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Plate tectonics: Geological features of convergent plate boundaries

Video transcript

we've already talked a lot about plate boundaries where essentially new crust material is being created and the plates and the plates are actually moving apart we call these divergent boundaries in the example we showed of this was the the mid-atlantic ridge where essentially new crustal material is being created now on the other side of the equation you have areas where plates are ramming into each other we see that over here where the Nazca plate is running into the South American plate we see it over here where the Pacific plate is running into is running into the Filipino plate they're running into each other so what happens over there so what we're going to do is just go through the different scenarios the general idea is that one plate is going to get subducted under another their ramming into each other one is going to get essentially pushed under the other one this diagram shows some subduction over here this is a essentially oceanic plate being subducted under another oceanic plate so not too different than what might happen where the pacific plate runs into the filipino plate right over here and then on this side of the diagram we see an oceanic plate and the oceanic crust getting subducted under a continental plate right over here and this is what's happening and when the Nazca plate is getting subducted under the South American plate and when that happens a couple of things so you have the oceanic plate being pushed under and what happens at the same time the continental plate gets pushed upwards causing mountain ranges like the Andes and that's exactly what causes what has created the Andes it's that upward force from the from the Nazca plate being pushed under the South American plate at that coastline and what you're also going to see is and you can imagine you have these huge plates grinding past each other and it's not a very smooth process every now and then you kind of reach a breaking point in huge amounts of energy and huge amounts of energy get released so you're also going to see a lot of earthquakes in those areas and you could and we know that Chile has a lot of earthquakes and then on top of that this is going to result in a lot of heat in a lot of the friction of the plates grinding past each other essentially allowing magma to form at that part of of the of the rocket because it's getting so heated and so you'll also have volcanoes in these areas where essentially something is being subducted underneath a continental plate now we also talked about what's happening in the Pacific where we have the Pacific plate being subducted under the filipino plate that's what we kept keep referring to over here and that's doing a couple of interesting things whenever you have subduction you have trenches but it's most interesting or at least in my mind the deepest trenches have been created where you have an oceanic plate being subducted under another oceanic plate so a couple of things are going to happen you're going to have a very deep you're going to have trenches form you're going to have a trench form over here we see in this diagram we also have a trench in the first example but you have trenches formed where the oceanic where one oceanic plate is being subducted under another and then you have that same type of friction that you saw over here create volcanoes and those volcanoes will initially be underwater volcanoes since these are both oceanic plates or they were kind of we're dealing with oceanic crust at that point of the plate it doesn't have to be an entirely an oceanic plate and they'll first be underwater volcanoes but as the lava piles up and hardens it'll eventually turn into a group of islands and we have that happening where the Pacific plate runs into the filipino plate and first we have the trench so let me just draw everything right here so this is the boundary roughly roughly speaking this is the boundary between the two plates this is the Pacific plate and this is the Filipino plate right over here and so where it's being subducted you have the Mariana Trench which is the deepest trench in the world it goes down 11 it goes down 11 kilometers 11,000 meters that's deeper than Mount Everest is high Mount Everest is about 9,000 meters high and we'll see that's also due to another convergent plate boundary another place where plates are running into each other so not only do you see the mariana trench here because one plate is being subducted under the other you see the formation of the mariana islands which are essentially created from underwater volcanoes because of all of the enter being released and this is actually a depiction of what's the subduction that's happening at the Mariana Trench you have this subduction over here and then you have the Mariana Islands being created by essentially the energy causing a magma and lava essentially magma before it surfaces to flow to the top and as lava it just goes and starts building these islands now the last type of convergent boundary is when you have to two parts of continental crust running into each other so that's the situation that we have in where the Indian plate is running into the eurasian plate and i think you might already guess what's going to happen there when you have two pieces of continental crust running into each other one isn't more or less dense than the other and so at least the crustal portions of them the crustal portions of them are just going to keep are just going to keep jamming into each other and so they're just going to push things up where this is a depiction right here that I got from the USGS now what step what's what's kind of depicting is this is the Indian plate this is Eurasian Plate this is if you if you rewind a good bit before they've really had a chance to jam into each other but as they're jamming into each other the Indian plate is kind of digging in a little bit not being fully subducted and it's causing the land to rise and what that essentially ends up with is you end up with something like you end up with something like the Himalayas and this right here is a picture of Mount Everest which is almost 9,000 meters high 9,000 meters above sea level so it's almost as high as the Mariana Trench is deep