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在上一期的節(jié)目中，咱們大致了解了板塊構(gòu)造說(shuō)。這個(gè)學(xué)說(shuō)能夠說(shuō)服咱們對(duì)于落基山的來(lái)源嗎？嗯，好像仍有很多的謎團(tuán)解不開，那么還是得借助于考古的發(fā)現(xiàn)，考古中最重要的就是化石。除了菊石化石，還有什么其他化石嗎？看看啰！
...remained. How did the collision of two tectonic plates at the western edge of North America cause the rise of the Rockies 500 to 1,000 miles inland?
Mountain ranges that formed on the margins of continents are pretty easy to explain, or where continents have collided. When India slams into Asia, we get the Himalayas. Where Oceanic crust dives beneath the continental margin in the northwest, the Cascades or in South America the Andes Mountains, but these mountains here, in the middle of the continent, are much harder to explain. And they've been / an enigma for decades.
Only recently, geologists have come up with a plausible theory. They suspect the Rockies formed along a line where the crust is very fragile.
What happens when the continent gets compressed, especially if there is a weak zone, or a zone that's prone to buckling? It rises. That's what's brought this granite to the surface.
Geologists now understood how the Rockies rose. And they had a date for when it happened. But what were these early mountains like? How did they compare to the mountains of today? On a site in the Rockies 70 miles northwest of Denver, geologists find a clue.
Mountains that we see here today aren't the mountains that were around millions of years ago. They are always evolving. Rivers are shifting. Peaks are shifting. It's a very dynamic process. Someone says as if mountains are alive themselves.
Miller sets out to estimate the height of the early mountains. But how can you measure something that is no longer there? Once more, fossils provide the evidence he is looking for.
What's amazing about collecting fossils is that you are really the first person to see this when you crack open a rock. It's first time it sees light again after 16 million years.
Miller has uncovered a 16-million-year-old fossilized leaf. It's from a tree that grew here just 10 million years after the Rockies began to form. And intriguingly, this leaf holds a clue to the height of these early mountains, or more precisely, it's the edges of the leaf, known as leaf margins. Botanists know that in colder temperatures the margins tend to have more teeth than leaves that grow in warmer areas.
小編有約：今天小編考考大家的發(fā)散性思維，"Mountains that we see here today aren't the mountains that were around millions of years ago. They are always evolving. Rivers are shifting. Peaks are shifting. It's a very dynamic process. Someone says as if mountains are alive themselves. " 你喜歡山嗎？你有時(shí)間在山里走一走，呼吸山里的空氣嗎？對(duì)于最后兩句你是怎樣理解的？
對(duì)這段話Daisy有特殊的體會(huì)。從小生活在山邊的我，對(duì)于山的變化是很敏感的。山也是有呼吸的。走在山里，那種靜謐與安詳?shù)沫h(huán)境，人在不知不覺中就感到安定。偶爾的鳥叫，和蝴蝶的飛舞，會(huì)讓人感到各種各樣的生物都絢爛地活在這個(gè)世界，大自然的一切都那樣的美好。所以請(qǐng)愛護(hù)大自然吧。這是Daisy的感想，你的呢？
