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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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What is diffuse plate rifting?

For example in the Philippine Sea Plate the West Marianas Ridge has formed due to diffuse rifting in the south of the Marianas trough. What does it mean?
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What formations are to be expected to develop between the transform boundaries of oceanic and continental plates?

This could be needed in the Worldbuilding stack exchange instead of here, but when I was mapping out the movements of the tectonic plates, then there's a few locations where oceanic and continental ...
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Is it ever possible for an continental plate to subduct under an oceanic plate?

It is well known that oceanic plates subduct under continental plates. This may be attributed to the plate's age and density, plus the water on top of it. So I was wondering if it is ever possible for ...
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Will the oceans swallow all of the land?

I am wondering why, since the oceans could feasibly hold all of the dry land, they in fact do not. For example, the Mariana Trench drops to -10.9km, while Mount Everest only reaches to +8.8km. ...
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Minimum Surface Water for Plate Tectonics?

There is good evidence that the presence of water on a planet's surface is necessary for that planet to have plate tectonics. My question is this: Do we know if there is a minimum amount of surface ...
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How likely is that next big earthquake (and tsunami) will hit Philippines again?

We recently had an earthquake in Bali (August 5th 2018), then in Palu, Indonesia (October 1st 2018). Considering the distance and time between Bali and Palu, is it more likely that it will be near ...
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How do scientists reconstruct pre Cretaceous continent if all plates that are currently left are younger than Cretaceous?

I have read that the oldest oceanic plate that we see today is from the Cretaceous period. If so, how do scientists reconstruct plate movements and continental structure pre Cretaceous? And aren't all ...
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Calculating geological age

Suppose we assume a constant rate of plate motion at 3.8cm per year. How old would the Atlantic Ocean be right now? I'd like a simple answer and explanation.
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Could glacial melt alter plate tectonic movement?

Let's say some event caused runaway glacial melt, and removed half of the ice currently locked away in specific areas of the planet. Would the significant weight changes on various plates and fault ...
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A hypothetical geological case study regarding and an alternate possibility of tectonic plate mechanics

I'm a noob when it comes to tectonics but I have quite a bit of interest in physics so bear with me. Okay, imagine a hypothetical geological situation where tectonic plate motion is in full swing but ...
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What was the percentage of land mass in prehistoric times when temperatures were high enough that we had no ice caps?

I grew curious after watching a presentation about the large creatures of prehistoric times. One of the theories cited about why creatures were so big was the increased oxygen in the atmosphere due to ...
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Plate Tectonics vs Gravity for Creating Highs and Lows

I have a question that I thought of when discussing a Worldbuilding scenario here. In that question, a super earth with gravity 1.35 times that of earth's is discussed, and is assumed to have shallow ...
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Why are the latest additions to the Hawaiian-Emperor seamount chain the highest?

The Hawaiian-Emperor seamount chain stretches from Russia to the Hawaiian islands. When I look at them on a map, it seems that the oldest seamounts by Russia are shorter and smaller than the newer ...
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Plate boundary lon/lat data

I'm working on a map in GMT and am having trouble finding lon/lat data for the minor plate boundaries (specifically the adriatic). Is there a database I can refer to?
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Why does the lithosphere thickness vary within a short distance?

Can someone explain why the lithosphere thickness varies within a short distance (30-100km) at the same upper mantle viscosity around the polar region? And what is the behaviour of a thin (20-70km) ...
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Do ocean level rise estimates account for mantle elasticity and plate mass changes?

In the mainstream media the problem of ocean level rise is presented rather... over-simplistically - ice melts -> more water flows into the oceans -> water level rises -> continents sink. But it is ...
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Number of tectonic plates

I came across a question asking what's the number of tectonic plates in this illustration: I don't know on which basis we count the tectonic plates. And I'm confused because I think they are 5 but ...
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How many times in total has Earth formed a super continent?

I know there was a Pangaea at one point in history that broke into the continents of today, but I could have sworn there was another instance in Earth's history that there was a super continent, maybe ...
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Is there a correlation between the underwater geological activity and topology of the mid Atlantic ridge/ South American plate and the Gulf Stream?

I just had a little eureka moment! I was looking again at this mid atlantic ridge along the western edge of the Eurasian plate. https://en.wikipedia.org/wiki/Lists_of_volcanoes How it and the way it ...
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How did New Zealand's continental crust get split between two plates?

In New Zealand today, the Alpine fault features two pieces of continental crust sliding past each other, with the whole Eastern side of the South Island falling on the Pacific plate. But when New ...
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How, exactly, do scientists know location of earliest continents?

How can scientists know where the earliest continents were located? Supposedly, Pangaea has formed, re-formed, moved all around, etc. Do paleogeologists primarily rely on paleomagnetism, ...
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Can the process of subduction flatten the shape of a subducting plate relative to the plate it's going under?

There's something I’m still not quite getting about why island arcs are arcs. In the examples I’ve seen, the subducting plate is compared to a knife slicing across the surface of an orange - but it ...
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Has our understanding of the East African Rift significantly changed recently?

I've noticed many reports in the media about the East African Rift Valley recently, apparently because some large fissures opened up. Washington Post: A huge crack provides evidence that Africa is ...
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Movements of the tectonic plates - collison between Indian Plate & Eurasian Plate

I am a high school student, my question is about the collision between the Indian Plate and the Eurasian Plate. When this happens what happens to the area of the Asian continent. Does it increase or ...
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How much heat flow is needed to maintain plate tectonics?

The Earth is emitting about 47 terawatts of heat energy, producing a heat flow of 0.0921 W/m$^2$ due to radiogenic and primordial heat energy. The heat flow drives mantle convection which in turn ...
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Volcanoes in the Alps and Himalayas and the subduction of Tethys Sea

Geologist have theorized that the Tethys Sea subducted under Eurasian plates. But where are the volcanoes that would have resulted due to this? Where are the volcanoes in the Alps and the Himalayas?
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Can a shock wave travel around the Earth's curvature?

Can an explosion be felt in the ground on the opposite side of the Earth like from an asteroid? Would planes in the air on that side of the Earth be able to survive? Does the shock waive follow the ...
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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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What structures form due to the melting of subducting plates? [closed]

What structures form from the melting of subducting plates? Plutons, Accretionary wedges, Deep sea trenches, Faults?
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On which software can I simulate landmass collisions?

Such as in 3D simulations of vehicule crashes but this time with huge rocks or bodies of water (continental plates). I need to be able to set the properties of the material (density, size etc) and see ...
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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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242 views

Divergent boundary and trenches between oceanic plates

Why Divergent boundary create ridges between oceanic plates and rift valley between continental plates? I think that the ridges are formed because of the volcanic eruptions. But like rift valley in ...
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What separates the Karakoram Range, the Hindu Kush, and the Himalayan Range?

In Google Maps, I don't see any boundary between the Karakoram (a.k.a. Karakorum) Range, the Hindu Kush, and the Himalayan Range. What separates these ranges?
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The formation of West Mata

I was wondering if anyone knows how the formation of the West Mata volcano came to be? I was reading that a lot of underwater volcanoes were formed by convergent boundary. Is this how West Mata was ...
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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 ...
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Could diamonds be formed from coal?

Diamonds are predominately formed in cratons and brought to the surface in kimberlite pipes. However, it seems theoretically possible that diamonds could form at either subduction zones or from ...
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How can isostatic compensation of the crust be reconciled with a relatively strong upper mantle?

As I understand it, the outer portion of the Earth can be divided into the crust and mantle on chemical grounds (separated by the Moho), or into the lithosphere and asthenosphere based on mechanical ...
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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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Movement of the Prime/Greenwich Meridian

The line on the ground at the Greenwich Observatory is itself on a tectonic plate that is moving, so is the prime meridian still 0 degrees, 0 minutes, 0 seconds? If not - what are the implications (...
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Water gaps in mountain ranges: which is older, the river or the mountains?

"Water Gaps", where rivers cut through montains, seem impossible. What came first? If the mountain was there first, the river would have simply found lower ground. If the river was there first, it ...
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For slab rollback, what allows the subducting plate to begin descending at a steeper incline?

I recently learned about slab rollback, specifically of the Juan de Fuca plate subducting underneath the North American plate. From what I understand, the subducting plate over time begins descending ...
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How Do Plateaus Really Form?

Any time I hear the word "plateau", I usually associate it with the tallest in the world, Tibet. Anyone who looks closely at a map will see that the southern line of the plateau parallels the ...
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Effects of Mexican Earthquake in San Andreas Fault Line

Could the recent 8.1 Magnitude Earthquake at the Cocos and Nazca plates off the Mexican coast have a knock on effect to the Pacific and Juan de Fuca Plates further north at the San Andreas Fault Line?
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Could water pressure at the coast be the cause of continental drift?

For example the Northern Africa is getting closer to Europe, where the depth of the sea is lower than in south African coast Could it be that the water's pressure pushes the continent from where the ...
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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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How did Australia separate from India?

So on a lot of maps of tectonic plates, it appears that India and Australia share a tectonic plate (hence the Indo-Australian plate). But in maps of Pangaea, India and Australia appear to have once ...
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How do tectonic plates move upward? [closed]

And also, can this push continents and land-masses upward as well?I have not been informed of the phenomenon of tectonic plates rising up. I am yet unable to find a satisfactory answer on the internet,...
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What causes jagged appearance of mountains in SE Asia?

For some time now, I've noticed that mountains in southeast Asia seem to be unusually "jagged" with steep surfaces. My basic knowledge of how mountains are formed (via geologic processes) tells me ...
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Lake Manasarovar v.s. Lake Rakshastal: fresh-water v.s. salt-water

In Tibetan Plateau, about 4600m elevation, If Lake Manasarovar and Lake Rakshastal ("lake of the demon" ) used to be the same lake, but due to the tectonic activity now they are separated to two by ...
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What fraction of Earth's crustal material survives the supercontinent cycle?

I know that things are not as simple, but for the sake of argument I'll assume a supercontinent cycle of $\sim$400 Myr periodicity is active on Earth. If that is the case, then my naive ...