Random flowline spike?

Worldbuilding
1

I’m splitting apart my continents (similar to the offset flowline issue described here) and I have a persistent issue in one particular spot that I haven’t found anywhere else. I’m reconstructing my flowlines from the start of the simulation at 1500 Ma, so it may pop up later and I just haven’t got to it yet. What happens is a random spike appears in the flowlines at exactly 1299.99 Ma, as if the connected oceanic plate has zoomed halfway around the globe and then returned. I’ve double-checked my rotation file and there’s no corresponding anomaly, I’ve asked chatgpt for answers on what might cause it and zero possible hits on what it suggested. It happens to three flowlines, I deleted two of them to make it easier to follow.
I add the oceanic crust every 50 Ma, and this is just before that happens. Everything looks good until…

Gplates_flowlines3
Gplates_flowlines31920×1015 353 KB

Suddenly all is not well. The dreaded spike appears, and the mid-ocean ridge is apparently halfway around the globe for zero reason whatsoever. I have no idea why this is happening.

Just for completionists’ sake, I guess I should also add in the code for the two plates at this time. The anomaly, as stated before, happens between 1300.00 Ma and 1299.99 Ma.
…
102 0.0 90.0 0.0 0.0 000 ! Ocean V end
102 1.0 4.2901 -103.5883 40.1216 000 ! Drift correction
102 1150.0 4.2901 -103.5883 40.1216 000 !
102 1200.0 90.0 0.0 0.0 000 ! Start moving independently
102 1200.0 10.5453 -70.9437 -78.7799 100 ! End following A
102 1500.0 10.5453 -70.9437 -78.7799 100 ! Ocean V start
…
901 0.0 90.0 0.0 0.0 000 ! Ocean IV end
901 1.0 46.2197 -21.3653 171.3508 000 ! Drift correction
901 1150.0 46.2197 -21.3653 171.3508 000 !
901 1200.0 45.1426 -13.6379 235.3395 000 !
901 1250.0 53.0885 -18.7692 304.0887 000 !
901 1290.0 36.918 -8.7956 349.979 000 !
901 1300.0 90.0 0.0 0.0 000 ! Start moving indepentently
901 1300.0 33.8942 -99.7586 59.6946 900 ! End following I
901 1500.0 33.8942 -99.7586 59.6946 900 ! Ocean IV start
I sincerely doubt that 102 is the offender, it’s just following 100 at this stage. 901 changes from following 900 to moving independently, but I have this exact same transition elsewhere/elsewhen on this simulation with no ill effects.

Any ideas folks?

1 Like
2

I had this same issue as well, what fixed it for me was fully closing Gplates then reopening it reloading all files. Nothing in the rotation code seemed to be wrong in mine either.

3

It might be the above crossover needs to be re-calculated?

If you haven’t already, try following exercise 3 in tutorial 2.2 (Changing Rotations, Equivalent Finite Rotations, and Cross-Overs).