"The Birth and Death of Plate Boundaries:
The following processes can form new plate boundaries:
a. continental rifting
b. continental collisions "
(quoting from notes)

I truly understand how "continental rifting" can form new plate boundaries, but how can "continental collisions" form new plate boundaries?

Furthermore, the above only explains the "birth" part........how can continental rifting and continetal collisions give "death" to plate boundaries?

Awaiting for your favorable reply! :)

My speculation would infer that when a continental plate collision stops and another subduction occurs at a distance away from the original subduction, another plate boundary occurs.
If a continental colision does not give rise to subduction at the point of colision then a new plate boundary arises, thus, as you say, continemtal collisions give death to plate boundaries.
If continental rifting ceases and arises in another location then continental rifting gives death to new plate boundaries.
In saying this I have not looked up if this has actually hapened in the Earth's history, but it seems logical, I hope you agree.

"when a continental plate collision stops and another subduction occurs at a distance away from the original subduction, another plate boundary occurs."
But the note is saying "continental collision" where no subduction occurs...

"If a continental colision does not give rise to subduction at the point of colision then a new plate boundary arises, thus, as you say, continemtal collisions give death to plate boundaries."
Why a new plate boundary arises? And why give death to it?

[The bad thing is that when I seearch the web for "the birth and death of plate boundareis", there is nothing good that matches...]

"The BIRTH and DEATH of Plate Boundaries:
The following processes can form new plate boundaries:
a. continental rifting
b. continental collisions

Continental Rifting
Divergent boundaries are formed when a continent splits into two in a process known as continental rifting.
-lithosphere stretches until the fomration of a lower area
-the asthenosphere rises because of less compression, causing partial melting and fomration of volcanoes
-if continent splits completely, a mid-oceanic ridge will form and seafloor spreading occurs
-e.g. East African Rift

Collision
-subduction of oceanic plates between two continents, e.g. between India and Asia
-formation of the Himalayan mountains, crust also becomes thincker"
http://pubs.usgs.gov/publications/graphics/Fig24left.gif

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This is the whole note! If nobody understands (neither do I), I would have to ask the instructor next Monday (hopefully not too late...a test is coming up)

Sorry about that, after rereading my reply, I am confused as well, I must have been a bit wasted when I wrote that.
I think that it was your terminology of "death" of plate boundaries that confused me.
First off I can't see anywhere in your posted note where it says anything about "continental collision" where no subduction occurs this seems like an impossibility to me. OK, I could speculate that 2 continents moving towards each other could "concertina" the ocean crust between them but I doubt that this has ever happened inthe Earth's history. The point is that continental crust is less dense that oceanic crust so the continental crust always overrides the oceanic crust. It is possible however that subduction stops before the collision ceases i.e. when the ocean has closed and only uplift is occurring at the collision site.
What I meant to say in my other post instead of "If a continental collision does not give rise to subduction at the point of collision then a new plate boundary arises, thus, as you say, continental collisions give death to plate boundaries." was that when subduction and collision stops a new plate boundary probably occurs in another place and the point at which the continents collided ceases to be a plate boundary.
To answer your question of why a new plate boundary arises, if there are still stresses on the crust forcing it in the same direction and continental collision has stopped then subduction re occurs as the stress forces the ocean crust to subduct again at a point between the ocean ridge and the original continental collision.
Now that I have got my logical head screwed back on again, I do remember an example of this, forgive me if i get the details wrong but it was a long time ago that I studied it (and I would have to look in the loft to find my old notes)
When the Iapetus ocean closed in mid Silurian times it left a "suture" in the Silurian rocks this "suture" was uncovered not so long ago in South Wst Scotland (where I live) when there was work being done on the main North/South Road of the area. I remember seeing the discovery in a local geology journal at the time. This is no longer considered a plate boundary. (This suture continues on the other side of the Atlantic because North America and Scotland were part of the same landmass at the time.)
I am sure that there are many other examples of this hapening all over the world.

As for the diagrams in the notes, I also can't see anything in these diagrams showing the formation of a new plate boundary.

I could argue that it is showing an existing plate boundary migrating position.

I suppose someone else could argue that the major thrust plane is the plate boundary and some of the other minor thrust planes are "old" plate boundaries.

However my best interpretation of the diagrams is that the actual plate boundary is the position of the boundary between the rocks that were formed when the continents were separate i.e. the line between the pink rocks and the grey rocks. If movement between these rocks has ceased then it shows "death" of the plate boundary and the thrust plane is just a fault line in a newly created continent.

The big question is when do we start calling it the indo-Eurasian plate?
When the thrust stops moving between the 2 layers of continental rocks? And how do we know when this point is reached?

Did anyone mention to you that geology is not an easy subject, before you started studying it? :confused: