侏羅紀搏擊俱樂部 第168期:全球變暖是罪魁禍首

The K-T boundary marks the end of the age of dinosaurs, and the beginning of the age of mammals.

KT界限層標志著恐龍時代的終點和哺乳動物時代的開端。

But does the K-T boundary really signify the absolute end of all dinosaurs?

不過KT界限層真的標志著所有恐龍的徹底消亡嗎?

Many experts believe that dinosaurs, are still among us.

很多專家認為恐龍仍生活在我們之中。

At 65 and a half million years ago, the age of dinosaurs came to an end.

在六千五百萬年前，恐龍的紀元走向終結(jié)。

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After that point, mammals were the dominant land living creature.

在那以后，哺乳動物是陸地上的統(tǒng)治性生物。

However, it's important to remember that although the age of dinosaurs came to an end, the dinosaurs themselves did not.

但是，不要忘了，盡管恐龍的時代走到了終點，恐龍本身并沒有。

Well, it turns out that one branch of that group survived, and that's the great group of birds.

其實它們中的一個分支得以幸存，那就是如今繁多的鳥類。

Birds themselves are the descendants of creatures very closely related to things like Deinonychus and Utahraptor, and so birds are, by definition, part of the dinosaur group.

鳥類的祖先與恐爪龍和猶他盜龍這類恐龍親緣關(guān)系很近，所以從定義來說鳥類是恐龍族群的一部分。

So the dinosaur survived, but I have to say, all the really cool ones died out.

所以恐龍得以幸存，不過我得承認，真正有意思的都死光了。

This extinction event was not only distinctive for its speed, but the force of this blast is almost unimaginable.

這次滅絕事件不僅因為其發(fā)生速度而獨特，而其摧毀力也幾乎令人無法想象。

There are numerous kinds of extinction events.

歷史上有過很多種滅絕事件。

Some can be local, where only a few plants and animal species are affected.

有些是本地的，只影響幾種植物和動物種類。

Some can be regional, where quite a few species get it.

有些是區(qū)域性的，涉及的物種數(shù)量就比較多。

And then there are those events that are so enormous, they make modern Hollywood effects look like an Ed Wood movie effect.

還有那些極大的事件，它們使得現(xiàn)代好萊塢特效看起來像是艾德·伍德(1994年的電影)電影效果。

Scientists were initially at a loss to explain how this could have happened.

科學(xué)家們開始時無法解釋這是如何發(fā)生的。

One theory pointed to global warming.

一種理論指向全球變暖。

Climate change had probably been a major factor in the first dinosaur extinction, so it seemed a likely candidate in the second one.

在第一次恐龍滅絕事件中氣候變化可能是主要原因，所以它似乎是第二次的嫌疑對象。

The fact that the blast impacted on land and sea creatures alike, seemed to support this theory.

這次災(zāi)難對陸地生物和海洋生物的影響相似，這似乎支持這種理論。

Extinction is actually worldwide, it's not just a terrestrial phenomena, it doesn't occur just on land.

這次滅絕是全球性的，這不是陸地事件，它不僅發(fā)生在陸地上。

In fact most of the really spectacular extinctions have been based in the oceans.

其實很多非常驚人的物種滅絕都發(fā)生在海里。

So we have whole groups of animals which are simply not around today.

所以我們有很多類動物今天都無法見到了。

And extinction in the marine realm is really for the same reasons it occurs on land.

在海洋王國的滅絕其實和陸地上發(fā)生的原因一樣。

In 1980, an unusually discovery would finally lift the veil of mystery.

在1980年，一個不尋常的發(fā)現(xiàn)最終揭開了謎團的面紗。

What Dr. Louis Alvarez, and his son, Dr. Walter Alvarez, uncovered set off a firestorm.

路易斯·阿爾弗雷茲博士和他兒子沃爾特·阿爾弗雷茲博士的發(fā)現(xiàn)，掀起了風(fēng)暴。

In 1980, when Louis and Walter Alvarez were looking at the sedimentation rates, they weren't really interested so much in the extinction of dinosaurs,

在1980年路易斯和沃爾特·阿爾弗雷茲當時在研究沉積速度，他們對恐龍滅絕并沒多大興趣，

they were looking at, measuring the rate of sedimentation of deep ocean sediments.

他們關(guān)注的是，對深海沉積物沉積速率的測量。

One particular little layer though, however, showed a whopping increase in the concentration of the metal Iridium.

但其中有一小層卻表現(xiàn)出金屬銥的高度富集。

And they calculated if you were to spread the amount of Iridium in this layer that adds up to a total amount of material about equivalent to a ten-kilometer diameter asteroid.

他們計算過，要是把這一層里的銥的數(shù)量分散開來，那其材料總量就相當于一顆直徑10千米的小行星。

A 10-kilometer asteroid, that's 6 miles wide - the size of Mount Everest.

直徑10千米的小行星，那就是六英里寬，大小如同埃佛勒斯峰。

The reason why an asteroid was looked at as the cause of the Iridium spike at the K-T boundary, is because asteroids have an enormous amount of Iridium in them.

一顆小行星被看做是引起KT界限層銥猛增的原因，是因為小行星中有相當多的銥。

The earth has Iridium in it, but because it is a heavy metal, most of it settles towards the center of the planet.

地球也有銥，但因為它是重金屬，多數(shù)都沉降到行星的中心。

But this thick layer of Iridium that separates the Cretaceous and Tertiary periods clearly was an anomaly and it had been deposited over a very short time.

但這個隔開了白堊紀和第三紀的厚銥層顯然是個異常事物，而且它在很多的時間內(nèi)便沉積下來。

But something else supported the asteroid theory.

還有其它證據(jù)支持小行星理論。

Along with the high levels of Iridium, they found something even more fascinating - shocked-quartz.

除了高度富集的銥以外，他們還發(fā)現(xiàn)了更為奇妙的東西——沖擊石英

Shocked-quarts is a form of quartz that has a very different structure.

沖擊石英是石英的一種形式，有很不一樣的結(jié)構(gòu)。

Under incredible pressure, the crystals within the quarts are deformed and actually fractured.

在極高壓下，石英的內(nèi)部結(jié)晶變現(xiàn)破裂。

Well, under magnification, you can see these deformations.

經(jīng)過放大后就能看到這種變形。

There was only one other place where scientists had seen shocked-quartz - at the site of a nuclear bomb test that was conducted at the Alamogordon test range in New Mexico in 1945.

科學(xué)家們此前只在另外一處地方見過這種沖擊石英 ，在一個核彈測試點，該核彈測試在1945年新墨西哥州的阿拉莫戈多試驗場進行。

Shocked-quartz was first identified at the site of an underground nuclear bomb test.

沖擊石英首次被確定是在一個地下核彈試驗場。

It's that kind of force that causes this particular quartz to form,

正是那種巨大的力量導(dǎo)致了這種特殊石英的形成，

so finding shocked-quartz mixed within the high levels of Iridium was pretty darn clear evidence that something massive had hit the earth.

所以找到?jīng)_擊石英加上高度富集的銥，就是相當確鑿的證據(jù)，說明曾經(jīng)有巨大物體撞擊地球。