What forces drive tectonic plate movement?

[ChinleShale]

TL;DR

Much of the Evolution of the Earth is described in terms of tectonic plate movement. What causes tectonic plates to move? What is the dynamical system?

I have been trying to learn about the geology of the western United States since recently moving to New Mexico. There are many videos and articles on line that explain the present and the past both in terms of tectonic plate movements. But the ones I have looked at do not describe why tectonic plates move the first place. What forces drives them? Do they satisfy a differential equation of some kind? How can geologists play the dynamics backwards to create pictures of past continents and oceans? Is this based on a theory of plate movement or is it an empirical analysis based on dating of formations?

Here is a lecture on the geologic history of the Mesozoic Era.

triassic geologial history youtube

 

[anorlunda]

There are several. This Wikipedia article gives the basics.

https://en.wikipedia.org/wiki/Plate_tectonics#Driving_forces_of_plate_motion

 

[Baluncore]

How can geologists play the dynamics backwards to create pictures of past continents and oceans? Is this based on a theory of plate movement or is it an empirical analysis based on dating of formations?

The correlation of formations and fossils makes it possible to run the process backwards.
Looking at the magnetism and structure in the ocean floor demonstrates the spreading.

The theory of why plates move is incomplete. Thermal convection is insufficient.

 

[davenn]

How can geologists play the dynamics backwards to create pictures of past continents and oceans? Is this based on a theory of plate movement or is it an empirical analysis based on dating of formations?

Both
But even without the fossil record, plate motions can be played backwards just by measuring faultline and spreading ridge movement.

 

[Klystron]

Summary:: Much of the Evolution of the Earth is described in terms of tectonic plate movement. What causes tectonic plates to move? What is the dynamical system?
{snip}

Without offering textbook sources, the more recent plate tectonic dynamic systems appear modeled on fluid dynamics; specifically convection hydrodynamics and characteristics of molten rock.

How can geologists play the dynamics backwards to create pictures of past continents and oceans?

Early global cartographers noticed that continental land edges separated by oceans appeared to be inverse images in the sense that the western borders of the European continent fit the eastern borders of North America; Africa with Meso and South America, and so on for all the Earth's continents.

Cut out shapes, images of the continents modified from spherical to a flat plane, fit together into larger shapes that merge into super-continent Pangaea, meaning 'all Earth'. This topographical correspondence inferred continental drift leading to the current theory of plate tectonics.


Artists' conception of Pangaea with component pieces merged.

{edit 20210209: replaced general field 'hydrodynamics' with specific term 'convection' described in University of Toronto paper in post #9.}

 

[ChinleShale]

Without offering textbook sources, the more recent plate tectonic dynamic systems appear modeled on fluid dynamics; specifically hydrodynamics and characteristics of molten rock.

So modern research describes plate tectonics in terms of differential equations? I would like to understand that. Reference?

Also while recreating past plate configurations seems to be based on empirical modeling, projecting forward to future configurations would presumably not be. Would this then use these differential equations?

 

[ChinleShale]

Both
But even without the fossil record, plate motions can be played backwards just by measuring faultline and spreading ridge movement.

So one extrapolates from current small movements?

 

[ChinleShale]

Thinking about the formation of Pangea and then its subsequent separation into separate continents, if one thinks of this as flows along convection currents in the mantle then it would seem that the direction of these currents reversed. If this is true, what are the dynamics of this convection flow reversal? What happens to convection flows when two plates collide?

 

[Keith_McClary]

Here is a review article from 2011:
https://www.utsc.utoronto.ca/~lowman/papers/Lowman_Tect_11PP.pdf

 

[Klystron]

Here is section 4 of a video series about plate tectonics utilizing fluid mechanics at a beginner's level.

The origin of plate tectonics part 4: fluid mechanics and the mantle - YouTube

 

[Tom.G]

You might find this sight interesting for visualization of spreading data:
http://portal.gplates.org/#SEAFLOOR