Numerical simulation and a geochemical model of supergene carbonate-hosted non-sulphide zinc deposits

Reichert, Jörg; Borg, Gregor

doi:10.1016/j.oregeorev.2007.02.006

Cited by 72 publications

(61 citation statements)

References 25 publications

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“…Considering the tectonic and metallogenic evolution of the region [1][2][3] and its climatic history [26], it could be considered that the Tunisian nonsulfide mineralizations have formed through sulfide weathering since the middle Miocene-late Miocene interval, when uplift-related erosion (e.g., "post-nappe" shortening phase) was able to produce sulfide uncapping and alteration (e.g., "Zeit Wet Phase"; [27]). Alteration and supergene oxidized minerals formation likely continued during the Pliocene and between the late Pleistocene and Holocene, during the onset of some relatively wet climatic periods, creating a favorable environment for weathering of sulfides (e.g., "African Humid Period"; [34,35]) and locally also under semi-arid to arid climates [70].…”

Section: Discussionmentioning

confidence: 99%

“…After [67], it is possible to use the smithsonite-water and cerussite-water oxygen isotope fractionation equations: 1000 ln α smithsonite-water = 3.10 (10 6 /T 2 ) − 3.50 (1) 1000 ln α cerussite-water = 2.29 (10 6 /T 2 ) − 3.56 (2) to determine the relationships between temperature and isotopic composition of the fluids from which the carbonate minerals precipitated. The most favorable atmospheric temperatures for the formation of supergene nonsulfide deposits are commonly comprised between 15 and 25 • C (e.g., [67,69,70]), which are compatible with the climate persisting in northern Tunisia during the intervals of time (middle Miocene-late Miocene, Pliocene, late Pleistocene and Holocene (e.g., [71,72])), which can be supposed to be the most favorable periods for sulfide weathering and nonsulfide deposition. .…”

Section: Discussionmentioning

confidence: 99%

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C–O Stable Isotopes Geochemistry of Tunisian Nonsulfide Zinc Deposits: A First Look

et al. 2018

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A preliminary C-O stable isotopes geochemical characterization of several nonsulfide Zn-Pb Tunisian deposits has been carried out, in order to evidence the possible differences in their genesis. Nonsulfide ores were sampled from the following deposits: Ain Allegua, Jebel Ben Amara, Jebel Hallouf (Nappe Zone), Djebba, Bou Grine, Bou Jaber, Fedj el Adoum, Slata Fer (Diapir Zone), Jebel Ressas, Jebel Azreg, Mecella (North South Axis Zone), Jebel Trozza, Sekarna (Graben Zone). After mineralogical investigation of selected specimens, the C-O stable isotopic study was carried out on smithsonite, hydrozincite, cerussite and calcite. The data have shown that all the carbonate generations in the oxidized zones of Ain Allegua and Jebel Ben Amara (Nappe Zone), Bou Jaber, Bou Grine and Fedj el Adoum (Diapir Zone), Mecella and Jebel Azreg (North South Zone) have a supergene origin, whereas the carbonates sampled at Sekarna (Graben Zone) (and in limited part also at Bou Jaber) precipitated from thermal waters at moderately high temperature. Most weathering processes that controlled the supergene alteration of the Zn-Pb sulfide deposits in Tunisia had probably started in the middle to late Miocene interval and at the beginning of the Pliocene, both periods corresponding to two distinct tectonic pulses that produced the exhumation of sulfide ores, but the alteration and formation of oxidized minerals could have also continued through the Quaternary. The isotopic characteristics associated with the weathering processes in the sampled localities were controlled by the different locations of the sulfide protores within the tectonic and climatic zones of Tunisia during the late Tertiary and Quaternary.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

C–O Stable Isotopes Geochemistry of Tunisian Nonsulfide Zinc Deposits: A First Look

et al. 2018

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“…Examples of non-sulfide Zn ± Pb deposits include Upper Silesia district, Sardinia, Italy, Irish Midlands district, the Alpine district in Italy and Austria, La Calamine district, Belgium, and the Reocin deposit, Spain (Boni and Large, 2003). Large nonsulfide zinc deposits (Mehdiabad, Irankuh, and Kuh-e-Surmeh) also occur in Iran (Reichert and Borg, 2008).…”

Section: Supergene Ore and Gangue Characteristics Mineral Assemblagesmentioning

confidence: 99%

A deposit model for Mississippi Valley-Type lead-zinc ores

Leach¹,

Taylor²,

Fey³

et al. 2010

Scientific Investigations Report

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Sample of spheroidal sphalerite with dendritic sphalerite, galena, and iron sulfides (pyrite plus marcasite) from the Pomorzany mine. Note the "up direction" is indicated by "snow-on-the-roof" texture of galena and sphalerite alnong colloform layers of light-colored spahlerite. Hydrothermal sulfide clasts in the left center of the sample are encrusted by sphalerire and iron sulfides. Size of sample is 20x13 cm. Photo by David Leach. Chapter A of Mineral Deposit Models for Resource Assessment COVER:Sample of spheroidal sphalerite with dendritic sphalerite, galena, and iron sulfides (pyrite plus marcasite) from Pomorzany mine. Note the "up direction" is indicated by "snow-on-the-roof" texture of galena and sphalerite along colloform layers of light-colored sphalerite. Hydrothermal sulfide clasts in the left center of the sample are encrusted by sphalerite and iron sulfides. For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. AbstractThis report is a descriptive model of Mississippi ValleyType (MVT) lead-zinc deposits that presents their geological, mineralogical and geochemical attributes and is part of an effort by the U.S. Geological Survey Mineral Resources Program to update existing models and develop new models that will be used for an upcoming national mineral resource assessment. This deposit modeling effort by the USGS is intended to supplement previously published models for use in mineral-resource and mineral-environmental assessments. Included in this report are geological, geophysical and geochemical assessment guides to assist in mineral resource estimation. The deposit attributes, including grade and tonnage of the deposits described in this report are based on a new mineral deposits data set of all known MVT deposits in the world.Mississippi Valley-Type (MVT) lead-zinc deposits are found throughout the world but the largest, and more intensely researched deposits occur in North America. The ores consist mainly of sphalerite, galena, and generally lesser amounts of iron sulfides. Silver is commonly an important commodity, whereas Cu is generally low, but is economically important in some deposits. Gangue minerals may include carbonates (dolomite, siderite, ankerite, calcite), and typically minor barite. Silicification of the host rocks (or quartz gangue) is generally minor, but may be abundant in a few deposits. The deposits have a broad range of rel...

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“…While sphalerite oxidation decreases with increasing pH, it begins to increase again above pH 7, primarily due to the influence of the oxidant O 2 (Ziping et al 2012). Oxidation may also be aided in part by armouring of calcite grains by gypsum and hydrous ferric oxide, inhibiting fast neutralization of the acidic solution produced by oxidation of the sulphides and allowing the establishment and stability of an acidic pH within the oxidation zone (Reichert & Borg 2008). At Prairie Creek, dissolution and alteration of sphalerite is more apparent than galena, likely due to anglesite and cerussite rims protecting the galena from further oxidation (Stavinga 2014).…”

Section: Sulphide Oxidation Under Alkaline Conditionsmentioning

confidence: 99%

“…At Prairie Creek, dissolution and alteration of sphalerite is more apparent than galena, likely due to anglesite and cerussite rims protecting the galena from further oxidation (Stavinga 2014). This may explain why in highly oxidized samples, the only trace of original sulphides is typically galena, as is common in many oxidized sulphide ores as well as in many gossans (Reichert & Borg 2008;e.g. Jeong & Lee 2003).…”

Section: Sulphide Oxidation Under Alkaline Conditionsmentioning

confidence: 99%

Geochemical and mineralogical controls on metal(loid) mobility in the oxide zone of the Prairie Creek Deposit, NWT

Stavinga

Jamieson

Layton‐Matthews

et al. 2017

GEEA

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Prairie Creek is an unmined high grade Zn-Pb-Ag deposit in the southern Mackenzie Mountains of the Northwest Territories, located in a 320 km 2 enclave surrounded by the Nahanni National Park reserve. The upper portion of the quartzcarbonate-sulphide vein mineralization has undergone extensive oxidation, forming high grade zones, rich in smithsonite (ZnCO 3 ) and cerussite (PbCO 3 ). This weathered zone represents a significant resource and a potential component of mine waste material. This study is focused on characterizing the geochemical and mineralogical controls on metal(loid) mobility under mine waste conditions, with particular attention to the metal carbonates as a potential source of trace elements to the environment. Analyses were conducted using a combination of microanalytical techniques (electron microprobe, scanning electron microscopy with automated mineralogy, laser-ablation inductively-coupled mass spectrometry, and synchrotron-based element mapping, micro-X-ray diffraction and micro-X-ray absorbance). The elements of interest included Zn, Pb, Ag, As, Cd, Cu, Hg, Sb and Se.Results include the identification of minor phases previously unknown at Prairie Creek, including cinnabar (HgS), acanthite (Ag 2 S), metal arsenates, and Pb-Sb-oxide. Anglesite (PbSO 4 ) may also be present in greater proportions than recognized by previous work, composing up to 39 weight percent of some samples. Smithsonite is the major host for Zn but this mineral also contains elevated concentrations of Pb, Cd and Cu, while cerussite hosts Zn, Cu and Cd, with concentrations ranging from 6 ppm to upwards of 5.3 weight percent in the two minerals. Variable concentrations of As, Sb, Hg, Ag, and Se are also present in smithsonite and cerussite (listed in approximately decreasing order with concentrations ranging from <0.02 to 17 000 ppm). A significant proportion of the trace metal(loid)s may be hosted by other secondary minerals associated with mineralization. Processing will remove significant mineral hosts for these elements from the final tailings, although some may remain depending on whether the smithsonite fraction is left as tailings. Significant Hg and Ag could remain in tailings from cinnabar and acanthite that is trapped within smithsonite grains, which were found to act as a host for up to 53% of the Hg and 79% of the Ag contained in some samples.In a mine waste setting, near-neutral pH will encourage retention of trace metal(loid)s in solids. Regardless, oxidation, dissolution and mobilization is expected to continue in the long term, which may be slowed by saturated conditions, or accelerated by localized flow paths and acidification of isolated, sulphide-rich pore spaces.

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Numerical simulation and a geochemical model of supergene carbonate-hosted non-sulphide zinc deposits

Cited by 72 publications

References 25 publications

C–O Stable Isotopes Geochemistry of Tunisian Nonsulfide Zinc Deposits: A First Look

C–O Stable Isotopes Geochemistry of Tunisian Nonsulfide Zinc Deposits: A First Look

A deposit model for Mississippi Valley-Type lead-zinc ores

Geochemical and mineralogical controls on metal(loid) mobility in the oxide zone of the Prairie Creek Deposit, NWT

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