The geochemistry of possible metavolcanic rocks and their relationship to mineralization at Montauban-Les-Mines, Quebec

1977 ◽  
Vol 14 (11) ◽  
pp. 2440-2452 ◽  
Author(s):  
Karen Stamatelopoulou-Seymour ◽  
Wallace H. MacLean
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Igneous Rocks ◽  
Gold Ores ◽  
Sulfide Deposits ◽  
Metavolcanic Rocks ◽  
Granitic Intrusions ◽  
Distinguishing Features ◽  
Volcanic Environment

Base metal and gold ores in thin calc-silicate and cordierite gneiss units at Montauban-Les-Mines have historically been described as pyrometasomatic deposits related to granitic intrusions. They are stratigraphically overlain by quartzo–feldspathic gneiss and amphibolite, the uppermost amphibolite unit being a pillowed metabasalt.Chemical analysis shows all the amphibolites to be derived from basic igneous rocks, probably basaltic flows or shallow intrusives. Some analyses of quartzo–feldspathic gneisses follow igneous trends on variation diagrams and plot closely with those of indisputable volcanic rocks associated with massive sulfide deposits from the Kuroko District, Japan, and Noranda, Quebec. They appear to be metamorphosed intermediate to acidic volcanic tuffs and associated sediments, and are thus termed 'leptites'.The volcanic environment of the ore deposits, their general conformability to stratification, and other distinguishing features, strongly suggest they may be exhalite deposits formed in the overlapping carbonate–sulfide facies.

scholarly journals Highly Metalliferous Potential of Framboidal and Nodular Pyrite Varieties from the Oil-Bearing Jurassic Bazhenov Formation, Western Siberia

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 449
Author(s):  
Kirill S. Ivanov ◽  
Valery V. Maslennikov ◽  
Dmitry A. Artemyev ◽  
Aleksandr S. Tseluiko
Keyword(s):  
Oil And Gas ◽  
Massive Sulfide ◽  
Global Scale ◽  
Ore Deposits ◽  
Black Shales ◽  
Ural Mountains ◽  
Sulfide Deposits ◽  
Bazhenov Formation ◽  
Zn And Cu In ◽  
Positive Correlations

In the Bazhenov Formation, framboidal clusters and nodular pyrite formed in the dysoxic–anoxic interface within organic-rich sediments. Some nodule-like pyritized bituminous layers and pyrite nodules are similar to pyritized microbial mat fragments by the typical fine laminated structure. Framboidal pyrite of the Bazhenov Formation is enriched in redox-sensitive elements such as Mo, V, Au, Cu, Pb, Ag, Ni, Se, and Zn in comparison with the host shales and nodular pyrite. Nodular pyrite has higher concentrations of As and Sb, only. Strong positive correlations that can be interpreted as nano-inclusions of organic matter (Mo, V, Au), sphalerite (Zn, Cd, Hg, Sn, In, Ga, Ge), galena (Pb, Bi, Sb, Te, Ag, Tl), chalcopyrite (Cu, Se) and tennantite (Cu, As, Sb, Bi, Te, Ag, Tl) and/or the substitution of Co, Ni, As and Sb into the pyrite. On the global scale, pyrite of the Bazhenov Formation is very similar to pyrite from highly metalliferous bituminous black shales, associated, as a rule, with gas and oil-and-gas deposits. Enrichment with Mo and lower Co and heavy metals indicate a higher influence of seawater during formation of pyrite from the Bazhenov Formation in comparison to different styles of ore deposits. Transitional elements such as Zn and Cu in pyrite of the Bazhenov Formation has resulted from either a unique combination of the erosion of Cu–Zn massive sulfide deposits of the Ural Mountains from one side and the simultaneous manifestation of organic-rich gas seep activity in the West Siberian Sea from another direction.

Evidence from lead isotopes regarding the genesis of ore deposits in the Chibougamau region, Quebec

1981 ◽  
Vol 18 (4) ◽  
pp. 708-723 ◽  
Author(s):  
R. I. Thorpe ◽  
Jayanta Guha ◽  
Jules Cimon
Keyword(s):  
Lead Isotopes ◽  
Spatial Association ◽  
Massive Sulfide ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Carbonate Sediments ◽  
Sulfide Deposits ◽  
Copper Gold ◽  
Genesis Of Ore Deposits ◽  
Isotope Analyses

Twenty-three lead isotope analyses are reported for massive sulfide deposits, the main copper–gold shear zone deposits in anorthosite of the Doré Lake complex, and two gold deposits, all in Archean terrane, in the Chibougamau district. Five analyses were also obtained for lead occurrences in Proterozoic carbonate sediments in the Mistassini Basin.Galenas from the Coniagas and Lemoine deposits of volcanogenic massive sulfide type, from the Taché Lake deposit of possibly the same type, from the Norbeau and Ayrhart gold properties, and one from within the Opemiska mine, have Archean compositions. Of these, the Lemoine, Norbeau, and Opemiska mine galenas are slightly younger than the others or were contaminated during later deformation and (or) metamorphism.Analyses for the main Cu–Au deposits generally form a cluster, although the spread in 206Pb/204Pb ratios is significant and three analyses for the Copper Rand deposit, in particular, are distinct from data for the other deposits. One interpretation is that the data, in combination with the Archean analyses, define a secondary isochron reflecting a primary age of Archean deposits and rocks at 2735–2800 Ma and a secondary event, including genesis of the Cu–Au ores, at 2240–2160 Ma. Additional evidence for a metamorphic–plutonic(?) event at about 2200 Ma has been provided by previous paleomagnetic studies. One galena from the Opemiska deposit appears to have had uranogenic lead added at 1735–2075 Ma. Three analyses of galena from the Campbell (Merrill) pit are anomalous or indicate they were formed at 162–300 Ma, and it is suggested they may have resulted from multiple episodic additions of ambient rock lead to galena originally deposited at about 2200 Ma.Two new analyses, together with four older values, for Mistassini Basin lead occurrences define a possible secondary isochron that may indicate an integrated source age of 2655 or 2940 Ma at mineralization ages of 2100 and 1700 Ma, respectively. This secondary isochron is very poorly defined because three other new analyses plot above the line.This study suggests that further geochronological investigation of the Cu–Au orebodies, and of felsic dykes that occur in many cases in close spatial association with them, should be undertaken.

A Special Issue on Archean Magmatism, Volcanism, and Ore Deposits: Part 2. Volcanogenic Massive Sulfide Deposits Preface,

2013 ◽  
Vol 109 (1) ◽  
pp. 1-9 ◽  
Author(s):  
P. Mercier-Langevin ◽  
H. L. Gibson ◽  
M. D. Hannington ◽  
J. Goutier ◽  
T. Monecke ◽  
...  
Keyword(s):  
Massive Sulfide ◽  
Ore Deposits ◽  
Special Issue ◽  
Volcanogenic Massive Sulfide ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Volcanogenic Massive Sulfide Deposits

Massive sulfide deposits of the Noranda area, Quebec. III. The Ansil mine

1991 ◽  
Vol 28 (11) ◽  
pp. 1699-1730 ◽  
Author(s):  
T. J. Barrett ◽  
W. H. MacLean ◽  
S. Cattalani ◽  
L. Hoy ◽  
G. Riverin
Keyword(s):  
Hanging Wall ◽  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Hydrothermal Activity ◽  
Sulfide Deposit ◽  
Sulfide Deposits ◽  
Almost All ◽  
Host Rocks ◽  
Low K ◽  
General Range

The Ansil massive sulfide deposit occurs at the contact of the underlying Northwest Rhyolite and the overlying Rusty Ridge Andesite, in the lower part of the Central Mine sequence of the Blake River Group. The orebody, which is roughly ellipsoidal in outline and up to 200 m × 150 m across, contained reserves of 1.58 Mt of massive sulfide grading 7.2% Cu, 0.9% Zn, 1.6 g/t Au, and 26.5 g/t Ag. Production began in 1989. Least-altered host rocks are low-K basaltic andesites and low-K rhyolites. These rocks have Zr/Y ratios of ~5 and LaN/YbN ratios of ~2.3, typical of tholeiitic volcanic rocks, although their major-element chemistry is transitional between tholeiitic and calc-alkaline volcanic rocks.The Ansil deposit, which dips ~50° east, is a single orebody comprising two main massive sulfide lenses (up to ~35 m thick) connected laterally via a thinner blanket of massive sulfides, with thin discontinuous but conformable massive magnetite units at the base and top of the orebody. Sulfide ore consists of massive to banded pyrrhotite–chalcopyrite. In the downplunge lens, up to 10 m of massive magnetite are capped by up to 10 m of massive sulfide. Finely banded cherty tuff, with sphalerite–pyrite–chalcopyrite, forms a discontinuous fringe to the deposit.The two main lenses of massive sulfide have the highest contents of Cu, Ag, and Au and are thought to have formed in areas of major hydrothermal input. Altered feeder zones contain either chlorite + chalcopyrite + pyrrhotite ± magnetite, or chlorite + magnetite ± sulfides. Footwall mineralization forms semiconformable zones ~5–10 m thick that directly underlie the orebody and high-angle pipelike zones that extend at least 50 m into the footwall. Ti–Zr–Al plots indicate that almost all altered footwall rocks were derived from a homogeneous rhyolite precursor. Hanging-wall andesites were also altered. Despite some severe alteration, all initial volcanic rock compositions can be readily identified, and thus mass changes can be calculated. Silica has been both significantly added or removed from the footwall, whereas K has been added except in feeder pipes. Oxygen-isotope compositions up to at least 50 m into the hanging wall and footwall are typically depleted in δ18O by 2–6‰. These rocks have gained Fe + Mg and lost Si. Altered samples in general range from light-rare-earth-element (REE) depleted to light-REE enriched, although some samples exhibit little REE modification despite strong alkali depletion. Mineralized volcanic rocks immediately below the orebody are enriched in Eu (as are some Cu-rich sulfides in the orebody).Contact and petrographic relations generally suggest that the main zone of massive magnetite formed by replacement of cp–po-rich sulfides, although local relations are ambiguous. Magnetite formation may reflect waning hydrothermal activity, during which fluids mixed with seawater and became cooler and more oxidized. Cu-rich feeder pipes that cut magnetite-rich footwall indicate a renewal of Cu-sulfide mineralization after magnetite deposition. Chloritic zones with disseminated sulfides occur up to a few hundred metres above the orebody, attesting to continuing hydrothermal activity.

Compositional peculiarities of the host rocks and ores of the Lazursky ore field, Zmeinogorsk ore region of the Rudny Altai minerogenic zone

2021 ◽  
pp. 36-47
Author(s):  
Tatyana SERAVINA ◽  
Svetlana KUZNETSOVA ◽  
Ludmila FILATOVA
Keyword(s):  
Massive Sulfide ◽  
Ore Deposits ◽  
Sulfide Ores ◽  
Volcanogenic Massive Sulfide ◽  
Sulfide Deposits ◽  
Ore Bodies ◽  
Ore Minerals ◽  
Copper Pyrite ◽  
Host Rocks ◽  
Volcanogenic Massive Sulfide Deposits

The article describes composition of the host rocks and ores of the Lazursky and Maslyansky polymetallic volcanogenic massive sulfide deposits of the Lazursky ore field located within the Zmeinogorsk ore region of the Rudny Altai minerogenic zone. The ore field is composed of various facies of the Devonian (Late Givetian – Frasnian) ore-bearing siliceous-terrigenous basalt-rhyolite formation containing horizons of synvolcanic metasomatites. All rocks of the ore field were subjected to folding and schistosity with zones of tectonic brecciation. Hydrothermal alterations are represented by carbonatization and chloritization. The ore bodies exposed at the Lazursky and Maslyansky ore deposits are represented by copper-pyrite, copper, and zinc-copper-pyrite massive sulfide ores and other varieties. The major ore minerals of the deposits are chalcopyrite, pyrite, sphalerite, marcasite, and pyrrhotite.

Geochemistry, U–Pb geochronology, and genesis of granitoid clasts in transported volcanogenic massive sulfide ore deposits, Buchans, Newfoundland

2013 ◽  
Vol 50 (11) ◽  
pp. 1116-1133 ◽  
Author(s):  
J.B. Whalen ◽  
A. Zagorevski ◽  
V.J. McNicoll ◽  
N. Rogers
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Volcanogenic Massive Sulfide ◽  
Zircon Age ◽  
Felsic Volcanism ◽  
Mass Flows ◽  
Plutonic Rocks ◽  
Felsic Volcanic

The Buchans Group, central Newfoundland, represents an Ordovician continental bimodal calc-alkaline arc sequence that hosts numerous volcanogenic massive sulfide (VMS) occurrences, including both in situ and mechanically transported sulfide breccia–conglomerate orebodies. Diverse lithic clasts associated with transported deposits include rounded granitoid clasts. Earlier workers have suggested that Buchans Group VMS-hosting felsic extrusive units, small granodiorite intrusions (e.g., Wiley’s Brook), and granitoid cobbles associated with transported ore represent co-genetic products of the same magmatic system. The granitoid cobbles and small granodiorite intrusions are geochemically similar and closely resemble Buchans Group felsic volcanic units. U–Pb zircon age determinations show a (i) 466.7 ± 0.5 Ma crystallization age for the Wiley’s Brook granodiorite (WBG), (ii) 464 ± 4 Ma crystallization age for a granitoid cobble, and (iii) 466 ± 4 Ma maximum deposition age for a conglomerate–sandstone sequence associated with transported ore. Thus, Buchans Group felsic plutonic rocks are within experimental error of felsic volcanism and VMS deposition. Furthermore, εNd (T) (T, time of crystallization) values of four granitoid cobbles (–1.95 to –4.0) overlap values obtained from Buchans Group felsic volcanic units. Our results are compatible with plutonic and volcanic rocks being related through fractional crystallization or partial melting processes but do not support a petrogenetic link between VMS deposition and exposed felsic plutons. Comparisons to modern arc analogues favour exhumation of plutonic rocks by extension along caldera or rift walls and (or) subaerial erosion. Enigmatic rounding of Buchans granitoid clasts was likely accomplished in a subaerial or shallow marine environment, and the clasts transported into a VMS-active basin by mass flows.

scholarly journals Geologic interpretation of aeromagnetic and chemical data from the Oaks Belt, Wabigoon subprovince, Minnesota: implications for Au-rich VMS deposit exploration

2016 ◽  
Vol 53 (2) ◽  
pp. 176-188 ◽  
Author(s):  
Michael D. Hendrickson
Keyword(s):  
Base Metal ◽  
Volcanic Rocks ◽  
Correlation Coefficients ◽  
Massive Sulfide ◽  
Iron Formation ◽  
Geochemical Data ◽  
Volcanic Complex ◽  
Sulfide Deposits ◽  
Massive Sulfide Deposits ◽  
Subvolcanic Intrusion

The Oaks Belt (OB) is a Neoarchean volcanic complex located in northwestern Minnesota, USA. It is part of the Wabigoon granite–greenstone terrane that hosts the world-class Rainy River gold deposit in nearby Ontario, Canada. Rocks in the OB form a north-dipping homocline in the fault-bounded pressure shadow of a sigma-shaped volcano-plutonic wedge that spans east–west for 220 km across the Minnesota, USA – Ontario, Canada border. Exploration drilling in the area delineated pyrrhotite–pyrite massive sulfide deposits, iron formation, chert, and semi-massive sphalerite mineralized zones. High-resolution aeromagnetic data indicate a large (∼60 km2) composite subvolcanic intrusion underlies these iron-rich strata in the OB. The position of this inferred intrusion elucidates the low base metal content of known massive sulfide deposits, as they were too far away (6–10 km) from a heat source to have been favorable sites for base metal deposition. The relative abundance of Au and Zn in the OB, alongside correlation coefficients between metals in massive sulfide deposits, iron formation, and chert, indicates the rocks were affected by a low-temperature hydrothermal system under relatively shallow water conditions (<1000 m). Negative correlation between Na2O and CaO in basalt, and their mutual moderate positive correlation with immobile corundum (Al2O3), implies alteration in the upper part of the volcanic pile did not result in substantial element mobility in most samples. Geochemical data from mafic and felsic volcanic rocks plot mainly in the calc-alkaline field. Thus, the OB is most prospective for hosting Au-rich VMS deposits and future exploration should focus on paleo-thermal corridors and favorable stratigraphic horizons near the newly inferred composite subvolcanic intrusion.

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