隨著歐洲、非洲和美洲的分裂，大西洋越來(lái)越寬

隨著歐洲、非洲和美洲的分裂，大西洋越來(lái)越寬

Every year, the Americas are moving further away from Europe and Africa. The separation between the Atlantic-facing continents increases by 4 centimeters (1.6 inches) per year, but what was driving this has been a bit of a puzzler. The dividing line where new plates are formed is known as the Mid-Atlantic Ridge. A ridge is usually driven by a balancing act between the lighter and heavier parts of tectonic plates. But this is not the case for the Atlantic ocean, which is not surrounded by dense sinking plates.

每年，美洲大陸都在遠(yuǎn)離歐洲和非洲。面向大西洋的大陸之間的距離每年增加4厘米(1.6英寸)，但到底是什么原因讓人有點(diǎn)困惑。新板塊形成的分界線是中大西洋洋脊。山脊通常是由板塊的較輕部分和較重部分之間的平衡作用形成的。但大西洋卻不是這樣，它沒(méi)有被稠密的下沉板塊包圍。

In a new paper published in Nature, researchers suggest a new mechanism to explain this process: the region experiences an upsurge of matter from the deeper layers of our planet, which is pushing the continents apart.

在《自然》雜志發(fā)表的一篇新論文中，研究人員提出了一種新機(jī)制來(lái)解釋這一過(guò)程:該地區(qū)經(jīng)歷了來(lái)自地球深層物質(zhì)的激增，這將大陸推開(kāi)。

One possibility was an upwelling of material from the mantle, the region beneath the Earth’s crust. These tend to originate at depths of 60 kilometers (37 miles) but the one driving the Mid-Atlantic Ridge is much deeper, over 10 times those depths.

一種可能是地殼下面的地幔物質(zhì)上涌。它們往往起源于60公里(37英里)的深處，但驅(qū)動(dòng)中大西洋脊的海底要深得多，超過(guò)這些深度的10倍。

Dr Alfredo Carpineti

To work out this mystery the team of researchers embarked on two research cruises deploying 39 seismographers at the bottom of the Atlantic ocean on each side of the ridge. This is one of the few experiments to have studied the mantle below the ocean's floor in such detail. In fact, it delivers the first large-scale and high-resolution imaging of the mantle.

為了解開(kāi)這個(gè)謎團(tuán)，研究人員展開(kāi)了兩次巡查，分別在海脊兩側(cè)的大西洋海底部署了39臺(tái)地震儀。這是為數(shù)不多的對(duì)海底下地幔進(jìn)行如此細(xì)致研究的實(shí)驗(yàn)之一。事實(shí)上，它提供了第一個(gè)大規(guī)模和高分辨率的地幔成像。

“This was a memorable mission that took us a total of 10 weeks at sea in the middle of the Atlantic Ocean. The incredible results shed new light in our understanding of how the Earth's interior is connected with plate tectonics, with observations not seen before,” lead author Dr Matthew Agius, from Università degli studi Roma Tre, said in a statement.

“這是一次令人難忘的任務(wù)，我們?cè)诖笪餮笾醒氲暮Ｉ峡偣不?0周時(shí)間。該研究的主要作者、Università degli studi Roma Tre的馬修·阿吉斯博士在一份聲明中說(shuō):“這一令人難以置信的結(jié)果為我們對(duì)地球內(nèi)部如何與板塊構(gòu)造聯(lián)系的理解提供了新的線索。”

In particular, they studied how structures changed between depths of 410 and 660 kilometers (255 and 410 miles). They also observed abrupt changes to mineral phases, which suggests the presence of an upwelling.

特別是，他們研究了410到660公里(255到410英里)深度之間的結(jié)構(gòu)變化。他們還觀察到礦物相的突然變化，這表明存在上涌現(xiàn)象。

The findings suggest that the Mid-Atlantic Ridge is an active player in the plate tectonics of the region. Since, plate tectonics influence earthquakes and volcanoes, as well as sea levels, understanding their role helps us improve our planetary and climate models, leading to better warning systems for natural disasters.

研究結(jié)果表明，中大西洋洋脊是該地區(qū)板塊構(gòu)造活動(dòng)的活躍參與者。由于板塊構(gòu)造影響地震和火山，以及海平面，了解它們的作用有助于我們改進(jìn)我們的行星和氣候模型，導(dǎo)致更好的自然災(zāi)害預(yù)警系統(tǒng)。

“This was completely unexpected. It has broad implications for our understanding of Earth's evolution and habitability,” co-author Dr Kate Rychert from the University of Southampton, added. “It also demonstrates how crucial it is to gather new data from the oceans. There is so much more to explore!”

“這完全出乎意料。它對(duì)我們理解地球的進(jìn)化和可居住性有廣泛的影響，”來(lái)自南安普頓大學(xué)的合著者凱特·瑞切特博士補(bǔ)充道。“這也表明，從海洋中收集新數(shù)據(jù)是多么重要。還有更多的東西等著我們?nèi)ヌ剿?”