ADM-201 dump PMP dumps pdf SSCP exam materials CBAP exam sample questions

北美洲是怎么变成现在这样的 – 译学馆
未登录,请登录后再发表信息
最新评论 (0)
播放视频

北美洲是怎么变成现在这样的

How North America got its shape - Peter J. Haproff

地球的地理在变动
The geography of our planet is in flux.
每一个大洲在地球上的不同板块上移动
Each continent has ricocheted around the globe on one or more tectonic plates,
随着时间有很大的变化今天
changing quite dramatically with time.
我们来讲讲
Today, we’ll focus on North America
北美州现在的风景是如何通过
and how its familiar landscape and features
亿万年形成的
emerged over hundreds of millions of years.
我们的故事开始在7.5亿年之前
Our story begins about 750 million years ago.
超级大陆罗迪尼亚变得越来越不稳定
As the super continent Rodinia becomes unstable,
它沿着北美的西海岸裂缝
it rifts along what’s now the west coast of North America
形成了泛大洋海洋
to create the Panthalassa Ocean.
这是劳伦大陆
You’re seeing an ancestral continent called Laurentia,
岛链与它碰撞 在接下来的几亿年里
which grows over the next few hundred million years
一直增加它的面积
as island chains collide with it and add land mass.
4亿年前
We’re now at 400 million years ago.
在今天北美的东岸 非洲板块向西移动
Off today’s east coast, the massive African plate inches westward,
把古老的巨神海关起来了
closing the ancient Iapetus Ocean.
2.5亿年前 它终于与劳伦碰撞
It finally collides with Laurentia at 250 million years
形成了另一个超级大陆
to form another supercontinent Pangea.
盘古巨大的压力导致断层和折叠
The immense pressure causes faulting and folding,
让石头形成了阿巴拉契亚山脉
stacking up rock to form the Appalachian Mountains.
让我们跳到一亿年前
Let’s fast forward a bit.
盘古裂开时
About 100 million years later, Pangea breaks apart,
在新的北美盘和非洲盘之间
opening the Southern Atlantic Ocean
开通了南大西洋再
between the new North American Plate and the African Plate.
往前
We forge ahead,
向东移动的法拉龙板块
and now the eastward-moving Farallon Plate
与今天的西海岸融合
converges with the present-day west coast.
法拉龙板块更稠密 并且沉到北美底下
The Farallon Plate’s greater density makes it sink beneath North America.
这叫俯冲
This is called subduction,
俯冲把水扩散到充满岩浆的地幔
and it diffuses water into the magma-filled mantle.
降低了岩浆的熔点
That lowers the magma’s melting point
导致板块升到顶上的北美板块
and makes it rise into the overlying North American plate.
岩浆从一个地下室往上移动
From a subterranean chamber, the magma travels upwards
从一串火山中爆发
and erupts along a chain of volcanos.
还在地下的岩浆慢慢冷却
Magma still deep underground slowly cools,
结晶成岩石
crystallizing to form solid rock,
比如说优胜美地和内华达山脉
including the granite now found in Yosemite National Park
的花岗岩
and the Sierra Nevada Mountains.
我们等会儿再来谈这个
We’ll come back to that later.
8500万年前
Now, it’s 85 million years ago.
法拉龙板块变得没有那么陡
The Farallon Plate becomes less steep,
导致火山向东伸展 逐渐停下来
causing volcanism to stretch eastward and eventually cease.
法拉龙板块在俯冲的
As the Farallon Plate subducts,
同时在压缩北美
it compresses North America,
造成山脉 比如落基山脉
thrusting up mountain ranges like the Rockies,
延伸大于3000英里
which extend over 3,000 miles.
不久之后 欧亚板块跟北美裂开了
Soon after, the Eurasian Plate rifts from North America,
打开北大西洋
opening the North Atlantic Ocean.
我们再往后看
We’ll fast forward again.
科罗拉多高原隆起
The Colorado Plateau now uplifts,
多半是由于向上的地幔流
likely due to a combination of upward mantle flow
与更厚的北美板块
and a thickened North American Plate.
在未来的一千年中
In future millennia, the Colorado River will eventually sculpt the plateau
科罗拉多河会将高原塑造成大峡谷
into the epic Grand Canyon.
3千万年前 大部分法拉龙板块沉进地幔
30 million years ago, the majority of the Farallon Plate sinks into the mantle,
只剩下小角落在俯冲
leaving behind only small corners still subducting.
太平洋板块与北美板块汇集
The Pacific and North American plates converge
形成新的边界 圣安德烈亚斯断层在这里
and a new boundary called the San Andreas Fault forms.
北美州向南移动
Here, North America moves to the south,
滑在太平洋板块旁边 太平洋板块向北移动
sliding against the Pacific Plate, which shifts to the north.
这个板块边界今天仍然存在
This plate boundary still exists today,
每年移动30毫米
and moves about 30 millimeters per year
能够引起强烈的地震
capable of causing devastating earthquakes.
圣安地列斯也在很宽的裂谷带
The San Andreas also pulls apart western North America
拉开北美州
across a wide rift zone.
这种外延区域叫做盆地和山脉省
This extensional region is called the Basin and Range Province,
通过隆起和侵蚀
and through uplift and erosion,
暴漏了以前 埋在优胜美地和内华达深处的花岗岩
is responsible for exposing the once deep granite of Yosemite and the Sierra Nevada.
1500万年后
Another 15 million years off the clock,
地幔的岩浆在西边的北美州烧一个大洞
and magma from the mantle burns a giant hole into western North America,
定期喷发到表面现在
periodically erupting onto the surface.
这个热点养着一个超级活火山
Today, this hotspot feeds an active supervolcano
就在黄石公园地下
beneath Yellowstone National Park.
它174 000年都没有爆发了
It hasn’t erupted in the last 174,000 years,
但是如果它真爆发了
but if it did,
它的力量可以把大部分北美州覆盖在灰尘里
its sheer force could blanket most of the continent with ash
把天色变黑 并且对人类有很大的危险
that would blacken the skies and threaten humanity.
黄石的超级火山是在提醒我们
The Yellowstone supervolcano is just one reminder
地球在我们脚底下一直在沸腾
that the Earth continues to seethe below our feet.
地球的板块导致它不断变化
Its mobile plates put the planet in a state of constant flux.
数亿年后
In another few hundred million years,
谁也不知道北美州的景观会有什么变化
who knows how the landscape of North America will have changed.
只有时间可以透露
As the continent slowly morphs into something unfamiliar,
以后的北美
only geological time will tell.

发表评论

译制信息
视频概述
听录译者

收集自网络

翻译译者

收集自网络

审核员

自动通过审核

视频来源

https://www.youtube.com/watch?v=jzqnUvE66HA

相关推荐