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第一段
1 .Listen to part of a lecture in a geology class.
听一段地质学课上的演讲
第二段
1 .As we've discussed, Earth's crust is made up of large plates that rest on a mantle of molten rock.
正如我们讲过的，地壳由附在地幔上的一些巨大的板块组成的。
2 .These plates... uh... known as tectonic plates support the continents and oceans.
这些板块，也叫做构造板块，支持着地球上的大陆和海洋。
3 .Over time, the tectonic plates move and shift, which moves the continents and the ocean floors too.
时间一长，这些板块发上移动和错位，导致了大陆和海底的移动。
4 .Once it was understood how these plates move, it was possible to determine past movements of Earth's continents and how these slow movements have reshaped Earth's features at different times.
一旦理解了这些板块如何移动， 就能判断地球大陆过去的运动，已经这些缓慢的移动是如何在不同时期改变地貌的。
第三段
1 .Ok, Well, studying the movement of the plates can tell us about the location of the continents in the past, it can conceivably tell us about their location in the future too, right?
好的。如果研究板块运动能告诉我们这些大陆过去的位置，可想而知我们也能预知他们未来的位置，对吗？
2 .So, in recent years, some geologists have used plate tectonic theory to make what they call geopredictions.
所以近些年来地质学家用板块构造论来做一些地球预测。
3 .Geopredictions are guesses about what Earth's surface might look like millions of years from now.
地球预测就是一些对地球表面几百万年后是什么样的猜测。
第四段
1 .So, we know how certain continents are currently moving.
我们知道一些大陆正在移动。
2 .For example, the continents of Africa has been creeping north toward Europe.
比如，非洲大陆一直在慢慢向北面的欧洲移动，
3 .And Australia has been making its way north too, toward Asia.
而澳大利亚也在向北，向亚洲移动
第五段
1 .Does anyone know what's happening to the Americas?
有人知道南北美洲在怎样移动吗？
2 .I... I think we've talked about that before. Lisa?
我认为我们应该讲过。Lisa？
第六段
1 .They are moving westward away from Europe and Africa. Right?
它们在向西移动，远离欧洲和非洲，对吗？
第七段
1 .Right. And what makes us think that?
是的。是什么使我们这样认为？
第八段
1 .The Atlantic Ocean floor is spreading and getting wider, so there is more ocean between the Americas and Europe and Africa.
大西洋的海底正在变大变宽，所以在两个美洲与欧洲和非洲之间的海洋更大了。
第九段
1 .Ok, And why is it spreading?
没错。大西洋为什么变大？
第十段
1 .Well, the seafloor is split.
嗯。海底裂开了。
2 .There is a ridge, a mountain ridge that runs north and south there.
那儿有个南北走向的山脉，
3 .And new rock material flows up from Earth's interior here, at the split, which forces the two sides of the ocean floor to spread apart, to make room for the new rock material.
而缝隙中流出从地球内部的新岩石，为了给新岩石腾出空间，海底两岸被迫分开。
第十一段
1 .Good. And that means, over the short term, uh... and by short term I mean 50 million years, that's a blink of the eye in geological time.
答得好。着意味着在短期，也就是五千万年后，这对于地质时期来说只是一眨眼。
2 .Um... over the short term, we can predict that the Americas will continue to move westward, farther away from Europe, while Africa and Australia will continue to move northward.
在短期，我们能预测到美洲大陆会继续详细移动，远离欧洲，而非洲和澳大利亚则会继续向北移动。
第十二段
1 .But what about over the long term, say 250 million years or more?
但是长期后是什么情况呢？
2 .Well, over that length of time, forecasts become more uncertain.
大约2.5亿年或更久。嗯，在这么长的时间内，预测变得更不准确。
3 .But lots of geologists predict that eventually all the continents, including the 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.
但是很多地质学家都预计最终所有的大陆，包括南极，都会合并形成一个巨大的大陆，一个超级大陆，一个科学家管它叫最终的超级大陆，大概是最后的超级大陆的意思。
第十三段
1 .Now, how that might happen is open to some debate.
有争议的是超级大陆会如何形成。
2 .Some geologist believe that the Americas will continue to move westward and eventually merge with East Asia.
一些地质学家认为美洲会继续向西移动，最终和东亚结合。
3 .This hypothesis is based on the direction the Americas are moving in now.
这一假设是根据现在美洲大陆的移动方向，
4 .But others hypothesize that a new super continent will form in a different way.
但是另一些人猜想新超级大陆会以一种不同的方式形成。
5 .They think that a new subduction zone will might occur at the western edge of the Atlantic Ocean.
他们认为，一个新的隐没带将可能出现在大西洋洋西部边缘。
第十四段
1 .Paul, can you remind us what a subduction zone is?
Paul你能提醒我们隐没带是什么意思吗？
2 .Yeah... Um... basically, a subduction zone is where two tectonic plates collide.
好的。在两个板块碰撞的地方是个隐没带。
3 .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.
。因此，如果一个海洋板块遇到大陆的边缘，他们会互相推挤，那么比较重的板块会下沉到另一个板块下面。
4 .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.
嗯，海洋板块是由密度较大较沉的岩石构成，因此它会沉入大陆板块下，并进入地幔。
第十五段
1 .Right. So the ocean floor would kind of slide under the edge of the continent.
正确。海底会滑到大陆的边缘一下。
2 .And once the ocean plate begins to sink, it would be affected by another force - slab pull.
而当海洋板块开始下沉时，它会受到下沉拉力的作用。。
3 .Slab pull happens at the subduction zone.
下沉拉力发生在隐没带
第十六段
1 .So to continue 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.
继续我们的举例，当海洋板块开始沉入地幔，它会拉动整个板块一起下沉。
2 .So more and more of this plate, the ocean floor, would go down under the continent into the mantle. OK?
所以，这个板块，就是海底，越来越多的部分，会下沉到大陆之下陷入地幔。没问题吧？
第十七段
1 .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.
正如我说的，目前大西洋的海底正在扩张，变宽，但是一些学者猜测最终在海洋板块和美洲大陆板块之间会产生一个隐没带。
2 .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.
如果隐没带形成了，下沉拉力就会将海洋板块拉到大陆之下，其实会引起美洲向欧洲向东移动，而海底会变小。
3 .That is, the Atlantic Ocean would start to close up, narrowing the distance between the eastern edge of the Americas and Europe and Africa.
也就是，大西洋会变小，使得美洲东边和欧非建的距离变小。
4 .So they form a single super continent.
于是他们三者形成一个超级大陆。