Plate Tectonics
美音、自然拼读、分级阅读与词汇复习
Table of Contents Introduction.
导言表。
4 Earth’s Structure.
4 《地球结构》。
5 Earth’s Fragile Crust.
5 地球脆弱结壳.
8 Tectonic Plates.
8 特克通克平板电脑.
10 Pangaea.
10潘加埃亚.
11 Ocean Ridges and Trenches.
11 洋脊与海沟.
13 Conclusion.
13 结论。
17 Glossary.
17 词汇表。
19 Introduction When you look at a globe, do you ever wonder why Earth looks the way it does?
19 导言 当你看着一个地球, 你有没有想过 为什么地球看起来像它一样?
Why are there big areas of land separated by oceans?
为什么大片土地被海洋隔开?
Why isn’t there just one large land mass?
为何没有一大块土地?
Why are there separate continents?
为什么有不同的大陆?
In this book, you will look for answers to these questions.
在这本书中,你会寻找这些问题的答案.
You will learn about Earth’s structure and how it has changed.
你们将了解地球的结构及其变化。
You also will learn a little about how it may look in the future.
你也会了解未来会怎样看
One thing you will certainly learn is that Earth is always changing.
地球总是在变
In fact, it’s changing right now.
事实上,它正在改变。
Before you learn about why Earth looks the way it does and how it changes, you will learn a little about how it is put together.
在你了解地球的长相和变化之前, 你会了解它是如何组合在一起的。
If you can understand the way Earth is made, you will better understand how it changes.
如果你能理解地球的形成方式, 你会更了解它是如何变化的.
Do You Know?
你知道吗?
There is an earthquake every 11 seconds.
每11秒就有一次地震发生.
There are more than 600 active volcanoes in the world.
世界上有600多座活火山.
Each earthquake and volcanic eruption is part of Earth’s way of changing.
每次地震和火山爆发都是地球变化方式的一部分。
Earth’s Structure The size of Earth— about 12,249 kilometers (7,650 mi) in diameter—has been known since the time of the ancient Greeks.
地球结构 地球的大小——直径约12,249公里(7,650米)——自古希腊人时代起就已闻名.
But it wasn’t until the early 1900s that scientists knew Earth was made up of three main layers: the crust, the mantle, and the core.
但直到1900年代初,科学家才知道地球是由地壳,地幔和地心等三个主要地层组成的.
This picture shows the internal structure of Earth.
这张图片显示了地球的内部结构.
The picture is drawn to scale (relative size of each layer, just much smaller).
图片被绘制成比例(每层相对大小,只是小得多).
The crust, or outer layer, is very rigid and thin compared to the other two layers.
地壳,或外层相较于其他两层地壳,地壳非常僵硬而薄.
Its thickness changes in different areas of the Earth.
其厚度在地球不同地区会发生变化.
Under the oceans, the crust is very thin, around 4.
在海洋下,地壳非常薄,约4个.
8 kilometers (3 mi) thick.
8公里(3米)厚.
But under a mountain range, like the Swiss Alps or the Cascades in the northwestern United States, the crust can be as much as 100 kilometers (62 mi) thick.
但是在一个山脉下,如美国西北部的瑞士阿尔卑斯山脉或克斯卡德山脉等地,地壳可以有多达100公里(62米)厚.
Earth’s crust is brittle and can break when under great pressure.
地壳很脆,在巨大的压力下会断裂。
Below the crust is the mantle.
地壳下是地幔.
The mantle is a dense, hot layer of semi-solid rock that is about 2,800 kilometers (1,750 mi) thick.
地幔是一层密集而热的半固态岩石,厚约2800公里(1750米).
It is semi-solid because the mantle is much hotter than the crust.
它是半固态的,因为地幔比地壳热得多。
The pressure at the depths of the Earth is much greater than at the surface.
地底深处的压力远大于地表.
The pressure causes the mantle to be both hotter and denser at its deepest part.
压力使得地幔在最深处既更热又更密集.
Beneath the mantle and at the center of the Earth is the core.
地幔下方和地心为核心.
The core is almost twice as dense as the mantle because the pressure is even greater in the core.
核的密度几乎是地幔的两倍,因为核心中的压力更大.
The core is mostly metal, rather than rock like the mantle.
地心多为金属,而不像地幔那样是岩石.
Earth’s center has two layers.
地心有两层.
The liquid outer core is about 2,080 kilometers (1,300 mi) thick.
液外核厚约2,080公里(1,300米).
There is also a solid inner core, the true center of the Earth.
还有坚固的内核 地球的真正中心
The inner core is made almost entirely of iron.
内核几乎完全由铁制成.
As Earth rotates, the liquid outer core spins.
随着地球旋转,液体外核会旋转.
This spinning action creates Earth’s magnetic field.
这种旋转动作创造了地球的磁场.
So, there is the thin outer crust, which is kind of stiff and can break.
因此,有薄的外壳, 它有点僵硬,可以断裂。
There is the middle layer, the mantle, which is much hotter and not quite solid.
有中层,地幔, 它更热 和不相当固体。
And in the middle is the core, which has a solid center and a liquid-like outer layer.
而中间是核,它有一个坚实的中枢和一个类似液体的外层.
Some people like to compare Earth to a hard-boiled egg.
有些人喜欢把地球比作一个被煮熟的鸡蛋.
The crust is the shell, the mantle is the white, and the core is the yolk.
地壳为外壳,地幔为白色,核为蛋黄.
You might want to use this comparison to help you remember the layers of the Earth.
你也许想用这个比较来帮助你记住地球的地层.
But remember—unlike an egg yolk, Earth’s core has two layers.
地球核心有两层,
Earth’s Fragile Crust When you think about the mantle, remember that it is very hot.
地球脆弱的地壳 想想地幔,记得它很热
When rock or metal is heated to high temperatures, it begins to get softer and turn to liquid.
当岩石或金属被加热到高温时,会开始变软并变成液体.
For example, when a blacksmith makes a horseshoe, he heats the metal until it turns red.
例如,当铁匠做马蹄时,会将金属加热到会变成红色.
When it gets that hot it becomes soft, and he can hammer it to fit the horse’s hoof.
当它变得这么热, 它变得柔软, 他可以锤它适合马蹄。
Well, the mantle is always at a very hot temperature, so it is not quite solid.
地幔的温度总是非常高 所以不太牢固
It’s like Silly Putty ® or Play-Doh ®.
这就像傻子Putty 或 Play-Doh 。
It may feel solid, but if you push on it, it will change shape.
它可能感觉固体,但如果你推下去,它会改变形状.
This is how the mantle works.
地幔就是这样工作的
The mantle is kind of solid, but not quite.
地幔有点坚固,但并不完全。
It is stuck between the rigid crust of Earth’s surface and the spinning, liquid outer core.
它被困在地表的坚硬地壳和旋转的液态外核之间。
Being caught in the middle causes stress to build up.
被夹在中间会引发压力积聚.
The mantle is continually caught between two powerful forces.
地幔不断被夹在两股强大的力量之间.
As a result, the mantle stays in constant motion.
因此地幔会保持常动.
Riding on top of the moving mantle is the crust.
在地幔上骑行就是地壳
Most of the time, the crust is solid and stays in one piece.
大多数时候,地壳是坚固的并保持一成不变.
However, stress and pressure, which cause the mantle to move, can cause large slabs of Earth’s crust to move, too.
然而,造成地幔移动的压力和压力也会导致地壳上的巨大板块移动.
The pressure and motion can cause the crust to crack.
压力和运动可以使地壳裂开.
The cracks, called fault lines, are where earthquakes are known to occur.
裂缝被称作断层线,是已知地震发生地.
Fault lines are commonly found where large slabs of Earth’s crust meet.
断层线常见于地壳大板块相接之处.
You will learn about this movement in the next section.
你将在下一节了解这个运动。
If the pressure is great enough, enough heat is created to turn the mantle into a liquid called magma.
如果压力足够大,就会产生足够的热量来将地幔变成一种叫"岩浆"的液体.
The hot magma expands and places pressure on the crust above.
热岩浆会扩张并给上面的地壳造成压力.
The magma is pushed through cracks in the crust.
岩浆被推进到地壳的裂缝中.
In time it can get very close to Earth’s surface.
随着时间的推移,它可以非常接近地表。
If the pressure is great enough, the magma will break through the surface and form a volcano.
如果压力足够大,岩浆会突破地表并形成火山.
Sometimes the pressure is so great that the magma explodes through the crust, shooting dust, ash, steam, and liquid rock called lava into the air.
有时压力会很大到岩浆会从地壳中爆炸,会射出灰尘,灰烬,蒸汽等被称作熔岩的液体岩石进入空气.
Like earthquakes, volcanoes are usually found in areas where two or more slabs of Earth’s crust meet.
与地震一样,火山通常分布在地壳两块或多块板块相会的地区.
Tectonic Plates Earth’s crust is made of about fifteen enormous slabs, or plates.
地壳由大约15个巨型地板或板块组成。
Some of the plates are moving apart.
一些板块正在分开移动.
Others are moving together.
其他人正在一起行动。
Still others are sliding past each other.
还有一些人正在相互滑倒。
The plates are located under both land masses and oceans.
板块位于陆地和海洋下。
Those under land are called continental plates.
地下被称作大陆板块.
Those under the oceans are called oceanic plates.
海洋下的那些被称为海洋板块.
Over time, one plate may disappear and another one may appear, so the number of plates can change.
随着时间的推移,一个板块可能消失而另一个板块可能出现,因此板块的数量可以改变.
But the number won’t change during your lifetime.
但数字不会在你一生中改变。
It takes millions of years for these changes to happen.
这些变化需要上百万年的时间才能发生。
The process of plates forming and moving is called plate tectonics.
板块形成和移动的过程称为板块构造.
The word tectonic comes from a Greek word that means “to build.”
构造学一词出自一个希腊语单词,意为"建设". “
The phrase plate tectonics means that Earth is built from plates of rock.
短语"板块构造"指地由岩石板块所建.
These plates probably formed very early in Earth’s five-billion-year history.
这些板块可能形成于地球50亿年历史的很早期.
A very long time ago, all the continental plates were joined as one large plate.
很久以前,所有的大陆板块都作为一个大板块加入.
There was only one continent at that time.
当时只有一个大陆.
We call that continent Pangaea, meaning “all lands” in Greek.
我们称该大陆为Pangaea,意思是希腊语的“所有土地”。
Pangaea The illustrations on the next page show how the seven continents were one giant mass of land long ago.
潘加埃亚语Name 下页的插图显示,七大洲是很久以前的一块巨大的陆地.
Over many hundreds of millions of years, forces within the Earth have caused the continental plates to move and spread apart.
数亿多年来,地球上的势力已使大陆板块相去甚远并相去甚远.
The spreading plates have moved the continents to the locations we know today.
扩张板块把大陆移到我们今天知道的地方。
As you move from one picture to the next, notice how the continents look like puzzle pieces.
当你从一幅相片移到一幅相片时, 注意这些大陆看起来如何像拼图片。
You can see how South America once fit right into the coast of Africa.
你可以看到南美洲曾经如何适合 非洲海岸。
Who knows how the continents might look hundreds of millions of years from now?
谁知道几亿年后的大陆会是什么样子?
It has taken 225 million years for the continents to separate and move to their current locations.
历时2.25亿年,各大洲分出并迁入现址.
Some scientists believe most of the continents will someday be a single mass again.
一些科学家认为,大多数大陆有一天会再次成为单一的质量.
This movement of the continents over time is called continental drift.
这种大陆随时间推移而来的运动被称为大陆漂移.
What forces in Earth could be powerful enough to cause huge plates of the crust to move?
地球上有什么力量足以 使地壳的巨大板块移动?
Ocean Ridges and Trenches In the middle of the Atlantic Ocean, scientists found a strange chain of mountains.
洋脊和海沟 在大西洋中部,科学家发现了一串奇怪的山脉链.
Over the years, they found that this mountain chain exists between all the continents, winding its way around the Earth.
多年来,他们发现这个山链 存在于所有大陆之间, 环绕地球。
This mountain chain is called the global mid-ocean ridge.
这个山链被称作全球中洋脊.
Along this ridge, hot magma seeps to the surface through fault lines in the crust.
沿着这道山脊,热岩浆从地壳的断层线渗入地表.
The magma spreads out along the ocean floor and cools.
岩浆沿着洋底散出并冷却.
This buildup of magma causes the oceanic plates to change and grow.
这种岩浆的积聚使海洋板块发生变化并生长.
These plates push out toward the other plates.
这些盘子向其他盘子推去
In some places along the ridge, underwater volcanic eruptions occur.
在山脊一带的一些地方,会发生水下火山喷发.
Some of these eruptions have brought enough magma to the surface to form islands in the ocean.
其中一些喷发给地表带来了足够的岩浆来形成海洋中的岛屿.
The island of Iceland formed in this way.
冰岛岛就是这样形成的.
Around the Pacific Ocean is a series of deep trenches.
环太平洋是一系列深沟.
Some of the older crust is pushed into these trenches as new crust is created.
随着新地壳的形成,一些更古老的地壳被推入了这些地沟.
These trenches are places where one plate is pushed under another plate.
这些战壕是将一板推入另一板下的地方.
Wherever this happens, there are lots of earthquakes and volcanoes.
每当发生这种情况时,都会有大量的地震和火山.
For this reason, the rim of land that surrounds the Pacific Ocean is called the Ring of Fire.
出于这个原因,环绕太平洋的陆地边缘被称作"火环".
The mountain ranges along the western shores of North and South America and the eastern shores of Asia were created when oceanic plates pushed beneath continental plates.
南北美洲西海岸和亚洲东海岸一带的山脉是在大洋板块推入大陆板块后形成的。
These mountain ranges, which contain many volcanoes, were formed when the colliding plates pushed the crust upward.
这些包含多座火山的山脉是相撞板块将地壳向上推时形成的.
A similar process pushed India into the Asian continent millions of years ago.
类似的进程将印度推入了数百万年前的亚洲大陆.
India was an island off the Australian coast when Pangaea broke up.
印度在潘加埃阿分道扬镳时是澳大利亚沿海的一个岛屿.
Over a long period of time, India moved northward at a rate of about 9.
在很长一段时间内,印度以约9个的速度北上.
1 meters (30 ft) per century.
每世纪一米(30英尺).
When it finally hit the Asian coast, it moved much more slowly but continued to move north.
当它最终撞上亚洲海岸时,它移动得更慢,但继续向北移动.
The northern movement of India pushed its coastal edge upward against the unmoving Eurasian continent.
印度的北方运动将其沿海边缘向上推向了无法移动的欧亚大陆.
The coastal edge of India grew to become the Himalaya Mountains, the largest and tallest mountain range in the world.
印度的沿海边缘逐渐成为喜马拉雅山脉,是世界上最大和最高的山脉.
Some of the mountains are nearly 9.
部分山地已接近9个.
6 kilometers (6 mi) tall and are still growing.
高6公里(6米),仍在生长.
Sandstone and other rocks found in the Himalayas contain fossils of water creatures, proving that the land was once under salt water.
在喜马拉雅山脉发现的砂岩等岩石中含有水生生物的化石,证明了这片地曾一度被盐水所淹没.
An oceanic plate moves under a continental plate.
大洋板块在大陆板块下移动.
This illustration shows how India has moved north over the last 80 million years.
这个例子说明印度在过去8000万年中如何向北迁移.
These illustrations show how the tip of the Indian plate has been pushed upward to form the Himalayas by the pressures of the colliding plates.
这些插图显示了印度板块的尖端如何被相撞板块的压力推向上形成喜马拉雅山脉.
The Indian plate is still moving, causing the Himalayas to continue to grow.
印度板块仍在移动,使喜马拉雅山脉继续生长.
Do You Know?
你知道吗?
The Himalaya Mountains continue to grow at a rate of 1 centimeter (.
喜马拉雅山脉以一公分(.
39 in) a year.
39 in) 一年时间.
In a million years, that is 9.
万年之内,即九.
66 kilometers (6 mi) of growth!
66公里(6米)的增长!
Conclusion The study of plate tectonics tells us a lot about how Earth has changed over the years and how it will continue to change.
结论 对板块构造学的研究告诉我们很多关于地球在过去几年中是如何变化的,以及它会如何继续变化.
Plate tectonics is still a new science.
板块构造学仍然是一门新的科学.
Over time it will offer many more insights into how the Earth is made.
随着时间的推移,它将为地球的形成提供更多的见解。
Throughout your lifetime, several major earthquakes and a few serious volcanic eruptions will occur.
在你一生中,将发生多起大地震和几起严重的火山爆发.
Each of these events will reveal information about how Earth is put together.
每一个事件都会揭示关于地球如何组合的信息.
It is now possible to track these changes on a daily basis.
现在可以每天跟踪这些变化。
Some Web sites keep track of earthquakes and volcanic eruptions around the world.
一些网站不断追踪世界各地的地震和火山爆发.
The study of plate tectonics teaches us a lot about Earth’s past.
对板块构造学的研究 教给我们了很多关于地球过去的故事。
It also can suggest Earth’s possible future.
它还可以说明地球可能的未来。
For example, many scientists believe that Los Angeles will eventually be right next to San Francisco.
例如,许多科学家认为洛杉矶最终会紧邻旧金山.
Los Angeles is on an oceanic plate that is moving northward.
洛杉矶位于向北移动的大洋板块上.
San Francisco is safely on a continental plate and isn’t moving.
旧金山安全地位于大陆板块上,
One day in the far future, Los Angeles may be in the area where Alaska is now.
在遥远的未来的某一天,洛杉矶可能位于阿拉斯加现在所在的地区.
This is an illustration of the movement of the Pacific Plate and the North American Plate.
这是太平洋板块和北美板块运动的一个例子.
One day, Los Angeles will be next to San Francisco.
有一天,洛杉矶会紧邻旧金山.
Wouldn’t it be fun to live long enough to see this happen?
活得够久,
Well, okay, that is a long time.
好吧,这是很长一段时间。
But for Earth, it’s just the blink of an eye.
但对于地球来说,