Black shales and massive sulfide deposits: causal or casual relationships? Insights from Rammelsberg, Tharsis, and Draa Sfar

Sáez, Reinaldo; Moreno, Carmen; González, Félipe; Almodóvar, G. R.

doi:10.1007/s00126-010-0311-x

Cited by 61 publications

(41 citation statements)

References 108 publications

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“…This Series consists of a >1,000-m-thick succession of metamorphosed schistose and lower greenschist-facies marine black shale, sandstone, and bimodal tuffs of the Lower Member, which grade upward into the proximal Upper Member composed of black shale, siltstone, and sandstone punctuated by minor intercalations (<10 % of surface outcrops) of felsic and ulramafic-mafic igneous bodies and associated volcaniclastic strata largely of dacitic to rhyolitic compositions. Paleogeographic reconstructions suggest that the Sarhlef Series was deposited in a tectonically driven, pull-apart marine basin ) under rapid sedimentation rates of 19-27 cm/ka (Sáez et al 2011). During the Namurian and Westphalian, the marine basins closed (Piqué and Michard 1989).…”

Section: Stratigraphymentioning

confidence: 97%

“…Massive to semi-massive sulphide mineralization occurs at the interface between late Visean footwall bimodal intrusions, lava flows, high-silica rhyolite and tuffaceous volcaniclastic rocks and overlying hanging wall black argillite interbedded with siltstone and sandstone. Although mostly exposed, the stratigraphy and structure of the Jebilet-Guemassa VHMS province have been largely refined from detailed mineralogical and geochemical underground mining studies and extensive diamond drilling over the past two decades (Essaifi et al 2004;Belkabir et al 2008;Marcoux et al 2008;Moreno et al 2008;Lotfi et al 2008;Sáez et al 2011). Proposed (modified from Huvelin 1977).…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Geologic, Hydrothermal, and Geochemical Relationships Between Bimodal Magmatism and Massive Sulphide Mineralization in the Central Jebilet-Guemassa Province (Western Moroccan Hercynides)

Bouabdellah

Hibti²,

Maacha³

et al. 2016

Mineral Deposits of North Africa

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The Jebilet-Guemassa volcanic-hosted massive sulphide (VHMS) province comprises four sheet-like, polymetallic deposits. These are referred to as Kettara (>20 Mt at 0.6 % Cu with traces of Pb and Zn), Hajar (*20 Mt at 10.5 % Zn, 3.2 % Pb, 0.6 % Cu, and 60 g/t Ag), Draa Sfar (*11 Mt at 5.9 % Zn, 2.2 % Pb, and 0.3 % Cu), and Koudiat Aicha (3-5 Mt at 3 % Zn, 1 % Pb, and 0.6 % Cu), which collectively total >80 Mt of Pb-Zn-Cu ore. Host rocks consist predominantly of variably altered, mafic to felsic, submarine volcanic and tuffaceous volcaniclastic rocks within the metasedimentary Visean Sarhlef Series composed of black argillite with interbedded carbonate, siltstone, and sandstone. Hydrothermal alteration is distinctly asymmetric, occurring regionally in rocks of the stratigraphic footwall, immediate footwall, and hanging wall. In order of decreasing abundance, alteration assemblages consist of varying proportions of sericite, chlorite, quartz, carbonates (calcite, siderite, ankerite, and dolomite), talc, and epidote, with minor albite and tremolite-actinolite. These assemblages were controlled mainly by temperature and pH of the hydrothermal fluids. Mass-balance calculations indicate that hydrothermal alteration of the footwall rocks was accompanied by pervasive leaching of K 2 O, Na 2 O, and CaO, moderate loss of SiO 2 , and addition of FeO, MgO, and MnO under a high-temperature (>150°C) regime and high water/rock ratios (>10). In contrast, sericite-and calcite-rich alteration of hanging wall rocks involved lower temperatures (<150°C) and water-rock ratios of <5. Sulphide ores are dominated by pyrrhotite with variable proportions of sphalerite, chalcopyrite, galena, and pyrite ± tetrahedrite ± arsenopyrite ± marcasite ± bismuthinite ± cassiterite ± stannite ± cobaltite ± cubanite ± electrum. Overall, the ore and host rocks were strongly deformed, foliated, and mylonitized under greenschist-facies metamorphic conditions. Lithogeochemistry, alteration mineralogy, mineral chemistry, fluid inclusion data, and stable and radiogenic isotope constraints indicate that the Jebilet-Guemassa VHMS deposits formed in the Upper Visean (*330 Ma) from an evolving hydrothermal system that was initiated by regional-scale convection of magmatic-hydrothermal fluids and ambient seawater. Compared to classical VHMS systems, the Jebilet-Guemassa deposits possess a number of distinctive attributes that set them apart. These include (1) a banded sheet-like morphology, (2) predominance of pyrrhotite (up to 90 vol.%) over pyrite, (2) lack of well-developed stockwork zones, (4) absence of barite, (5) high Zn/Cu ratio, and (6) volumetrically minor igneous rocks.

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Section: Stratigraphymentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

Geologic, Hydrothermal, and Geochemical Relationships Between Bimodal Magmatism and Massive Sulphide Mineralization in the Central Jebilet-Guemassa Province (Western Moroccan Hercynides)

Bouabdellah

Hibti²,

Maacha³

et al. 2016

Mineral Deposits of North Africa

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show abstract

“…Furthermore, these units can locally shield massive sulfides from an oxic environment, thereby increasing their preservation potential (e.g., Goodfellow and McCutcheon, 2003;Peter, 2003;Sáez et al, 2011). Redox-sensitive trace elements, including the transition elements/oxyanions concentrations in shales/mudstones, are particularly useful for discriminating paleoredox conditions in ancient environments (e.g., Tribovillard et al, 2006;Algeo and Tribovillard, 2009).…”

Section: Anoxia Versus Scavengingmentioning

confidence: 98%

Geology, Mineralogy, and Lithogeochemistry of Metalliferous Mudstones Associated with the Lemarchant Volcanogenic Massive Sulfide Deposit, Tally Pond Belt, Central Newfoundland

Lode

Piercey

Devine³

2015

Economic Geology

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The Cambrian Lemarchant Zn-Pb-Cu-(Au-Ag) bimodal felsic volcanogenic massive sulfide (VMS) deposit, Tally Pond group, central Newfoundland, Canada, contains metalliferous mudstones that occur either immediately on top or laterally along strike from massive sulfide mineralization, or as interflow mudstones within hanging-wall basaltic rocks. The mudstones are brown to black, graphite rich, and locally have intercalations of siliciclastic, volcaniclastic and/or amorphous chert layers, and, in some cases, fine lamina of organic matter. The main sulfide phases are pyrite (framboidal and euhedral) and pyrrhotite, with minor chalcopyrite, sphalerite, arsenopyrite, and galena; barite is a common sulfate.The metalliferous mudstones occur at various stratigraphic levels and have variable inputs of hydrothermal (high Fe/Al and base metal values) and detrital components (lower Fe/Al and base metal values) with positive shale normalized Eu anomalies (Eu/Eu* ≥1), negative Ce anomalies (Ce/Ce* ≤1), and an average Y/Ho ratio of ~28.3. These signatures suggest precipitation from reduced, high-temperature hydrothermal vent fluids in an oxygenated water column, coupled with the hydrothermal particles having a short residence time within the hydrothermal plume (i.e., a vent proximal setting). Deposition from an oxygenated water column is also supported by the presence of abundant barite in both the Lemarchant massive sulfides and the metalliferous mudstones, as well as locally preserved marcasite in the mudstones. Redox-sensitive trace elements (As, U, V, Mo, Cr, Ni, and Co) were scavenged as oxyanions onto Fe oxyhydroxides during mudstone formation, and these elevated levels of scavenged redox-sensitive trace elements cause apparent anoxic signatures. Immobile element systematics (La-Th-Zr/10 and Th-La-Sc) indicate that the detrital components of the Lemarchant mudstones were mixtures of both continental and mafic sources, most likely deposited within a pericontinental rifted arc environment. Our research illustrates that the lithogeochemistry of metalliferous mudstones can identify vent proximity and provides insights into the physiochemical conditions of the deposit formation and the ambient environment. These results have implications for similar precious metal-bearing VMS deposits globally.

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“…Among sedimentary rocks, those of detrital and volcanoclastic origin predominate. The presence of common chemical Hydrochemical characterization of an acid mine drainage-affected reservoirsedimentary rocks may also be observed, including massive sulphides, manganese jaspers and some discontinuous levels of fossiliferous limestones (Sáez et al 2010).…”

Section: Geological Frameworkmentioning

confidence: 99%

Hydrochemical characterization of an acid mine drainage-affected reservoir: the Sancho Reservoir, Huelva, southwest Spain

Cerón

Grande

Torre

et al. 2014

Hydrological Sciences Journal

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Black shales and massive sulfide deposits: causal or casual relationships? Insights from Rammelsberg, Tharsis, and Draa Sfar

Cited by 61 publications

References 108 publications

Geologic, Hydrothermal, and Geochemical Relationships Between Bimodal Magmatism and Massive Sulphide Mineralization in the Central Jebilet-Guemassa Province (Western Moroccan Hercynides)

Geologic, Hydrothermal, and Geochemical Relationships Between Bimodal Magmatism and Massive Sulphide Mineralization in the Central Jebilet-Guemassa Province (Western Moroccan Hercynides)

Geology, Mineralogy, and Lithogeochemistry of Metalliferous Mudstones Associated with the Lemarchant Volcanogenic Massive Sulfide Deposit, Tally Pond Belt, Central Newfoundland

Hydrochemical characterization of an acid mine drainage-affected reservoir: the Sancho Reservoir, Huelva, southwest Spain

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