Broken surface of quartzite.
I’ve been asked about the source for the quartzite clasts in Puget Lowland glacial till. They are diagnostic of a British Columbian provenance for the Puget Lobe of the Vashon advance, and the great glaciations that preceeded that one. Go to the quartzite page, where I discuss the source for these pebbles, and attempt to confuse everyone because there are two kinds of quartzite.
Filed under: British Columbia geology, geology, glacial erratics, glacial geology, North Cascades geology Tagged: | Cariboo Mountains, Fragrance Lake Trail, glacial till, quartzite, Selkirk Mountains, Vashon till
Dave, thanks for this post. I learned a couple of things, notably about the likely source of the quartzite in Vashon till, and also that it is orthoquartzite, not “true” metaquartzite. I hadn’t fully realized this, even though I have been teaching geology in these parts almost since these stones were carried here by ice!
Doug,
I didn’t even know there WAS such a thing as unmetamorphosed quartzite!
dt