книги / Английский язык для горных инженеров

these cracks or fissures are hardly noticeable but gradually they become wider and deeper until the whole surface of rock is finally transformed into gravel, sand or dust.

In the regions of a moderate or cold climate, where the tem­ perature in winter goes down to below 0 (zero), the decomposition of rocks is greatly facilitated by the action of water. When water freezes it increases in volume and develops enormous lateral pressure. Under the action of water, rocks decompose to pieces of varied forms and sizes.

The decomposition of rocks under the direct influence of heat and cold is called physical weathering.

Rocks are subjected not only to physical decomposition but also to chemical weathering, i.e. to the action of chemical agents, such as water, carbon dioxide and oxygen. In a general way, chemical weathering is an acid attack on the rocks of the Earth’s crust, in particular an attack on the most abundant minerals — quartz (sand) and aluminosilicates (clays). Only few minerals and rocks are resistant to the action of natural waters. The solvent action of water is stronger when it contains carbon dioxide. Water causes more complex and varied changes. With the participation of oxygen and carbon dioxide up to 90 per cent of rocks is transformed into soluble minerals, which are carried away by the waters.

Organisms and plants also take part in the disintegration of rocks. Certain marine organisms accelerate the destruction of rocks by making holes in them to live in. The action of plants can often be even more destructive. Their roots penetrate into the fissures of rocks and develop the lateral pressure which fractures and destroys rocks.

32. Укажите, какие предложены соответствуют содержанию текста. Подтвердите свои ответы фактами из текста.1

1.The process of sedimentation is called weathering.

2.The change in temperature causes physical weathering.

3.As a rule during the night rocks expand.

4.When freezing water decreases in volume and develops enor­ mous lateral pressure.

5.The decomposition of rocks is due to the influence of heat and

cold.

6.As a rule water contains-dissolved mineral substances.

7.The solvent action of water is stronger when it does not con­ tain carbon dioxide.

37. а) Изучите таблицу ■ затеи переведите следующие наречия.

uniformly, gradually, greatly, hardly, purely, finally, slowly, highly, generally, simultaneously, backward, eastward, homeward

б) Заполните пропуски в предложениях, выбирая одно из данных в скобках наречий.

1. Rocks are composed of different minerals, (purely, easily, generally)

2. The expansion and contraction of rocks do not occur ... and at

1.The world fossil which means “organic materials accumulated in the geologic past” was originally referred to anything that was dug (to dig — добывать) from the ground.

2.The decomposition of rocks is influenced by many factors.

3.A large expedition will soon be organized to study the Earth’s depth. It should be noted that later the expedition will be followed by another one.

44. Суммируйте содержание текста Б, используя слова в скобках.

1.The main cause of physical weathering, {the change in tem­ perature, to observe, to expand, to contract, to crack, to be hardly noticeable, to be facilitated by)

2.The main cause of chemical weathering, {to be subjected to, to contain, to act as, to cause changes, to be transformed into)

3.The effect of organisms and plants on the disintegration of rocks, {to accelerate the destruction of rocks, to penetrate into, to develop lateral pressure, to destroy rocks)

В

45. Прочитайте текст В без словаря. Скажите, о чем говорится в нем.

Слова для понимания текста:

suspended particles — взвешенные частицы define [di'fam] — определять

ТЕКСТ В The Earth’s Crust

Most mineral resources are derived from the Earth’s crust. The crust is composed of minerals that are crystalline solids with specific and rather simple composition. Minerals in the Earth’s crust are concentrated into specific groups which are called rocks. Two distinctly different types of crust are recognized: oceanic and continental.

Since it is difficult to investigate the floor of the ocean, the composition of the oceanic crust is not known completèly. Scientists say that it is relatively constant in composition. The oceanic floor, consists largely of minerals rich in calcium, magnesium, iron and silicon, and it is formed by the cooling of lavas extruded on the sea floor to form a type of rock called basalt. It is subjected to the same forces of erosion and weathering.

The continental crust contains less iron and magnesium than the oceanic crust, but relatively more silicon, aluminium, sodium and potassium. The continental crust is more complicated and has a more variable thickness and a less well defined structure.

A systematic examination of all known rock types shows that two principal types predominate: 1) Igneous rocks which are formed by the cooling and crystallization of liquids from deep in the crust called magma; 2) Sedimentary rocks which are formed by

sedimentation and gradual cementation of sediments by the .action of water, ice, wind and organisms. They are layered or stratified. Most of the sediments are deposited in the sea along the continents.;

As sediments grow larger and are buried deeper, increasing' pres­ sure and rising temperature produce physical and chemical ohanges in them. The resulting metamorphic rocks generally show whether they originated from sedimentary or igneous rocks. This process is slow — hundreds of millions of years are necessary. As weathering and erosion occur, some substances are dissolved and removed in solution while others are transported as suspended particles.

Continental crust contains extremely varied types of rock. It is quite possible to say that the rock-forming processes which we can observe today, have been active for at least 3,500 million years.

The oceanic crust, by contrast with the continental crust, shows little variation in composition. It leads to the idea that the rocks of the sea floor might not contain as many valuable mineral resources as do the rocks of the continental crust. The solution of the problem will be one of the main problems of oceanographic research in future.

46. а) Найдите а каждом абзаце текста В предложение, аыражаюцее его основную мысль.

б) Найдите в тексте В предложения, в которых говорится об исследо­ вании недр Земли.

в) Составьте план текста В и краткую аннотацию текста, используя следующие разговорные формулы:

The subject of the text is ...

The text deals with ...

It is pointed out th a t...

It is obvious that

To sum it up

47. а) Прочитайте и переведите текст со словарем.

Leonardo da Vinci (1452-1519)

Leonardo’s all-round genius brought him face-to-face with prob­ lems of understanding the Earth. He saw the Earth undergoing endless change, largely occasioned by the forces of weather and water (both marine erosion of coasts and river erosion of hills). Solid land was constantly decaying into alluvial plains. The creation by rivers of their own valleys, which they then silted up, fascinated