A diagramI am designing a fictitious continent, and as part of this I am also designing the prehistoric development of the continent up to the present day.

A particular tricky part of this has been that, in my present day version, off the Southeast coast of the continent, a region of continental crust that rifted off of the main landmass has a slip-strike fault running through it that has effectively trapped part of the continental crust on the other plate and is currently dragging it to the south-southwest.

However, when this terrain separates from the main continent due to back-arc formation, it is bordered to the east solely by a subduction zone. I need a way for a new fault to develop at that NNE-SSW boundary, one that traps a fragment of crust on the other plate, creating a new slip-strike boundary that separates the subduction of oceanic crust to the west underneath the separated continental crust to the south, and the original eastern oceanic plate sinking underneath the terrane to the west in the north.

Is there anyway that this situation can be achieved realistically?

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    $\begingroup$ This question would greatly benefit from a map of what you’re trying to achieve. I am a geologist and I’m having a hard time following your description. $\endgroup$ – Gimelist Sep 7 '19 at 4:09
  • $\begingroup$ Welcome to Worldbuilding, Antarctica07. Is this a reimagined version of planet Earth or a wholly fictional planet.? Without some idea about the rest of the planet's tectonics it isn't possible to have clear notion of what is involved. $\endgroup$ – a4android Sep 7 '19 at 5:46
  • $\begingroup$ Your question suggests you have done the research and given thought to the geology of your world. Suggestions about different kinds of strike-slip tectonics can be found here: en.wikipedia.org/wiki/Strike-slip_tectonics $\endgroup$ – a4android Sep 7 '19 at 5:52
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    $\begingroup$ @Gimelist have added a map that I hope can clarify what I had in mid a bit. Thank you. $\endgroup$ – Antarctica07 Sep 7 '19 at 6:18
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    $\begingroup$ you may want to look at the fiji plate with which is a spreading center tightly confined by two subduction zones. $\endgroup$ – John Sep 9 '19 at 3:16

Grow the size of your planet

First, about sources...

  1. This question doesn't ask for "hard" science, only a "base" in science; I'm citing a researcher who has done some work in this.

  2. YouTube isn't a source of proof, but a video can be a 3-D or animated model to explain an idea.

  3. Reportedly, the ocean floor age maps used in this video model are based on real science from the US government, but I have not fact-checked that claim.

This may seem absurd, but there have been no answers from a month and a half since the question was asked. So, I'm humbly offering a suggestion.

Could it work in your story? I think so...


Look at this video: Earth is Growing researched by Neal Adams. At 5:22, his model of the ocean floor starts to spread in what—looks like to me—could be something like your slip strike faults. Lines that look like what you want are visually explained by a. real ocean floor maps and b. a growing planet.

At least, the "growing planet" in this animated model produces the kinds of lines on ocean floor maps that you are looking for.


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