The Hudsonian Orogeny Near Flin Flon, Manitoba: A Tentative Interpretation of Rb/Sr and K/Ar Ages

Mukherjee, A. C.; Stauffer, Mel R.; Baadsgaard, H.

doi:10.1139/e71-083

Cited by 20 publications

(4 citation statements)

References 6 publications

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“…gestion reported earlier by Sinha (1970) and confirmed by Rb-Sr whole rock analyses by Mukherjee et al (1971). The latter found that volcanic rocks near Flin Flon yielded an isochron of 1775 -C 89 m.y.…”

Section: Stall Lakesupporting

confidence: 70%

Isotopic Studies of Ore-Leads in the Hanson Lake-Flin Flon-Snow Lake Mineral Belt Saskatchewan and Manitoba

Sangster¹

1972

Can. J. Earth Sci.

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Lead isotope abundances in 4 stratabound sulfide ores are presented and show characteristics of being single-stage lead deposits. Model ages based on these data range from 1780 t 44 to 1900 & 44 m.y. and are considered to be close approximations of the time of ore formation. Geological evidence in the massive sulfide deposits suggests they are coeval with their host rocks, which are predominantly volcanics of the Amisk Group. If this assumption is correct the average model lead age of the ores is essentially the age of the enclosing rocks. Within error limits the results are in good agreement with published Rb-Sr ages for Amisk rocks of the Flin Flon area, and with U-Pb ages in zircons of rhyolites, which also contain similar, massive sulfide ores in the Churchill Province of Arizona. This is considered to be good evidence that the Hanson Lake-Flin Flon-Snow Lake volcanic mineral belt, previously regarded as Archean, is Aphebian in part.A previously published Archean, Rb-Sr isochron for volcanic rocks in the Hanson Lake area may indicate that Amisk-type rocks are a folded complex of both Aphebian and Archean lithologies. The suggested Aphebian age of the Amisk-Missi Groups and their equivalents, indicates they are possibly eugeosynclinal equivalents of the miogeosynclinal Hurwitz sediments. L'abondance des isotopes du plomb dans quatre gisements stratiformes de sulfures est discutke et l'on montre des Cvidences indiquant que le plomb rCsulte d'un seul Cpisode de formation. Les ages obtenus B partir de ces donnks s'ttendent de 1780 & 44 B 1900 t 44 m.a. et sont considkrCs comme Ctant de bonnes approximations de l'Pge de formation du minerai. Les Cvidences gkologiques rencontrees dans les dCp8ts de sulfures massifs sugghent que ceux-ci sont du meme Ige que les roches encaissantes, en grande partie des roches volcaniques du Groupe d'Arnisk. Si cette supposition est juste. l'gg moyen du minerai dEtermint B partir du plornb est essentiellement I'gge de la roche encaissante. A I'intCrieur des m a r g s d'erreur, ces rksultats sont en accord avec ce qui a CtP publi6 sur les ages Rb-Sr des roches d'Amisk de la rkgion de Flin Flon et avec les Sges U-Pb dans les zircons de rhyolites, contenant des sulfures massifs sernhlables, dans la province de Churchill, en Arizona. Ceci est considGrh cornme une Cvidence que la bande de roches volcaniques minCralisks du lac Hanson-Flin Flon-lac Snow, auparavant considCrCe comme archknne, est en partie AphCbienne.Un isochrone Rb-Sr Archken, prCc6demment publie pour les roches volcaniques de la rCgion du lac Hanson peut indiquer que les roches du type Amisk forment un complexe plissC de lithologies AphCbiennes et ArchCennes. La suggestion que les Groupes d'Amisk-Missi, ainsi que leurs Cquivalents, sont d'age AphCbien en fait des Cquivalents eugCosynclinaux possibles pour les sediments miogCosynclinaux d'Hurwitz.

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Section: Stall Lakesupporting

confidence: 70%

Isotopic Studies of Ore-Leads in the Hanson Lake-Flin Flon-Snow Lake Mineral Belt Saskatchewan and Manitoba

Sangster¹

1972

Can. J. Earth Sci.

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“…[28] GBS can also operate as an independent process, and this can be accommodated by pumping out intragranular dislocations (from triple junctions that impede sliding), which glide to the opposite boundary and are eliminated by climb into the grain boundary (Figure 7d). Although the process was modeled originally by considering the simultaneous sliding of multiple grains by Ball and Hutchison, [29] it was modified later by Mukherjee [30] to consider sliding along individual grain boundaries. Langdon [31] developed a broad unified approach of GBS in coarse-grained and fine-grained materials and obtained the following expression for the superplastic strain rateε GBSÀSP in fine-grained materials, shown schematically in Figure 7ḋ…”

Section: The General Characteristics Of Superplastic Flowmentioning

confidence: 99%

Grain Boundary Processes in Strengthening, Weakening, and Superplasticity

Chokshi

2019

Adv Eng Mater

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Grain boundaries provide strength to materials at low temperatures by impeding slip transfer and they weaken materials at high temperatures by intergranular creep processes such as grain boundary sliding (GBS) and diffusion creep. At very fine nanocrystalline grain sizes of <10 nm, it is possible to observe grain boundary weakening rather than strengthening at room temperature. Superplastic flow is observed in a wide range of materials, but the common phenomenology of a high strain rate sensitivity and extensive GBS may arise from varying importance of GBS accommodated by dislocations, diffusion creep, and interface‐controlled diffusion creep. Thus, superplasticity in metals and ceramics involves GBS with dislocation accommodation and interface‐controlled diffusion creep, respectively. It is recognized that grains retain their equiaxed shapes during diffusion creep by grain switching and grain growth. Ultrafine‐grained and nanocrystalline materials with a high strain rate sensitivity of >0.3 deform with a large GBS contribution to total strain of ≈40–80%. There are a limited number of studies showing superplasticity in fine‐grained high‐entropy alloys, involving GBS accommodated by dislocations.

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“…He concluded that the rocks containing the deposit are Aphebian in age, and he accepted the Rb-Sr isochron age of 1750 ± 80 m.y. of Mukherjee et al (1971). At the Universities of Saskatoon and Alberta, zircon studies on the associated volcanic rocks are corroborating the approximate age of 1800 m.y.…”

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confidence: 71%