scholarly journals Petrochemistry of Lake George granodiorite stock and related gold mineralization, York County, New Brunswick

2002 ◽  
Author(s):  
X Yang ◽  
D R Lentz ◽  
G Chi
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.


1984 ◽  
Vol 79 (5) ◽  
pp. 1159-1186 ◽  
Author(s):  
R. B. Scratch ◽  
G. P. Watson ◽  
R. Kerrich ◽  
R. W. Hutchinson
Keyword(s):  

1961 ◽  
Vol 93 (11) ◽  
pp. 1010-1010
Author(s):  
R. C. Clark

In November, 1957, several specimens of adult beetles were collected from beaver pelts taken in the Lake George area of New Brunswick by a local trapper, Mr. Donald Millican. These were referred to me and were later identified as Leptinillus validus (Horn), an ectoparasite of the beaver, Castor canadensis Kuhl, by Mr. W. J. Brown of the Entomology Research Institute, Ottawa. This is the first record of the species having been found in New Brunswick.


Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 566 ◽  
Author(s):  
Carlin Lentz ◽  
Kathleen Thorne ◽  
Christopher R. M. McFarlane ◽  
Douglas A. Archibald

The Lake George antimony mine was at one time North America’s largest producer of antimony. Despite being widely known for the antimony mineralization, the deposit also hosts a range of styles of mineralization such as multiple generations of W-Mo bearing quartz veins as well as a system of As-Au bearing quartz–carbonate veins. In situ U-Pb zircon geochronology, using LA ICP-MS, of the Lake George granodiorite yielded a weighted mean 206Pb/238U age of 419.6 ± 3.0 Ma. Step heating of phlogopite separated from the lamprophyre dykes produced a 40Ar/39Ar plateau segment date of 419.4 ± 1.4 Ma. Single molybdenite crystal analysis for Re-Os geochronology was conducted on two W-Mo-bearing quartz veins, which cross-cut altered granodiorite and altered metasedimentary rocks and yielded two dates of 415.7 ± 1.7 Ma and 416.1 ± 1.7 Ma respectively. 40Ar/39Ar geochronology of muscovite from alteration associated with Au-bearing quartz–carbonate veins yielded one representative plateau segment date of 414.1 ± 1.3 Ma. The dates produced in this study revealed that the different magmatic–hydrothermal events at the Lake George mine occurred over approximately a 10-million-year period at the end of the Silurian and the start of the Devonian following the termination of the Acadian orogeny.


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