Talk:Orogenic collapse

Orogenic collapse vs Post-orogenic collapse

Hey everyone, I've noticed that both the terms "orogenic collapse" and "post-orogenic collapse" are used in the articles I've found, but I'm not sure whether they are interchangeable or if there's a specific difference between the two. If they are distinct, then that would definitely be something worth clarifying in the article and possibly splitting into two pages. Can someone help me figure this out?

CrunchyRocks (talk) 02:11, 11 December 2021 (UTC)

As soon as a mountain belt forms it can start to spread under its own weight, the Himalayas/Tibetan Plateau are doing that right now, even though the collision is ongoing. In that particular case the spreading is mainly going towards the east. So this is a continuous process, that starts during the orogeny and continues into the post orogenic period. I like to speculate as to what would happen if a subduction zone was formed in the older oceanic crust south of India, not an unlikely occurrence over the next few million years. The Indian Plate would head back south at relatively high speed, driven by the gravitational potential of all that thickened crust, leaving large successor basins behind, bound by large extensional structures. Something similar is thought to have happened towards the end of the Caledonian Orogeny in the Devonian. This used to be an area of research for me back in the 1980s and something I've tried to stay up to date with. The Basin and Range extensional province is another example that could be added to the article. I would be happy to help out on improving things. Mikenorton (talk) 12:03, 1 January 2022 (UTC)

That sounds super interesting! I hadn't considered that the Basin and Range could be an example here but I'll be on the lookout for how to update the information on it. I think it would make sense to rename the article from "Post-orogenic collapse" to just "Orogenic collapse" since it's a discussion about the collapse of orogens which can start during an orogeny, rather than just what happens post-orogeny. Do you agree?

CrunchyRocks (talk) 05:05, 13 January 2022 (UTC)

Wherever you have thickened crust the potential for collapse is there and there's no doubt that Basin and Range crust was thickened (see for example Cassel et al. 2014). Most of the discussion is about the trigger for the extension in that case and why the Colorado Plateau was not involved. I agree about the renaming. Mikenorton (talk) 08:49, 13 January 2022 (UTC)

Thanks for the direction. I'll go ahead and move the page and continue working on it

CrunchyRocks (talk) 05:09, 14 January 2022 (UTC)

The Variscan orogeny is another that has been associated with orogenic collapse, see for example here and here. Mikenorton (talk) 10:05, 14 January 2022 (UTC)