scholarly journals Identification of mineralized zones in the Zardu area, Kushk SEDEX deposit (Central Iran), based on geological and multifractal modeling

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Ahmad Heidari Dahooei ◽  
Peyman Afzal ◽  
Mohammad Lotfi ◽  
Alireza Jafarirad

AbstractThe aim of this paper is to delineate the different lead–zinc mineralized zones in the Zardu area of the Kushk zinc–lead stratabound SEDEX deposit, Central Iran, through concentration–volume (C–V) modeling of geological and lithogeochemical drillcore data. The geological model demonstrated that the massive sulfide and pyrite+dolomite ore types as main rock types hosting mineralization. The C–V fractal modeling used lead, zinc and iron geochemical data to outline four types of mineralized zones, which were then compared to the mineralized rock types identified in the geological model. ‘Enriched’ mineralized zones contain lead and zinc values higher than 6.93% and 19.95%, respectively, with iron values lower than 12.02%. Areas where lead and zinc values were higher than 1.58% and 5.88%, respectively, and iron grades lower than 22% are labelled “high-grade” mineralized zones, and these zones are linked to massive sulfide and pyrite+dolomite lithologies of the geological model. Weakly mineralized zones, labelled ‘low-grade’ in the C– V model have 0–0.63% lead, 0–3.16% zinc and > 30.19% iron, and are correlated to those lithological units labeled as gangue in the geological model, including shales and dolomites, pyritized dolomites. Finally, a log-ratio matrix was employed to validate the results obtained and check correlations between the geological and fractal modeling. Using this method, a high overall accuracy (OA) was confirmed for the correlation between the enriched and high-grade mineralized zones and two lithological units — the massive sulfide and pyrite+dolomite ore types.

2020 ◽  
Vol 57 (12) ◽  
pp. 1447-1462
Author(s):  
Michael D. Hendrickson

The McAra deposit is in eastern Ontario, Canada, and is hosted in an Archean inlier to the Paleoproterozoic Huronian basin. It is currently estimated to contain ∼2.4 million pounds of cobalt at an average grade of 1.25%. New drill data show the mineralized zone comprises glaucodot–cobaltite veins and breccias that transect a mafic–siliciclastic volcanogenic massive sulfide (VMS) deposit. The high cobalt grade and host stratigraphy at the McAra deposit contrast with five-element (Ag–Co–Ni–Bi–As) deposits at the Cobalt and Gowganda camps in the region that produced high-grade silver and by-product cobalt from veins spatially associated with Nipissing Gabbro intrusions. However, geochemical data from recent core samples alongside fluid inclusion and mineralogical data suggest the cobalt zone at McAra and the five-element veins share a similar metal assemblage and were deposited from similar fluids. The mafic–siliciclastic VMS deposit at McAra contains anomalous amounts of cobalt, suggesting the Archean host stratigraphy was the source for the high-grade cobalt zone. Basin brines in the Paleoproterozoic are interpreted to have leached cobalt from Archean rocks and then redeposited it through oxidation–reduction reactions along synvolcanic faults that controlled earlier VMS deposit formation. High-resolution aeromagnetic data show that McAra is immediately adjacent to a mafic dike that transects the Huronian basin along a northwest-striking, crustal-scale fault system. These data, alongside observations from field mapping, also suggest the deposit is on the margin of a sub-basin that contains an 80 km2 Nipissing sill that may have originally overlain the deposit area and been a hydrologic seal during mineralization. The new deposit- and regional-scale data and interpretations are used to create a model for the McAra deposit and provide evidence for why it is cobalt-rich relative to other five-element veins. The model and data can be used to guide exploration for additional cobalt-rich deposits in the region and similar settings globally.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdolrahim Foroutan ◽  
Majid Abbas Zadeh Haji Abadi ◽  
Yaser Kianinia ◽  
Mahdi Ghadiri

AbstractCollector type and pulp pH play an important role in the lead–zinc ore flotation process. In the current study, the effect of pulp pH and the collector type parameters on the galena and sphalerite flotation from a complex lead–zinc–iron ore was investigated. The ethyl xanthate and Aero 3418 collectors were used for lead flotation and Aero 3477 and amyl xanthate for zinc flotation. It was found that maximum lead grade could be achieved by using Aero 3418 as collector at pH 8. Also, iron and zinc recoveries and grades were increased in the lead concentrate at lower pH which caused zinc recovery reduction in the zinc concentrate and decrease the lead grade concentrate. Furthermore, the results showed that the maximum zinc grade and recovery of 42.9% and 76.7% were achieved at pH 6 in the presence of Aero 3477 as collector. For both collectors at pH 5, Zinc recovery was increased around 2–3%; however, the iron recovery was also increased at this pH which reduced the zinc concentrate quality. Finally, pH 8 and pH 6 were selected as optimum pH values for lead and zinc flotation circuits, respectively.


Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Mónica Arias ◽  
Pablo Nuñez ◽  
Daniel Arias ◽  
Pablo Gumiel ◽  
Cesar Castañón ◽  
...  

The Touro volcanogenic massive sulfide (VMS) deposit is located in the NW of the Iberian Variscan massif in the Galicia-Trás-os-Montes Zone, an amalgamation of several allochthonous terrains. The Órdenes complex is the most extensive of the allochthone complexes, and amphibolites and paragneisses host the deposit, characterized as being massive or semimassive (stringers) sulfides, mostly made up of pyrrhotite and chalcopyrite. The total resources are 103 Mt, containing 0.41% copper. A 3D model of the different orebodies and host rocks was generated using data from 1090 drill core logs. The model revealed that the structure of the area is a N–S-trending antiform. The orebodies crop out in the limbs and in the hinge zone. The mineralized structures are mostly tabular, up to 100 m in thickness and subhorizontal. Based on the petrography, geochemistry and the 3D model, the Touro deposit is classified as a VMS of the mafic-siliciclastic type formed in an Ordovician back-arc setting, which was buried and metamorphosed in Middle Devonian.


2018 ◽  
Vol 82 (S1) ◽  
pp. S5-S41 ◽  
Author(s):  
J. R. S. Carvalho ◽  
J. M. R. S. Relvas ◽  
A. M. M. Pinto ◽  
M. Frenzel ◽  
J. Krause ◽  
...  

ABSTRACTHigh concentrations of indium (In) and selenium (Se) have been reported in the Neves-Corvo volcanic-hosted massive sulfide deposit, Portugal. The distribution of these ore metals in the deposit is complex as a result of the combined effects of early ore-forming processes and late tectonometamorphic remobilization. The In and Se contents are higher in Cu-rich ore types, and lower in Zn-rich ore types. At the deposit scale, both In and Se correlate positively with Cu, whereas their correlations with Zn are close to zero. This argues for a genetic connection between Cu, In and Se in terms of metal sourcing and precipitation. However, re-distribution and re-concentration of In and Se associated with tectonometamorphic deformation are also processes of major importance for the actual distribution of these metals throughout the whole deposit. Although minor roquesite and other In-bearing phases were recognized, it is clear that most In within the deposit is found incorporated within sphalerite and chalcopyrite. When chalcopyrite and sphalerite coexist, the In content in sphalerite (avg. 1400 ppm) is, on average, 2–3 times higher than in chalcopyrite (avg. 660 ppm). The In content in stannite (avg. 1.3 wt.%) is even higher than in sphalerite, but the overall abundance of stannite is subordinate to either sphalerite or chalcopyrite. Selenium is dispersed widely between many different ore minerals, but galena is the main Se-carrier. On average, the Se content in galena is ~50 times greater than in either chalcopyrite (avg. 610 ppm) or sphalerite (avg. 590 ppm). The copper concentrate produced at Neves-Corvo contains very significant In (+Se) content, well above economic values if the copper smelters recovered it. Moreover, the high In content of sphalerite from some Cu-Zn ores, or associated with shear structures, could possibly justify, in the future, a selective exploitation strategy for the production of an In-rich zinc concentrate.


2001 ◽  
Vol 73 (1) ◽  
pp. 99-119 ◽  
Author(s):  
SILVIA R. MEDEIROS ◽  
CRISTINA M. WIEDEMANN-LEONARDOS ◽  
SIMON VRIEND

At the end of the geotectonic cycle that shaped the northern segment of the Ribeira Mobile Belt (Upper Proterozoic to Paleozoic age), a late to post-collisional set of plutonic complexes, consisting of a wide range of lithotypes, intruded all metamorphic units. The Várzea Alegre Intrusive Complex is a post-collisional complex. The younger intrusion consists of an inversely zoned multistage structure envolved by a large early emplaced ring of megaporphyritic charnoenderbitic rocks. The combination of field, petrographic and geochemical data reveals the presence of at least two different series of igneous rocks. The first originated from the partial melting of the mantle. This was previously enriched in incompatible elements, low and intermediate REE and some HFS-elements. A second enrichment in LREE and incompatible elements in this series was due to the mingling with a crustal granitic magma. This mingling process changed the composition of the original tholeiitic magma towards a medium-K calc-alkalic magma to produce a suite of basic to intermediate rock types. The granitic magma from the second high-K, calc-alkalic suite originated from the partial melting of the continental crust, but with strong influence of mantle-derived melts.


2020 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Odika, P.O. ◽  
Anike, O.L. ◽  
Onwuemesi, A.G. ◽  
Odika, N.F. ◽  
Ejeckam, R.B.

Mining activities have long been recognized as a major source of environmental contamination associated with heavy metals and metalloids. This study evaluated the relationship between the occurrence and mining of lead-zinc sulphide ores at Ishiagu, Nigeria, and heavy metal and metalloid contamination. A comparative study of two zones in the area, with and without mining activities was also made Water, soil, stream sediment and ore samples were analyzed, after acid digestion, using atomic absorption spectrophotometer (AAS).  The concentration levels of seven heavy metals and a metalloid namely Pb, Cu, Ni, Zn, Mn, Co, Cd and as were evaluated. While the highest concentration levels of As, Co and Pb (5.20 mg/l, 0.54 mg/l and 3.40 mg/l respectively) were found in water, those of Ni and Mn (2.26 mg/l and 5.48 mg/l respectively) occurred in soil.  For Cu and Zn, highest levels of concentration (2.80 mg/l and 0.41 mg/l respectively) occurred in stream sediments. The variations in the concentration levels of these elements in varying geologic media (soil, water and sediment) indicate influence of rock types, human activities and media physiochemical characteristics. Geostatistical analyses using QQPlot, semivariogram and kriging showed normal distribution of these elements. Distribution and dispersion patterns of the heavy metals indicated increase in concentration levels in the local stream flow direction. Pb, Cu, As, Cd, Mn, and Ni concentrations had reached pollutant levels in water based on WHO standards, while Zn level is below. Since the local people use untreated surface water and groundwater for drinking and other domestic purposes, soil for farming and lead for cosmetics, long term exposure poses significant health risk for humans, animals and plants.


2018 ◽  
Vol 22 (6) ◽  
pp. 1377-1393 ◽  
Author(s):  
Peyman Afzal ◽  
Ahmad Adib ◽  
Naser Ebadati

Author(s):  
A. L. Dergachev

Tectonic evolution of the Earth is a principle global factor responsible for uneven distribution of lead and zinc reserves in geological time. Cyclic changes in productivity of lead-zinc ore-formation processes resulted from periodical amalgamation of most blocks of continental crust, formation, stabilization and final break-up of supercontinents. Many features of age spectrums of lead and zinc reserves are caused by gradual increase of volume of continental crust resulting from accretion of island arcs to ancient cratons, widening of distribution of ensialic environments of ore-formation and increasing role of continental crust in magmatic processes.


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