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The event that killed the dinosaurs might be the most famous mass extinction ever.
恐龙灭绝事件可能是有史以来最著名的大规模灭绝事件。
And scientists are pretty sure they've identified the scene of the crime: a meteor crater in the Gulf of Mexico.
科学家们非常确定他们已经确认了犯罪现场：墨西哥湾的一个陨石坑。
But that event sixty-six million years ago is neither the only one in Earth's history, nor the worst. Not by a long shot.
但这场6600万年前的事件并不是地球历史上的唯一一次，也不是最糟糕的一次。绝对不是。
Scientists studying a remote swath of land in Russia have pieced together clues about an extinction event
研究俄罗斯一大片遥远之地的科学家们拼凑出了一场灭绝事件的线索，
that makes the demise of the dinosaurs look tame.
这场事件让恐龙灭绝显得有些平淡。
The extinction event in question happened at the end of the Permian period,
问题中的灭绝时间发生在二叠纪末期，
which was a geologic span of time that ran from about 299 million to 252 million years ago.
地质时间跨度约为2.99亿年前到2.52亿年前之间。
This was before the dinosaurs, but not so far back that life on Earth would have seemed totally alien.
这段时期是在恐龙之前，但距离地球似乎都是外星生物也不太远。
There were no birds or mammals, but there were reptiles, amphibians, ferns, and insects.
没有鸟类，也没有哺乳动物，但有爬行动物、两栖动物、蕨类和昆虫。
Granted, some Permian creatures, like Dimetrodon look pretty strange to us now,
当然，一些二叠纪生物，比如异齿龙，现在在我们看来是相当怪异的，
but you'd still be able to walk around and see plants and animals you could put a name to.
但你还是可以到处逛逛，看看那些你能够叫得出名字的植物和动物。
But at the end of the Permian, a lot of life suddenly went extinct. Like, a lot.
但在二叠纪末期，很多植物突然就灭绝了。很多。
Within no more than two hundred thousand years, most of the marine and terrestrial species on Earth vanished.
在不到20万年内，地球上的大部分水生和陆地物种都消失了。
Estimates vary, but more than 90% of all species may have disappeared.
对此估计各不相同，但超过90%的物种可能都消失了。
It would take about 8 to 9 million years for Earth's ecosystems to really recover.
地球生态系统要花约8到9百万年才能真正恢复。
This extinction was so dramatic that scientists have nicknamed it "The Great Dying".
这场灭绝非常剧烈，因此科学家们称其为“大灭绝”。
There have been a handful of hypotheses over the years to explain this massive die-off.
多年来有一些解释这场大规模灭绝的假说。
Some researchers have proposed another big asteroid, like the one that would kill off the dinosaurs.
一些研究人员提出可能是另一个大的小行星，就像灭绝恐龙的那颗一样。
But one place on Earth seems to stand out as the most likely scene of the crime:
但地球上有一个地方似乎是最有可能的犯罪现场：
a massive volcanic region in Russia known as the Siberian Traps.
在俄罗斯一个被称为西伯利亚暗色岩的大规模火山地区。
The rock underneath this area of Siberia is relatively stable,
西伯利亚这片区域下的岩石相对稳定，
it's not on a tectonic plate boundary, like many volcanoes are.
它不像许多火山那样位于构造板块边界。
But about the same time as the Great Dying, a massive pulse of magma from deep inside the Earth,
但大约在大灭绝同一时间，来自地球深处的巨大岩浆脉冲，
known as a mantle plume, melted through the crust.
即地幔柱，在地壳中融化。
The plume triggered the biggest volcanic eruptions ever known, which may have lasted more than a million years,
地幔柱触发了有史以来最大的火山爆发，可能持续了一百多万年之久，
and covered an area bigger than Greenland in lava.
并且熔岩覆盖的面积比格陵兰岛还大。
After the initial eruptions, there was a quiet period for a while, followed by one big, final burst of activity.
最初火山爆发之后平静了一段时间，随后是最后一次大规模的火山爆发。
These eruptions happened at pretty much the same time as the mass extinction,
这些火山爆发的时间几乎和大规模灭绝发生在同一时间，
and scientists think this volcanic activity is a pretty likely explanation for what happened.
并且科学家们认为这次火山活动很可能是对所发生事情的一种解释。
The eruptions could have spewed massive amounts of carbon dioxide and methane into the Earth's atmosphere,
火山喷发可能向地球大气中喷射了大量的二氧化碳和甲烷
changing the chemistry of the Earth's air and water.
改变了地球空气和水的化学性质。
The oceans, for instance, would have abruptly become more acidic and as much as ten degrees warmer
例如，海洋突然变得更具酸性，且温度增加了10度，
and would have lost almost all of their oxygen. If that seems bad, you're right!
还几乎失去了所有的氧气。如果这听起来很糟糕，你是对的！
But there's still some details to work out.
但仍有一些细节需要解决。
Sure, we found a site of massive volcanic activity, and it's about the right age.
当然，我们发现了一个大规模火山活动的地点，而且它的年龄也差不多。
But the timeline actually isn't quite right for the initial burst of eruptions at the Siberian Traps to have caused the Great Dying.
但时间线和西伯利亚暗色岩初始火山爆发导致大灭绝的时间不太匹配。
By the time the extinction event started, the traps had already been erupting for about three hundred thousand years
灭绝事件开始时，西伯利亚暗色岩已经爆发了约30万年
and had spewed out two-thirds of their magma.
并且它们的岩浆已经喷出了三分之二。
Also, this kind of massive eruption has happened in other times and in other places.
还有，这种大规模爆发发生在其他时间和地点。
Some of those are associated with mass extinctions, but not all.
其中一些和大规模灭绝有关，但但并非全部。
So does that let the Siberian Traps off the hook? One leading hypothesis, published in 2009,
所以西伯利亚暗色岩因此就摆脱了吗？2009年发表的一个主要假说提出
proposes that it was volcanic activity but, remarkably, it might have not been those huge initial eruptions.
这是火山活动，但值得注意的是，这可能不是那些最初的大规模喷发。
Remember that quiet period? During that period, magma was still flowing, but instead of erupting dramatically,
还记得那段安静的时期么？在那段时期，岩浆还在流动，但却没有剧烈的喷发
it spread underground, intruding in between layers of existing rock to form what are known as sills.
而是在地下蔓延，侵入现存岩层之间，形成了我们所知的基岩。
Visible today in places like river banks, the sills look kind of like the frosting in between the layers of a giant cake.
如今可以在河岸等地方看到，基岩看上去有点像是巨型蛋糕层之间的霜。
As the magma spread out, it heated and altered the surrounding rocks in a process known as contact metamorphism.
随着岩浆的扩散，它加热并改变了周围的岩石，这一过程被称为接触变质作用。
These existing rocks, put downs by millions of years of geologic activity,
由百万年的地质活动沉积下来的这些现存岩石中
contained quite a bit of carbon, and even included coal beds.
含有相当多的碳，甚至还有煤层。
The intruding magma would have effectively "cooked" all these rocks,
侵入的岩浆有效地“煮熟”了所有这些岩石，
creating and releasing greenhouse gases like carbon dioxide and methane.
创造并释放了温室气体，如二氧化碳和甲烷。
They would also have released a type of chemical called halocarbons,
它们还会释放出一种叫做卤化碳化学物质，
which would have stripped the ozone layer, just like CFCs in more recent years.
这种物质会破坏臭氧层，就像近些年来的氯氟烃一样。
And researchers have calculated that the contact metamorphism
研究人员计算出，接触变质作用
generated four to nine times more carbon dioxide than the lava itself contained.
产生出来的二氧化碳是火山岩浆本身所包含二氧化碳的四到九倍。
In 2017, researchers took a closer look at the start of this quiet, deadly period.
2017年，研究人员仔细观察了这个安静而致命时期的开端。
And they were able to pin the timing down to line up with the onset of the mass extinction,
他们能够确定时间与大灭绝开始的时间一致，
thanks to very precise radiometric dating, which uses the steady decay of radioactive elements like a clock
这多亏了非常精确的放射性年代测定，其利用放射性元素的稳定衰变
to estimate the age of rocks and other materials.
准确地判断出了岩石和其他物质的年龄。
This research would explain why it took 300,000 years for the extinction to start.
这一研究将解释为什么30万年后灭绝才开始。
The big eruptions, though dramatic, may not have brought up enough carbon dioxide by themselves,
大型火山爆发虽然剧烈，但其本身并没有产生足够的二氧化碳，
nor did they cook as much of the underground rock as the sills.
它们煮熟的地下岩石也没有基岩那么多。
And all that carbon dioxide, once released from the cooking rocks, would be enough to change the Earth's atmosphere,
并且这些二氧化碳一旦从煮熟的岩石中释放出来，将足以改变地球的大气，
leading to warmer temperatures and acidic, de-oxygenated oceans.
导致气温更高，大海更酸，也更脱氧。
And from there to the most staggering loss of life our planet has ever seen.
从那到最令人震惊的生命灭绝，这是绝无仅有的。
This may be the best smoking-gun evidence we ever get to tie the Great Dying to a place on Earth
这可能是我们能找到的最确凿的证据，能够将大灭绝和地球上某个理论上
that you could actually theoretically visit. And it's a bunch of volcanic rock in Siberia.
你可以去参观的地方相关联。而这是西伯利亚的一堆火山岩。
Thanks for watching this episode of SciShow, and thanks to our channel members for your support.
感谢收看本期《科学秀》，感谢频道会员的支持。
Did you know you can become a member of this very channel?
大家都可以成为我们频道的会员。
Because you can, and channel memberships are one great way to help us do what we do.
成为频道会员是帮助我们继续制作节目的好方法。
Perks include access to members-only behind the scenes pictures and other exclusive content,
会员特权包括会员可看的幕后图片和其他独家内容，
special emojis to use in live chats and the warm, fuzzy feeling
聊天专用表情包以及
that you're helping us make great science content for the whole Internet to enjoy.
帮助我们制作备受大家喜爱的科学内容的美妙感觉。
If that sounds like something you're interested in, hit the "Join" button to learn more.
如果感兴趣，点击‘加入’了解更多。
