Bill Minarik

A photo of a Cretaceous dyke intruding into Appalachian-deformed sedimentary rocks deposited in the lower Paleozoic: Earth history from 110 to almost 500 million years ago.

But #kyanite records more of the story: it's part of xenoliths brought to the surface by these dykes that document Grenville crust (1.1 billion years old) at depth.

See: Trzcienski: Kyanite-garnet-bearing Cambrian rocks and Grenville granulites from the Ayer's Cliff, Quebec... Geology (1989)
#MinCup25 #Quebec #Appalachians

Sep 27, 2025 at 1:54pmWeb
Show threadBill MinarikSep 28, 2025
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
Show threadAlex, the Hearth FireSep 28, 2025
@silicatefondue lesbian rock formations are cool regardless of how well they photograph