Does Subduction really cause orogeny?

Question

This is the title of a presentation my Engineering Geology professor wants me to give. From all the research I have done, I believe that it subduction does build mountains. But, I'm afraid I might be missing something here. Is there some debate going on right now in the geologic community about whether or not this is true? It seems geoLOGICAL to me, ha.

Answer 1

although subduction undoubtedly causes compression, you may also want to address the extensional forces associated with subduction zones ie. the extension found in the back arc area of the overriding plate, and also found in a 'hinge-like' area of the subducting plate.

try this:
http://virtualexplorer.com.au/journal/2001/03/mantovani/paper.html

http://adsabs.harvard.edu/abs/2005AGUFM.G51B0812F

maybe too, he's wanting you to pick up that orogenies don't neccessarily depend on subduction. for example rifting may produce mountains (mid ocean ridge) but there is defentitley no subducting going on there.

Answer 2

Well if you take the statement literally, you could make a case for Orogeny being the result of what happens to a subducted plate after it is subducted. In my geophysics and petrology classes we talk about the processes of melting and such that cause orogenies.
If you consider that many geologists consider the process of subduction to be just the moving of one plate under another and not the subsequent melting, then subduction doesn't really cause the volcanism, it really depends on how much of the process you lump under the title of "subduction".
I would research professional papers on Orogenic processes (or orogenesis), also papers describing subducted slab hydration and temperature as it affects melting (A cold dry slab is less likely to melt easily than a warm wet one).
Also if you have taken a recent petrology class there are probably useful diagrams in the book, if not find an Igneous and metamorphic petrology book at the library. Geophysics books might also be helpful.
I have never taken an Engeneering geology class but it seems odd that they're talking about subduction and orogeny. Also I don't know your professor but mine tend to be a bit sarcastic like that so I imagine his goal is to get you thinking about it and doing some research in professional papers (which it sounds like you've done).
Overall the answer to the question really depends on where you draw the line between processes.
Subduction leads to orogeny is the joke we geologists tell (I know several people who have it on t-shirts).

Answer 3

Gee, that is logical. Hawaii builds mountains the old fashioned way, with lava from a hot spot beneath the earth's crust. The mid-oceanic ridges build mountains where the tectonic plates are separating. However subduction accounts for much orogeny (like Mt. Everest).

Answer 4

You can understand it like:
Subduction is a part of geodynamic process and orogeny is the result or end product at the site of subduction. Subduction provides the site for huge deposition, burial, sinking, compression, metamorphism, diaperism etc. and finally uplift.
thnks

Answer 5

It wasn't that long ago -- it was more like a hundred million years ago. The currents in the molten rock far below the earth's surface move the continents around, as well as moving things up and down. This motion is visible today; the Americas are separating from Europe and Africa by an inch or so a year. New seabed is being created in the middle of the Atlantic to fill the gap. The seabed traps the earth's magnetism as it cools below the Curie temperature, and gives a record of the reversal of the earth's magnetic field over the millenia. Postscript: Previous answer is thorough, and technically accurate.

Answer 6

Subduction does cause orogeny, but not all orogenies are created by subduction.

Answer 7

No there's no debate. Subduction does cause orogeny.

That phrase is one of geologist's little dirty jokes.