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  • 均变论

    Molten lava flowing on a landscape, illustrating volcanic activity and rock formation.
     

    What does this mean: "The present is the key to the past"?
    ::这是什么意思: "现在是过去的关键"?

    How can this photo help you to figure out what happened in Earth's history? You see the molten  lava . You see what the   looks like when the lava cools. What if you see that type of rock in an  outcrop ? You can assume that it formed from molten lava. This is the best tool for understanding Earth history. Earth scientists use what they know about Earth in the present to figure out what happened in the past.
    ::这张照片怎样才能帮助你弄清楚 地球历史上发生了什么呢? 你看到熔岩了。 当熔岩冷却时你可以看到它是什么样子。 如果你看到岩块外的这种岩石会怎么样? 你可以假设它是由熔岩形成的。这是了解地球历史的最佳工具。地球科学家们利用他们目前对地球的了解来了解过去发生了什么。

    Ask a Question: Earth History
    ::问一个问题:地球历史

    The outcrop in  Figure    is at Checkerboard Mesa in Zion National Park, Utah. It has a very interesting pattern on it. As a  geology  student you may ask: how did this rock form?
    ::数字中的悬崖是犹他州锡安国家公园的奇格板梅萨。它有一个非常有趣的图案。作为一个地质学学生,你可以问:这块岩石是如何形成的?

    Checkerboard Mesa in Zion National Park showing distinct sandstone patterns and layers.
     
    Checkerboard Mesa in Zion National Park, Utah.

    If you look carefully at the rock, you will see that it’s made of sand. This rock formation is called the Navajo sandstone. Does knowing that the rock is sandstone tell you how it formed? No, although it limits the possibilities. The next thing to do is to make observations now and apply them to this rock that formed long ago.
    ::如果你仔细观察岩石,你会看到它是由沙子构成的。这种岩层被称为纳瓦霍沙岩。知道岩石是沙石,你是否知道它是如何形成的?不,尽管它限制了可能性。接下来要做的是现在就做观察,并将其应用到很久以前形成的岩石上。

    Uniformitarianism
    ::统一主义

    James Hutton is known as the father of modern geology. In the late 1700s, he came up with the idea that the present is the key to the past. He called this the  principle of uniformitarianism . It works like this: we understand a geological process that happens now. We see the outcome of that process, say a rock. Then we find evidence that same process happened in the past, like a similar rock. We can assume that the process operated the same way in the past.
    ::James Hutton被称为现代地质学之父。 在1700年代末期, 他提出了现在是过去的关键的想法。 他称此为统一主义原则。 它这样运作: 我们理解现在发生的地质过程。 我们看到了这个过程的结果, 比如说一块岩石。 然后我们发现了过去也发生过类似过程的证据, 就像一个类似的岩石。 我们可以假设这个过程在过去同样运作。

    Let’s go back to that outcrop. What would cause sandstone to have layers that cross each other, a feature called cross-bedding?
    ::让我们回到那个顶端去。 是什么让沙石有相互交错的层层,一个被称为交叉嵌入的特征?

    Answer a Question: Earth History
    ::回答一个问题:地球历史

    In this photo of this  sand dune  in Coral Pink Sand Dunes State Park, Utah ( Figure   ), we see that  wind  can cause cross-bedding in sand. Cross-bedding is due to changes in wind direction. There are also ripples caused by the wind waving over the surface of the dune.
    ::在犹他州Color Pink Sand Dunes州公园(图)的这张沙丘照片中,我们看到风能造成沙体交叉沉积。交叉沉积是风向变化的结果。还有风在沙丘表面挥舞而引发的波纹。

    Sand dune patterns at Coral Pink Sand Dunes State Park, illustrating wind effects on sediment.
     
    Sand dune in Coral Pink Sand Dunes State Park, Utah.

    This doesn’t look exactly like the outcrop of Navajo sandstone, but if you could cut a cross-section into the face of the dune it would look very similar.
    ::这与纳瓦霍沙岩的裂缝并不完全相似, 但如果你可以切开一个横截面切入沙丘的面部,

    Since we can observe wind forming sand dunes with these patterns now, we have a good explanation for how the Navajo sandstone formed. The Navajo sandstone is a rock formed from ancient sand dunes. The rock shows that the ancient wind direction changed from time to time.
    ::既然我们现在可以观察到风以这些模式形成沙丘,我们就能很好地解释纳瓦霍沙石是如何形成的。纳瓦霍沙石是由古沙沙丘形成的岩石。 岩石表明古风方向不时改变。

    This is just one example of how geologists use observations they make today to unravel what happened in Earth’s past. Rocks formed from  , oceans,  rivers , and many other features are deciphered by looking at the geological work those features do today.
    ::这只是地质学家如何利用今天的观测来揭示地球过去发生的事情的一个例子。 从海洋、河流和许多其他地貌形成的岩石通过观察这些地貌的地质工作而破解。

    Science Friday: Tar Noir: Paleoforensics at the La Brea Tar Pits
    ::科学周五:Tar Noir:在La Brea Tar Pits的Paleoforensics

    The La Brea Tar Pits contain a massive collection on animals. But how did all these animals die, and how did they get there? In this video by  Science  Friday, researchers explain how these processes occurred and what the La Brea Tar Pits tell us about Los Angeles thousands of years ago.
    ::La Brea Tar Pits 包含大量动物的收藏。 但所有这些动物是怎么死的,以及它们是如何到达的?在科学星期五的这段视频中,研究人员解释了这些过程是如何发生的,以及数千年前La Brea Tar Pits告诉我们的关于洛杉矶的情况。

     

     

     

    Summary
    ::摘要

    • You may need to apply what you know about the present to determine what happened in the past.
      ::你可能需要运用你对现在的了解 来决定过去发生的事
    • The idea that the present is the key to the past was recognized by James Hutton in the late 1700s.
      ::James Hutton在1700年代末期承认,认为现在是过去的关键。
    • If you see something forming by a process today and then find the end results of that process in the rock record, you can assume that the the process operated the same way in the past.
      ::如果你看到今天一个进程形成的东西,然后在岩石记录中找到该进程的最终结果,你可以假定,该进程过去以同样的方式运作。

    Review
    ::回顾

    1. What does an Earth scientist often need to answer a question about something that happened in Earth’s distant past?
      ::地球科学家通常需要什么来回答 地球遥远的过去所发生的问题?
    1. James Hutton is sometimes called the father of geology. Why does he deserve that title?
      ::詹姆斯·赫顿有时被称为地质学之父,为什么他有资格获得这个头衔?
    1. How can you use the principle of uniformitarianism to figure out how a lava rock formed?
      ::你如何利用统一主义原则 来找出岩浆岩的形成方式?