#grenville — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #grenville, aggregated by home.social.
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A gorgeous thin section of a xenolith-rich lamprophyre dyke from near Ayer's Cliff, Quebec (Cretaceous, Monteregian-age, so ~120 Ma). Pelitic crustal assemblages equilibrated at 700-800°C and 8-10 kbar, while we're currently studying the lherzolite mantle xenolith (above and right of center), which is likely Grenville (~ 1 Ga) in age. Image by Justin Plouffe, #McGillUniversity
#ThinSectionThursday #Quebec #Lithosphere #Grenville #Xenolith
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The Montreal Gem and Mineral Show is happening at the end of the month in the main convention center (Le Palais des Congrès).
No guarantee of fantastic #Tugtupite or #Kyanite samples, but many others for sure. There's always a good representation of Canadian and Quebec localities.
#MinCup25 #Montreal #Quebec #Canada #MontSaintHilaire #Grenville #Minerals
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This is one of the dykes found near Ayer's Cliff, just SE of Magog, Quebec. It's a set of three dykes, one of which has the deep-derived xenoliths. That one dyke (not photogenic) has weathered much faster, perhaps due to a higher carbonate content.
#kyanite #MinCup25 #Quebec #Xenolith #Grenville #Appalachians -
Repost from last year: A titanite lozenge imaged both using a cellphone through the microscope ocular, and with a proper imaging system. It's surrounded mostly by quartz (+feldspar).
Likely from the Grenville, but from a teaching collection two generations of retired professors ago.Titanite can be part of the record of temperature, pressure, and timing of crystallization.
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Repost from last year:
I've seen sphene! (Sounds better than "the rock is tippsy with titanite")Centimeter-size black sphene (titanite) with apatite (dark brown) and orthoclase feldspar (light brown). Folding pocket knife for scale.
From the Bancroft locality in Ontario, Canada. Grenville-aged (~1.2± billion years)
#MinCup25 #Titanite #Sphene #Bancroft #Ontario #Geology #Grenville
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Quebec has industrial quantities of kyanite -although I don't think any are being mined today. They're in the Grenville, the roots of the Himalayan-scale mountains formed over a billion years ago. The screenshot below is from MinDat: https://www.mindat.org/locentries.php?p=14009&m=2303
The Ministère has an awkwardly translated page "Mineral Substances in Quebec" that includes Kyanite in its list of wealth:
https://gq.mines.gouv.qc.ca/portail-substances-minerales_en/#MinCup25 #Kyanite #Quebec #Grenville #PlateTectonics #Minerals