affinity, likely corresponding to volcanic tephra or eolic loess-type sands

C−O Stable Isotope Geochemistry of Carbonate Minerals in the Nonsulfide Zinc Deposits of the Middle East: A Review

Zinc nonsulfides are well represented in the Middle East, with occurrences in Turkey, Iran, and Yemen. Their genesis can be constrained by using carbon and oxygen isotope systematics applied to carbonate minerals. The δ13C ratios of smithsonite and hydrozincite in Iran and Turkey are comprised in the typical interval of supergene Zn carbonates (−0.4 and −7.1‰ V-PDB). The oxygen isotope geochemistry is more complex. Oxygen isotope compositions of smithsonite of the Hakkari deposit (Turkey) (δ18O from 24.2 to 25.6‰ V-SMOW) point to precipitation temperatures between ~4 and ~18 °C, corresponding to a normal weathering environment at these latitudes, whereas δ18O of smithsonite from other Middle East deposits (Angouran in Iran, Jabali in Yemen) point to the precipitation from low- to medium-temperature hydrothermal fluids. The C–O isotopic compositions of hydrozincite from the Mehdi Abad, Irankuh, and Chah-Talkh deposits can be only partially compared with those of smithsonite, because the oxygen isotopes fractionation equation for hydrozincite-water is not known. A comparison between the geochemical characteristics of all Zn-nonsulfide ores in the Middle East indicates that, even though several mineral deposits are derived from supergene weathering processes, other ones have been deposited from fluids associated with magmatic activity (Angouran, Iran) or with hydrothermal systems (Jabali, Yemen). This suggests that it is not possible to apply a common interpretative model to the genesis of all nonsulfide deposits in the Middle East

New C- and O-isotopic compositions of smithsonite from Skorpion and Rosh Pinah Zn-(Pb) deposits (Namibia): preliminary results and implications

The Skorpion and Rosh Pinah Zn-(Pb) deposits are hosted in Neoproterozoic rocks that are part of a volcano-sedimentary sequence within the Gariep Belt in southern Namibia. Genetically, the Gariep sequence is related to the progressive opening of a failed intracratonic rift graben in the east (Rosh Pinah/Skorpion Graben) that was separated by a basement horst from a half graben to the west, which then developed into the Adamastor ocean [1]. The deposits approximately 40 km north of the Orange river, are only at a 15 km distance from one another [1,2], however, Skorpion is located on an uplifted block whereas Rosh Pinah is located on a topographically lower block. Skorpion is the largest Zn-nonsulfide mineralization ever discovered, and is derived from the oxidation of a VMS-type sulfide protore [1]. It mostly consists of Zn-oxidized minerals (sauconite, smithsonite, hemimorphite, tarbuttite, skorpionite). Rosh Pinah is a typical sediment-hosted Zn massive sulfide mineralization. The original oxidized interval at the surface was of limited extent and has been almost completely removed. Secondary minerals at Rosh Pinah are: smithsonite, hemimorphite, Cu-oxidized phases and Fe-oxy-hydroxides [2]. The isotopic composition of Skorpion smithsonite, already partly published by previous authors [1], shows that the supergene alteration of the sulfide protore resembled typical weathering processes. Here we present the first results of a comprehensive carbon and oxygen isotope study in order to better characterize/understand the deep oxidation occurring at Skorpion, compared with the more limited weathering active in the Rosh Pinah area. A batch of 16 smithsonites and 5 (co-genetic) calcites from the Skorpion deposit and 10 gossanous samples (comprising host dolomite and smithsonite) from the uppermost levels of the Rosh Pinah mine have been analyzed. The Zn- and Ca-carbonates sampled at Skorpion occur mostly as cavity fillings and crusts consisting of mm-sized euhedral crystals. Skorpion smithsonite is characterized by δ13C values strongly variable between 0.1 and −9.1‰ VPDB, and by a small range in δ18O (28.0 to 29.9‰ VSMOW). Calcite shows more limited variations: the δ13C values are generally positive (0 to 1.6‰ VPDB). The δ18O values are slightly lower than those of smithsonite (25.4 to 27.1‰ VSMOW). The analyses of the Rosh Pinah samples show that the host dolomite is characterized by δ18O values ranging from 18.7 to 22.0‰ VSMOW and by negative δ13C values. The carbon isotope ratios of smithsonite, as in Skorpion, are negative but similar to those of the host dolomites. The δ18O values are on average the same measured at Skorpion. The similar negative δ13C values of smithsonite and dolomite from Rosh Pinah, point to the involvement of both organic and host dolomite carbon for smithsonite formation, whereas, at Skorpion, the involvement of isotopically light organic carbon is considered more probable. The same δ18O compositions of smithsonite from the two deposits imply similar ore-forming fluids and/or similar conditions during formation. References: [1] Alchin DJ et al. (2005) S Afr J Geol 108: 19-3 [2] Borg G et al. (2003) Econ Geol 98: 749-771 [3] Alchin DJ and Moore JM (2005) S Afr J Geol 108: 71-8

The Pb-Zn (Ba) Nonsulfide Mineralizations at Bou Caïd (Ouarsenis, Algeria): Mineralogy, Isotope Geochemistry, and Genetic Inferences

The ore deposits of Bou Caïd (Ouarsenis, Algeria) occur in Jurassic and Cretaceous sedimentary rocks. The barite and Pb-Zn (Fe, Cu, and F) ore deposits of Bou Caïd belong to vein- and karst-type. The mineralization is represented in the whole area by a mixture of barite (currently still exploited) and nonsulfides consisting of hemimorphite, smithsonite, cerussite, hydrozincite, and Fe-oxy-hydroxides, with remnants of galena and sphalerite in variable proportions. Mineralogical and geochemical analyses were carried out on the Bou Caïd nonsulfides. Several samples representing nonsulfide mineralization (Grand Pic and at Srâa Abdelkader) were subjected to a multidisciplinary analytical approach, using optical microscopy (OM), powder X-ray diffraction (PXRD), Scanning Electron Microscopy with Energy Dispersive Spectrometry (SEM-EDS). Nonsulfide mineralization consists of a mixture of hemimorphite, hydrozincite, smithsonite, cerussite, and Fe-oxy-hydroxides, often with zebra-like textures. In the proposed paragenetic scheme, covellite and chalcocite are followed by cerussite, jarosite, smithsonite, and hydrozincite. Then, hemimorphite crystallizes, accompanied by mimetite, traces of malachite and clay minerals (also Zn-bearing), precipitate. Fe-(Mn)-oxy-hydroxides can form during various phases of the supergene stage. Small amounts of late barite can be related to partial remobilization and occur as reprecipitation products. Stable isotope analyses were performed on the calcites and metal carbonates of the supergene ores. Carbon and oxygen isotope values of smithsonite and hydrozincite were comparable to published supergene Zn carbonate data. The isotope values of the Bou Caïd calcites fell both into the hydrothermal carbonate and in the supergene fields

The Zn-Nonsulphides district of Bongarà (Northern Peru)

The Bongarà complex of deposits consists of a stratabound Pb-Zn Nonsulphide/Sulphide mineralization located in the Amazonas District, near the Yambrasbamba village (Peru) [1]. The deposits (Mina Grande, Mina Chica, and Rio Cristal) are hosted by Mesozoic limestone (Toarcian) of the Pucarà Group (Condorsinga Fm.), locally dolomitized and brecciated. The primary mineralization is considered a MVT, similar to the San Vicente deposit in Central Peru. There are multiple distinct ore concentrations scattered over a large area; the mineralization appears to be open-space filling and/or manto replacement associated with karstification. The economic value is currently considered as related to the concentrations of nonsulphide Zn minerals [2]. The Mina Grande deposit consists of several, partly exploited mineralized areas, where the ore consists of masses of nonsulphides (mainly hydrozincite>>smithsonite) mixed with brown soil. The mineralized body is 1.5 km long, 0.4 km wide, and extends to depths of 20 to 60 m below surface. The economic mineralization is concentrated in karstic cavities and earthy-looking mantos. The zinc “oxides” form a residual cap along the crest of an anticlinal structure [1]. This mineralization can be classified as belonging to Type 3 (residual in karsts cavities) among the supergene nonsulphide deposits [3]. The Rio Cristal prospect [1] is probably the most extensive area of zinc mineralization occurring at Bongarà to date. Diamond drilling has encountered both near-surface primary base metal sulphides (only in traces), and oxidized mineralization at depths of over 50 m down-hole, with grades of up to 20 to 30% Zn. The mineralization occurs in a sigmoidal zone, approximately 1.5 km long by 0.5 km wide. Several sub-horizontal manto-like bodies have been detected, which dominantly consist of masses of orange-brown and white zinc “oxides”, which include smithsonite, hydrozincite, cerussite and Fe-hydroxides. A mineralogical, petrographic, and isotope geochemical study of the Bongarà complex of deposits is being conducted by our research group. The ore grade is quite high (up to 35% Zn), with the metal mostly contained in hydrozincite (Mina Grande), smithsonite and hemimorphite (Rio Cristal). To calculate the temperature of smithsonite precipitation at Rio Cristal, a mean δ18O value has been considered between those of rain- and groundwater in the area. To calculate the temperature of calcite (and co-genetic hydrozincite) at Mina Grande, the mean δ18O annual value of the meteoric water (IAEA) has been considered. The temperatures resulting from stable isotopes geochemistry are comparable with the mean annual temperature values in the Bongarà district (21-23°C). At Bongarà there is considerable economic potential both for nonsulphides (occurring in the surficial karst network throughout the whole district, as at Mina Grande) and for sulphides (along several structures detected in the Rio Cristal area). The supergene mineralization is possibly related to weathering episodes (Tertiary to Recent) occurring under a climate not very different from today. References: [1] Wright C (2010) NI 43-101 Technical Report: 102 pp. [2] Boni M and Mondillo N (2015) Ore Geology Reviews 67: 208-233. [3] Hitzman MW et al (2003) Econ Geol 98: 685-714

Mapping hydrothermal and supergene alteration zones associated with carbonate-hosted Zn-Pb deposits by using PRISMA satellite imagery supported by field-based hyperspectral data, mineralogical and geochemical analysis

Delineating hydrothermal alteration and supergene caps is fundamental for mineral exploration of sulfide ores. The aim of this study is to apply a multi-scale workflow based on hyperspectral remote and proximal sensing data in order to delineate hydrothermal dolomitization and supergene alteration associated with the Mississippi Valley-Type Zn-Pb(-Ag) deposit of Jabali (Western Yemen). The area was investigated through hyperspectral images derived from the new launched Italian Space Agency’s PRISMA satellite, which has a higher spectral resolution compared to multispectral sensors and covers the mineral-diagnostic wavelength regions (such as the 2100 nm to 2300 nm range) with a Signal to Noise Ratio (SNR) ≥ 100. Spectral mineral maps were produced through the band ratios method using specific feature extraction indices applied to the hyperspectral satellite data. The results were validated by using Visible Near InfraRed (VNIR) to Short Wave InfraRed (SWIR) reflectance spectra, mineralogical (XRPD) and geochemical (ICP-ES/MS) analyses on rock samples collected in the Jabali area. The dolomites footprint was mapped using a PRISMA Level 2C image, by enhancing the spectral differences between limestones and dolomites in the SWIR-2 region (major features centered at 2340 nm and 2320 nm, respectively). Gossans were detected due to the Fe3+ absorption band in the VNIR region at 900 nm. The Zn-Pb mineralized area, extended for approximately 25 km2, was thus identified by recognizing gossan occurrences in dolomites. The study demonstrates that the PRISMA satellite is effective in identifying Zn-Pb mineralized outcrops in sedimentary basins

Genesis of the Florida Canyon Nonsulfide Zn(-Pb) ores (Northern Peru): new insights on mineralizing events in the Bongará district

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Developing Islamic Economic Production

There are rules, manner, behaviours or arrangements in Islam in respects to production. Some muslims and Islamic economic agents have been practicing the rules and the regulations. Lack of primary needs production as food has threatened the stability of the life in this world, especially in the underdeveloped and the developing countries in which most muslims live. Shortages of foods may cause unstable life. Muslim and Islamic economist and leaders have to take economic (production) problems into serious consideration if they don’t want to be the victim of world non-muslim economic domination. Muslim must not be consumer or just be a sale agent of the products of others, but must select and develop appropriate technology suitable with their human and natural potentials. Agricultural Industry is suitable for Indonesia and for some other muslim contries.. Our Prophet encouraged us to generate the production by cultivating the idle land (ihya al-mawat) to yield crops for foods

Methodological approach for the assessment of ultrasound reproducibility of cardiac structure and function: a proposal of the study group of Echocardiography of the Italian Society of Cardiology (Ultra Cardia SIC) Part I

When applying echo-Doppler imaging for either clinical or research purposes it is very important to select the most adequate modality/technology and choose the most reliable and reproducible measurements. Quality control is a mainstay to reduce variability among institutions and operators and must be obtained by using appropriate procedures for data acquisition, storage and interpretation of echo-Doppler data. This goal can be achieved by employing an echo core laboratory (ECL), with the responsibility for standardizing image acquisition processes (performed at the peripheral echo-labs) and analysis (by monitoring and optimizing the internal intra- and inter-reader variability of measurements). Accordingly, the Working Group of Echocardiography of the Italian Society of Cardiology decided to design standardized procedures for imaging acquisition in peripheral laboratories and reading procedures and to propose a methodological approach to assess the reproducibility of echo-Doppler parameters of cardiac structure and function by using both standard and advanced technologies. A number of cardiologists experienced in cardiac ultrasound was involved to set up an ECL available for future studies involving complex imaging or including echo-Doppler measures as primary or secondary efficacy or safety end-points. The present manuscript describes the methodology of the procedures (imaging acquisition and measurement reading) and provides the documentation of the work done so far to test the reproducibility of the different echo-Doppler modalities (standard and advanced). These procedures can be suggested for utilization also in non referall echocardiographic laboratories as an "inside" quality check, with the aim at optimizing clinical consistency of echo-Doppler data