Some points (present day coordinates) can not be reconstructed back to paleo-location?

I found there were some present day coordinates can not transfer to paleo-positions when I used the URL of web service part in GPlates. It returned {“type”: “MultiPoint”, “coordinates”: [[999.99, 999.99]]}. Did some wrong I make? Or this point doesn’t belong to any Plate ID, therefore it can not reconstruct in this reconstruction model, GOLONKA?,18&time=72&model=GOLONKA

Hi Wendy,

If the service returns 999.99, it means the present-day coordinates do not exist at the given paleo-time. Usually it happens when you give a paleo-time which is earlier than the birth age of the coordinates.

In you case, it seems the (-72,18) has got a plate ID 0 in the GOLONKA. See the link below.,18&time=72&model=GOLONKA&fc

Hi again,

I just checked GOLONKA model, it seems this model can only handle coordinates on land.

Hi machin,
Thanks for your answers. Just two more little questions.‘handling coordinates on land’ means that present coordinates must locate on land? And Does earlier paleo-time mean these Plates with these points haven’t enough data to return earlier time or just disappear due to subduction?

Hi Wendy,

It seems to me that the GOLONKA model is a bit special. It can only reconstruct the present-day coordinates locate on land. I don’t know much about the history of the GOLONKA model. If possible, I would suggest you to use other reconstruction models.

Each plate has a valid time range. For example range (410, 0) means the plate appeared at 410Ma and still exists at the present-day. The 410Ma is the birth age of the plate. If you try to reconstruct the plate back to, for example 420Ma, the service will return null or 999.999 to indicate the plate cannot be reconstructed back that far.

Hi machin,
Thanks again. That sounds so sad. Because this model, GOLONKA model, is the using one in PBDB. and if I try to reconstruct these present-day coordinates back to Cambrian, 540Ma ago, which model is better?
Best wishes!

maybe try MERDITH2021 or MULLER2019? If you want more info about PBDB and GOLONKA model, this paper might be helpful Towards community-driven paleogeographic reconstructions: integrating open-access paleogeographic and paleobiology data with plate tectonics – EarthByte,18&time=72&model=MERDITH2021&fc,18&time=72&model=MULLER2019&fc

Got it! Thanks. I will try to it.

Yours Sincerely,

It is unfortunate that the PBDB uses the Golonka plate model only. They should really provide some alternative plate models for their reconstruction service. I would recommend to talk to them about this. Dietmar