Questions tagged [plate-tectonics]

The theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core.

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How is felsic magma produced at subduction zones?

I previously believed that continental crust owes its lower density to the partial melting of oceanic crust; the mantle would partially melt at mid-ocean ridges to produce basaltic crust, and when ...
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Would obliquity and precessional changes of Earth affect the accuracy of GPS-based measurement of tectonic movements?

The rate and direction of tectonic movements can be measured by comparing the coordinates of the same GPS receiver over time. The coordinates are obtained using trilateration. All materials I could ...
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Does the Plate tectonics contradict the theory of continental drift?

According to the theory of continental drift, South America and Africa was so closed to each other that the convex triangle of South America meets the concave hollow of Africa. Source: usgs.gov; ...
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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. How can the plates move? Before you suggest me some page to read about plate movement mechanics, let me clarify that I am ...
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1 answer
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Is there any research on the relation of asteroid impacts and hot-spots?

In a new video by Atlas Pro on Hawaii linked below, he indicates a curious observation: Most hotspots antipode’s have sign’s of heavy impacts from asteroids. He postulated that the force of these ...
1 vote
2 answers
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Are oceanic plates or continental plates heavier?

If you take a cilindrical section with radius 1 meter of both kinds of plate, which will have a larger mass? My guess is that continental plates are heavier than oceanic plates, because they are more ...
4 votes
2 answers
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Why aren't the Hawaiian islands a continuous strip of land?

My understanding is that the Hawaiian islands were produced as the Pacific plate moved over a stationary hot spot, which sent magma burning up through the plate as it passed over, forming a trail of ...
5 votes
1 answer
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Why does the ocean floor look so scratchy?

Why does some part of the ocean floor look so scratchy? If you look at Google Earth image of the Indian ocean floor, especially the area south-west of Sumatra, it looks like some cosmic beast ...
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What is causing the crustal extension exhibited by the Basin and Range province in western North America?

Is there any link with the subduction of the Farallon Plate and the associated spreading center?
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Why are there no volcanoes where continents collide with each other?

I understand that volcanoes occur where oceanic crust is subducted under continental crust such as the Andes. However, they don't occur at places like the Himalayas and Alps where continental crust is ...
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Why is the Colorado Plateau so stable?

The Colorado Plateau somehow has avoided all the tectonic activity around it over hundreds of millions of years. Is it just luck, or is there something about that chunk of crust? I have toured the ...
3 votes
2 answers
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Can continental plates collide and fuse together without an orogenic band or magmatic arc or at the junction?

I have seen this diagram on Wikipedia (link below). It shows that some North American mini-plate boundaries are orogenic bands and some are magmatic arcs, and I think those correspond to continent/...
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2 answers
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How likely are caverns inside the mantle?

Almost everyone wrongly assumes that the Earth's mantle is liquid, but it isn't (only the outer core is). Is it possible then that there are hollow spaces within the mantle, similar to caves in the ...
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Difference between Ocean-Ocean subduction and Continental-Ocean from earthquake data

I am having a hard time finding this anywhere -- if no one can answer, I would appreciate a reference. I was doing introductory homework in earth science, and we had to determine the kind of plate ...
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1 answer
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Is there a geological explanation for the recent Mammoth tusk discovery 185 miles off the California coast?

A recently publicized discovery of a Columbian Mammoth tusk located well of the coast of California in quite deep water made me wonder if geological conditions 100,000 years ago can explain how it got ...
2 votes
1 answer
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What role does the hydrosphere play in tectonic plate convection?

I need to do a "how do different 'Earth's spheres' interact with each other" and I'm trying to figure out how the hydrosphere would affect the lithosphere if the ozone layer were to ...
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4 answers
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Can garbage be sent into the (near-)center of the world?

I've been thinking about how difficult it is to eliminate toxic chemical waste -- it usually needs high temperatures and pressures. So: would it be feasible (and maybe cheaper) to send it into the ...
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What is the consensus among geologists about climate change being caused by humans?

I'm terribly frustrated with the way that climate change has been debated in Europe. I live in the Netherlands and members of one of the biggest parties here, the Party for Freedom (PVV), frequently ...
3 votes
2 answers
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When did the proto-Himalayas become non-volcanic?

In the normal course of events, when continents move toward each other, at least one coast will be associated with a subduction zone and corresponding volcanic activity. When the Indian subcontinent ...
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1 answer
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Tectonic plates terminology

I have a very basic doubt regarding what the tectonic plates mean. In Wiki article Subduction is defined as: Subduction is a geological process in which the oceanic lithosphere is recycled into the ...
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Why does sea level correspond to boundary between oceanic and continental crust?

Is it a coincidence? the first is determined by the amount of water on the Earth and the second comes from evolution of tectonic plates. Still, oceans seem to fill exactly the oceanic crust.
8 votes
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Cause of Wallace line

First off, I am a biologist, not an earth scientist. Very recently I heard about a very interesting biological phenomenon that has its origins rooted in geology : The Wallace Line. From a ...
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3 answers
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Why do some earthquakes and volcanoes occur within plates?

I know that volcanoes and earthquakes occur on plate margins. But, do some of them also occur within plates?
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(Why) Is there more landmass on Earth's Northern hemisphere than the Southern Hemisphere?

This Question on Worldbuilding is based on the presumption that there is a greater amount of landmass on the Earth's Northern Hemisphere than there is on the Southern Hemisphere. While researching ...
12 votes
3 answers
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Is the Mid-Atlantic Ridge a ridge or a trench?

I am confused after reading conflicting text from different sources. For example, I read that divergent oceanic plates form ridges. National Geographic calls Mid-Atlantic Ridge a valley! On the other ...
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1 answer
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Active rifting in Antarctica?

The West Antarctic Rift exists between the Trans-Antarctic Mountains and Marie Byrd Land (see map below for reference) Image source: NASA The rift system is believed to be like the East African Rift,...
11 votes
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How could this pyramidal Mountain have been formed?

How could this pyramidal peak have been formed in Antarctica? Little is known about it as far as I know but what is known is that its miles away from any existing plate boundary and its shape is also ...
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Is there any source that shows all of Earth's terrain changes from Pangea to present?

I teach a class on my state's history to middle school students. Our textbooks do not cover much historical geology, but its a subject students are fascinated in, and feel needs to be added. I want to ...
3 votes
1 answer
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Slab-breakoff - always connected to continent/continent collision?

The question came to me when pondering the Andes: Is a slab-breakoff always connected to the transition from subduction of oceanic crust to a continent/continent collision? Current understanding is ...
2 votes
1 answer
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Will California become a subduction zone in the distant future

California is one of the few places in the world that lie on a transform fault. My question is why considering the fact that North American Plate is moving westward shouldn't California be a ...
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3 answers
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Is Mount Everest currently becoming taller or shorter every year?

Is Mount Everest becoming taller or shorter every year? By how much? I would like an explanation in terms of tectonic plate movement if possible. Source: IamKatieHoffman.com
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How do the Andes get so high?

I'm interested in the limiting factors on the height of mountains. There is a very good explanation at https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-...
4 votes
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What sort of a plate is the Sunda plate?

I have read that the islands of Sumatra & Java have resulted from the subduction of oceanic crust of the Indo-Australian plate beneath the Sunda plate. I want to know whether this boundary is ...
4 votes
1 answer
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What will happen to the Indian plate after it slides under the Eurasian Plate?

What will happen if the Indian Plate is done sliding under the Eurasian plate? I hypothesied some possible answers. Tell me the answer and if my hypothesis is not correct. Most likely to least. It ...
21 votes
3 answers
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What caused the bend in the Emperor/Hawaii chain of islands, 45 million years ago?

What caused the bend in the Emperor/Hawaii chain of islands, 45 million years ago? Has there been any updates to this mystery I am unaware of? Are there any new theories that could potentially ...
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Farallon plate subducting under North American plate: is it a factor in "the next big one"?

I am a writer, not a scientist of any kind. I live in the SW AZ desert (USA), so we get earthquakes from time to time. I grew up in southern CA, right next to the San Andreas fault, so I have a ...
2 votes
1 answer
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How many supercontinents have there been? [duplicate]

With plate tectonics, supercontinents split up into smaller continents, and then the smaller continents get mashed up together to form a new supercontinent. There used to be a single supercontinent ...
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1 answer
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How on "Earth" can you make all those measurements of Earth forming?

This question is a result of recent news that Earth had a "boring billion" years in which mountains ceased to grow, and subsequently hindered life evolution. The article went on to give ...
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Are the oceans rising or the continents going down? How can we know?

The century old sustained rising of oceans, at a rate of 2-4 mm/y, remains a unexplained phenomenon; there is no correlation with temperature variations, so it is not due to the thermal variation of ...
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Why are there no subduction trenches on continental land?

The ocean has some of the deepest locations on earth, typically caused by subduction zones. Why are there no subduction trenches on land?
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Why isn't Iberia a tectonic plate?

I usually read that Iberia is a subplate, while India is a plate. But it was a plate at the beginning of the Alpine Orogeny: Source: wikimedia.org Description: Tectonic map of southern ...
1 vote
1 answer
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What happens when a mid-ocean ridge sub-ducts underneath continental crust?

I'm aware that oceanic crust always sub-ducts to continental crust, but surely the geologic forces pushing the ridge apart in the first place isn't just going to turn off, right? Any answers would be ...
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Is COMSOL Multiphysics good for subduction CFD modelling? Are there alternatives?

As a beginner for CFD modelling of plate subduction, I heard comsol to be a good software. Can anybody suggests alternatives and the demerits of using COMSOL Multiphysics? Thank you.
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Is it possible for Mexico to have a magnitude 9 earthquake?

Everyone has heard of the Cascadia Subduction Zone and the potential threat it poses. However, I have heard nothing about The Cocos Subduction Zone, even though it caused a devastating earthquake over ...
8 votes
1 answer
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How did the Ural mountains form?

A nice picture for "how mountains formed" on Earth is due to the motion of tectonic plates. As the plates crash together, mountains may get "pushed upwards". However, a quick look at a map of the ...
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Nickel question - non geologist me

Why are there no giant nickel porphyry deposits like those of copper, or SEDEX deposits, like those of zinc? Why is all the nickel found in direct magmatic intrusions from the mantle to the surface? ...
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Seismic activity in the UK [duplicate]

On 8th September 2020 there was a magnitude 3.9 earthquake here in the UK at 51.817°N 0.665°W which is approx. 10km/6.2miles east of Aylesbury or roughly 50km/31miles east of Oxford. This got me ...
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Why aren't there ultra acid igneous rocks?

In my study, I found that in volcanoes when the magma is going up it formed different types of rocks. There are basic, acidic and ultrabasic. My question is why isn't there ultra acid igneous rocks ...
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Why is Europe still considered a continent(along with Asia)? [closed]

It is true that there are multiple definitions of a continent. But it is also true that Europe fails to satisfy any of them. One of the boundaries between Europe and Asia was chose arbitrarily(the ...
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What was the Earth's continent's positions 10000 years ago, or 11700 years ago, AKA when the late Pleistocene epoch was coming to an end?

In many articles online, geologists and geographers have described and depicted the theorized locations of all our continental plates with great detail and illustration, providing pictures, time-lapse ...

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