新西蘭位于一座古老火山噴發(fā)出的巨大熔巖泡的頂端

新西蘭位于一座古老火山噴發(fā)出的巨大熔巖泡的頂端

Scientists may have found the most compelling evidence yet that the Earth's molten core belches out blobs of lava that eventually find their way to the surface.

科學(xué)家們可能已經(jīng)發(fā)現(xiàn)了迄今為止最令人信服的證據(jù)，證明地球熔融的核心噴出的熔巖最終會(huì)到達(dá)地表。

In fact, the evidence is hard to ignore. It’s New Zealand.

事實(shí)上，證據(jù)不容忽視。這就是新西蘭。

About 120 million years ago, a vast, unbroken volcanic plateau formed beneath the sea. (Photo: verticalberto/Shutterstock)

In a study published in Science Advances, researchers from the Victoria University of Wellington suggest the country is perched on a vast bubble of lava produced by an ancient volcano.

在發(fā)表在《科學(xué)進(jìn)展》雜志上的一項(xiàng)研究中，來(lái)自惠靈頓維多利亞大學(xué)的研究人員認(rèn)為，這個(gè)國(guó)家棲息在一個(gè)由古代火山噴發(fā)的巨大熔巖泡上。

Now, if you’re in New Zealand, there’s no reason to panic. Or even tread lightly. That lava has had more than 100 million years to cool and harden. In fact, as the researchers point out, those ancient volcanic eruptions likely created an undersea plateau during the Cretaceous Period. That India-sized plateau eventually fragmented, with a big chunk becoming the box spring for New Zealand. That lava-cooled slab would become known as the Hikurangi Plateau.

現(xiàn)在，如果你在新西蘭，沒(méi)有理由恐慌。甚至可以隨意走動(dòng)。熔巖冷卻硬化的時(shí)間超過(guò)1億年。事實(shí)上，正如研究人員指出的那樣，那些古老的火山噴發(fā)可能在白堊紀(jì)形成了海底高原。印度大小的高原最終分裂，其中一大塊成為了新西蘭的方塊彈簧。這個(gè)熔巖冷卻的板塊被稱(chēng)為Hikurangi高原。

“Our results show that New Zealand sits atop the remains of such an ancient giant volcanic plume,” the researchers explain in The Conversation. “We show how this process causes volcanic activity and plays a key role in the workings of the planet.”

研究人員在對(duì)話中解釋說(shuō):“我們的研究結(jié)果表明，新西蘭位于如此古老的巨大火山煙羽的遺跡之上。我們展示了這一過(guò)程是如何導(dǎo)致火山活動(dòng)的，并在地球的運(yùn)轉(zhuǎn)中發(fā)揮了關(guān)鍵作用。”

Sitting atop a powerful force

坐落在一股強(qiáng)大的力量之上

Their research paints a fascinating picture of the heavy forge at the heart of our planet. There’s a long-standing theory that the Earth’s interior churns “like a lava lamp, with buoyant blobs rising as plumes of hot mantle rock from near Earth's core,” the researchers note in the article.

他們的研究描繪了一幅地球中心的重熔爐的迷人圖畫(huà)。有一種長(zhǎng)期存在的理論認(rèn)為，地球內(nèi)部的攪動(dòng)“就像一盞熔巖燈，有浮力的水滴從靠近地球核心的熱地幔巖柱中升起，”研究人員在文章中寫(xiě)道。

As those plumes creep toward the surface, the theory suggests, they melt — and volcanic eruptions ensue. But evidence supporting that theory was scant — until scientists took a closer look at New Zealand’s underpinnings.

該理論認(rèn)為，當(dāng)這些煙羽慢慢向地表移動(dòng)時(shí)，它們就會(huì)融化，然后火山就會(huì)爆發(fā)。但支持這一理論的證據(jù)很少——直到科學(xué)家們更仔細(xì)地觀察了新西蘭。

Specifically, they measured the speed of seismic pressure waves moving through rocks beneath the Hikurangi Plateau. Those waves, known as P-waves, are essentially sound waves. And they move at a consistent and measurable speed through the planet’s roiling interior. But they move more slowly when travelling vertically outward, as opposed to horizontally in every direction.

具體來(lái)說(shuō)，他們測(cè)量了地震壓力波在Hikurangi高原下穿過(guò)巖石的速度。這些波被稱(chēng)為p波，本質(zhì)上是聲波。它們以一致的、可測(cè)量的速度穿過(guò)地球內(nèi)部的漩渦。但在垂直向外移動(dòng)時(shí)，它們的移動(dòng)速度要慢一些，而不是水平向各個(gè)方向移動(dòng)。

That speed difference helped researchers determine the staggering scope of the superplume beneath New Zealand. The research also hints at the even more vast, unbroken plateau that once stretched beneath the sea.

這種速度差異幫助研究人員確定了新西蘭地下超級(jí)地幔柱的驚人范圍。這項(xiàng)研究還暗示了曾經(jīng)延伸到海底的更廣闊、更完整的高原。

"The extraordinary thing is that all these plateaus were once connected, making up the largest volcanic outpouring on the planet in a region over 2,000 km across,” the researchers note. "The associated volcanic activity may have played an important role in Earth history, influencing the planet's climate and also the evolution of life by triggering mass extinctions.

研究人員指出:“不同尋常的是，所有這些高原曾經(jīng)連接在一起，形成了地球上最大的火山噴發(fā)區(qū)，這個(gè)區(qū)域橫跨2000多公里。相關(guān)的火山活動(dòng)可能在地球歷史上扮演了重要的角色，影響了地球的氣候，也引發(fā)了大規(guī)模的物種滅絕，從而影響了生命的進(jìn)化。”

"It is an intriguing thought that New Zealand now sits on top of what was once such a powerful force in the Earth."

“這是一個(gè)有趣的想法，新西蘭現(xiàn)在坐落在地球上曾經(jīng)如此強(qiáng)大的力量之上。”