<p>Tectonic plates almost all comprise a mix of both oceanic and continental crust in different areas. The exceptions are all minor plates.</p>
<ul>
<li><p>Where the edges of these plates spread apart you get divergent boundaries. These are always found in a single rock type; in continental crust these are the <a href="https://en.wikipedia.org/wiki/Rift_valley" rel="nofollow noreferrer">rift valleys</a> while at oceanic boundaries they are the <a href="https://en.wikipedia.org/wiki/Mid-ocean_ridge" rel="nofollow noreferrer">mid-ocean ridges</a>.</p>
</li>
<li><p>Where the edges come together you get convergent boundaries, these almost always involve subduction of denser plate material under lighter rock. The density split is often defined by rock type with dense basaltic oceanic crust being pushed under lighter continental rock along <a href="https://en.wikipedia.org/wiki/Oceanic_trench" rel="nofollow noreferrer">deep ocean trenches</a> but there are several places where older, cooler oceanic rock subducts below younger, hotter oceanic crust.</p>
</li>
<li><p>Where two continental plate boundaries collide neither can subduct because they are so much less dense than the underlying mantle so you get massive mountain ranges like the Himalaya. The Atlas, Alps, and Pyrennes are at the beginning of the process as Africa slowly closes the Mediterranean and crashes into Europe.</p>
</li>
</ul>

CC BY-SA 4.0
2021-10-07T07:35:29.763Z
So these plates can also slide across or they just pull(divergent) and push(convergent)?
dark_prince
CC BY-SA 4.0
2021-10-07T11:44:35.920Z
@dark_prince The can also slide across one another. These are called transform boundaries or slip-strike boundaries. The San Andreas Fault in California is an example.
David Hammen
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2021-10-07T13:42:23.820Z
@DavidHammen thanks; please edited question. I think my question wasn't clear enough.
dark_prince
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2021-10-07T05:50:08.217Z
2021-10-07T05:50:08.217Z
Ash
<p>I have a very basic doubt regarding what the tectonic plates mean. In Wiki article <a href="https://en.wikipedia.org/wiki/Subduction" rel="nofollow noreferrer">Subduction</a> is defined as:</p>
<blockquote>
<p>Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at <strong>convergent boundaries</strong>.</p>
</blockquote>
<p>and when I follow the link to <a href="https://en.wikipedia.org/wiki/Convergent_boundary" rel="nofollow noreferrer">convergent boundary</a> it is defined as:</p>
<blockquote>
<p>A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more <strong>lithospheric plates</strong> collide.</p>
</blockquote>
<p>Now from what I know is that the tectonic plates comprise of oceanic and continental crust and convergent and divergent boundaries exist where two tectonic plates meet. So this subduction should <strong>only</strong> happen where two or more <strong>major or minor</strong> plates meet and not between continental crust and oceanic crust. So do plates sometime refer to crust as well and there are more minor and major plates which are still not defined.</p>
<p>Edit: Is there a possibility of subduction between continental crust and oceanic crust of the same plate?(If answer is yes then these crusts can also be called plates).</p>

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2021-10-08T05:15:18.643Z
I'm not understanding what you are now asking, or perhaps you aren't understanding plate tectonics. While there are a few places where the plate boundaries aren't quite clear, the basic idea of plate tectonics is that every square centimeter of the Earth's solid surface, whether it be oceanic or continental crust, is a small part of exactly one tectonic plate. You appear to be thinking that plate tectonics is something else.
David Hammen
CC BY-SA 4.0
2021-10-08T06:10:42.677Z
@DavidHammen ok got it; so there is no possibility of subduction in the same plate.
dark_prince
CC BY-SA 4.0
2021-10-12T20:50:39.567Z
for the edit if they are on the same plate then they are not a boundary, a boundary is a contact point between two plates.
John
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2021-10-12T20:57:38.300Z
@DavidHammen you couldn't be more wrong about that.  Plate boundaries are often not always well defined, or depend on scale or interpretation, and may comprise many plates which are only considered a single plate on a different scale. this is especially true of transform boundaries. Then you have cratons which are ancient plates now fused to other plates, California could contain on two plates or hundreds depending on your scale.
John
<plate-tectonics><tectonics><subduction><lithosphere>
Tectonic plates terminology
dark_prince
# Tectonic plates terminology

(Asked by: username_0 on 2021-10-06)

I have a very basic doubt regarding what the tectonic plates mean. In Wiki article [Subduction](https://en.wikipedia.org/wiki/Subduction) is defined as:

> Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at **convergent boundaries**.

and when I follow the link to [convergent boundary](https://en.wikipedia.org/wiki/Convergent_boundary) it is defined as:

> A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more **lithospheric plates** collide.

Now from what I know is that the tectonic plates comprise of oceanic and continental crust and convergent and divergent boundaries exist where two tectonic plates meet. So this subduction should **only** happen where two or more **major or minor** plates meet and not between continental crust and oceanic crust. So do plates sometime refer to crust as well and there are more minor and major plates which are still not defined.

Edit: Is there a possibility of subduction between continental crust and oceanic crust of the same plate?(If answer is yes then these crusts can also be called plates).

**Tags:** plate-tectonics, tectonics, subduction, lithosphere

> **Comments:**
> **username_1**: I'm not understanding what you are now asking, or perhaps you aren't understanding plate tectonics. While there are a few places where the plate boundaries aren't quite clear, the basic idea of plate tectonics is that every square centimeter of the Earth's solid surface, whether it be oceanic or continental crust, is a small part of exactly one tectonic plate. You appear to be thinking that plate tectonics is something else.  
> **username_0**: @username_1 ok got it; so there is no possibility of subduction in the same plate.  
> **username_2**: for the edit if they are on the same plate then they are not a boundary, a boundary is a contact point between two plates.  
> **username_2**: @username_1 you couldn't be more wrong about that.  Plate boundaries are often not always well defined, or depend on scale or interpretation, and may comprise many plates which are only considered a single plate on a different scale. this is especially true of transform boundaries. Then you have cratons which are ancient plates now fused to other plates, California could contain on two plates or hundreds depending on your scale.  

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## 1 answers

### Answer by username_3 on 2021-10-07. Score: 1

Tectonic plates almost all comprise a mix of both oceanic and continental crust in different areas. The exceptions are all minor plates.

* Where the edges of these plates spread apart you get divergent boundaries. These are always found in a single rock type; in continental crust these are the [rift valleys](https://en.wikipedia.org/wiki/Rift_valley) while at oceanic boundaries they are the [mid-ocean ridges](https://en.wikipedia.org/wiki/Mid-ocean_ridge).
* Where the edges come together you get convergent boundaries, these almost always involve subduction of denser plate material under lighter rock. The density split is often defined by rock type with dense basaltic oceanic crust being pushed under lighter continental rock along [deep ocean trenches](https://en.wikipedia.org/wiki/Oceanic_trench) but there are several places where older, cooler oceanic rock subducts below younger, hotter oceanic crust.
* Where two continental plate boundaries collide neither can subduct because they are so much less dense than the underlying mantle so you get massive mountain ranges like the Himalaya. The Atlas, Alps, and Pyrennes are at the beginning of the process as Africa slowly closes the Mediterranean and crashes into Europe.

> **Comments:**
> **username_0**: So these plates can also slide across or they just pull(divergent) and push(convergent)?  
> **username_1**: @username_0 The can also slide across one another. These are called transform boundaries or slip-strike boundaries. The San Andreas Fault in California is an example.  
> **username_0**: @username_1 thanks; please edited question. I think my question wasn't clear enough.  

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