How do tightly packed plates move in the theory of plate tectonics?

Question

Here are two questions I had ever since I first heard about plate-tectonics.

1. How can the plates move? Before you suggest me some page to read about plate movement mechanics, let me clarify that I am not asking about the mechanics behind plate movement here. But I am talking about the physical possibility of plate movement.

When we look at the map of plates, all of them are tightly packed, with not an inch of space or gap to move. The complex shape of surrounding plates, blocks all freedom of movement. Then how can the theory say that plates can move?

If you can't follow my explanation, consider a jigsaw puzzle in which the blocks are correctly set up. Can we move a block from the middle now? We can not because the blocks are tightly interlocked, and because of their complex shape. The same is the situation here too, in fact much more complex! Each plates is tightly surrounded by complex shaped other plates, making any movement in any direction impossible!

See the below given a map of tectonic plates for example. It is evident the plates are actually interlocked so tightly that, it is impossible to move in any direction, because of the presence of another plate in opposite direction. There is no freedom of movement available, in any direction! The complex shape of plates make movements impossible!

2. My second question is this: It is said that, all continents were a single large continent millions of years ago. And then much later, continents 'drifted away', reaching current shape and locations.

If tectonic plates does not even have hundreds of miles of gaps between them to move, how can continents drift away so far, even thousands of miles away? Certainly plates can't move this far, because the whole earth surface is divided into plates, with no space left for plates to move thousands of miles.

So how did the continents drift away this far? Or do we have to assume that continents are simply floating over the tectonic plates?

Is the plate tectonics theory a complete hoax?

Answer 1

isn't the plate tectonics theory a complete hoax?

No, it isn't. It's a perfectly valid theory that has much supporting evidence from all disciples of earth sciences, and it explains features that would otherwise remain unexplained. It is so widely and universally accepted that questioning it (particularly in the way you are doing) is likely to elicit a very hostile response from the scientific community, similar to how people would react to questioning Newton's laws of gravity.

How can the plates move? (before you suggest me some page to read about plate movement mechanics, let me clarify that i am not asking about the mechanics behind plate movement here. But i am talking about the physical possibility of plate movement)

Since you are not asking about the mechanics I will spare you from explanation about mantle convection and similar processes.

all of them are tightly packed, with not an inch of space or gap to move...

You are entirely correct. They don't have any gap to move. This is why we have mountain ranges where continental plates collide (or converge):

In places where an oceanic plate converges, plates can go underneath one the other in a process called subduction. This causes melting around the subducting plate, causing the formation of volcanic arcs:

Where plates pull apart and diverge you can have impressive rift valleys:

Or submarine trenches:

And of course, let's not forget about the earthquakes that occur when all of these things form. While you may doubt it, it is very real to the people affected by such natural disasters.

Everything I just mentioned happens because the plates are so tight and have nowhere to move. Just because you think a theory is incorrect because it doesn't fit your extremely simplistic way of how things should work, does not mean it is in fact incorrect. Nature does its thing regardless of what you, me, and everyone else thinks.

^{(Photographs either public domain or mine)}

Answer 2

tectonic plates are not completely rigid they can bend, flex, and in the case of oceanic plate, get pushed under each other and melted back down.The plates move by sliding under each other, melting, or bending

Take a toffee-bar candy, hang most of it off the side of a table and put something heavy on the other end to hold it in place, wait a few hours, just under its own weight it will bend 90 degrees. However bend it fast by only a few degrees and it will snap. Rock behaves in a similar fashion, do it slowly enough and with enough force and you can bend it. Basically all solids behave like this to a certain extent. tectonic plates are not rigid on the large scale.

bending rock leaves behind traces like this and this

bend it to fast and the rock breaks creating a fault lines like this and this

plates pushed down get remelted, it helps if you think of oceanic crust as exposed mantle that has been cooled into a solid, while continental crust is much less dense and sort of floats on top of the more liquid mantle. that's why continental crust does not subduct but oceanic does. In essence there are huge gaps between the the permanent plate material, it just cools when exposed forming a hard surface skin called an oceanic plate.

we can even see that in how earth quakes behave around subduction zones getting deeper and deeper in the direction of movement until the stop indicating where there are no solids left to break.

here is an earthquake depth map for japan. notice how they get deeper in the direction of the movement of the pacific plate (west by NW) as it dives under japan.

If you look at a global map of plate movement you will notice that at then end of a moving plate (in the direction of movement) is either a mountain range or a subduction zone, or often both.

Answer 3

At continental scales, plates don't really behave like solid objects. Furthermore, their edges can't compete with the forces below in the mantle, that move them around willy nilly over the earth' surface. Your mental "block" is that you think of plates as solid, like concrete, or sheets of ice floating on water. They are not!

It may be more useful to think of a tectonic plate as a large sheet of semi-solid caramel floating around on a thick sludge of gooey hot chocolate. To a tiny, microscopic bug, the caramel plate might feel solid but to an omnipotent being with a wooden spoon, the plate is weak and bendy.

Answer 4

Plate movements can be detected with GPS, as this short outreach document made by US earthquake researchers explains: http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/14/1.GPS_Background.pdf . Measurement accuracies of GPS and geodetic technologies get better all the time.

Central to the theory of Plate Tectonics are Subduction processes, which are also the subject of much current research. For instance accurately characterizing deep earthquakes, in particular those occuring in Subduction Zones along the "Ring of Fire" around the Pacific gives us evidence for Subduction Processes and therefore Plate Tectonics.

Numerical modeling of the Earth as a giant sphere, or nested set of spheres, combined with experimental data (rock melting experiments, high-pressure experiments) show that Plate Tectonics is possible.

Also we have more evidence from radiogenic dating of Oceanic crust. Most of the rocks on the seafloor are much younger than continental crust. The youngest are at Mid-Oceanic Ridges, where submarine volcanism and deeper volcanic processes drive Plate Tectonics (together with Subduction - now, since the mid-seventies, interpreted as a "recycling process" of ocean crust)

Observing other celestial bodies show that similar processes are occuring in the Solar system. Jupiter's Moon Europa and Saturn's Moon Enceladus for instance, seem to have huge cracks/gaps in their crust/surfaces. (This is of course also subject of much research).