Catherine wrote: > I don't get the whole continent thing either, > especially why Europe and Asia are supposedly two > separate continents - they're completely stuck > together for God's sake! At least N and S Amer have > this little peninsula thing (plus that friggin' > man-made canal) dividing them. Australia's easy - it's > out there in the middle of the ocean, attached to > nothing. Same with Antarctica. Africa's connected to > Europe/Asia in a small part too, so it's kind of like > the Americas, a bit iffy in the continent department, > if you ask me.
I can attempt an answer - dredged up from the recesses of my brain! After all, the two years of this I did at University were over 15 years ago now, but it's still interesting stuff - to me, anyway! I got some help from some of my old text books (which I can't believe I still have), so I'm paraphrasing from there. The outer shell of the Earth, is made up of moving slabs, known as tectonic plates. Each plate has a portion of oceanic crust, or continental crust (or both). The plates move over the malleable inner crust beneath. There are seven major tectonic plates, and several smaller ones. These are all constantly moving in relation to each other - resulting in earthquakes and volcanic activity. When they collide, one plate plunges beneath the other, creating ocean trenches and mountain ranges. There is a theory that says that the current continents have not always been as separate as they are now. The first scientifically-based theory was put forward by a German meteorologist in 1912 (Alfred Wegener) that the continents as we know them now, were one large "super continent" (called Pangea). Heat and energy formed by movements under the Earth's crust caused disruption to this land mass. There is some basis in fact for this theory, as similar rocks and patterns of geological history have been found in widely separated places. The theory then states that this super-continent then split into two, Laurasia in the Northern Hemisphere, and Gondwanaland in the Southern Hemisphere. Laurasia and Gondwanaland then continued to break apart into the various smaller continents that exist today. Note: remember we're talking about a process that has been happening for the last 600 million years, or so. The seven major resulting continents from this "continental drift" are North America, South America, Europe, Asia, Africa, Australia (despite it also being considered an island) and Antarctica. Europe and Asia, although joined, are on different tectonic plates, and the movement between them has resulted in the Himalayas being formed. Other factors, like various Ice Ages, the subsequent melting of the polar ice caps and volcanic activity etc., have further shaped the continents. If you want to know more, this site is pretty good, and has some nice pictures ;o) http://pubs.usgs.gov/publications/text/dynamic.html Hell ____________________________ "To have great poets, there must be great audiences too." - Walt Whitman [EMAIL PROTECTED] Hell's Personal Photo Page: http://homepages.ihug.co.nz/~hell/main/personal.htm Visit the NBLs (Natural Born Losers) at: http://www.nbls.co.nz
