scholarly journals Volcanic relationships and gold mineralization in the Wolverine-Madrid corridor, Hope Bay volcanic belt, Nunavut

2002 ◽  
Author(s):  
R L Sherlock ◽  
R L Carpenter ◽  
M Bardoux ◽  
E Flood ◽  
P Kleespies
Author(s):  
Dennis Sánchez-Mora ◽  
Christopher R.M. McFarlane ◽  
James A Walker ◽  
David R. Lentz

Gold mineralization at Williams Brook in northern New Brunswick is hosted within the Siluro-Devonian, bimodal, volcano-sedimentary rocks of the Tobique-Chaleur Zone (Wapske Formation). Gold mineralization occurs in two styles: 1) as disseminations (refractory gold) in rhyolite, and 2) in cross-cutting quartz veins (free gold). Dating of the felsic volcanic host rocks by in situ LA-ICP-MS zircon U-Pb geochronology returned ages of 422 ± 3, 409 ± 2, 408 ± 3, 405 ± 2, 401 ± 9 Ma. Zr/Y of subvolcanic felsic intrusion (<8 for syn-mineralization and >8 for post-mineralization) suggests evolution from transitional to more alkalic affinities. Two mineralizing events are recognized; the first is a disseminated mineralization style formed at ~422–416 Ma and the second consists of quartz vein-hosted gold emplaced at 410–408 Ma. Felsic rocks from Williams Brook and elsewhere in the Tobique Group (i.e. Wapske, Costigan Mountain, and Benjamin formations), and the Coastal Volcanic Belt have similar Th/Nb ratios of ~0.1 to 1, reflecting similar levels of crustal contamination, and similar Nb and Y content, suggesting A-type affinities. These data indicate a similar environment of formation. Regionally, mafic rocks show similar within-plate continental signatures and an E-MORB mantle source that formed from partial melts of 10–30%. Mafic volcanic rocks from Williams Brook have a more alkaline affinity (based on Ti/V), and derivation from lower percentage partial melting (~5%). The chemical and temporal variations in the Williams Brook rocks suggest that they were erupted in an evolving transpressional tectonic setting during the oblique convergence of Gondwana and Laurentia.


2020 ◽  
Vol 118 ◽  
pp. 103355 ◽  
Author(s):  
Meng–Ting Chen ◽  
Jun–Hao Wei ◽  
Yan–Jun Li ◽  
Wen–Jie Shi ◽  
Nai–Zhong Liu

2021 ◽  
Vol 24 (1) ◽  
pp. 26-33
Author(s):  
E.V. Nigai

The author addresses an issue of gold presence in pre-Quaternary crusts of weathering that are widespread in sub-mountain areas of the doming-block geomorphological structures of the Amur Region, the Khabarovsk and Primorsky Territories along the periphery of large- and medium-sized Cenozoic basins and depressions. For a more detailed mining and geological study and assessment of the gold content of the weathering crusts, we recommended the Rybachy site as one of these objects (insufficiently studied), and the entire Mukhenskaya area as a promising one. These sites are located in the zone of articulation of the eastern side of the Middle Amur Depression with the folded structures of the West Sikhote-Alinsky volcanic belt. The author gives examples of large gold deposits, related to weathering crusts with their brief description (Olympiada, Kuranakh), as well as a brief description of alluvial deposits of weathering crust (sub-basalt cl.Paskhalny, an eluvial-alluvial placer of the Bolotisty Stream). The search work of the DVIMS (Far Eastern Institute of Mineral Raw Materials) in 2002 indicated the potential of weathering crusts within the Rybachy prospect for gold mineralization. This is supported by elevated gold in heavy mineral concentrates from the linear weathering crusts and residual blankets, as well as from non-commercial placers (from 0.01 to 4.0 g/t and higher); the occurrence of fracture zones, brecciation, secondary silicification close by fractures, and abundant Late Cretaceous silicic and intermediate dikes. Zones of hydrothermally altered rocks (silicification, chloritization, sericitization, argillization) are widespread here.


Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1093
Author(s):  
Evgeny G. Sidorov ◽  
Andrey A. Borovikov ◽  
Nadezhda D. Tolstykh ◽  
Daria S. Bukhanova ◽  
Galina A. Palyanova ◽  
...  

Microthermometry study of fluid inclusions in quartz veins of the Maletoyvayam deposit (Koryak Highland, Russia) was carried out. This epithermal gold deposit contains unique Au compounds including maletoyvayamite, which has not been reported anywhere else. Two paragenetic mineral associations (pyrite-quartz and maletoyvayamite-quartz) with quartz of different generations corresponding to different pulses were also described. Only early generations of quartz (Q1) include ore minerals: pyrite for the first mineral assemblage, and in Au-bearing minerals, sulfosalts, bismuthinite, and others—for the second assemblage. A study on fluid inclusions in quartz showed a salinity (mainly NaCl + KCl) range from 0.2 to 4.3 wt.% NaCl eq., increasing from the first mineral association to the second due to boiling fluids. The obtained temperature variations for quartz crystallization were 295–135 °C, the fluid pressure ranged from 79 to 4 bar. On the other hand, the range of conditions obtained for the gold productive ore association is more narrow: salinity of the fluid inclusions is 4.3 wt.% NaCl eq., the temperatures vary from 255 °C to 245 °C, and the pressure from 39 to 32 bar. These physicochemical characteristics of the Maletoyvayam ore deposit greatly coincide with other HS-type epithermal deposits; however, within the Central Kamchatka Volcanic Belt it is so far the only deposit of this type reported.


Sign in / Sign up

Export Citation Format

Share Document