Chord - Yet Another tectonics/winds/climate/etc World Map Project

[Charerg]

Is a mid-ocean subduction that strange? Looking at Earth at least the Pacific and Australian plates seem to have this going on (on the non-Australian/large landmass side of that plate). Nonetheless I also note that subduction is a lot more common (because of crust type density) on oceanic/continental areas so I've reworked many of my convergent plate borders to fall more along the coastlines of major landmasses. Regarding Plate O in particular, I reworked that convergent boundary along with the boundary/directions of plates V2, E, and V although I still have some oceanic subduction where O hits the spreading zone between V and A.

Yes, or rather oceanic-oceanic (crust) subduction is relatively rare. Even in the Pacific/Australian border there is a lot of continental crust forming the submerged continent of Zealandia. Also note that this zone is the intersection of three major converging plates (Australian, Eurasian and Pacific), creating a rather special situation.

It's worth looking at the formational process behind the area in a bit more detail, here's Australia 65 Mya (blue=continental crust, the rest is oceanic):



Note the ancient orientation of the S. Pacific ridge and the fragments of Zealandia rifting off.

35 Mya:


Around this time the Tasman Sea ridge has become an extinct ridge and the South Pacific ridge has connected up with the Indian Ocean ridge. Note the formation of several island arcs to accommodate the convergent movements of the Eurasian, Australian and Pacific plates.

And the present day situation:


I hope this provides some insight into the matter. I'll try and post some extra feedback later.