scholarly journals U-Th-He Geochronology of Pyrite from the Uzelga VMS Deposit (South Urals)—New Perspectives for Direct Dating of the Ore-Forming Processes

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 629
Author(s):  
Olga Yakubovich ◽  
Mary Podolskaya ◽  
Ilya Vikentyev ◽  
Elena Fokina ◽  
Alexander Kotov
Keyword(s):  
Methodological Approach ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
South Urals ◽  
Volcanogenic Massive Sulfide ◽  
Ore Formation ◽  
Relative Simplicity ◽  
Facies Metamorphism ◽  
Thermal Extraction ◽  
Pyrite Sample

We report on the application of the U-Th-He method for the direct dating of pyrite and provide an original methodological approach for measurement of U, Th and He in single grains without loss of parent nuclides during thermal extraction of He. The U-Th-He age of ten samples of high-crystalline stoichiometric pyrite from unoxidized massive ores of the Uzelga volcanogenic massive sulfide (VMS) deposit, South Urals, is 382 ± 12 Ma (2σ) (U concentrations ~1–5 ppm; 4He ~10−4 cm3 STP g−1). This age is consistent with independent (biostratigraphic) estimations of the age of ore formation (ca, 389–380 Ma) and is remarkably older than the probable age of the regional prehnite-pumpellyite facies metamorphism (~340–345 Ma). Our results indicate that the U-Th-He dating of ~1 mg weight pyrite sample is possible and open new perspectives for the dating of ore deposits. The relative simplicity of U-Th-He dating in comparison with other geochronological methods makes this approach interesting for further application.

3D seismic imaging of volcanogenic massive sulfide deposits in the Flin Flon mining camp, Canada: Part 2 — Forward modeling

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC81-WC93 ◽  
Author(s):  
Michal Malinowski ◽  
Ernst Schetselaar ◽  
Donald J. White
Keyword(s):  
Synthetic Data ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Earth Model ◽  
Seismic Modeling ◽  
Volcanogenic Massive Sulfide ◽  
Data Set ◽  
Rock Interaction ◽  
Time Migration ◽  
Flin Flon

We applied seismic modeling for a detailed 3D geologic model of the Flin Flon mining camp (Canada) to address some imaging and interpretation issues related to a [Formula: see text] 3D survey acquired in the camp and described in a complementary paper (part 1). A 3D geologic volumetric model of the camp was created based on a compilation of geologic data constraints from drillholes, surface geologic mapping, interpretation of 2D seismic profiles, and 3D surface and grid geostatistical modeling techniques. The 3D modeling methodology was based on a hierarchical approach to account for the heterogeneous spatial distribution of geologic constraints. Elastic parameters were assigned within the model based on core sample measurements and correlation with the different lithologies. The phase-screen algorithm used for seismic modeling was validated against analytic and finite-difference solutions to ensure that it provided accurate amplitude-variation-with-offset behavior for dipping strata. Synthetic data were generated to form zero-offset (stack) volume and also a complete prestack data set using the geometry of the real 3D survey. We found that the ability to detect a clear signature of the volcanogenic massive sulfide with ore deposits is dependent on the mineralization type (pyrite versus pyrrhotite rich ore), especially when ore-host rock interaction is considered. In the presence of an increasing fraction of the host rhyolite rock within the model volume, the response from the lower impedance pyrrhotite ore is masked by that of the rhyolite. Migration tests showed that poststack migration effectively enhances noisy 3D DMO data and provides comparable results to more computationally expensive prestack time migration. Amplitude anomalies identified in the original 3D data, which were not predicted by our modeling, could represent potential exploration targets in an undeveloped part of the camp, assuming that our a priori earth model is sufficiently accurate.

Development of a laser ablation ICP-MS method for the analysis of fluid inclusions associated with volcanogenic massive sulfide deposits

2021 ◽  
pp. geochem2020-043
Author(s):  
Madison A. Schmidt ◽  
Matthew I. Leybourne ◽  
Jan M. Peter ◽  
Duane C. Petts ◽  
Simon E. Jackson ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Fluid Inclusions ◽  
Inductively Coupled Plasma ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Volcanogenic Massive Sulfide ◽  
Metals And Metalloids ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Vms Deposits

There is increasing acceptance of the presence of variable magmatic contributions to the mineralizing fluids in the formation of volcanogenic massive sulfide (VMS) deposits. The world-class Windy Craggy Cu-Co-Au deposit (>300 MT @ 2.12 wt.% Cu) in northwestern British Columbia is of interest because, unlike most VMS deposits, quarts fluid inclusions from within the deposit range from relatively low to intermediate salinity (most 6-16 wt.% equivalent). In this study we used an excimer (193 nm) laser ablation system interfaced to a quadrupole inductively coupled plasma mass spectrometer to quantify key metals and metalloids that are considered by many to be indicative of magmatic contributions to hydrothermal ore deposits. Although LA-ICP-MS signals from these low-salinity inclusions are highly transient, we were able to quantify Na, Mg, K, Ca, Mn, Fe, Co, Cu, Zn, Sr, Sn, Ba, Ce, Pb and Bi consistently – of the 34 elements that were monitored. Furthermore, Cl, Sb, Cd, Mo, Rb, Br, and As were also measured in a significant number of inclusions. Comparison of the fluid inclusion chemistry with unaltered and altered mafic volcanic and sedimentary rocks and mineralized samples from the deposit indicate that enrichment in the main ore metals (Cu, Zn, Fe, Pb) in the inclusions reflects that of the altered rocks and sulfides. Metals and metalloids that may indicate a magmatic contribution typically show much greater enrichments in the fluid inclusions much greater over the host rocks at the same Cu concentration; in particular Bi, Sn and Sb are significantly elevated when compared to the host rock samples. These data are consistent with the ore-forming fluids at Windy Craggy having a strong magmatic contribution.

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

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.

THE 3D TRANSIENT ELECTROMAGNETIC FORWARD MODELING OF VOLCANOGENIC MASSIVE SULFIDE ORE DEPOSITS

2016 ◽  
Vol 59 (6) ◽  
pp. 725-733 ◽  
Author(s):  
LI Rui-Xue ◽  
WANG He ◽  
XI Zhen-Zhu ◽  
LONG Xia ◽  
HOU Hai-Tao ◽  
...  
Keyword(s):  
Forward Modeling ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Volcanogenic Massive Sulfide ◽  
Transient Electromagnetic ◽  
Sulfide Ore
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