07 Geology: Ice Age
地質學：關于更新世時期冰期的研究

導讀

冰期（Ice Age）是地球上氣候寒冷、具有強烈冰川作用的地質時期。大冰期、冰期和間冰期都是根據氣候劃分的地質時間單位。

 

放射性元素的衰變有一定的速率（the rates of decay of various radioactive elements）。半衰期是放射性元素的原子核有半數發生衰變需要的時間。每一種放射性元素的原子核有一定的半衰期，不同的放射性元素半衰期不同。

 

The term “Ice Age” may give a wrong impression. The epoch that geologists know as the Pleistocene and that spanned the 1.5 to 2.0 million years prior to the current geologic epoch was not one long continuous glaciation, but a period of oscillating climate with ice advances punctuated by times of interglacial climate not very different from the climate experienced now. Ice sheets that derived from an ice cap centered on northern Scandinavia reached southward to Central Europe. And beyond the margins of the ice sheets, climatic oscillations affected most of the rest of the world; for example,in the deserts, periods of wetter conditions (pluvials) contrasted with drier, interpluvial periods. Although the time involved is so short, about 0.04 percent of the total age of the Earth, the amount of attention devoted to the Pleistocene has been incredibly large, probably because of its immediacy, and because the epoch largely coincides with the appearance on Earth of humans and their immediate ancestors.

There is no reliable way of dating much of the Ice Age. Geological dates are usually obtained by using the rates of decay of various radioactive elements found in minerals. Some of these rates are suitable for very old rocks but involve increasing errors when used for young rocks; others are suitable for very young rocks and errors increase rapidly in older rocks. Most of the Ice Age spans a period of time for which no element has an appropriate decay rate.

Nevertheless, researchers of the Pleistocene epoch have developed all sorts of more or less fanciful model schemes of how they would have arranged the Ice Age had they been in charge of events. For example, an early classification of Alpine glaciation suggested the existence there of four glaciations, named the Gunz, Mindel, Riss, and Wurm. This succession was based primarily on a series of deposits and events not directly related to glacial and interglacial periods, rather than on the more usual modern method of studying biological remains found in interglacial beds themselves interstratified within glacial deposits. Yet this succession was forced willy-nilly onto the glaciated parts of Northern Europe, where there are partial successions of true glacial ground moraines and interglacial deposits, with hopes of ultimately piecing them together to provide a complete Pleistocene succession. Eradication of the Alpine nomenclature is still proving a Herculean task.

 

There is no conclusive evidence about the relative length, complexity, and temperatures of the various glacial and interglacial periods. We do not know whether we live in a postglacial period or an interglacial period. The chill truth seems to be that we are already past the optimum climate of postglacial time. Studies of certain fossil distributions and of the pollen of certain temperate plants suggest decreases of a degree or two in both summer and winter temperatures and, therefore, that we may be in the declining climatic phase leading to glaciation and extinction.

Sentence Translation

句子翻譯

1. And beyond the margins of the ice sheets, climatic oscillations affected most of the rest of the world; for example, in the deserts, periods of wetter conditions (pluvials) contrasted with drier, interpluvial periods.

2. Nevertheless, researchers of the Pleistocene epoch have developed all sorts of more or less fanciful model schemes of how they would have arranged the Ice Age had they been in charge of events.

Key

1．而在大片冰層外緣，氣候的變動影響地球其余大部分地區。例如，在沙漠中，洪水（洪積世）時期同洪水期之間的干旱時期形成對照。

2．然而，更新世時期的研究者們提出了各種各樣多少有點怪異的模式方案，說假如過去讓他們負責的話，他們早就把冰期的時期作如何如何的劃分了。

Emulation美文自己寫得出——學生仿寫

仿寫范例

Self-reliance

Goethe once said that whoever is always paying nothing all the life will achieve nothing, and whoever can not dominate oneself will be a slave forever. Indeed, I can not imagine anything we can not do so long as we are self-reliant. As far as my own experience as a student is concerned, nothing is more important than self-reliance in achieving success.

First things first, life is a journey full of stumbling blocks, dangerous traps and unexpected crises. If you have known clearly what you want your life to be, it is self-reliance that carries you there. Moses was a stutterer, yet he was called on to be the voice of God; Abraham Lincoln overcame a difficult childhood, depression, the death of two sons, and constant ridicule during the Civil War to become unarguably the greatest President ever; Helen Keller made an impact on the world despite being deaf, dumb and blind from an early age. These examples prove that there is no better royal road to great accomplishment than self-reliance.

Second, it goes without saying that self-reliance forces us to set a higher goal in our daily existence. Just as a famous man put it, “living without an aim is like sailing without a compass.” The society is full of competition which is becoming more and more intense, what we can get often depends not on how much we have done but how much better we have done than others. Without self-reliance, we would probably be satisfied with and remain what we are, leaving our potentials to go to waste.

Last but not least, self-reliance can banish the greatest evil in the world: laziness. Take myself for example, I was born in a small village where many parents were illiterate, few children could pursue fundamental education, let alone college. So this is why I so cherish the college time. College time can fly away as quick as a wink. Many of my classmates squander their time by indulging in computer games, hanging around and sleeping in dorm. On the contrary, I spared no effort to learn and worked harder than any classmate, because I knew that it will never rain rose, when we want to have more roses, we must plant trees. When I enjoy the fruits of my labor, I believe more firmly that self-reliance makes perfect.

As an old Latin American saying goes: “Self-reliance is superior to the hand of God.” Indeed, no pain, no palm; no thorns, no throne; no gall, no glory; no cross, no crown. What we sow at present shall be reap in the future, so our future is determined by our present actions—self-reliance.