Part I
Professor: Geologists, we examine layers of sediment on the Earth’s surface to approximate the dates of past geologic time periods. Uh, sediment, as you know, is material like sand, gravel, fossil fragments that is transported by natural processes like wind, water flow or the movement of glaciers. So, uh, sediment is transported and then deposited and to form layers on the Earth’s surface over time. We examine these layers to learn about different geologic time periods including when they began and ended.
如你所知，沉积物就是沙子、砾石、化石碎片等之类的材料，它们通过风、水流或冰川运动等自然过程的作用输送。
1. approximate|əˈprɒksɪmət|
verb. to calculate or estimate sth fairly accurately 近似计算；概略估算
E.g.: a formula for approximating the weight of a horse
估算一匹马重量的公式
2. deposit|dɪˈpɒzɪt|
verb. (especially of a river or a liquid 尤指河流或液体) to leave a layer of sth on the surface of sth, especially gradually and over a period of time 使沉积；使沉淀；使淤积
E.g.: Sand was deposited which hardened into sandstone.
沙经沉积固结形成沙岩。
Part II
For example, from about 1.8 million years ago to around 11,000 years ago was the Pleistoceneepoch. The Pleistocene epoch was an ice age. During this epoch, sediment was made by the kind of erosion and weathering that happens when the climate was colder, and part of those sediments are fossils of plants and animals that lived at that time.
The Holocene epoch followed the Pleistocene epoch when the Earth’s climate warmed up around 11,000 years ago. The Holocene epoch is characterized by different sediments, ones that formed when the climate is warmer. Because the climate changed, the types of plants and animals changed also. Holocene sediments contain remnants of more recent plants and animals. So it’s pretty easy to differentiate, geologically, between these two epochs.
在这个世代，沉积物是由气候较冷时发生的侵蚀和风化形成的，其中一部分沉积物是当时生活的动植物化石。
1. pleistocene |ˈplaɪstosin|
noun. from two million to 11 thousand years ago; extensive glaciation of the northern hemisphere; the time of human evolution 更新世
E.g.: The most recent ice age was during the pleistocene.
最近的冰河期是在更新世。
2. epoch|ˈepək|
noun. (geology 地) a length of time which is a division of a period 世（地质年代，纪下分世）
E.g.: Two main glacial epochs affected both areas during the last 100 million years of Precambrian times.
在前寒武纪的最后1亿年中，两个主要的冰川时期对两个地区都产生了影响。
3. weather|ˈweðə(r)|
verb. to change, or make sth change, colour or shape because of the effect of the sun, rain or wind （因受风吹、日晒、雨淋等，使）退色，变色，变形
E.g.: This brick weathers to a warm pinkish-brown colour.
这块砖经日晒雨淋退成了带粉红的暖褐色。
4. holocene |ˈhɑləˌsin|
noun. approximately the last 10,000 years 全新世
E.g.: Dodos are flightless birds from the late Holocene.
渡渡鸟是全新世晚期不会飞翔的鸟类。
5. characterize |ˈkærəktəraɪz|
verb. to give sth its typical or most noticeable qualities or features 使…具有特点（或最引人注目的特征）
E.g.: The city is characterized by tall modern buildings in steel and glass.
这座城市的特点是钢铁和玻璃建造的现代化高楼大厦林立。
6. remnant |ˈremnənt|
noun. a part of sth that is left after the other parts have been used, removed, destroyed, etc. 残余部分；剩余部分
E.g.: The woods are remnants of a huge forest which once covered the whole area.
这片树林只是剩下的一部分，原来这一带是一大片森林。
7. differentiate |ˌdɪfəˈrenʃieɪt|
verb. to recognize or show that two things are not the same 区分；区别；辨别
E.g.: It's difficult to differentiate between the two varieties.
这两个品种很难辨别。
Part III
Now there is growing evidence that the presence of humans has altered the Earth so much that a new epoch of geologic history has begun–the Anthropocene epoch, a new human-influenced epoch. This idea, that we’ve entered a new Anthropocene epoch, was first proposed in 2002. The idea is that around the year 1800 CE, the human population became large enough, around a billion people, that its activities started altering the environment.
这个观点是，在公元1800年左右，人口变得足够大，大约有10亿人，人类的活动开始改变环境。
1. alter |ˈɔ:ltə(r)|
verb. to become different; to make sb/sth different （使）改变，更改，改动
E.g.: Nothing can alter the fact that we are to blame.
错在我们，这是无法改变的事实。
2. Anthropocene|ˈan(t)-thrə-pə-ˌsēn|
noun. the period of time during which human activities have had an environmental impact on the Earth regarded as constituting a distinct geological age 人类世
E.g.: It was a map for the anthropocene.
它是描述人类世的一张地图。
3. CE=Common Era 公元; AD=Anno Domini 公元; AH=Anno Hegirae 伊斯兰教纪元，回历; BC=before Christ 公元前; BCE=before the Common Era 公元前
Part IV
This was also the time of the Industrial Revolution, which brought a tremendous increase in the use of fossil fuels such as coal. The exploitation of fossil fuels has brought planet-wide developments–industrialization, construction, um, mass transport–and these developments have caused major changes like additional erosion of the Earth’s surface and deforestation. Also, things like the damming of rivers has caused increased sediment production, not to mention the addition of more carbon dioxide and methane in the atmosphere. Naturally, all these changes show up in recent sediments and these sediments are quite different from pre-year 1800 sediment layers.
自然而然地，所有这些变化都出现在最近的沉积物中，而这些沉积物与1800年前的沉积物层有很大不同。
1. exploitation|ˌeksplɔɪˈteɪʃn|
noun. the use of land, oil, minerals, etc. 利用；开发；开采
E.g.: commercial exploitation of the mineral resources in Antarctica
南极洲矿物资源的商业开采
2. mass|mæs|
adj. affecting or involving a large number of people or things 大批的；数量极多的；广泛的
E.g.: weapons of mass destruction
大规模杀伤性武器
3. deforestation |ˌdi:ˌfɒrɪˈsteɪʃn|
noun. the act of cutting down or burning the trees in an area 毁林；滥伐森林；烧林
E.g.: Firewood scarity offers the most visible and dramatic example of deforestation's effects.
薪材短缺是毁林后果的最明显和最引人注目的实例。
4. dam |dæm|
verb. to build a dam across a river, especially in order to make an artificial lake for use as a water supply, etc. （在河上）筑坝
E.g.: This reservoir was formed by damming the River Blith.
这个水库是通过在布莱斯河上筑坝形成的。
5. methane 甲烷; carbon dioxide 二氧化碳; carbon monoxide 一氧化碳; oxygen 氧气; hydrogen 氢气; nitrogen 氮气; hydrogen sulfide 硫化氢
Part V
Interestingly, there are some speculation that human started having a major impact on Earth much earlier about 8,000 years ago–that’s when agriculture was becoming widespread. Early farmers started clearing forests and livestock produced a lot of extra methane. But I want to stress this is just a hypothesis. The idea that early humans could have had such a major effect…well, I’m just not sure we can compare it with the industrial age.
Geologists in the far future will be able to examine the sediment being laid down today, whereas right now we can say that, yes, human impact on the Earth is clear. It’ll be future researchers who'll have a better perspectiveand will be able to really draw a line between the Holocene and the Anthropocene epochs.
早期人类可能产生如此重大影响的观点，嗯，我只是不确定我们可以将它与工业时代的影响进行比较。
1. speculation |ˌspekjuˈleɪʃn|
noun. the act of forming opinions about what has happened or what might happen without knowing all the facts 推测；猜测；推断
E.g.: His private life is the subject of much speculation.
他的私生活引起诸多猜测。
2. livestock |ˈlaɪvstɒk|
noun. the animals kept on a farm, for example cows or sheep 牲畜；家畜
E.g.: The heavy rains and flooding killed scores of livestock.
暴雨和大水淹死了许多牲口。
3. lay down
to produce sth that is stored and gradually increases 积存某物
E.g.: If you eat too much, the surplus is laid down as fat.
要是吃得太多，过剩的营养就会堆积成为脂肪。
4. perspective |pəˈspektɪv|
noun. a particular attitude towards sth; a way of thinking about sth 态度；观点；思考方法
E.g.: His experience abroad provides a wider perspective on the problem.
他在国外的经历使他以更广阔的视角看待这个问题。
