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

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!

1. 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?

• You forgot the #FAKE NEWS.
– Siv
Commented Feb 17, 2017 at 21:30
• Might have a better response here: skeptics.stackexchange.com Commented Feb 17, 2017 at 21:38
• Please read up on the basic fundamentals of plate tectonics like this Wikipedia article and show us that you understand how they're supposed to work. If after that, you find something to question in the science, come back and give us a science-based question. Commented Feb 17, 2017 at 23:10
• @ boris plates that get pushed down, melt forming volcanoes, this is extremely basic and had you done any research you would have seen it.
– John
Commented Feb 18, 2017 at 16:53
• There is nothing wrong with this question, it is a very basic plate tectonics question but well with the earth science wheelhouse. I for one would rather answer the question of someone who asks rather than encourage them to wallow in ignorance. The word "hoax" is a poor choice Boris and is putting people in the wrong state of mind. It makes it seem like you have already made up your mind and are not really asking.
– John
Commented Feb 21, 2017 at 1:15

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)

• @boris as I said in my answer, there is a process called "subduction", where one plates moves underneath the other. This forms a "gap" on the other side of the plate, where formation of new plates occurs. This causes movement of the plate. It's hard to explain in words, and videos or animations are much better for this. YouTube has some, and Plate Tectonics Basics 1 is a favourite of mine. You can follow links from that to other videos that are also good. Notice that you watch science videos, not people claiming that it's a hoax (it is not). Commented Feb 18, 2017 at 3:14
• @boris and a good tip for life in general: when you don't understand something, don't storm in the room claiming that it's a lie or a hoax. This will make you more enemies than friends, and you don't want that to happen. Commented Feb 18, 2017 at 3:15
• The continents are the plates. Each plate has a continental part and oceanic part to it. For example, in the image you added to your question you can see that the North American plate has a continental bit on the left and an oceanic bit (which is half of the Atlantic ocean) on the right. This entire thing (continental and oceanic parts of the same single plate) move together. Another useful video that may help you understand this: Plate Tectonics Explained Commented Feb 18, 2017 at 3:30
• @boris the plates also change their shape. Parts of them are formed and destroyed. Even at slow rates of several cm per year, this is a significant movement and change of shape over millions of years. Commented Feb 18, 2017 at 4:31
• @boris: How do packages move on conveyor belts? Now visualize two conveyor belts running towards each other. Some of the packages pile up at the join (mountains), and some get sucked down the gap between the belts (ocean trench). Meanwhile the actual belt (mantle/ocean crust) keeps running around and around. Commented Feb 19, 2017 at 19:36

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.

• This doesn't really answer the question. You need to say how this relates to plate tectonics.
– bon
Commented Feb 18, 2017 at 17:50
• @bon I actually think it's a good answer that complements mine and adds the perspective of plates changing their shape. Commented Feb 18, 2017 at 22:22
• This doesn't answer the question, but it does address the fundamental thing that the op is missing and which will enable them to understand the other answers. Moreover, it is helpful and not aggressive, which appears to be unusual in answers to this question. I would encourage the author to add a short summary at the end of why this is important, and how it relates to the other answers. Commented Feb 20, 2017 at 9:26

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.

• thanks for the explanation friend @Knob Scratcher, but then another doubt occurs.. suppose the event when continental parts of two plates collide.. what will happen? will the oceanic part (caramel in ur analogy) continue to move? if so, won't the continental part get detached from the oceanic part eventually? or will the movement be stopped?... for example, the case with indian subcontinent plate and asian plate.. the continental parts of both plates are now pushed against each other. So what will be now happening to the oceanic parts of those two plates? Commented Feb 19, 2017 at 22:30
• Boris, may I suggest a short video? Fast forward to 3:00 here: youtube.com/watch?v=zbtAXW-2nz0 and pay close attention to the idea that the earth's crust is constantly being destroyed and reborn at plate boundaries. For some better detail, I suggest the Khan Academy video on Plate Tectonics, here: khanacademy.org/science/cosmology-and-astronomy/…. Commented Feb 20, 2017 at 3:35

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).