Movement of plates

[kingwinner]

I have found 3 other tectonic plate movement graphs! But the third one looks a bit crazy to me...is it true that the creator of this graph mess up the convergent and divergent boundaries? It is the exact opposite of the usual one! Anyone seeing the same thing as me?

And also, plate teconic theory states that there are 30 plates, but the 4 graphs (including invert_nexus') each only have about 15 plates, why?

[Oh gosh, my teacher expect us to know all the plates and which plates converge, diverge, transform...like challenging our memories]

[Turtle]

___The third graph does appear mislabled. The others likely leave off most of the microplates for formatting reasons, i.e. uncluttered diagram.

[kingwinner]

And a lot of sources (including my text book) treat Indian and Australian Plates as separate ones, but why are the ones I found on the internet treat them as one single plate?

[kingwinner]

Are there two other plates called Fiji Plate and Sandwich Plate? If so, where are they?

[Turtle]

___I found these maps for you Kingwinner:


Fiji Plate:
http://www.mrd.gov.fj/gfiji/geology/...e/platect.html

Sandwich Plate (off tip of South America)
http://denali.gsfc.nasa.gov/dtam/data/ftp/gtam.pdf

[kingwinner]

Thanks Turtle!

One thing I do not understand is "why at the convergent boundary where Indian Plate and Eurasian Plate collide, all maps are showing Indian Plate subducted under the Eurasian Plate?" (Continental-continental convergence should have no subduction occuring because continental plates have the same density.)

[Turtle]

Originally Posted by kingwinner

Thanks Turtle!

One thing I do not understand is "why at the convergent boundary where Indian Plate and Eurasian Plate collide, all maps are showing Indian Plate subducted under the Eurasian Plate?" (Continental-continental convergence should have no subduction occuring because continental plates have the same density.)

___I noticed that in one of the diagrams you posted in another thread; I'm afraid I don't know this one.

[kingwinner]

Now I understand that oceanic Indian Plate once subdcted under continental Eurasian Plate (oceanic-continetal convergence), but now the subduction have stopped because the 2 continents are colliding and they can't subduct, this is no longer an oceanic-continental convergence. Why are the first and second maps still showing Indian Plate subducting under Eurasian Plates, is it because these maps are wrong, or not up-to-date?

[In the key, it says:

overriding plate
/\ /\ /\
------------
subducting

-the side with these little triangles indicates that that plate is overriding the other]

Some major sources from the internet also says that there is no subduction occuring at the Indian-Eurasian boundary:
http://pubs.usgs.gov/publications/te...rstanding.html
"The Himalayan mountain range dramatically demonstrates one of the most visible and spectacular consequences of plate tectonics. When two continents meet head-on, neither is subducted because the continental rocks are relatively light and, like two colliding icebergs, resist downward motion. Instead, the crust tends to buckle and be pushed upward or sideways. The collision of India into Asia 50 million years ago caused the Eurasian Plate to crumple up and override the Indian Plate. After the collision, the slow continuous convergence of the two plates over millions of years pushed up the Himalayas and the Tibetan Plateau to their present heights."

[Turtle]

Originally Posted by kingwinner

The collision of India into Asia 50 million years ago caused the Eurasian Plate to crumple up and override the Indian Plate. After the collision, the slow continuous convergence of the two plates over millions of years pushed up the Himalayas and the Tibetan Plateau to their present heights."

____The wording here seems to carefully avoid saying "subduction" by substituting "override". I posted more commentary on this in one of the other plate threads.

PS Please check your private message feature King as I have sent a question to you not immediately germain to the discussion.