Excellent presentation. McDannell (2022) makes a pretty impelling case for exhumation of the Pikes Peak area by Cambrian time as a result of continental glaciation associated with the Croygenian snowball earth, as well as Shanan Peters’ work. But with all things, there were likely several things going on, as Rebecca Flowers and Francis MacDonald’s recent work on the topic, focusing on diachronous development of the GU…
The Laramide Orogeny shut down prior to 45Ma, right? I believe at around 45Ma there was the earliest volcanic activity associated with the Ancestral Cascades arc -- that means subduction had already jumped to the west after the Siletzia oceanic LIP jammed the prior subduction zone. I was under the impression that the accretion of Siletzia coincided with the termination of the Laramide Orogeny, and that occurred prior to 45Ma.
