The continents are moving. When will they collide? - Jean-Baptiste P. Koehl

翻译人员: Yip Yan Yeung 校对人员: Jacky He

In the early 20th century,

20 世纪初，

a meteorologist named Alfred Wegener noticed striking similarities

一位名叫阿尔弗雷德·魏格纳 （Alfred Wegener）的气象学家

between the coasts of Africa and South America.

发现了非洲和南美洲 海岸之间的惊人相似之处。

These observations led him to propose a controversial new theory:

这些发现促使他 提出了一个备受争议的新理论：

perhaps these and many other continents had once been connected

也许这两块大陆及其他大陆 曾经互相联结

in a single, gigantic landmass.

呈一整块巨型陆块。

Wegener’s Theory of Continental Drift directly contradicted the popular opinion

魏格纳的大陆漂移学说 与普遍观点相悖，

that Earth’s continents had remained steady for millennia,

即地球上的大陆 千年以来不曾变化，

and it took almost 50 years for his advocates

魏格纳的支持者 花了差不多 50 年

to convince the larger scientific community.

说服更广的科学届。

But today, we know something even more exciting—

时至今日，我们发现了 一个更激动人心的事实：

Pangea was only the latest in a long lineage of supercontinents,

盘古大陆（Pangea） 只是超大陆历史长河中最新的一段，

and it won’t be the last.

而且它不会是最后一段。

Continental Drift laid the foundation for our modern theory of plate tectonics,

大陆漂移学说为如今的 板块构造学说打下了基础，

which states that Earth’s crust is made of vast, jagged plates

即地壳由巨大、参差的板块组成，

that shift over a layer of partially molten rock called the mantle.

板块会在一层部分熔化的岩石， 称为“地幔”的结构上滑动。

These plates only move at rates of around 2.5 to 10 centimeters per year,

这些板块移动的速度 仅为每年 2.5 至 10 厘米，

but those incremental movements shape the planet's surface.

但是这些逐渐剧烈的移动 会改变地表结构。

So to determine when a new supercontinent will emerge,

如果要判断何时会出现 一块全新的超大陆，

we need to predict where these plates are headed.

我们先得预估 这些板块移动的方向。

One approach here is to look at how they’ve moved in the past.

一个方法是观察 它们以前移动的情况。

Geologists can trace the position of continents over time

地质学家通过测量地球磁场的变化

by measuring changes in Earth’s magnetic field.

持续追踪着大陆的位置。

When molten rock cools, its magnetic minerals are “frozen”

熔岩冷却后，其中的磁性矿物

at a specific point in time.

会在某一时间点“冻结”。

So by calculating the direction and intensity

通过计算某块岩石磁场的

of a given rock’s magnetic field,

方向和强度，

we can discover the latitude at which it was located at the time of cooling.

我们可以得出它冷却时 所在位置的纬度。

But this approach has serious limitations.

但是这个方法有明显的缺陷。

For one thing, a rock’s magnetic field doesn’t tell us the plate’s longitude,

其中一点是岩石的磁场 不会展现板块经度的信息，

and the latitude measurement could be either north or south.

而纬度的测量结果 不是北纬就是南纬。

Worse still, this magnetic data gets erased when the rock is reheated,

更糟糕的是，岩石再次升温时， 磁场数据就会被抹消，

like during continental collisions or volcanic activity.

比如大陆碰撞或火山活动时。

So geologists need to employ other methods to reconstruct the continents’ positions.

因此，地质学家需要采用 其他的方式重现大陆的位置。

Dating local fossils and comparing them to the global fossil record

追溯当地化石， 将其与全球的化石记录对比，

can help identifying previously connected regions.

有助于寻出原本相连的地区。

The same is true of cracks and other deformations in the Earth's crust,

同样的方式也可以应用于 地裂和其他地壳形变现象，

which can sometimes be traced across plates.

这是能够跨板块研究的。

Using these tools, scientists have pieced together

科学家们利用这些工具拼凑成了

a relatively reliable history of plate movements,

一段相对可靠的板块运动历史。

and their research revealed a pattern spanning hundreds of millions of years.

他们的研究展现了 跨越亿年的板块运动规律。

What’s now known as the Wilson Cycle

我们现在所知的“威尔逊旋回” （Wilson Cycle），

predicts how continents diverge and reassemble.

预测了大陆将如何分离、拼合。

And it currently predicts the next supercontinent will form

它准确地预计下一个超大陆

50 to 250 million years from now.

会在距今 5000 万 至 2.5 亿年后形成。

We don’t have much certainty on what that landmass will look like.

我们不太确定 这个陆块会是什么形态。

It could be a new Pangea that emerges from the closing of the Atlantic.

它可能会是一块 源于大西洋收缩的新盘古大陆。

Or it might result from the formation of a new Pan-Asian ocean.

或者源于一片新泛亚海洋的形成。

But while its shape and size remain a mystery,

虽然它的形状和面积 依旧是个未解之谜，

we do know these changes will impact much more than our national borders.

但我们知道这些变化影响的 远不止我们的国境线。

In the past, colliding plates have caused major environmental upheavals.

在以前，板块碰撞造成了 严重的环境剧变。

When the Rodinia supercontinent broke up circa 750 million years ago,

罗迪尼亚（Rodinia）超大陆 在大约 7.5 亿年前分解时，

it left large landmasses vulnerable to weathering.

产生了易受到风化侵蚀的巨型陆块。

This newly exposed rock absorbed more carbon dioxide from rainfall,

这些刚暴露在空气中的岩石 从降水中吸收了大量二氧化碳，

eventually removing so much atmospheric CO2

大气里被去除的二氧化碳多到

that the planet was plunged into a period called Snowball Earth.

地球一下进入了“冰球时期”。

Over time, volcanic activity released enough CO2 to melt this ice,

随着时间的推移，火山活动 释放出的二氧化碳足以使其融化，

but that process took another 4 to 6 million years.

但是这个过程 经历了 400 到 600 万年。

Meanwhile, when the next supercontinent assembles,

与此同时， 下一块超大陆的形成

it's more likely to heat things up.

很有可能会造成升温。

Shifting plates and continental collisions could create and enlarge

板块漂移和大陆碰撞 会产生、扩大

cracks in the Earth’s crust,

地壳上的裂缝，

potentially releasing huge amounts of carbon and methane into the atmosphere.

可能会向大气释放出 大量碳和甲烷。

This influx of greenhouse gases would rapidly heat the planet,

温室气体的骤增会迅速使地球升温，

possibly triggering a mass extinction.

并也许会引发一场大灭绝。

The sheer scale of these cracks would make them almost impossible to plug,

如此规模的地裂是根本无法填补的，

and even if we could, the resulting pressure would just create new ruptures.

即使我们可以填补， 造成的压强只会增加新的裂缝。

Fortunately, we have at least 50 million years to come up with a solution here,

好在我们至少还有 5000 万年的 时间想出一个解决办法，

and we might already be onto something.

而且我们可能已经有了一些想法。

In Iceland, recently conducted trials were able to store carbon in basalt,

在冰岛，最近已经有试验 可以将碳存储在玄武岩中，

rapidly transforming these gases into stone.

快速将这些气体转化为岩石。

So it’s possible a global network of pipes

那么，如果有一个全球管道网络，

could redirect vented gases into basalt outcrops,

将排出的气体导入 玄武岩地面岩层，

mitigating some of our emissions now and protecting our supercontinental future.

我们便能减少一些目前的排放， 保护我们未来的超级大陆。