CHAPTER 24 History of Our Planet 第24章 我们行星的历史

CHAPTER 24 History of Our Planet 第24章 我们行星的历史

Uncovering the bones of ancient beasts is only part of the story. Walking in the country, you must have noticed that a valley often has a river or stream running down the middle of it. Hills and mountains, too, will surround the valleys. In some parts of the world, say, the Alps of Switzerland, it is striking how the mountains are very high and the valleys are very deep.

发现古代野兽的骨头只是故事的一部分。在乡村行走的时候，你肯定注意到过，峡谷当中经常有一条河流向下流去。山坡和山脉也会围绕着峡谷。在世界的某些地方，比如瑞士的阿尔卑斯山，山脉的高度和峡谷的深度让人震惊。

How were the earth's features formed? Mountains and valleys could not have always been the way they are now, since the landscape is changed every year by earthquakes, volcanic eruptions, rivers and glaciers. The change in any one year may be slight, but even in your lifetime, visible differences occur. Coastlines wear away and houses sometimes fall into the sea. Multiply that by several, or many, generations, and the changes are even larger.

地球的这些特征是怎么形成的呢？山脉和峡谷不可能一直是它们现在的样子，因为地震、火山爆发、河流和冰川每年都在改变地貌。任何一年中的变化可能都是微小的，在即使在你的有生之年，也有看得到的变化。海岸线逐渐磨损，房子有时候会被大海淹没。这些细小的变化经年累月，会变得非常可观。

Violent earthquakes, volcanoes and tsunamis are nothing new. Mount Vesuvius, near Naples in Italy, erupted in AD 79. It buried the town beneath it, Pompeii, killing many people, and the volcanic ash and lava changed the coastline dramatically. Today you can walk along the streets of Pompeii, which have been excavated from the ash and pumice that settled there.

剧烈的地震、火山爆发和海啸不是什么新东西。公元79年，意大利那不勒斯附近的维苏威火山爆发，将庞贝城埋在下面，杀死了很多人，火山灰和岩浆极大的改变了海岸线。今天庞贝城已经从那些火山灰和浮石中挖掘出来，你可以沿着庞贝城的街道行走。

Many people wondered about what these kinds of dramatic happenings meant. Some thought they were supernatural acts. But from the late 1600s, observers began to study the earth as an object of natural history. Modern geology was born when they grappled with three problems. The first was a new way of understanding ‘history’.

很多人想知道这些巨大的事故意味着什么，有的人认为这些是超自然的行为，但从17世纪晚期开始，观察者开始将地球视为自然历史的一个物体来进行研究。现代地质学诞生于解决三个问题的过程中。第一个问题是一种理解历史的新方式。

In earlier times, 'history' really meant ‘description’. Natural history was simply a description of the earth and the things on it. Gradually, 'history' acquired its modern meaning of change through time. We are used to things changing quickly: clothes, music, hairstyles, slang, and anything to do with computers and mobile phones. We see photographs of people in the 1950s and think how different they looked then. This is not really new – the Romans dressed differently than the ancient Greeks, for instance - but the pace of change is much faster now. So, we accept change as natural. History is the study of that change.

较早的时候，“历史”的意思就是“描述”。自然历史就是地球和地球上物体的简单描述。逐渐的，历史的意义随着时间变化，成为了现在的意思。我们习惯于迅速变化的东西：衣着，音乐，发型，俚语，以及与电脑和手机相关的任何东西。我们看20世纪50年代的照片，就会想那时候的人看起来真是不同。这其实没那么新奇，比如古罗马人与古希腊人衣着就不一样，但现在变化的节奏的确更快了。所以，我们认为变化是自然的。历史就是有关变化的研究。

The second problem was that of time. Aristotle assumed that the earth is eternal, and had always been much as it was when he lived. Ancient Chinese and Indian scientists also believed that the earth was very old. With the coming of Christian and Islamic views of the earth, time shrank. ‘Time we may comprehend, 'tis but five days older than ourselves’, said the writer Sir Thomas Browne in 1642. What he meant was that the Book of Genesis tells the story of Creation, in which God created Adam and Eve on the sixth day. During the previous five days the earth, sky, stars, sun, moon and all the plants and animals were created. For Christians like Browne, our planet, the earth, was created only shortly before Adam and Eve saw the first dawn in the Garden of Eden.

第二个问题是关于时间的问题。亚里士多德认为地球是永恒的，在他活着的时候基本没有变化。古代中国和印度科学家也相信地球是非常古老的。随着基督教和伊斯兰教关于地球的观点来临，时间缩水了。作家Thomas Browne在1642年说，“我们可以理解时间，不过比我们大五天罢了”，他意思是《创世纪》告诉的我们上帝创造天地的故事，故事里上帝在第六天创造了亚当和夏娃。在之前的五天里，创造了地球，天空，星星，太阳，月亮和所有的行星和动物。对于Browne这样的基督教徒来说，亚当和夏娃看到伊甸园的黎明前不久，地球才被创造出来。

If you read the Bible carefully, and add up all the ages of the descendants of Adam and Eve mentioned in the Old Testament, that gives an approximate date for the first couple. In the mid-1600s, an Irish archbishop did just that. His addition told him that the earth was created on 22 October 4004 BC, in the early evening, to be precise! Archbishop Ussher's calculations were not accepted by many Christians in the 1650s. But for people wanting to know how the geological features of the earth were formed, it was difficult to explain how, say, river valleys could have gradually come about if the earth was less than 6,000 years old.

如果你仔细阅读圣经，将旧约中亚当和夏娃所有的后代的年龄加在一起，就可以得到第一对人的大致时间。在17世纪中期，一个爱尔兰大主教做了这件事，他计算出地球在公元前4004年10月22日创造出来，精确的说，在那天傍晚！大主教Ussher的计算在17世纪50年代大部分基督教徒都不认可。但对于想知道地球的地质特征怎样形成的人来说，如果地球的年龄小于6000年，就很难解释峡谷河水是怎样逐渐形成的。

This limited period of time also created difficulties explaining how shells could be found on mountain tops, far above the present oceans and seas. What geologists needed above all was to find more time for the earth to have been in existence. Then the things they were observing could be put into some kind of sensible perspective. And this they did. Beginning in the late seventeenth century, naturalists began to argue that the world must be older than the few thousand years allowed by Ussher. Several decades later, the Comte de Buffon (the pioneering natural historian we met in Chapter 19) worked out a scheme that combined cosmology and geology. His cosmology had the earth as originally a very hot ball, flung off from the sun. It gradually cooled down, and life became possible. He tentatively put the date of the separation of the earth from the sun at about 80,000 years ago, being careful with his exact language so as not to offend the Church.

地球有限的历史也很难解释为什么会在远离现在的大海的山顶发现贝壳，地质学家首先需要的就是为地球存在更多时间找到证据，这样他们观察的事物可以得到有意义的解释。这一点他们做到了。从17世纪晚期开始，博物学家争论世界可能比Ussher所说的几年前历史要更古老，几十年后，Comte de Buffon（第19章中提到的自然历史学家先驱）提出了一个结合了宇宙学和地质学的计划。他从宇宙学的观点出发，认为地球最开始是太阳甩出来的一个炙热的球，逐渐冷却，出现生命。他尝试性的将地球与太阳分离的时期放在了大约8万年前，并非常小心自己的用语，以免惹怒教廷。

The third problem was to understand the nature of rocks and minerals. All rocks are not the same. Some are hard, some soft and crumbly, and they are made up of different kinds of materials. They also seemed to be of different ages. Naming and analyzing rocks and minerals allowed the geologists who studied them to put together a picture of the earth's history. Abraham Werner (1749-1817) in Germany did a lot of this early work. He worked in a university, but he was actively involved in mining. Mines deep under the earth helped scientists by providing samples of materials not easily obtained on the earth's surface. Werner based his classification of rocks not simply on their composition, but also on their relative ages. The oldest ones were very hard and never contained fossils.

第三个问题是理解岩石和矿物的本质。并不是所有的岩石都是一样的，有的很硬，有点很软并且易碎，并由不同种类的矿物组成，而且看起来它们的年龄也不一样。地质学家为岩石命名并进行分析，这使他们可以拼出地球历史的大图片。德国的Abraham Werner (1749-1817)做了很多早期的工作，他在一所大学里工作，但他非常热衷于采矿。深藏在地下的矿井可以挖出很多地表很难获得的矿物样本，这使科学家大为受益。Werner不仅基于岩石的成分，还基于它们的相对年龄，来进行分类工作，最古老的岩石非常坚硬，而且从来没有化石。

Thus the kinds of rocks found in a given place provided a clue to the age of the place, relative to other places. Digging downwards, where the layers of rocks and earth (the strata, as geologists call

them) contained fossils, these too provided clues to the relative ages of both the fossils and the strata in which they were found. The man who showed that the fossils were very important in this dating process was a surveyor, William Smith (1769-1839). Smith helped build Britain's canals in the early nineteenth century. Before railways, water was the best way to transport goods, particularly heavy things like coal. Smith measured many miles of land, helping to decide the best route for a new canal. What he gradually realized, as he created a geological map of England and Wales, was that the most important characteristic of a layer of the earth's crust was not simply the kind of rock it contained, but also the fossils that could be found within it.

所以在一个特定地区发现的岩石会提供这个地区年龄的线索，这是在与其他地区相对来说。继续向下挖，挖到包含化石的岩石和土壤层（地层，地质学家这么称），这也为化石和发现的地层的相对年龄提供线索。测量师William Smith (1769-1839)表示，化石在确定时间的过程中非常重要。Smith在19世纪早期帮助修建了英国的运河。在有火车之前，水是运送物资的最好方式，尤其是对于像煤这样的重物。Smith测量了广阔的土地，帮助确定新运河的最佳路径。在绘制英格兰和威尔士地质地图的过程中，他逐渐意识到，地壳的某一层最重要的特征不仅仅是它包含的岩石种类，更是其中发现的化石。

With an expanded timescale for the earth's history, an understanding of the different kinds of rocks, and Smith's insight into the importance of the fossils, geologists could try to 'read' the earth's history. In the early 1800s, most geologists were 'catastrophists'. Piecing together the record uncovered through mining, canal building, and then railway building, they found many instances where volcanoes and earthquakes had thrown up layers previously buried deep in the earth's crust. So it seemed to most naturalists that the history of the earth had been one of periods of stability separated by periods of violent events - catastrophes - across the globe. Floods counted as catastrophes, so as geologists tried to fit their findings with the Bible, they were happy that there seemed to be evidence of massive and widespread flooding in the past, including a recent one (in geological terms) that could be the universal flood in which Noah took the animals two by two into his ark.

有了地球历史的扩展时间尺度，对不同种类岩石的理解，还有Smith对化石重要性的深入见解，地质学家就可以“阅读”地球的历史了。在19世纪早期，大多数地质学家都是灾变说者。将采矿、开凿运河，然后是铁路修建中发现的地质记录拼在一起，他们发现了火山爆发和地震将原来深埋在地壳中一些地层甩到上面来的很多例子。所以对大多数博物学家来说，地球的历史看起来就是稳定时期与剧烈灾难的时期相间隔的样子，而且全球都是这样。将大洪水也算作灾难，这样地质学家就可以将发现与圣经联系起来，他们很高兴看到似乎有证据证明过去有大规模分布广泛的洪水，包括最近的一次（在地质时间意义上），可能就是这次全球性的大洪水中，诺亚方舟带上了一双一双的各种动物。

The catastrophists found a lot of evidence to support their view of the earth's history. The fossils in any of the various layers showed obvious differences from those below or above. The newer strata had fossils that were more like present-day living plants and animals than did the ones in the older layers. In Paris, Georges Cuvier (whom we met in the last chapter) was using 'comparative anatomy' and reconstructing vivid pictures of the animals of bygone ages. One of his followers was William Buckland (1784-1856), a liberal English clergyman who taught geology at Oxford University. Buckland was especially energetic in his search for geological evidence for the biblical flood. He found lots of things that he thought were obviously caused by water: debris washed into caves, and rocks and even huge boulders spread over the fields. In the 1820s, he was very sure that these were the result of Noah's flood; by the 1840s, as geological investigations had revealed more detail, he became less sure. Glaciers (huge rivers of ice) could have had an effect even in Britain, he realized. They provided a more convincing explanation of things like the scattered boulders, which could have been left behind as the ice moved slowly onwards.

这些灾变说者发现了很多证据支持其地球历史的观点。众多地层的任意一层的化石都与上面或下面地层的化石明显不同。较新地层的化石与现在活着的动植物比较接近，而更老的地层则没那么相似。在巴黎，Georges Cuvier（上一章中提到过）运用了比较解剖学，重建了过往时代动物的生动的图画。他的一个追随者是William Buckland (1784-1856)，一个自由主义的英国牧师，在牛津教授地质学。Buckland非常热心于为圣经中的大洪水寻找地质证据。他发现了很多明显是由水导致的东西：被水冲进洞穴的残骸，田野中散布着岩石甚至是巨型卵石。在19世纪20年代，他非常确定这就是诺亚大洪水的结果；到19世纪40年代，随着地质调查发现了更多细节，他变得没那么确定了。他意识到冰川（巨型冰河）可能甚至影响到英国。他们认为这些散布的巨型卵石是由于冰慢慢的向内陆移动，并将卵石留在了内陆，这个解释更加可信一些。

In the 1820s and 1830s, most geologists believed that these ancient catastrophes coincided with new geological strata. Because the fossils in the layers were generally slightly different, they concluded that the earth's history consisted of a series of cataclysmic events - massive floods, violent earthquakes - followed by the creation of new plants and animals that were adapted to the new conditions that had come into being. The earth, it seemed, had undergone a progressive history in preparation for its crowning glory: the creation of mankind. This scheme fitted with the account of Creation in the Book of Genesis, either by assuming that its six days of creation were actually six long periods, or that the Bible only described the last creation, the age of human beings.

在19世纪20年代和30年代，大多数地质学家相信这些古老的灾难与新的地质地层不谋而合。因为这些地层中的化石一般都略微不同，他们得出结论，地球的历史包含一系列灾难性事件，大规模的洪水，剧烈的地震，然后产生适应新环境的动植物物种。似乎地球经过了不断前进的历史，然后才到达了辉煌的顶点，也就是诞生了人类。这个计划与创世纪中的大造物的记述相吻合，可以将创世纪中的六天解释为六个很长的阶段，或者圣经只描述了最后一次造物，也就是人类的时代。

In 1830, Charles Lyell (1797-1875), a young lawyer-turned geologist, challenged this general account. Lyell had looked at rocks and fossils in France and Italy. He was studying geology at Oxford and his teacher was William Buckland, the catastrophist. Lyell was dissatisfied with Buckland's geological vision. What could we show, Lyell asked, if we assumed that the geological forces that operated on the earth had actually always been uniform (the same)? He became the leader of the ‘uniformitarians’, who grew to be opposed to the ‘catastrophists’. Lyell wanted to see how much of the whole geological history of the earth he could explain by using his principle of uniformity. He could see that at the present time the earth was very active geologically; there were still volcanoes, floods, erosion and earthquakes. If the rate of these changes was the same as long ago, was that enough to explain all the evidence of periods of ancient violent catastrophes? Yes, he said, and set out his reasons in a three-volume work, The Principles of Geology (1830-33). He would revise it for the next forty years, carefully taking into account his own and other geologists' research.

在1830年，Charles Lyell (1797-1875)，一位年轻的律师转行过来的地质学家，向这个一般的记述提出了挑战。Lyell调查了法国和意大利的岩石和化石，当时他正在牛津学习地质学，他的老师就是William Buckland，那个灾变说者。Lyell对Buckland的地质学见解不是很满意，Lyell问到，如果我们假设在地球上运作的地质力量一直以来都是一样的，那会得到什么结论呢？他成为了“均变论者”的领导人物，他们反对“灾变说者”。Lyell想知道用他的不变性原则能解释地球整个地质历史中的多少。他知道当时地球在地质上还是非常活跃的，仍然到处都有火山、洪水、地震和侵蚀。如果这些变化的速度和很久以前是一样的话，能解释古代剧烈灾变时期的那些迹象吗？他说，是可以解释的，并在他的三卷本著作中说出了原因，《地质学原理》（1830-33）。他在后续40年不断的进行修订，小心的纳入他自己和其他地质学家的研究。

Lyell's uniformitarianism was a bold attempt to get rid of catastrophes and the reliance on miracles such as Noah's flood. He wanted to set geologists free to interpret the earth's history without interference from the Church. Lyell was a deeply religious man who held that mankind was a unique, moral creature, with a special position in the universe. And he saw more clearly than most that the catastrophists' idea of successive creations of plants and animals, approaching ever nearer those living in the present day, looked very much like evolution. Where the catastrophists compared deep fossils with shallow ones and saw progress, Lyell argued instead that fossils displayed no overall development. He was very excited when a fossil mammal was uncovered in an old layer, deep underground. Mammals were generally found only in recent strata, so this suggested to him that there was no real progress in the history of plants and animals, except for humans. If it looked like progress, that was only a fluke. No more than a tiny number of the species that existed in prehistoric times had been preserved as fossils.

Lyell的均变论是去除灾变说以及对诺亚大洪水这样的奇迹的依赖的大胆尝试。他希望地质学家能自由解释地球的历史，而不受到教廷的影响。Lyell是对宗教非常虔诚的人，相信人类是唯一的有道德感的生物，在宇宙中占有特殊的位置。他比大多数人都更清楚的看到，灾变说者认为动植物物种连续相继创造出来，逐渐接近今天的物种，与演化的观点非常类似。灾变说者将深层的化石与浅层的进行比较，看到了进步，Lyell则辩论认为化石没有展现出总体的发展。当在地底深处的一个古老地层中发现了哺乳动物化石，他非常兴奋。哺乳动物一般在更近代的地层发现，所以这意味着历史上动植物没有得到真正的发展，除了人类。如果看起来像是进步，那肯定只是偶然事件。史前时代的物种只有极少的几种成为了化石。

Charles Lyell helped create modern geology. The way he thought about geology, and his extensive fieldwork, were both outstanding. He showed that, if our earth had a long enough history, much could be explained by simply observing what was going on now and using present-day geological events or forces to explain the past. A young naturalist, Charles Darwin, was much impressed with Lyell's Principles of Geology. He took the first volume with him (and had the other two sent out to him) when he set off on his travels around the globe on the Beagle. Darwin said that he looked with Lyell's eyes at the geological world – the world of earthquakes, rocks and fossils - during his voyage. But he came to very different conclusions about what the fossil record actually meant.

Charles Lyell帮助创立了现代地质学。他对地质学的思考方式，以及他广泛的实地调查，都是非常杰出的。他表示，如果我们的地球历史足够长，只需要观测现在进行的事件，用现代地质学事件或影响就可以解释过去的事件。一个年轻的博物学家，Charles Darwin，对Lyell的地质学原则非常印象深刻。当他从Beagle开始环球旅行时，随身带着了Lyell著作的第一部（并将另两部寄给他）。Darwin说在旅行中他用Lyell的眼睛来观察地质世界，也就是地震、岩石和化石的世界，但他对于化石记录的实际意义得出了非常不同的结论。