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Well, over that length of time, forecasts become more uncertain.
經過那么長的時間，預測就更加不準確了。
But lots of geologists predict that eventually all the continents, including Antarctica, will merge and become one giant land mass, a super continent, one researchers calling Pangaea Ultima, which more or less means the last super continent.
但很多地質學家預測，最終所有的大陸， 包括南極洲在內，會融合為一體，形成一個巨大的大陸塊，一片超級大陸，研究人員稱為“終極盤古大陸”，意思差不多是指最后的超級大陸。
Now, how that might happen is open to some debate.
怎么可能發生那種事，人們仍無定論。
Some geologists believe that the Americas will continue to move westward and eventually merge with East Asia.
一些地質學家認為，美洲會繼續向西移動，最終于東亞合為一體。
This hypothesis is based on the direction the Americas are moving in now.
這個假說是建立在目前美洲移動方向的基礎上的。
But others hypothesize that a new super continent will form in a different way.
其他人也提出假設，一片新的超級大陸會以不同的方式形成。
They think that a new subduction zone will might occur at the western edge of the Atlantic Ocean.
他們認為，也許在大西洋西邊會形成一條新的俯沖帶。
Paul, can you remind us what a subduction zone is?
保羅，你能提醒一下我們什么是俯沖帶嗎？
Student: Yeah. Um...basically, a subduction zone is where two tectonic plates collide.
好。基本上，俯沖帶就是兩個構造板塊碰撞的地方。
So if an ocean floor tectonic plate meets the edge of a continent and they push against each other, the heavier one sinks down and goes under the other one.
一旦一個洋底構造板塊和大陸板塊邊緣相碰，兩個板塊會相互擠壓，較重的板塊會下沉到另一個板塊的底部。
So the...um...the oceanic plate is made of denser and heavier rock, so it begins to sink down under the continental plate and into the mantle.
海洋板塊由更緊密，更重的石塊構成，所以海洋板塊開始下沉到大陸板塊之下，沉到地幔表面。
Professor: Right. So the ocean floor would kind of slide under the edge of the continent.
對。海洋底部某種程度上會滑到大陸邊緣之下。
And once the ocean plate begins to sink, it would be affected by another force—slab pull.
一旦海洋板塊開始下沉，另一股力量也會對此產生影響——巖板拉力。
Slab pull happens at the subduction zone.
在俯沖帶會產生巖板拉力。
So to continue with our example... As the ocean floor plate begins to sink down into the mantle, it would drag or pull the entire plate along with it.
繼續說我們的例子……在洋底板塊開始下沉到地幔上時，它會把整個板塊一起拖或拉下來。
So more and more of this plate, the ocean floor, would go down under the continent into the mantle. OK?
所以，此洋底板塊越來越多地沉到大陸之下地幔之上，明白了嗎？
So, as I said, currently the Atlantic Ocean floor is spreading, getting wider, but some researchers speculate that eventually a subduction zone will occur where the oceanic plate meets the continental plate of the Americas.
正如我所說的，最近大西洋海底正在擴張，變得越來越寬，但一些研究人員猜測，最終在海洋板塊和美洲大陸板塊相遇之處，會形成一條俯沖帶。
If that happens, slab pull could draw the oceanic crust under the continent, actually causing the Americas to move eastward toward Europe and the ocean floor to get smaller.
若果真如此，巖板拉力會將海洋地殼拽到大陸之下，真的會使美洲大陸向東移動靠近歐洲，且海底也會縮小。
That is, the Atlantic Ocean would start to close up, narrowing the distance between the eastern edge of the Americas and Europe and Africa.
這意味著，大西洋會開始閉合，美洲東邊和歐非大陸之間的距離正在縮小。
So they form a single super continent.
接著這些大陸就形成了一片單一超級大陸。
