Really big meteorite or asteroid strikes may cause melting and deep deformations that eventually lead to volcanic eruptions. 

大型陨石和小行星的撞击可能会导致熔化和深部变形，这在最后会导致火山爆发。 

撰文/播音：朱莉娅·罗森（Julia Rosen） 

翻译：郭鑫鹏 

审校：杨枭 

Other rocky planets in our solar system show a common feature: within giant craters caused by impacts there’s evidence of volcanic activity. Which made scientists wonder-can big impacts actually cause volcanic activity? And has that scenario ever happened here? To find out, scientists went to one of the few massive craters on Earth not erased by plate tectonics: the Sudbury crater in Canada. 

我们太阳系中其他岩质行星[MY1] 有一个共同特征：由于冲击造成的大型陨石坑内有火山活动的证据。这让科学家们思考，巨大的冲击是否真的会导致火山活动？这样的事件是否曾经发生在地球上？为了寻找答案，科学家们前往了加拿大的萨德伯里陨石坑，它是少数没有被板块运动抹去的大型陨石坑之一。 

“Sudbury is a 1.85-billion-year-old impact structure.” 

“萨德伯里陨石坑有18.5亿年的年龄，它是冲击后形成的结构。” 

Teresa Ubide, a geochemist at the University of Queensland in Australia. 

澳大利亚昆士兰大学地球化学家特里萨·乌维德（Teresa Ubide）说。 

“[Sudbury] was generated when a bolide of 10 to 15 kilometers in diameter hit Earth…and what happened was it obviously generated a large basin and also it melted the…crust on top of the Earth at that time. And generated a massive melt pool, 2.5 kilometers in depth.” 

“（萨德伯里）是因为一个直径10到15千米的火流星撞击地球造成的。我们可以清楚地看到，它造成了一个大型盆地，以及当时它熔化了地球一部分外壳。这生成了一个深2.5千米的大型熔坑。” 

But Ubide and her colleagues found that the impact did more than that: it also seems to have triggered eruptions of magma that came from deep in the mantle. The evidence lies in the fact that the chemistry of the lava that erupted at Sudbury changed over time. At first, it matched the surface rocks, suggesting it was just from local melting. But as the eruptions continued, the lava appeared to come from deep in the mantle, suggesting the impact stirred things up inside the Earth. 

但是乌维德和她的同事们发现冲击还产生了一些其他后果：它似乎还造成了深层地幔中岩浆的喷发。证据显示，萨德伯里喷发的岩浆化学成分随着时间而变化。起初，它与表面岩石差不多，说明它由该处地表岩石熔化而来。但是随着喷发继续，岩浆似乎来自于地幔深处，说明冲击扰动了地球内部的东西。 

No one knows yet exactly how the impact could have sparked a prolonged episode of volcanism. One possible explanation is that after the object smashed into the surface, the crust would have rebounded upward, temporarily decompressing the mostly solid mantle and causing it to melt and produce magma. The results are in the Journal of Geophysical Research: Planets. [Teresa Ubide et al., Protracted volcanism after large impacts: Evidence from the Sudbury impact basin] 

没人清楚地知道，那次冲击对于火山有着怎样深远的影响。一个可能的解释是外物猛烈撞击地球表面后，地壳向上反弹，这导致近乎固态的地幔压强暂时变小，从而发生熔化产生岩浆。这项研究结果发表在期刊《地球物理学研究：行星》上。 

It’s hard to know if the same thing happened on other planets, Ubide says. In many spots in the solar system it looks like volcanism happened much longer after the impact than what she saw at Sudbury. But without material to examine directly, we can’t be sure. 

我们很难知道其他星球上是否发生了相同的事件，乌维德说。在太阳系中的许多地方，比起她在萨德伯里看到的，冲击之后引起的火山活动似乎持续了更长时间。但由于没有直接检测材料，我们也不能确定。 

Nevertheless, these results do help explain a mysterious chapter in Earth’s own history. Most major impacts on our planet happened about four billion years ago, when the solar system was still settling down. But there’s no crust around from that time, suggesting the entire planet got a makeover soon after. 

不过，这些结果确实帮助解释了地球历史中一个神秘的部分。我们星球上的大部分大型撞击发生在约四十亿年前，那时太阳系还正在形成中。但是那时还不存在地壳，而整个星球随后很快便有了一个大转变。 

“We’re suggesting that impacts are able to not only generate the crater, but also, generate melting deeper, say, in the mantle, and bring to the surface material from depth. So actually, recycle and resurface.” 

“我们认为那些冲击并不只是生成了陨石坑，还导致了更深处地幔的融化，并且把深处的物质运输到表面。所以实际上，这是一个重新循环和重新置换表面的过程。 

It seems the pummeling that Earth endured in the beginning may have triggered volcanic activity that helped wipe away the evidence of those very impacts. In other words, our planet took a beating that may have accelerated its own recovery. 

看起来地球早期受到的撞击可能引发了火山活动，火山运动又帮助抹去了那些大型冲击的痕迹。换句话说，我们的星球受到的打击可能加速了它自身的恢复。 

-Julia Rosen