Английский язык в сфере профессиональной коммуникации. Геология. Учебное пособие

EXERCISES

IV. Найдите в списках А и В антонимы:

A.1. fine, 2. rapid, 3. minute, 4. wholly, 5. visible, 6. dissolve.

B.a. slow, b. partly, c. solve, d. invisible, e. coarse, f. huge.

V. Найдите русские эквиваленты английским словам:

VI. Заполните пропуски соответствующим по смыслу глаголом:

1. The grain size … the rate at which the magma cooled.

VIII. Поставьте вопросы к подчеркнутым членам предложения:

Under conditions of extremely rapid cooling magma solidifies into a homogenous substance.

IX. Перескажите текст по вопросам:

1.What is meant by texture of an igneous rock?

2.What kinds of texture have igneous rocks?

3.What factor does the texture of an igneous rock depend on?

4.Under what conditions are a fine-grained, a coarse-grained, an aphanitic and glassy texture formed?

5.What texture is called porphyritic?

6.What is a matrix and what is a groundmass?

X. Прочитайте текст без словаря и выполните тесты:

The rate of cooling is an important factor which influences the texture of an igneous rock.

Reduction (уменьшение) in temperature induces (вызывает) cooling which may be very gradual (постепенный) or rapid. When magma is cooling a temperature will be reached at which some of the nonvolatile (нелетучие) constituents will begin to separate from the hot solutions as crystals.

If the cooling is vary slow, so that the magma does not soon become viscous (вязкая), relatively few crystals will be formed and they will grow by addition (прибавление) of molecules until the mass has become a coarse crystalline rock.

But the cooling is very rapid, the magma may become so sticky (липкая) that the molecules cannot move about and combine. The liquid becomes harder, without crystallization, until it is a glass.

If cooling is not so rapid but act so slow as in the first example the molecules will be able to move before the liquid becomes too viscous. Crystals may originate (возникать) at very many points so near together that they will soon interfere (сталкиваться). The resulting rock will be fine-grained.

The volatile constituents make the magma less viscous, thereby (тем самым) they help its crystallization.

The fluidity (текучесть) of a magma is also influenced by the proportion of the nonvolatile components.

So, the viscosity and crystallization of magmas and the texture of igneous rocks are determined by various factors of which temperature change and content (содержание) of volatile substances are the most important.

XI. Определите какой из заголовков соответствует содержанию прочитанного текста:

1.Consolidation of molten magma.

2.Rate of cooling of magma.

3.Texture of igneous rocks.

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XII. Укажите номер абзацев, в которых находятся ответы на вопросы:

a. What does reduction of temperature induce?

b. What will be the texture of on igneous rock if the cooling of magma is very slow?

c.What rate of cooling of magma is necessary to form a fine-grained rock?

d.Under what condition is glassy texture formed?

e.What is the role of the volatile constituents in crystallization of magma?

f.What factors determine the texture of igneous rocks?

XIII. Кратко изложите содержание текста на английском языке.

XIV. Прочитайте текст и передайте его содержание на английском языке:

Some rocks are coarse-grained in texture, others are fine-grained. In some rocks no minerals have crystallized, in this case the magma has solidified as glass and the rocks have a glassy texture. The texture of a rock shows its physical conditions under which magma has solidified.

One of the most important factors which influence the development of rock texture are the rate of cooling of magma, its chemical composition, temperature, pressure and the presence of volatile constituents of the magma.

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Gabbros proper are dark-coloured rocks similar to diorites in texture and structure. The specific gravity will average between 2.9 and 3.2. They are susceptible to a high degree of polish and have been used to some extent for monumental stock.

Peridotite. Peridotites are ultrabasic intrusive rocks consisting chiefly of olivine, with usually more or less pyroxene, sometimes hornblende, and with little or no feldspar. Dunite, composed chiefly of olivine, is an important variety.

Peridotites are usually very dark massive-granular rocks having a specific gravity of 3.0 to 3.3. Under atmospheric conditions peridotites are very susceptible to rapid alteration, the chief product being serpentine, with talc not uncommon.

Volcanic or Dense Igneous Rocks. In this group are included those igneous rocks that have formed on or near the surface.

Basalt. Basalts include very dark-coloured igneous rocks. The basalts megascopically are recognized by their dark colour and high specific gravity.

Glassy Igneous Rocks. Glassy igneous rocks are composed essentially or entirely of glass and they represent with only rare exceptions molten lavas poured out onto the surface which have undergone quick solidification. Any magmas under proper conditions of rapid chilling may solidify as glass but the acidic ones corresponding to granite in composition are the most common.

EXERCISES

V. Заполните пропуски соответствующим по смыслу глаголом:

VI. Поставьте вопросы к подчеркнутым членам предложения:

1.Peridotites are very susceptible to rapid alteration.

2.Glassy igneous rocks are composed of glass.

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VII. Дайте краткое описание гранита, диорита и других видов изверженных пород по плану:

1.Composition.

2.Colour.

3.Specific gravity.

4.Practical Application.

VIII. Прочтите текст без словаря и кратко передайте его содержание на английском языке:

ULTRA-BASIC ROCKS

There are intrusive rocks. They have a high specific gravity (about 3.25), which is due to their mineralogical composition. Olivine and pyroxene are the minerals forming ultra-basic rocks. These rocks contain practically no other minerals of the silicate class. The most common representatives of this group of rocks are peridotite, pyroxenite and dunite.

Peridotite consists essentially of olivine. There is also a large quantity of pyroxenites.

Dunite consists mainly of olivine; chromite and magnetite are present in small amounts. This rock often contains native platinum.

Pyroxenite. The dominant minerals in it are pyroxenes. Olivine is present in a small amount. Peridotites and pyroxenites usually contain iron, chromium and nickel ores.

BASIC ROCKS

The principal minerals forming basic rocks are pyroxenes and plagioclases; in addition, hornblende and, less often, olivine may be present. Basic rocks are darkcoloured because of the dark colour of the minerals composing them. Gabbro, basalt and diabase are the representatives of this group of rocks. Gabbroid rocks are connected with titano-magnetite and copper deposits.

IX. Переведите тексты со словарем:

COMPOSITION OF IGNEOUS ROCKS

The composition of an igneous rock depends on the chemical composition of the magma from which it solidified. Magma is made up of two parts: a volatile part consisting chiefly of gaseous water with carbon dioxide, sulphur and other substances amounting to a few per cent, and a non-volatile part, consisting of the mixed constituents, chiefly molten silicates. The volatile part is very important in rock formation because it increases fluidity of the magma, but it is almost completely eliminated during solidification, and the molten silicates crystallize from the magma to form rocks. Many thousands of igneous rocks from all parts of the world have been chemically analyzed.

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CRYSTALLIZATION OF MINERALS FROM MAGMA

Magma is a solution: it contains various compounds in a more or less unorganized state. If the magma cools slowly enough, the dissolve matter in it separates from it in the form of crystalline grains, the minerals. This crystallization continues as the temperature falls until the whole magma becomes solid mass of mineral grains. The molten liquid has become rock. The minerals begin to separate from magma in a definite order, which depends upon their solubility in that magma.

Since magma is differ in chemical composition, not only minerals separating from them, but also the relative amounts of these minerals must differ. Thus, a silicic magma containing much silica and very little alkalies and alumina forms a rock that consists mostly of feldspars; whereas a basic magma, in which lime, magnesia and iron are abundant make a rock containing abundant pyroxene, hornblende and other ferromagnesian minerals.

OCCURRENCE OF IGNEOUS ROCKS

Intrusive and extrusive rocks. There are two chief modes of occurrence of igneous rocks: the intrusive and the extrusive. In the former the magma, rising from the depth below, has stopped before attaining the surface and has cooled and solidified, surrounded by other rock masses of the earth’s outer shell. In the extrusive the magma has reached the surface, come out upon it and solidified there, forming rock masses called extrusive or volcanic rocks.

Intrusive rocks are formed under conditions that differ greatly from these under which extrusive rocks are formed.

In forming an intrusive body the magma cools under a thick layer of rocks; hence its dissolved gases cannot escape easily, and because rocks are exceedingly poor conductors of heat, it loses heat solely and therefore solidifies slowly.

In an extrusive body the magma cools under the influence of the atmosphere and therefore solidifies rapidly. Because of this difference in the way they are formed intrusive rocks differ greatly in appearance from extrusive ones.

IGNEOUS ROCKS

These rocks result from the cooling of molten rocks either at the earth's surface or not far beneath it. Such rocks as lava erupted upon the earth's surface and are called extruded rocks. Other molten rooks which were irrupted into the earth's crust are called intruded rocks. Intruded rocks, which did not reach the earth's surface at the time of their irruption, might be exposed later by erosion of the overlying rocks.

Extrusive rocks are rocks which have been erupted by volcanoes, and consist of large and small fragments and of lava which has been poured oat. One type of lava is basalt. Basalt is a glassy fine-grained, dense rock. It is sometimes cellular, i.e. it may have cavities in it. When molten, it flows easily, and the stream may extend for several miles.

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Intruded rock forms various structures. If it has penetrated between strata to form a thin layer, it is called a sheet or sill. If in pressing upward it has formed cracks in the overlying rocks and then filled these cracks, these more or less vertical walls of a rock are called dikes. They are known to be from a few inches to many feet thick. The type of rock usually found in sills and dikes is dark-coloured and fine-grained, and is usually called diabase.

A laccolith is an intrusion of igneous rock into stratified rock, arching up the strata into the form of a circular or elliptical dome.

Batholiths are the largest of the intruded bodies of rock. They have come from great depths, having risen by melting the rocks above them. They form the roots of mountains, and are only exposed by erosion.

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IV. Найдите прилагательные среди следующих слов и переведите их:

1.original, 2. thickness, 3. glacial, 4. deposition, 5. numerous, 6. fluidity,

7.abundant, 8. aqueous, 9. relative, 10. majority.

V. Найдите русские эквиваленты английским словам:

VI. Заполните пропуски соответствующим по смыслу глаголом:

1. Sedimentary rocks have been … by disintegration and decomposition of pre-

VII. Поставьте вопросы к подчеркнутым членам предложения:

1.Sedimentary rocks are of secondary origin.

2.The materials composing sedimentary rocks were laid down under water or

on land.

3.The most characteristic feature of sedimentary rocks is their layered

structure.

4.Moving water, mechanical action of wind and ice are the principal agents in shifting the position of the material composing sedimentary rocks.

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