Talk:Back-arc basin

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Merge

Merge is self explanatory.Rolinator 10:40, 29 October 2006 (UTC)[reply]

Done :-) Vsmith 14:37, 29 October 2006 (UTC)[reply]

Please give cause and effect in lay-language

I'm an educated person of above-average intelligence, but I couldn't see clearly the cause of back-arc basins. They seem to be a trench formed by sea-floor spreading near a major subduction zone. But I don't see the cause and effect. It seems to me that the opening section could explain this for lay-people, with details in geologic jargon in following sections.JWorkman 15:50, 18 November 2012 (UTC) — Preceding unsigned comment added by James K. Workman (talk • contribs)

As I understand it, the cause isn't so clear. Plate tectonics are slow movements, they creep (deformation), no crystal clear physics. You have to remember that the seafloor at the subduction zone is old, thick and heavy; at the mid-ocean ridge time it had a higher bouyancy. The subducting slab pulls the seafloor downwards, modifying its apparent density, the ocean is closing. The Eurasian, the Antarctic and the African tectonic plate are quite static in comparison with other plates. --Chris.urs-o (talk) 19:55, 18 November 2012 (UTC)[reply]

Thanks for that. I'm just asking whether the opening section could be written for lay-people with following sections in geologic jargon. Your point that the cause of back-arc basins is not clear would be a good point for the opening. JWorkman 14:21, 19 November 2012 (UTC) JWorkman 14:19, 19 November 2012 (UTC) — Preceding unsigned comment added by James K. Workman (talk • contribs)

You're welcome. More: rocks cope with compression much better than with tension. Microplates have faults and a heterogenity. The sinking slab pulls somehow on the microplate. The microplate under extension (geology) undergoes a rifting process. As most things on plate tectonics, you get a fact: there is extension, and then u try to explain it. --Chris.urs-o (talk) 08:20, 23 November 2012 (UTC)[reply]

Okay, now I see it. Plus I see the meaning of "tension" in a new way. "Tension" must be a technical geological term for "pulling," as opposed to compressing. I think you need to put some of the language above into the opening section. Suggestion from a lay-person: The sinking continental slab-edge pulls somehow on the microplate. The microplate under extension (geology) undergoes a rifting process. I also, think the clause--"the ocean is closing"--is unclear. Thanks for humoring an interested reader.JWorkman 15:06, 23 November 2012 (UTC) — Preceding unsigned comment added by James K. Workman (talk • contribs)

Statics: tension (physics) and compression (physical). Cheers --Chris.urs-o (talk) 06:00, 24 November 2012 (UTC)[reply]

Not all back-arc basins are oceanic

Back-arc basins are not limited only to submarine basins associated with island arcs. They can also be land basins associated with continental arcs. Volcanoguy 16:08, 20 December 2015 (UTC)[reply]

This issue has come up on the Talk page for Cerro Tuzgle. The two articles seem to contradict each other on this point. The conflict should be clarified. Mr Serjeant Buzfuz (talk) 02:16, 23 June 2023 (UTC)[reply]

Compressional back-arc basins

The term "compressional back-arc basin" gets just 9 hits on Google Scholar. Munteanu et al. 2016 do indeed refer to both the Pyrenees and Swiss Alps as examples, but they cite Schmid et al. 1996 and Beaumont et al. 2000, neither of which mention back-arc basins, which is a bit strange. Is it worthy of a mention at all? Mikenorton (talk) 22:29, 26 May 2020 (UTC)[reply]

Thanks for raising this.

I found a few more hits in an ordinary Google search using the exact phrase "compressional back-arc basin" but they were only a conference presentation and a field trip guide (presumably not peer-reviewed), both for basins in Eastern Europe. Unfortunately, if I remove the quotation marks from my search terms, I then get more than 90,000 hits. I suspect that most of these hits could be because subduction zones, with which back-arc basins are associated, are compressional, and the compressional search term is describing a subduction zone rather than a back-arc basin. Trying to unpick any "compressional back-arc basin near a compressional subduction zone" hits from that would be difficult/impossible/waste-of-effort.

Currently, in this Wikipedia article, compressional back-arc basins are mentioned only very briefly, so I'm not yet sure that removal due to e.g. "undue weight" would be justified yet (assuming that such basins really do exist). I agree that Munteanu et al.'s sources not mentioning back-arc basins seems strange and adds doubt about Munteanu et al.'s reliability and, by the way, also raises questions about the quality of the peer review. How are basins in the Pyrenees and the Swiss Alps actually described by Schmid et al. and Beaumont et al.? I suggest keeping the current text for a while but at least adding a "better source needed" tag. GeoWriter (talk) 16:52, 27 May 2020 (UTC)[reply]

Reading Munteanu et al again, it seems that they're talking about extensional back-arc basins that have then been caught up in a collision and shortened/inverted, which doesn't really make them into a different class of back-arc basin in my view. To quote that paper's conclusions: "The Black Sea example demonstrates the mechanism of transition from an extensional back‐arc basin to a contractional one during the evolution of the Tethyan subduction and collision." Perhaps this is just somewhat clumsy language in their introduction? They say "The structural style of back‐arc basins can change in time from extensional to compressional with various intermediate classes [Uyeda and Kanamori, 1979; Jarrard,1986]. These processes generate sedimentary successions overlying a variety of crustal types, from continental to oceanic ones [e.g., Molnar and Atwater, 1978; Royden et al.,1982; Mathisen and Vondra, 1983]. Compressional back‐arc basins form due to back thrusting of the orogenic core, like in the Pyrenees or Swiss Alps [e.g., Schmid et al., 1996;Beaumont et al., 2000]." The references may be just there to provide examples of major backthrusting of the orogenic core. Mikenorton (talk) 17:40, 27 May 2020 (UTC)[reply]